Jump to content

Throttle Blip


Recommended Posts

Not sure if the blip or slip in taught at CSS, because I've only done level one, but I have read in various places about the throttle blip technique, why it is used, etc, and I'm having some problems with it I think. I have been practicing it for weeks now, but there are still some things that elude me, and it is affecting my corner entry. I ride an inline four, so maybe the first question is the revs, and how high they should be. Not looking for specific numbers for a specific bike, just an average for an inline. Like a few hundred, or maybe 4 to 5 thousand per blip?

 

Second question is the 'firing' order. The way I understand it is:

 

1. Disengage clutch and apply brake

2. Blip throttle(while maintaining brake pressure) while downshifting

 

At this point there is some confusion. Do I:

 

A. Engage clutch(how long does it take to smoothly do so? I shoot for about 1 sec tops), allowing engine to aid braking, clutch-blip-downshift, clutch-engine brake(repeating as necessary to proper gear)

 

or

 

B. Blip and downshift to necessary gear for that turn, then engage the clutch?

 

I understand that certain turns require different things, and I'm by no means a MotoGP level rider, but it seems that all I see pro riders do is Option B, but I read that they are using Option A.

Any guidance helps.

 

Third question. The chatter associated with blipping, is it the thunk of the rear wheel hopping across the pavement, or the clack clacking of the gears not meshing when I downshift? By this I mean that sometimes with a really hard drive in a low gear, say first, I'll attempt to shift to 2nd, and it will catch neutral or a false nuetral. I hear the whine, and when I go to upshift, clack clack clack, then it slips into gear. Is this the chatter that blipping technique is supposed to prevent? If so, it seems that sometimes it doesn't work, due to some fault of my own perhaps. Maybe I'm not upping the revs enough to match the engine spin, or I'm missing a step, or my timing is off. I know all the steps of the blip are supposed to happen almost simultaneously, I'm just not sure where I'm going wrong, and I would rather not tear up my bike trying to figure it out on my own.

 

Also, is it one blip while conducting a downshift, or multiple blips per downshift?

If the chatter that blipping prevents is back-end chatter of the rear wheel hopping along, wouldn't smoothly re-engaging the clutch solve this problem, which you do anyway? Thanks.

Link to comment
Share on other sites

Hey aj,

 

 

There is no specific or "average" RPM for any bike. Each transimission gear selection will have a different RPM for a given road speed. The RPM to blip toward is dictated by the ratio of the new gear to be selected and the current road speed.

 

That said, the higher up in the transmission pattern you are, the closer together the ratios will be and the less one will need to blip. A single shift between say 6th and 5th will require a bit less blip than between 3rd and 2nd. So, there really is no specific RPM to aim for, it is more a relative increase that will be generally consistent between the same two gears no matter the road speed.

 

 

When approaching a turn or reducing speed for any reason:

 

1. apply brake

2. when desired speed is achieved, execute blip/downshift(s) to appropriate gear for current speed. One blip per shift.

3. release brake (turn) and apply throttle to accelerate

 

It may help to start by practicing the blip/shift without the brake, but, to execute smooth riding technique you will need to blip the throttle while the front brake is still applied. Using two fingers on the brake lever, allow your fingers to slide back and forth without jerking the lever as you blip to match rev's for new gear. You can also practice the simultaneous brake/blip without the motor running until you start to get the hang of it.

 

 

Blip/downshift

 

1. Engage clutch

2. Blip throttle

3. Change gear as rev's match road speed for new gear

4. Release clutch

 

Clutch in/blip/shift/clutch out.

 

Although there are four distinct steps or actions, the entire process essentially happens in less than a half second as one fluid set of motions and no sound other than the motor revving up to the new rpm and a barely audible "snick" of the gearshift lever should be noticed when done properly.

 

I'm a little surprised this wasn't covered in your Level One class unless noone noticed you weren't doing it. It is considered a foundational skill in the CSS process and is a primary focus in Twist of the Wrist and evey CSS school seesion I have ever attended including practicing on Keith Code's special training bike that is set up just to learn this specific technique.

 

Cheers,

racer

Link to comment
Share on other sites

This should clear things up a bit. I'll test it out and let you know how it goes. Thanks.

 

You do not want to get distracted or caught up looking at the tacho while riding. That said ...

 

I don't have a speed in gear chart handy, but, off the top of my head, the amount of rev's you'll want to blip might be like 3500-4000 rpm between 1st and 2nd gear and maybe as little as 500 rpm between 5th and 6th gear depending on the bike. And that difference will be progressive, like each gear shift will need a bit more blip as you go down through the gears. The lower the gear change, the bigger the ratio change, the bigger the blip. (If you can really call a blip 'big' ... lol.)

 

Try blipping the throttle while sitting curbside to get a feel for it. And remember that when you are off idle the blip will happen faster and easier. So try blipping from different points in the rev range, too.

 

It should not take a big handful of throttle to "blip" an inline four sportbike. It shouldn't take more than the slightest twist of your wrist on the throttle to get just the right amount of 'blip' with the clutch in. Small moves. Start small and add a little more if the clutch is still slipping when you let it out.

 

You shouldn't need to really WHACK it. Just a little blip'll do ya to bring the rev's up just enough to match rev's without going too far. Blipping too hard might be what is giving you "clacking" noises inside the tranny because it is resisting the gear change.

 

Also, if you downshift before you are going slow enough for the next lower gear, you can lock up the rear and make it hop. So be sure to wait long enough until the roadspeed and rev's are down low enough before blipping and downshifting. Like you don't want to be trying to catch 1st gear at 50 mph ... bad deal.

 

 

I hope that gives you a bit more than I had time for yesterday.

 

 

Good luck.

 

Be safe.

Link to comment
Share on other sites

Significant edits to previous post.

Link to comment
Share on other sites

I finally found the original thread where Keith covers the technique, and it brings up more questions. I believe that I have the right hand action down, meaning I can adjust(or maintain pressure of) the brake lever any way that I want while blipping the throttle. But I guess that my busy little brain has to understand the whole point, the mechanics of, the importance of the throttle blip. I'm reading that it makes it easy on the tranny, gearbox, etc., and if that's the case, I'll do it just to save parts. But how is it making downshifting smooth? I'm just not seeing it while I ride. I can bang down the gears and it seems smooth enough to me. Am I not going fast enough or something to fully appreciate the technique? Or am I not doing it correctly and have nothing to compare it to?

Link to comment
Share on other sites

Hey AJ20

 

Thought I would chime in and clear up some the mechanical info for ya.

 

Blipping the throttle is a technique used to "match" the speed of the motor to the speed of the rear tire when a smaller gear ratio is selected. IE a downshift.

 

Think of it this way. If you were to travel down a (long) staight of way, pull in the clutch and hold it (without shifting), the engine RPM would drop and go to an idle. At this point, the bike would be coasting, EVEN THOUGH YOU ARE STILL IN 6TH GEAR. If you let the clutch out, the engine will rev back up to match the speed of the rear tire.

 

OK, if you were to do this and down shift, the transmission would give a big "clunk" because the gears are traveling a very different speeds, since 6th gear is engaged (traveling at the speed of the rear tire) and 5th gear (not yet engaged) is traveling at the speed of the motor. By blipping the throttle you are raising the RPM of the motor to help match the speed of the rear tire. The closer these two gears are in speed, the easier the bike will shift.

 

Now blipping the throttle in normal riding (fast paced) puts less load on the tranny, but also smooths out the transition between the two gears, which gives more control over the rear tire. IE Less chattering or rear tire lock up. Rear chatter is caused by the rear tire skipping along the roadway since it is now traveling slower than what the front tire is. Make sense? Ever see a top pro backing it in. This is what they are using to break the rear traction and "allow" the rear end to come around.

 

 

If your having trouble "feeling it" or using it, I suspect you may have a back torque limiting clutch (slipper clutch). Although a slipper clutch is a great tool, it promotes laziness and poor technique if relied on entirely.

If you dont have a slipper clutch, then you may be pulling the clutch lever in too far. Try pulling the clutch in just enough to disengage the motor, make your down shift and let the clutch back out.

 

JR.

 

If you gonna be doing level two, ask your riding coach to show you.

Link to comment
Share on other sites

Thanks for the reply 2big. For some reason, when I can understand the engineering of things, it makes it easier for me. My bike does have a slipper, but I didn't think that it would make such a difference. I've been spending a lot of attention wondering if I was getting the technique wrong, when I may have been getting it right all along. Just once more to clarify then.

 

Hypothetically(just focusing on the blip technique, and minus other factors like trailbraking), if I'm coming down a fourth gear straight approaching a second gear turn, when I reach my braking point I would:

 

1. Roll off the gas.

2. Apply the brake.

3. Disengage clutch.

4. Blip throttle, shift down.

5. Engage clutch.

6. Disengage clutch.

7. Blip throttle, shift down.

8. Engage clutch.

9. Release brake.

10. Make steering change.

11. Roll on the throttle.

 

Something similar at least right?

Link to comment
Share on other sites

Thanks for the reply 2big. For some reason, when I can understand the engineering of things, it makes it easier for me. My bike does have a slipper, but I didn't think that it would make such a difference. I've been spending a lot of attention wondering if I was getting the technique wrong, when I may have been getting it right all along. Just once more to clarify then.

 

Hypothetically(just focusing on the blip technique, and minus other factors like trailbraking), if I'm coming down a fourth gear straight approaching a second gear turn, when I reach my braking point I would:

 

1. Roll off the gas.

2. Apply the brake.

3. Disengage clutch.

4. Blip throttle, shift down.

5. Engage clutch.

6. Disengage clutch.

7. Blip throttle, shift down.

8. Engage clutch.

9. Release brake.

10. Make steering change.

11. Roll on the throttle.

 

Something similar at least right?

 

 

That's it in a nut shell!!! Sounds like you were doing it right all along.

Link to comment
Share on other sites

I finally found the original thread where Keith covers the technique, and it brings up more questions. I believe that I have the right hand action down, meaning I can adjust(or maintain pressure of) the brake lever any way that I want while blipping the throttle. But I guess that my busy little brain has to understand the whole point, the mechanics of, the importance of the throttle blip. I'm reading that it makes it easy on the tranny, gearbox, etc., and if that's the case, I'll do it just to save parts. But how is it making downshifting smooth? I'm just not seeing it while I ride. I can bang down the gears and it seems smooth enough to me. Am I not going fast enough or something to fully appreciate the technique? Or am I not doing it correctly and have nothing to compare it to?

 

 

Hey AJ,

 

I know just what you mean about understanding the mechanical process being helpful to understand the technique. I am exactly the same way.

 

I have found however, that it can be a case of TMI (too much information) to assimilate and digest the clutch and transmission all at once. So, I ususally do not start off with the mechanical overview as it seems that most folks eyes start to glaze over somewhere between the words "throw out bearing" and "synchro-mesh".

 

That said, I would like to add a few more ideas to 2big's in my own words ... and I find it helps to start with the concept of upshifting which everyone seems to get straight off and then seems to have less difficulty turning the idea around for downshifting.

 

The critical point to be aware of is that the clutch separates the engine (motor) from the transmission.

 

I think everyone is familiar with the basic function of the engine ... to spin faster to create more power by increasing revolutions. Add gas, go faster. When the engine reaches the top of its rev range the tacho communicates this visually with the infamous "redline".

 

So what happens when you reach redline and are not satisfied with your velocity through space and time? Like the greedy little speed demon you must be if you are here, you want to go still faster!

 

Heh heh heh heh (insert maniacal laughter here)

 

So, we "shift gears", right?

 

OK, so, think of a multi-speed mountain bike.

 

The bicycle has an engine (namely you) which imparts energy to a crankshaft with pedals for our legs/feet (instead of con-rods and pistons).

 

And you, the engine, are "connected" to a manual transmission that is held together by a chain. Due to the nature of the chain/gear/derailer realtionship, a separate clutch is not needed to disconnect the engine on your mountain bike. Instead, a derailer feeds the chain off one sprocket onto the next without upsetting the smooth operation of the system. Technically, the entire chain/sprocket/derailing action might be considered an automatic-clutch transmission, but, for our purposes...let's just concentrate on the end result for now.

 

So, when you can't pedal any faster, when your tired sweaty body reaches "redline", you "shift gears"...right? (Same thing as a motorcycle or car or truck, etc.)

 

You reach down and move the shift lever which is connected by a cable to the derailer at the rear which pushes the chain onto a smaller sprocket.

 

VOILÁ!

 

Suddenly, You don't have to pedal as fast to maintain the same road speed! AND you can now pedal faster again to increase your velocity toward warp one!

 

The smaller circumference of the new smaller sprocket has less teeth and now the front pedal sprocket will turn less for each revolution of the rear wheel!

 

You can also think of it as the rear sprocket and wheel will go around more times for each turn of the front pedal sprocket.

 

Either way ... c'est fantastique!

 

Now, another terminology/concept connection ... more rear wheel turns equals higher road speed.

 

Seems like a "well, duh" moment, but, I just wanna be sure to cover all the bases.

 

 

OK, so ... what happens when you are pedaling in like 39th gear (I don't how many gears a mountain bike has these days, they just have more than the ten I had as a kid and seem to have more everytime I ride one)...

 

So, you're jamming along in 39th gear and a really big hill arises on the horizon (whoa dude, that's a really big hill!) and what happens?

 

You hit the bottom of the hill and your engine's rpm's start to fall and you start to go slower. It gets harder and harder to pedal. The pedal crank goes around slower and slower. And, eventually, your pedal rpm gets so slow that if you don't do something, you are gonna STOP.

 

Now THAT'S a four letter word for any greedy speed demon!

 

So, by inborn instinct, we speed demons go reaching for that lovely little lever, and, we (all together now) DOWNSHIFT!

 

The chain goes onto a bigger rear sprocket, the pedal rpm's go back up again, (and it gets easier to pedal (less torque required)) ... and little Willy speed demon is happy again.

 

 

OK...for anyone who is still here enjoying this little story and hasn't already skipped to the end to see whodunnit ...

 

The critical commonality between going up a big hill on your mountain bike and negotiating a turn on the road/racetrack is the part where you slow down.

 

Less "roadspeed". From warp speed to impulse.

 

 

Now by experience, we tend to discover that if we try to shift gears on our mountain bike while pedaling hard, the process can become something less than "smooth".

 

In the upshift, the chain grinds while coming off the teeth of the big sproket and kinda SNAPS onto the smaller sprocket with a big ... well ...SNAP. or perhaps a big KA-CHUNK!

 

In any case, it is sort of an ugly sound. Not very pleasing to one's ear and one generally gets the impression that it might even be doing some damage ... which it probably is.

 

If we are pedaling hard when we try to down shift, chances are we might not even be able to move the bloody gear shift lever because there is too much "lash" or tension at the chain/tooth interface. The chain is gripping so hard to the sproket that it won't lift or slide over.

 

 

Now, comes the critical point of crossover between the motorbike and the pedal bike.

 

On the pedal bike, we need to not push so hard on the pedal so as to *let off some of the pressure on the drivetrain* (or chain and sprokets) to allow a smoother shift.

 

Same deal on the motorbike.

 

 

Imagine the inside of the transmission as a front and rear sproket set like the mountain bike except the motorbike doesn't actually have a chain between the front (input shaft) transmission gear and the rear (output shaft) transmission gear.

 

The gears mesh together directly. No chain. It would be like having no chain between the front and rear sprockets on your mountainbike. Like the front and rear sprockets were right next to each other and connected teeth to teeth.

 

And on the motorbike, instead of the chain sliding off one gear and onto the next, the entire rear gear slides over and another takes its place. Like that whole gear set on your rear wheel just moved over to engage another gear to gear instead of the chain moving over. (No chain)

 

Far out, huh?

 

Now, just like the mountain bike if you are pedaling hard ... if you are on the gas, it is difficult to slide those gears over because there is too much tension or lash on the gear. It is sticking too hard to other gear.

 

 

Enter ... the CLUTCH!

 

MOO HAA HAA HAA HAAAAA (more maniacal laughter)

 

 

The clutch disconnects the engine from the transmission so you can move that lovely shift lever which is rotates a beautiful round shift drum which is connected to a cute little shift fork which rests in a circumferential groove beside the teeth in the new gear to slide that puppy over with no lash or pressure on the gear teeth ... equals smooth snickety-snick gear shift.

 

 

So...that is the general idea. In fifty words or less...

 

A bigger sprocket at the rear means the pedals (engine) will be spinning faster. More teeth per rear wheel revolution means more revolutions up front.

 

Using the clutch separates the engine and eliminates any drive forces on the gears. You need to spin the engine up (like you would be pedaling faster) so when you let out the clutch, there is no slipping or shock. Just smooth mating of the clutch plates fibre to steel.

 

 

Draw some pictures of two diferent size circles touching each other and imagine them spinning. The bigger circle spins slower than the little circle. Adding teeth makes it easier to calculate since you can count the teeth, but, you can simply measure the circlearound the circumference and do the same thing.

 

 

 

 

And now a break for some interesting bicycle tech...

 

On the mountain bike, when you downshift from like 39th gear to 35th gear, the derailer is spring mounted and essentially matching the CHAIN length to the new gear and roadspeed by releasing or taking up slack. Due to this action, you can basically match revs on the fly as you shift. The chain climbs onto the new gear and automatically gets longer to accomadate more teeth and essentially absorbs some of the difference in torque in doing so. As long as you aren't pedaling too hard. all you the rider know is that suddenly you are pedaling faster because that's the way it is.

 

Utterly ingenious. And, actually, I have to thank you for making me go through all this because I never actually realized that before. Damn! That is SO cool!

 

 

And some more advanced details of the sequential transmission on your motorbike ... this may be impossible to imagine without pictures, but, I'm on a roll...

 

When you move the gear shift lever, it rotates a drum with squiggly grooves in it. These grooves are like a "transmission program" for where the shift forks will move. The forks are like they sound. They are a fork with two tines and at the shaft end are held and ride back and forth on a rod near the drum. The fork end rides in circumferential groove on the active sliding gear. So the active gear is between the times of the fork.

 

Now, the active new gear(s) that you slide over to mesh with the new input gear are not actuallay connected or "splined" onto the shaft which they are riding on. In fact, they are 100% "freewheeling" and they only connect to the driven shaft by way of "dogs" on the gear face of the gear next door that is actually connected or splined onto the shaft. These "dogs" are like little tabs that fit into little slots on the next gear AND these freewheeling gears need to get spun up to speed as well to match the dogs and slots on the gear next door BEFORE the dogs engage. This is accomplished with a little disk with little bumps like a golf ball on it that rides outboard of each gear and touches before the little boy dogs tabs can catch the little girl slots thereby mating the gears together. These little bumpy disks are called "synchro-mesh"...oooo aaahhh.

 

Because they ...."SYNCHONIZE" the "MESHING" of the gears.

 

We will now take a moment of silence to meditate on the miracle of the synchro-mesh. Please feel to worship or give thanks to the great creator of the synchro-mesh in whatever manner works best for you. Some folks prefer incense and candles while listening to new age music of the spheres. I prefer burning castor oil in a forged piston with the Matrix soundtrack. Whatever works best for you ...

 

I will share with you this mantra I learned from an old monk while studying at a Buddhist monastery in Borneo many years ago...

 

Oooooommmmmm. Oooooooommmmm. Oh mommy bring money home. Oh mommy bring money home. Oh mommy bring money home ...

 

 

OK ... we feel refreshed for the final leg of our spiritual journey down the rabbit hole of matching rev's tonight. Anyone who took the blue pill should log off now as there is no coming back.

 

Alrighty then ... God, I just love this stuff.

 

So, when you are moving that gear lever, the sliding gear must spin up to speed to connect to the gear that will actually connect it to the output shaft while meshing to the new input gear AND you must blip the engine to get the engine to match the new speed of the tranny that is spinning faster now because the gear set is a lower ratio. So, just like the mountain bike, there is a bigger gear on the output side now, so less reduction and you will be pedaling faster.

 

So, there is a whole 'nother level of things matching speed inside the transimission when you are shifting and blipping and hoping it doesn't blow up.

 

Mind blowing, eh?

 

 

We will discuss the mysteries of the manual clutch at our next gathering.

 

Peace, love and high octane baby!

 

racer

Link to comment
Share on other sites

WOW! I had to get my tech manual out. ;)

 

 

I just came back and read through that all ... holy ######. That is without doubt my longest post anywhere ever. And I was stone cold sober. Scary.

 

What I'm really afraid of is he's gonna read it and think, "Cool. So ... why do I have to blip the throttle?"

 

Groan.

 

:P

Link to comment
Share on other sites

Well, believe it or not, all you had to say was, "If you don't use the blip technique, you'll chew up the gears." Enough said, that works for me. However, I did thoroughly enjoy the read. I'm a bit of a grease monkey myself, although I'm not a tranny rebuilder in the least. Maybe this is why it helps me to be a better rider, because I understand what you said. Anyway, thanks for that post. Awesome stuff. And I'm looking for a tech manual for my bike, any thoughts on the Clymer?

Link to comment
Share on other sites

Well, believe it or not, all you had to say was, "If you don't use the blip technique, you'll chew up the gears." Enough said, that works for me. However, I did thoroughly enjoy the read. I'm a bit of a grease monkey myself, although I'm not a tranny rebuilder in the least. Maybe this is why it helps me to be a better rider, because I understand what you said. Anyway, thanks for that post. Awesome stuff. And I'm looking for a tech manual for my bike, any thoughts on the Clymer?

 

 

Erm, sorry. That's what I was afraid of. Technically, the purpose of the blip technique is to smooth out the clutch re-engagement if you are using the clutch.

 

If you are not using the clutch, then, yes, the blip will allow you to shift without chewing up your gears.

 

-----------------------

 

Nothing wrong per se with Clymer or Chilton. Often times they will include 'tips' that a factory service manual doesn't.

 

Personally, I used them all the time to keep my jalopies running and teach myself how to work on machines.

 

That said, nowadays, I always buy a factory service manual because they tend to be more model specific with certain spec's and some info a Clymer's won't have. And sometimes you can get factory technical updates that your Clymer won't have.

 

When I went from weekend warrior working on my worn out Subaru to serious race wrenching and motor re-building, I went full time to a factory service manual. It may be more expensive, but, to me it is worth it and I can always use the other for a fall back.

Link to comment
Share on other sites

Edit my last post, use the blip to save your clutch. I actually clutchless upshift, and my understanding is that helps save the plates too. I have the factory book for my bike, but it doesn't even mention things like the gear position sensor, or even the FI light. My owner's manual had more in it than the factory manual. The manual does give some steps, but not pictures for the specially educated, such as myself. Maybe I have the wrong one? It's a cd-rom adobe version. Anyway, thanks for your help racer. I noticed you did a lot of cornerworking, and I am quite sure that it helps with your riding, any advice?

Link to comment
Share on other sites

Edit my last post, use the blip to save your clutch. I actually clutchless upshift, and my understanding is that helps save the plates too. I have the factory book for my bike, but it doesn't even mention things like the gear position sensor, or even the FI light. My owner's manual had more in it than the factory manual. The manual does give some steps, but not pictures for the specially educated, such as myself. Maybe I have the wrong one? It's a cd-rom adobe version. Anyway, thanks for your help racer. I noticed you did a lot of cornerworking, and I am quite sure that it helps with your riding, any advice?

 

 

Yep. Not using your clutch saves wear on your clutch.

 

And blipping the throttle to match engine to road speed (or to transmission speed) will also avoid unnecessary wear as the plates won't spin against each other so much when they come back together.

 

The service manual will have information necessary to repair and maintain your machine. Sometimes, more basic maintenance spec's and service limits will be found in the owner's manual along with operational imformation like how to operate the bells and whistles or interpret the various indicator lamps or readouts. I have no idea what an FI light is. (fuel indicator?)

 

The only information I would expect to find on "indicator lamps" in your factory service manual would be harness layout and wiring schematics to trace or troubleshoot electrical problems. They sort of assume you know how to use a screwdriver and change a light bulb .. and would think to test a bulb in any case before tracing the entire electrical system for a fault.

 

Tips? Yeah ... go cornerwork!

 

It is a required duty to receive a racing license in at least some of the clubs I know of. Personally, I believe it should be mandatory duty for every rider/racer to volunteer to work some minimum schedule like once or twice a year. Broken into half day shifts if necessary. Working practice days are especially encouraged as this is when corner crews tend to be short handed.

 

As a rider, not only is it an invaluable learning tool to gain information from studying what the "experts" are doing with their lines and throttle in any specific corner from a more "up close and personal" angle and distance than the typical spectator's vantage point, but; cornerworking is the foundation for creating the environment that allows any of us to ride on track with any expectation of safety. They inspect the track surface and conditions and communcate with the tower and stations around the track to warn riders of any changes in conditions from the last lap or from standard/safe conditions in upcoming corneres by waving colored flags or hand signals.

 

Without corner workers, the race track would be only marginally safer than the street. You would never know what might be coming around the next bend. I have ridden practice days without a good flagging crew before and it is a truly scary thing. i have also seen practice days canceled outright for lack of a minimum crew and ambulance.

 

So, sure, I can be relatively certain that there won't be any little old ladies crossing the road or ten ton trucks coming head on "in my lane", but, that doesn't mean that the track won't be blocked by some level of carnage or covered with oil from a leaking bike as I tip into that next blind sweeper at something over 100 mph.

 

And the only way any of that mess gets cleaned up ... bikes and riders picked up, surface cleaned up ... is by the efforts of cornerworkers. And, the ugly truth is, chances are, it will be you or one of your buddies whose life depends on somebody's quick thinking, quick action or level of first-aid training on a corner while waiting for the ambulance. Racetrack riding as we know it today could not exist without cornerworkers.

 

So, do your duty, and do yourself and your riding skills a big favor, and go work a corner. Better yet, work all the corners. And do yourself and all your buddies a favor and take a basic first aid training course. And when you meet someone in whites around the paddock, make sure to thank them and treat them with the greatest respect as your life is literally in their hands.

 

In hindsight, I should really add to my little riding history/story that I posted yesterday to say that, in addition to crediting Keith Code's training for my taking second place in my first race ever, I would also have to credit the fact that I cornerworked every corner of Bridgehampton for two years before I raced there.

 

 

Hug a cornerworker today, your life depends on their well being tomorrow.

 

Cheers,

 

BH

Link to comment
Share on other sites

WOW! I had to get my tech manual out. ;)

 

 

It's been a few years since I rebuilt a motorcycle tranny and I was feeling a little hazy about some of the details of the motorcycle sequential transmission and all this blipping intrigue myself today so I went and found some links to try to get clear about it all. Here is some of what I found:

 

http://auto.howstuffworks.com/sequential-gearbox1.htm

 

http://auto.howstuffworks.com/motorcycle2.htm

 

http://www.timberwoof.com/motorcycle/honda...ansmission.html

 

The first two links may take some time to download but have really good illustrative detail and descriptions.

 

The last link is less detailed but is really cool and good because it lets you shift at your own pace.

 

I'll be back soon to try to sort it all out.

 

Have a great weekend all.

 

BH

Link to comment
Share on other sites

I'm diggin the websites. Helps tremendously. And I'll definately be looking for cornerworking classes. Since you have been a wealth of information, I have another question if you don't mind. The blip technique calls for engaging the clutch after each shift. I know this is because sequential transmissions need to be reloaded, but why? Any ideas?

Link to comment
Share on other sites

I'm diggin the websites. Helps tremendously. And I'll definately be looking for cornerworking classes. Since you have been a wealth of information, I have another question if you don't mind. The blip technique calls for engaging the clutch after each shift. I know this is because sequential transmissions need to be reloaded, but why? Any ideas?

 

 

Slept about 4 hrs and got up about 3am to skywatch for Perseids. Bear with my blurry head ...

 

While you might "get away" without letting the clutch out between every shift, it IS a very good idea to do so.

 

Off the top of my blurry head, I would say it (reloading) maybe helps a bit to "set" the dogs after each shift so they don't "pop out" and create a "false" neutral. The edges of the dogs are slightly beveled, or should be, and might not settle all the way to the bottom of the "hole" or "slot" in the mating gear unless the mainshaft is loaded a bit.

 

Anyway ...

 

Maybe it helps to spin up the mainshaft to be closer in rpm for the next shift, making for better chance of smooth engagement between each new gear ratio?

 

I think this (the mainshaft rpm issue) goes back toward what 2big said about letting the engine rpm fall to idle, and the blip assisting the actual gear engagement ... and is precisely where I am feeling hazy myself. I'll need to think it through later when I am sharper.

 

I don't know whether to make more coffee or go back to bed. I'll compromise and lay on the couch

Link to comment
Share on other sites

Ok, so here's the question ...

 

If the clutch separates the engine from the tramsmission, why does letting the rpm fall while the clutch lever is pulled in and while the engine is separated from the transmission seem to affect the nature or characterisitc of a shift?

 

 

Above, 2big said:

 

Think of it this way. If you were to travel down a (long) staight of way, pull in the clutch and hold it (without shifting), the engine RPM would drop and go to an idle. At this point, the bike would be coasting, EVEN THOUGH YOU ARE STILL IN 6TH GEAR. If you let the clutch out, the engine will rev back up to match the speed of the rear tire.

 

OK, if you were to do this and down shift, the transmission would give a big "clunk" because the gears are traveling a very different speeds, since 6th gear is engaged (traveling at the speed of the rear tire) and 5th gear (not yet engaged) ***is traveling at the speed of the motor.*** By blipping the throttle you are raising the RPM of the motor to help match the speed of the rear tire. The closer these two gears are in speed, the easier the bike will shift.

 

Now blipping the throttle in normal riding (fast paced) puts less load on the tranny, but also smooths out the transition between the two gears

 

While I am familiar with the "clunk" that happens just when, where and how 2big describes, the more I think it through and look at the sequential transmission diagrams ... the more confused I get.

 

There is definitely something happening ... but what?

 

How does the rpm of the motor affect the transmission if the clutch is pulled in?

 

And since the gears are essentially freewheeling and matched to the next gear by synchro-mesh, why does it matter what rpm the engine is moving with the clutch pulled in.

 

It took a few minutes of working through the standard transmission shift process before it occurred to me, and, after a few years of not looking at tranny shafts, I wanted to be certain so I dug up some diagrams which are linked above.

 

The phrase I highlighted with triple asterix in 2big's explanation is what really stuck in my craw. It sounds logical if we think about a transmission as being like a mountain bike's gear sets where the two sides of the gear set are in fact separated. However, looking at our transmissions diagrams, this does not seem to be the case.

 

It looks like each gear set is in fact constantly engaged with each other (input/mainshaft side to ouput/countershaft side) and that what is separated is one gear from the shaft on one side or the other.

 

Perhaps I am seeing it wrong and someone else would be kind enough to comment on what they see before I go out on a limb to offer my "final solution"?

Link to comment
Share on other sites

Think of it this way. If you were to travel down a (long) staight of way, pull in the clutch and hold it (without shifting), the engine RPM would drop and go to an idle. At this point, the bike would be coasting, EVEN THOUGH YOU ARE STILL IN 6TH GEAR. If you let the clutch out, the engine will rev back up to match the speed of the rear tire.

 

OK, if you were to do this and down shift, the transmission would give a big "clunk" because the gears are traveling a very different speeds, since 6th gear is engaged (traveling at the speed of the rear tire) and 5th gear (not yet engaged) ***is traveling at the speed of the motor.*** By blipping the throttle you are raising the RPM of the motor to help match the speed of the rear tire. The closer these two gears are in speed, the easier the bike will shift.

 

Now blipping the throttle in normal riding (fast paced) puts less load on the tranny, but also smooths out the transition between the two gears

 

Hey there 2big,

 

How is it that 5th gear (not yet engaged) is traveling at the speed of the motor when the clutch is pulled in at high road speed with 6th gear still engaged and engine RPM allowed to fall to idle?

 

BH

Link to comment
Share on other sites

Yup that was my bad. Nearly all manual transmissions are constant mesh, there for all gears and moving the same speed. Sorry for the confusion and sticking it to your "Craw". ;). I gotta lay off the grape juice.

 

 

LOL. No worries. I take full responsibility for clearing my own craw.

 

Sooo ... about that "clunk"?

 

Perhaps, in that circumstance, the difference in RPM between the fibers and steels inside the "wet" clutch creates some resistance due to hydraulic stiction applying a negative torque to the mainshaft during the "false neutral" between gears which might be more than the synchro-mesh is able to compensate for?

 

In other words, if the clutch basket/fiber plates and steel plates were closer in RPM during the shift, the oil might be less of a "brake" and the synchro's more able to overcome any rotational resistance when attempting to match the next gear for the dogs to engage?

 

If so, would that mean a "dry" clutch would not experience the same "clunk"?

 

 

 

Or I could be drinking too much grape juice myself...

 

 

;)

Link to comment
Share on other sites

You've really got me thinkin' now. I would have suggested oil friction on the plates of the clutch, but a dry clutch shouldn't have the same problem...but it does??? I assume there is always some amount of friction being transfered. That being said, I also ride an RT1150 that has a dry clutch and I can create the same clunk as a wet clutch. Although the BMW seems to complain more when NOT blipping the throttle, but I suspect that has more to do with the shaft drive more than the tranny. (that is a whole other thread.) Hehe. Obviously a false neutral is a deafening clunk, while the shifting after coasting is a much quieter clunk. I suspect the quieter clunk is the dogs meshing together after they've been worn IE slightly oval in shape. ??? Could the shift forks be bouncing or moving too???.

 

So now I've gotta question stuck in my craw after your last post.

Obviously your knowledge of a manual transmission FAR.............exceeds mine. (I would never even think about rebuilting one without parental supervision) ;)

What is it that actually makes the LOUD "clunk" when shifting from a false neutral, and why is you can up shift from a false neutral, but down shifting sounds like a spoon stuck in the garbage disposal??? But, if you pull in the clutch, really bring up the RPM's high and down shift, then feather the clutch out the trans will shift easier??? Mind you not perfect, but better than the silver spoon???. Inquiring minds wanta know???

Link to comment
Share on other sites

The only dry clutches I have personally experienced were on TZ's. And the two times I ever rode one, I never thought to conduct tests of this particular phenomemon...lol.

 

However, I can imagine that even without oil there is some contact and friction going on between the plates while "disengaged". Of course there is simply the rotating mass of the mainshaft itself to consider. I wonder if shifting really quickly to reduce time (in false "neutral") between engagements would have some effect on the characterisitic of "the clunk". Or if a faster more forceful shift would merely reduce the time the synchro's had to "help"? Hmmm...

 

IN any case, if the dogs are worn more on one side than the other, it sounds logical to account for a different sounding "clunk" while catching a gear off-speed in one direction or another. As for the rest of your points/questions ... I'm going to have sit down with a pot of coffee and think all of them through when I can devote the time. For the moment, I'm just going with overall limitations of the synchro-mesh no matter the circumstance. I mean the friction bumps are smaller than the divits in a bloody golf ball!

 

 

Oh, I definitely had professional "adult" supervision the first time I swapped out shaft and gear in my "old" RS. No shame in that. Just plain old common sense! And I was still gritting my teeth the first time I let out the clutch...reeeeal slow!

 

Of course, the "newer" model RS's have a "cassette" style tranny so that the cases don't need to be split at all! Although it sorta leaves one fat fingered and fumbling in the dark by feel for shift forks and farside shaft/bearing insertion (sorta like the first time...er...nevermind). It's always something of a trade off I suppose.

 

At the end of the day, it's just a machine. A machine designed and assembled by a human being. And, generally speaking, what one human can do, so can another. If you ever have need to attack a tranny, I'm sure you'll do jus' fine. Nuttin' but a few circlips, really.

 

 

"Spoons in a disposal" ... LMAO. Yeah and that's pretty much what they look like when yer done, too!

 

 

Have a great day!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...