Jaybird180

I rented a mini-van for my last 2 day. Took the seats out and loaded the bike in the back on the right side. I used the hooks in the floor from the seats to secure the bike with straps. Then I loaded all the gear (coolers, etc) on the left side. It was perfect. We got to the track, unloaded and rolled out the airmatress and slept in the van. Perfect I tell ya. I'm thinking of buying a mini-van just for getting more tracktime.

I talked to the "local" Racetech shop and they say they think there's a twist in the forks causing the springs to bind. Does this make sense?

I agree we may be missing each other but now I'm missing you as well. Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake. It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction. I don't think the position of the caliper has any bearing on this but I will stand corrected It's one of the reasons why rear brake calipers have been moved over recent years. Now regarding that chain pull thing: I'd have to reread it, however one thing that often gets overlooked is Newton's 1st law. F1=F2, for every action there's an equal and opposite reaction. Don't overlook opposing forces which often is not what we observe (ex. centripetal vs centrifugal force) Sorry, but that doesn't sound right to me. I will abstain from asking you for proof as I hope common sense will prevail. The position of the caliper is only relevant to weight distribution i.e. if it is on the top of the swingarm, then this obviously alters the COG. If it is on top of the swingarm, then it is less likely to pick up debris from the road. If it is on top of the swingarm, then a pushing force is applied to the stay as opposed to a pulling force on the stay should it be under the rear axle. The way the rear caliper is set up on my bike i.e.with the stay an integral part of the swingarm where the caliper holder slots into lugs on the swingarm, wouldn't really matter much if the caliper was above or below the disc. Are you the same Jaybird from BITOG btw? No I am not from BITOG Common Sense is not a Common Virtue Position of caliper does more than just COG and debris protection. Motorcycles have evolved and placement of componentry is not as arbitrary as "let's put it there because it fits" anymore. Anywho, I think I'm getting "stupider" by the minute. Peace.

Right. Only the mass of the machine and rolling friction to resist forward acceleration...which you don't have with the rear brake on. Not sure how good of a test this is either. Only one cuppa so far and I gotta leave for work. I'll think more about it. What kind of bike do you have? G'day Racer The bike's rear wheel offers the most resistance to forward movement as this is the one that has to do all the driving. What I'm saying is that most resistance comes from the rear wheel whereas the front wheel is "happy" to roll. Evidence?...Which one would wear the most in a 1/4 mile drag? To understand better why the rear rises and forgetting all about chain pull, I thought this might help... Picture the chain as merely the drive, it is rotating the rear wheel. The rear wheel transfers that drive through the axle alone. The axle transfers that drive via the swingarm to the swingarm pivot shaft which transfers it to the bike frame That rear axle is below the swingarm pivot shaft. Provided the suspension can keep the rear axle below the swingarm pivot shaft, then it will continue to try to push "under" the swingarm pivot point. I have an 02 ZX636. BTW, thanks for the interesting discussion. Dear sir, Pointing to tire wear does not prove your point. You cannot compare rolling resistance with the rearward force being applied from the engine through the rear tire. The rear tire must overcome the inertia of the bike AND continue powering thru just to maintain 0 (zero) acceleration.

I agree we may be missing each other but now I'm missing you as well. Let's stop thinking about the bike decelerating and think about constant drive or acceleration while applying the rear brake. It stands to reason that as the back of the bike comes down (due to chain pull, as I have proved to myself on my own bike), the front must become lighter as the motor is effectively now trying to revolve the rest of the bike around the back wheel. More weight = more traction. I don't think the position of the caliper has any bearing on this but I will stand corrected It's one of the reasons why rear brake calipers have been moved over recent years. Now regarding that chain pull thing: I'd have to reread it, however one thing that often gets overlooked is Newton's 1st law. F1=F2, for every action there's an equal and opposite reaction. Don't overlook opposing forces which often is not what we observe (ex. centripetal vs centrifugal force)

I've done the best that I can looking at the different org/ tracks, etc. Some of them (ViR/ NJMP) offer an auto club but no MC club. I'm gonna talk to my trackday club and see what they offer in the way of a bulk discount. That's the only way I can forsee getting more tracktime.

I totally agree with you Racer where applying brake decreases acceleration however regarding the rear traction issue under power...I think the two of you are missing each other. It depends on the location of the rear brake caliper as to where the parasitic force is being directed. If the caliper is directly above the front edge of the contact patch, then it will transfer the force to the rear wheel, thereby increasing traction.

Hi, all I've been to a few tracks that are within a few hours driving distance. I'm in D.C. and looking for a track that offers a membership where I can go as often as my schedule allows (every weekend). I've joined some Trackday orgs (NESBA, TeamProMotion) over the years and admire what the guys who go to Jennings and WSMC have. If I got more tracktime, I'd quit riding on the street. How do I find out who has something like this available?

Okay, how do I edit and add the breaks? I typed in word and cut/ paste and obviously they didn't transfer over. Makes it hard to read all one paragraph. I recall seeing something about a </BR> Syntax

What happened to my spacing in between paragrahps? Isn't this forum WYSIWYG? No wonder, no replies.

T8,9 at Summit main... the double apex carousel before the short straight that leads to the last corner onto the front straight? If the compression damping on a rear shock is set too low and/or rebound set too high, the shock can "pack up" in high speed sweepers. But that isn't hard acceleration. It's cornering force at high speed. In any case, your "buddy" probably needs glasses. Or he didn't know what he was looking at and was watching when you rolled out in the middle of the carousel to set up for the second apex. Unless of course you weigh like four hundred pounds and your rear spring is broken and the swingarm is angled up when you merely sit on the bike. Regardless, hearsay is inadmissable in any case. Go out and watch some bikes on track and tell us how many you see squatting under acceleration. I counted T8-9 as the section just after the carousel, but I flunked math too. Actually I had a problem where my shock adjustment knob was stuck in the max position. didn't seem to affect functionality. But I did purposely rest my heel on the swingarm so I can feel what it's doing. And it wa going up and down just like on TV while the chasis didn't move. It seemed to me that it compressed on accel, but I'm open to testing again. Buddy watching was on street and it was a roll-on situation, flat out straight

I'm intereseted to know about what the deal is with your club, why they don't allow timing--I know some tracks in Oz and UK don't, is that your situation? Good for getting out of the closet and not just lurking C Another club I rode with was the same way. I figured they didn't want N00bs looking at laptimers. They don't require the speedo is covered but I do it anyway.

The pleasure is all mine! Me too! If this is true (and it is, just try and do a burnout from standstill), what situations cause it to compress? On occasion coming out of the T8,9 sections of Summit Main my swingarm comes up enough that I can feel it on the bottom of my boot. Also a buddy riding behind me said he saw the rear end squat under hard acceleration.

About March 07, I had a set of forks built by Ed of Trackside Engineering in Wisconsin. Ed has since sold the business and the new owners haven’t returned any of my calls, emails or requests for information, so I now turn to you guys for advice. The forks were built with Racetech 1.0 springs and Racetech Gold Valves part #FMGV S2040nv CTRL# 040297 (from an old email between Ed and myself). I recall talking with Ed about some other kind of pistons, valving, etc. and honestly at the time I was on information overload (in spite of his excellent communication skills). So I’m reasonably sure the RT stuff is on compression side and he used a set of pistons he salvaged from another rider’s setup to use on my rebound side. I have no idea about the brand, weight or oil level used. He also installed new bushings and seals. During our pre-return shipping conversation, I recall him saying something about stiction but I have no recollection of what he was referring. At the time, I was still struggling with suspension vocabulary (and still do apparently) and so I didn’t retain that portion of the conversation. Possibly he was warning me to be aware of it in the future, that he solved the problem or that the problem still exists. At a local hangout I ran into Terrence, an all-around great guy, the proprietor of A&J Cycles, a former WERA racer and AMA Tech Inspector. I spoke with him about some of my handling concerns and trying to articulate the inconsistency I was experiencing. After I invited him over to my bike, he lifted on the front end and when it didn’t return to it’s original geometry he said that I should go inside the forks and find out why it has excess stiction (is this the correct term for this?). Terrence also complained that the 1.0 RT springs may be too stiff for a 233lb dressed weight on my 02 F4i. I haven’t conceded that point yet, as I’ve ridden on this setup with an Ohlins rear (properly sprung by Kyle and verified by Ohlins) since the abovementioned time. I told him that I wasn’t sure of what it feels like, but I believe I may have bottomed the forks a few times on the brakes at Summit Main, so I reasoned that I may have too little spring!?!? Further in the conversation I communicated that at times the bike seems on rails, goes where I point it, at other times it doesn’t want hold the line on exit and other times it falls mid-corner (Michelin Pilot Power tires). I have always blamed either myself for the inconsistency or blamed a recent change in rear preload from fiddling with the adjuster for 2-up rides. Now here comes the ending: Since I just had the shock serviced due to a malfunction, AND since I had this suggestion from Terrence about stiction, AND due to the fact that I’m doing some work to the bike anyhow, I want to service the forks; I want to eliminate them as a variable in my riding results, however I don’t know WHAT to do because of too many unknowns and uncertainties. I haven’t allocated money in this project budget to send the forks out, and besides, whom do I trust to do the work (???), and Terrence is too busy. So I reasoned that changing fork oil can’t be that hard, right? And while I’m doing that, I should be able to visually see if there’s something binding and causing the stiction (which I understand that some of it is normal friction from the bushings and seals). A confused mind can’t make a decision. Can someone help me get un-FusterClucked?

So how is the bottom point calculated? I have asked this and have only gotten a range. I am close to being convinced that it's time to disassemble my forks (a whole other story). If I have to do it in order to find the bottom then it's +1.

Yes, I'm all about the XX crew chief.

I've ridden balls of foot street or track for quite awhile now and don't feel in total command otherwise. I just wondered why the Pro's don't. BTW- Stock rearsets on F4i (for now).

I saw somewhere that Keith says to make up time in the fast sections and just get through the slow ones. Unfortunately, at my level my club doesn't allow lap timers. I have to get bumped for that (soon I hope). You say you're not familiar...and I didn't make it any easier describing it in reverse either (my bad). You've answered more questions than I've had the vocabulary to ask. I've been a lurker on this board for awhile, mostly reading Keith's articles. I've only recently decided to register and post. Keep up the good work-EVERYONE.

The section is a downhill series of esses ending with a flat hairpin right. By being easier I meant it felt like it flowed better than the line I had been using. It's at Summit Point, Shanendoah Circuit in West Virginia. The part that I had to change was not going in so deep into the uphill right. At the crest, is a left, which then starts the ess section. It felt like it was less energy, I didn't have to get as hard on the brakes at the top of the crest.

I know it's old but I had to respond to the comments about Rossi hitting Gibernau. If you go back to that last lap where Gibernau ends up off-course, you'll see that Rossi got underneath him because Sete ran wide and ran into Rossi. Rossi then came wide at the exit of the last turn on the last lap and kept pushing until Sete was in the dirt. Rossi said it was a mistake that he didn't mean to run that wide on exit, but personally I don't believe him. But IMHO, Sete did it to himself cause Rossi got in his head. I can't wait to see what'll happen when he saddles back up (this is gonna be good, now that he has an ally in Casey).

So here's my question from this topic. I had a similar experience at a trackday a few months back. The cones were laid out for TP, Apex, exit and there were perhaps 2 TP cones that I thought should be deeper. Why not, I could hold throttle longer, turn and still make the corner, right? Later in the day, I decided to "try" the established line and I found that it wasn't the upcoming corner that worked better (I thought it was worse and so goofy) but it made the upcoming SECTION easier. So based on Tweek's original question and my experience, it is just an "experience is best teacher" thing with knowing where you want to put your line?

No, just put that on your To Do list too. :-)

I agree with you 100000 percent on the sense of speed thing Cobie. However, I had been suffering with confidence problems. And doing it this way, I could enter at a predicable speed each and every time until I was satisfied with my line and throttle control (smooth roll on, looking through corner, etc). Then I could focus on small increments of speed increases 2,3 or 5 mph and remind myself to keep the SRs in check that I was well within the limits. When the confidence picked back up and faster riders joined me...the speedo had to go and the speed climbed using sense of speed. But alas, Soft Science is on my "To Do" list.

In my local area there is a section that has become somewhat of a practice area. I had realized how my poor throttle control habits were affecting SOOOO many areas of my riding and decided to change that. I used this area of sweeping turns. It takes about 2-3 mins to do the whole circuit. Over a 2-3 week period I worked this area, disciplining myself to stay in 3rd gear, not use any brakes and to stay in the gas and DRIVE the corners. I started at a well controlled speed and worked until I knew I could take each corner at a certain numbered speed as indicated on my speedo and I setup FOR THAT SPEED each time. Buddies that have ridden this with me, did not have the patience for this but I kept to my discipline. It has helped tremendously for me. Perhaps you should find a section that you could use where repetition is your ally. Keep it short and make measured progress.

For the longest time, I've heard that the "proper" position is to use the balls of your foot on the foot pegs. I noticed that top level including MotoGP guys lock their heel step onto the pegs. Are they just at a level of performance where they can transcend the rules or is this no longer a "rule"?