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Hotfoot

Picking Up Rpm Signal From S1000Rr?

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OK I need a little help. I've got a Starlane laptimer newly installed on the BMW S1000rr and want to connect the RPM sensor. It says you can do that by wrapping a sensor wire around the ignition coil to pick up an RPM signal but we can't get that to work. I called Yoyodyne and they said it is very difficult on the BMW to get a signal and the best thing is to just tap into the signal wire the feeds the RPM info to the tach.

 

Anybody know what wire that is or how to find it? As far as I know the BMW has a complex canbus and I'm not sure there IS a simple tach signal wire. Yoyodyne suggested we call our dyno expert and ask them what wire they hook into for RPM when running the bike on the dyno. So... Timmer? Any thoughts?

 

I have an older version Starlane on my Moriwaki and it picks up an RPM signal off the Moriwaki iginition wire with no trouble at all. But the new timer won't pick up a signal off the YZ450 Super Single rpm wire either, I have the same problem with THAT bike, so I'm trying to find a solution for that one, too.

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Hey Laura!

 

I believe you're right about the CAN bus on the S1000RR. I don't think there is a single wire that feeds the RPM to the tach. I believe it uses CAN communication for this. If there is a single wire for this, I don't know what it is.

 

Wrapping a wire around a coil wire for an RPM signal usually works best if you can wrap it around a wire on the secondary side of the coil(the spark plug wire). The wrapped wire around the spark plug wire picks up the change in the electrical field as the high voltage pulse goes down toward the spark plug to fire it. The S1000RR has a "stick coil" or "coil on plug" which has no spark plug wires, so this is not an option. You only have access to the primary side of the coil(side connected to the ECU), which is much lower voltage.

 

Another thing about the S1000RR is that it has 3 wires going to the coil. Other bikes typically only have 2 wires...power and signal. The 3rd wire on the BMW is for a feature they use called ion sense. I won't get into the details of ion sense, but this could be why you can't get a good signal when you wrap the wire around the bundle of wires going to the coil. Your RPM pickup wire could be picking up the ion sense signal as well, which will throw it off for sure.

 

Look at the picture I've attached of the coil connector on the S1000RR. This is the connector that plugs into the coils. The arrow in the picture is pointing out the SIGNAL wire location on the connector, which is the one you want. It is labeled as "1" on the connector.

 

If you can, pull this wire away from the bundle of wires and ONLY wrap your RPM pickup wire around that wire. If that doesn't work, you might be able to splice your RPM pickup wire directly into it. You might want to ask Starlane if this is Ok though.

 

Hopefully that helps a bit. Let me know how it goes.

 

Best,

Timmer

post-711-0-54531800-1390603096_thumb.jpg

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Can't you wrap it around the stick coil, it works that way for engine timers on most the dirt bikes I install them on that have a stick coil.

 

I don't have a pic, but I could usually get 3 wraps inside the top boot as long as they didn't overlap and still get it down in the head cover hole.

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Hotfoot

 

Per our conversation on saturday, here's two pics of how I have my TrailTech Vapor wired up for RPM pickup on my CRF450,

 

I was mistaken in what I said yesterday, the pickup is not fed into the spark plug wire, its the connector from the electronic "brain" into the Ignition Coil.

sorry the pic' aren't all that great but its the best I could manage without pulling it apart

 

 

Tyler

 

IMAG0311_zpsc58e8789.jpg

 

IMAG0317_zpsb37bdd49.jpg

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