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Auxiliary Drive Shaft
Posted: Sun May 08, 2016 8:05 pm
by Rowery
I see this term in the Clymer manual for my R1150R. It is behind the alternator support cover. There is a chain and chain tensioner associated with this that connect it to crankshaft. Is this simply the timing chain? Forgive my ignorance on this. I have a feeling the tensioner is bad. I have a bad knock on startup especially when cold that goes away when it warms up
Re: Auxiliary Drive Shaft
Posted: Sun May 08, 2016 11:11 pm
by Sunbeemer
This is most likely caused by the cam chain tensioner on the left-hand cylinder. It can be replaced with upgraded parts that correct this. While I don't have the part number at hand, you can find them by searching this forum or its archives...
It does not require any disassembly of the engine and can be replaced in a few minutes.
Re: Auxiliary Drive Shaft
Posted: Mon May 09, 2016 2:32 pm
by carl1957
Re: Auxiliary Drive Shaft
Posted: Wed May 18, 2016 6:44 pm
by Rowery
Thanks for the info. I just replaced the tensioner with the one from rubber chicken racing. However, I'm still getting the cold start slap/knock. Any other suggestions? The best I can tell it is coming from the front of the motor.
Re: Auxiliary Drive Shaft
Posted: Thu May 19, 2016 9:53 am
by kirby
Even with new and updated tensioners there still can be a knock on start of a cold engine for a couple seconds and sometime a bit longer. The only thing I can think of that would knock in the front (behind the alt cover) is a loose pulley, but that would not go away by warming the engine.
The throttle bodies will in time start (possibly) to knock at idle because of throttle shaft ware.
Bottom line is that if it knocks for a few seconds and then stops I would not worry about it.