Technical Q and A for classic motorcycle maintenance and repair.
Editor’s note: If you’re having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith’s Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.
Hard to kickstart
Q: I have a 1975 Yamaha XS650 twin. It has had a tuneup and runs great. My problem comes when I want to start it with the kickstarter. Warm, cold or hot, it does not matter. There’s no way it will start. All I have to do is touch the starter button and it will start immediately. The coils are still original. Are they my problem? — Mike Trunk/via email
A: I’ve had this question numerous times the other way around, where a bike will have a bad electric starter, but will start fine when kicked, but I’ve not seen one that won’t kick but will start on the button. My first thought is that kicking it may not be spinning it fast enough, especially if the compression is starting to fall off. Maybe the valve clearances are too tight and are letting the air out, so to speak. I had a look at the wiring diagram, thinking there might be a reason to be found there, but it’s pretty straightforward in 1975. Since it will start on the button, it’s not likely an electrical problem. I’d check the compression cold and hot, and compare it to spec. If it’s too far below spec, do a leak-down test to see where the compression is going, through the rings or valves, or even a blown head gasket.