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Tech Corner

Technical Q and A for classic motorcycle maintenance and repair.


1976 Triumph 750: Hard to Kickstart

Motorcycle Classics tech expert Keith Fellenstein

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, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with “Keith’s Garage” as the subject.

Compression question

Q: I have a 1976 Triumph 750 I’m restoring for a collector. This is the third one I’ve worked on for him. His complaint is that it’s very hard to kickstart the bike. And it is. If you take out the spark plugs it will kick over very easily. If you put just one plug back in the kickstarter gets very hard to kick down and, if the key is on, it can kickback and really hurt your leg. I’ve checked the valve settings, the timing side gears and the timing of the Boyer electronic ignition. I’m only 165 pounds and can’t kick it over at all. The clutch plates are stuck together and that’s what I’m going to fix next. If that doesn’t help, I’m stuck. — John Woolson/Houston, Texas

A: It sounds to me like the bike has been modified for higher compression and has excellent rings and valves, making it difficult to kick through the compression stroke. Unless the transmission is locked up, the clutch plates shouldn’t be causing this problem. Possible solutions include either a thicker head gasket or two head gaskets used together. You could also put a compression plate underneath the cylinders. Any of these will drop the compression ratio, which should result in easier kicking. Volumetric testing and a compression test before doing any of these modification should help determine if high compression is the cause. MC

jhutbeer
11/14/2013 1:14:13 PM

I know this may seem obvious, but perhaps the octane rating of the gas is too low. Often it is harder to get better than 92 octane gasoline at most gas stations, but high compression engines often were designed for higher than that and need 94 octane. Also, another solution may be a fuel additive to give the same result. It depends how badly you want to take apart that classic bike!