1st order of diagnosis.
What year model is it?
How many miles on it?
How many miles since last valve tappet adjustment?
What was the engine Cold Cranking Compression reading after the last valve tappet adjustment?
What is the current engine C. C. Compression reading?
90+ psi should start pretty good! As long as you use full 'choke' and leave the throttle Alone!
Thanks for the reply! Good to know it should start in near freezing temps.
The bike is a 2002 KLR650 A16.
There is 14K on the ODO. (suspiciously low for a 2002)
Valves were checked at 10K when I purchased the bike.
Exhaust .008 both sides
Intake .006 Left, .008 Right
I haven't checked compression but as you suggest that would be a good place to start, and hopefully eliminate as the problem. I will need to purchase or borrow a compression tester so it may be a while.
Is there a failure mode for the compression release that would cause low compression on starting even if everything else is OK?
Enricher cable is adjusted to 0.10" play.
Possibly some crud in the enricher passages?
I have read on some other threads that people have had success turning out the pilot mixture screw, but it seems to me that the mix would then be wrong when warm, plus, access to the screw is sealed off on my carburetor.
It doesn't get into the low 30's often in the California foothills where I live, so I will need to spend the night at higher elevation to reproduce the problem or to verify a fix. I want to try to understand and eliminate as many possible causes before heading up there again.
Any ideas are very much appreciated.