honda 1995 f3 600 started hard choke on open throttle. that is how i used to start my bike when i first got it. since I have re=shimed the intake & exhaust valves. It worked great!! started right up & has been for 6-8 weeks now. but now it is starting to the same thing,, but not as bad YET! would valves tighten back up over time?the bike does run rich. I am going to pull a plug or two to start the investigation. From there I will work back down to the valves. Any input would be appreciated. Thank you.Thomas.

 

About 4-6 weeks ago did valves shims. evry thing was great! Know no compression well 25psi. redone shims, good compression now. why would valves tighten up? Had to shim to 1.50-1.65 droped from 1.90-1.80. any help thank you.

 

That's a significant change in valve clearance. Generally you'll only see a .025" to maybe a .05" change. My gut feeling is that it was done wrong in the first place. I'm not trying to throw you under the bus, or discount the fact that it ran fine for a few weeks. But I just don't see how there could be that much change. Do you recall how much change there was in the shims the first time you did it ? Maybe bad cam position during the check phase ?

 

When I got the bike the valves were off. Started hard but ran good once started. The valves were to tight. When I tore it down I couldn't even get a .05 clearance. Once I reshimed & put the cam & chain back on I rotated the engine with lobs straight up. Had good clearances on all valves, .05-.07. It ran great for 3000 miles, about 6-8 weeks. It started having the same starting issues again. I droped about .20+/- .05 in each valve. The head appears to have had some work done to it. Would titanium valves cause the valves seats to push up into the head? Not sure what though, haven't tore it down that far yet. Was hoping to do that this winter, not in the riding season. Now doing the valves again I can tell the differance in power at low end. Well if it happens again I have enough shims to go one more drop of .20. hopfuly it will be winter by then & out come the sled.

 

Did some asking around. Possible that the head bolts stretched. May be origanal owner didn't torque properly. Either way I will purchase a good head & biuld it myself. This way I know its done right!