Questiongs1150 '84
This engine had a valve adjustment nut come loose and fall into the cam chain gear on the crank. The cam chain skipped 2 teeth. I extracted the nut, gear teeth look fine. Engine has been sitting for 3 years. Drained old gas, cleaned carbs,new oil and filter. KS stage1 carb kit to adjust for new kerker header. When nut fell into gear, engine stopped. No hard bang noise noted on engined stoppage. Before correcting the 2 tooth skip of the chain, rotating the crank would find a tight spot then clear, after correcting timing chain and triple checking, engine rotates freely. Checked coil wiring Hayes manual, orange leads to positive on coil. I have not performed an ohm test on coils. Spark seems weak. Compared to a car engine spark with a snappy spark, how should a spark look. It seems as if I have multiple small sparks when I should only have 1 big spark.. clueless on this phenomenon. Engine will only run with choke almost fully engaged, center 2 spark plugs look very light /lean mixture /clean compared to 2 outer plugs. 2 outer plugs look normal. No soot or oil. Plugs are new. No obstructions in airpath even removed air cleaner in one attempt. Rubber carb boots are sealed well. Carb floats work correctly.
Engine reaches 180+ oil temp in ~ 5 minutes. Extremely hot. No abnormal noises to note. Slight popping in exhaust. Engine dies when throttle is opened. Battery is fully charged. All instruments light up including headlight while cranking and running. I have not attempted to disconnect battery once it has started. Will perform a compression test tomorrow, but if that checks out ok and coils check out ok, what is my next step before ripping the top end off to check for valve damage. Perhaps an intake or exhaust valve not seating / bend? Cam chain stretch? I can't imagine that a degree or 2 on cam chain stretch would be that big of a deal. I'm at my wits end.
Thanks!!
AnswerI would start by posting this to www.thegsresources.com and ask if a 2 tooth skip can result in damage to the valve. Their forum is down right now but when it comes back you will have access to the best minds in the GS business right there. I think you are ok with a 2 degree skip but not sure.
Do the #2 and #3 plugs look wet? The coils on the GS run in a wasted spark mode where they fire twice what they need. One coil runs cylinder #1 and #4 and another runs on #2 and #3. It's possible one of the coils is shot or almost shot. You can try swapping coils to see if the problem follows the coil.
OTOH, dry plugs will almost certainly mean the carbs are still plugged up. Pay close attention to the idle mixture screws which may be capped on your carbs. You may need to remove the caps and clean out those passages with carb cleaner and compressed air.
There's a nice step-by-step guid to cleaning carbs somewhere in the tech section of www.thegsresources.com.
