QuestionHi, I have a Honda PC50 1968. I Bought it last year (2010) and it ran just fine. I took it on a few hills which it struggled with however I always made it home. But driving down the street the bike lost power and eventually stopped. I have just started to try and repair it this year and my findings are that there is power to the spark plugs and the engine is not seized. The plug is clean, new fuel. I removed the carburetor and splashed in some quick start and the bike putted over. I replaced the carb but left the air pipe cove off and splashed in fuel the bike does not start but does backfire. I am not at all mechanically minded but my suspicions are that not enough fuel is getting in, I suspect this as when it took the plug out i poked in a q tip and it came out completely dry. Any ideas what I should do?
AnswerDerek, I would check the valve clearances just to be sure that they are closing all the way, first.
The clearance is .002" cold on in/exhaust valves at TDC compression stroke.
After that, you need to be sure the spark timing is correct... points opening at the F mark alignment.
The carburetor has an idle circuit in it, which is probably plugged up from sitting.
http://www.cmsnl.com/honda-pc50-little-honda-usa_model1099/partslist/E++11.html
Take the carburetor apart, clean all air and fuel passages, plus check the o-ring on the main jet.
Idle mixture screw setting is about 1 1/8 turns out. Although the illustrations don't show an idle jet, the tune-up guide I have shows a #35 idle jet. If that is there and plugged it won't start and/or idle.
Bill Silver
