I recently acquired a 450 Honda foreman it’s got 1000 miles and roughly 400 hours I cleaned and check the valves both seem to check out pretty well. I can only get it to run for about three seconds if I put my hand over the carburetor and build up fuel once I do this, I can rive it up again for about three seconds, maybe five I ran into one years ago that kept jumping timing it would get better and then run like dog crap sometimes is there a chance this is ignition related or do I need to dig into the timing? The car was verified as clean and if I spray carb fluid in, it won’t run any different so I don’t think it’s a fueling issue, but it could be when it does run. It seems to run pretty all right.

 

Better to post this in the Honda section. Anyway fit a new plug "just in case" and check for a spark while the plug is out, but I would guess at the carb needing a good clean out. Don't bother with rebuild kits, it won't be worn but is 24 years old and has done 400 hours so it has not been used much per year, and carbs that sit get gummed up. Condensation can build in the tank turning to a layer of water in the bottom, and old fuel doesn't burn well anyway. So, with a cleaned out carb and fresh fuel in the tank it will probably run. If it doesn't, check compression, should be over 90psi, and suspect valve clearances first if it is low, no clearance means a valve is slightly open all the time, however a big clearance would indicate a valve sticking open, so same effect.