Motorcycle Repair: honda 125 atv, honda 125, cylinder compression

Question
i have a 1987 honda atv 125 it starts fine an idels fine ,but when you give it gas it backfires an runs real rough -i put in a new spark plug ,cleaned the carb ,put on a nother carb but still no help ,what do you think --thanks randy

Answer
Hi Randy,

I recommend having a local tech investigate the problem. There's not enough information given to accurately diagnose the problem(s).

Get a copy of the service manual. Learn how to perform cylinder compression and leak-down cheks. These would be the first things to do to learn the condition of the engine.

Next, check valve clearances. Cylinder compression and valve clearances must be within service limits before the carb wil work properly.

Clean the carb more thoroughly.

I return tech files by email. There was no email address with your question as requested.


Respectfully,
Mark Shively