potatoseus Posted November 14, 2015 Hello everyone! First time getting a 4 stroke. I tried it, it was powerful and great. But it didn't idle well, it had high rpm and it took a few kicks(like 10) to start. So I figured that it might be sucking in air or have a low compression. Can I connect a barometer instead of a spark plug, is there enough space there? And secondly the bike qas spitting out a bit of flames, not much. Like in this video: https://youtu.be/2s7U8Gk7slU The air is cold in this time of year, if that matters. (10 degrees celcius) Thank you Share this post Link to post Share on other sites
mlatour Posted November 15, 2015 (edited) Any past maintenance history on that bike? Like when were the valves last adjusted, how many hours on the piston etc.? An engine leakdown test is preferable to a compression test. Hard to start often points to valves needing attention. One thing for sure if that is you/your bike in the posted video, with an engine of unknown integrity, revving the piss out of it in neutral / bouncing off the rev limiter is looking for trouble. Edited November 15, 2015 by mlatour Share this post Link to post Share on other sites
potatoseus Posted November 15, 2015 No I just found the video online, not me . The bike has 190 hours in total, 50 hours on the new piston. The owner said that the bike had a high idle when still cold but that the revs dropped when the bike warmed up. Share this post Link to post Share on other sites
speedtoad Posted November 16, 2015 If the pilot jet is lean it will have a hanging or high idle. If you pull the clutch out a little and the idle stays dropped it is a symptom of a lean pilot jet. Another common cause is the throttle position sensor being out of adjustment. Likely someone took the carb off and did take the time to adjust it properly. In my experience riding the bike and warming it up won't solve the problem, but it's worth a try unless you have and air leak. Share this post Link to post Share on other sites
