Hi All,

Just purchased a used 2004 Kasea Skyhawk 250cc. I am getting it preped to run out in the desert this weekend. What should the plugs be gapped at? And what oil viscosity should be used? I get hesitation in the middle-high revs of 2nd and 3rd gear and I think the spark is blowing out. Currently the NGK's are at standard gap from the manufacturer.
My outside ambient temp is 40-80F. Searched the internet for hours, couldn't find the info.

Thanks,

Scott

 

Welcome to the forum Struv !

I would guess the plug gap is in the .028-.032 range. I would also think your Kasea suffers from extremely lean jetting. Every Chinese atv and most of the air cooled thumpers from Japan Ive worked on are jetted extremely lean to pass EPA/CARB tests. Thats where the tough part comes in..You will need to match up your jets with either Keihin (spelling?) or Mikuni. The other anternative is if you know someone who is a machinist...the stock jets can be drilled out to make them a little richer. There are number 60-80 drill sets that are in the .016 to .039 dias..You will need this set to make the pilot jet bigger. This helps with start up and warming up..No more cough and die syndrome. Making the Main jet bigger will most likell use a drill from the #50-60 range... As for oil I use Valvoline 10w-40 in all my air cooled thumpers, From Japan and China. No clutch slipping problems in any of them from using "car oil". Ive done this for 3 yrs with my Chinese thumpeers and a couple of decades on my air cooled Honda thumpers.

 

Mywifesquad,

Thanks for the welcome and the great information you provided! I'll work on getting the carbs to run a little richer and that oil changed.

Regards,

Scott

 

Your welcome Struv. Heres a little more info for the jets if you decide to drill them out. The size on the side of the jet is the size of the hole in the jet in metric. A 105 jet is 1.05 millimeters(mm's). a mm's is .03937. 1.05 x .03937 is .041. That is the size of the hole in a 105 jet. For jets under 100.. a 95 is .95 x.03937

 

Thanks, I'll keep those additional measurements handy.
Good news on the spark plug gapping. Went to .030 and it took away all the hesitation.
Well done Mywifesquad!