Once upon a time I was going through some shit so I built a moped cause it made me feel good. Well, here is where I have come. And yes before the sharks come to feast, I am a noob! So I built this E50 magnum that has a non ported non case matched k star with one base and one head gasket, stock clutch, vm20 with MLM intake and foam/mesh air filter, Simo pipe, 16x40 gearing, timing is 16 degrees from TDC.
I know that the kstar with a simo pipe isn't very wise…. And I wasn't wise when i paid for it because I didn't know any better than a 5 star rating on treats and liking the way it looked.
So now, I am having a horrible time tuning it. It is constantly 4 stroking as soon as I hit the throttle. I have ran through almost every jet size from 185 down to 115 mains and 17.5-22.5 for idle. The thing idles ok but boggs and four strokes as soon as the throttle is touched, I did get it to break 30 mph with what I believe was a 140 main jet but as soon as I added my heavy chain in my bag the thing would not move and just 4 stroke.
My concern is:
-Is there some major problem I am missing? I have checked for leaks. Could it be some leak the bottom end of the E50?
-Should I try a different needle jet? The bike idles fine and the main jet was small enough that the motor cut when I went straight into full throttle. The issue is constant 4 stroking anywhere in the middle throttle range that worsens with load
-If I get a low end pipe will this problem will go away??
A couple side notes:
The motor did soft seize on me once.
The bike 4 strokes at more throttle positions as you increase the load. When its on its stand, it 4 strokes less.
I am 230lbs
I have been trying to figure this out for a while and have been getting frustrated so I appreciate all the feedback.