mhoksch Posted March 23, 2012 Report Share Posted March 23, 2012 (edited) My bike is only firing on 1 cylinder @ WOT. 1/2 to 3/4 throttle is runs awesome but as soon as I go WOT it drops 1 cylinder. Did my plug chop thinking maybe it's due to jetting??? FMF Fatty pipes 4mil ported? (at least that's what I was told by the PO) Coolhead (unsure of dome size) 2-1 Intake w/ 38mm PWK -162 main - 60 pilot - Elevation 820 Temp 65F Compression is written next to the plugs in the pic Edited March 23, 2012 by mhoksch Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted March 23, 2012 Report Share Posted March 23, 2012 check leads, caps and coil. i dunno about jetting a single carb setup. Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 23, 2012 Author Report Share Posted March 23, 2012 How do I test the ignition? The probs are only at wot... Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted March 23, 2012 Report Share Posted March 23, 2012 He is talking about checking to make sure the caps, grounds and stuff all seem to be good. If its possible to know what side is cutting out then swap plug wires and see if its now bad on the other side. That would tell you whether the plug wire or cap is bad. The caps go bad frequently and are only a few bux each. Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 23, 2012 Author Report Share Posted March 23, 2012 And something like that could only affect it at high rpms? At low-mid rpms it runs great Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted March 24, 2012 Report Share Posted March 24, 2012 (edited) yep ignition can effect anywhere. especially in a hi load situation. check the plug caps by checking the resistance from on side of the cap to the other, they shouldnt be over 5k ohms, use a mutilmeter. and check the coil with a multimeter, primary and secondary resistance. as said swap leads and see if the prob changes sides. that will tell you which lead side is the prob. Edited March 24, 2012 by dirtydownunder Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 24, 2012 Author Report Share Posted March 24, 2012 thanks for pointing me in the right direction. I wont be home until mon or tues to take a look at it, I've got a multimeter but never really did much as far as electrical diagnostics. Are there any how-to/info threads on testing this stuff? What kind of resistance should I be getting from my coils? Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted March 24, 2012 Report Share Posted March 24, 2012 between 3.5 an 7.2kohms but i would be more concerned with those compression numbers so diffrent might wanna see shape of rings b4 shee goes boom Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 24, 2012 Author Report Share Posted March 24, 2012 between 3.5 an 7.2kohms but i would be more concerned with those compression numbers so diffrent might wanna see shape of rings b4 shee goes boom 10psi is a big difference? I guess I'm still learning about this stuff... I was hoping to be able to ride on this motor thru the summer and then send it to Jeff at F.A.S.T. for a full build this fall. Is it possible to just do a quick top end? ie rings and gaskets w/o honing the cylinders? I'm not trying to be cheap...just don't have much free time and want to ride instead of constantly working on it Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 25, 2012 Author Report Share Posted March 25, 2012 ok, tested coil and wires/caps. It all seems ok. could bad jetting be affecting this? It's not just the rpm's, it's the position of the throttle. Going roughly the same speed, 1/2 throttle is great, pulls super hard. But once I open it to WOT it has no power. I just want to get this going to have some fun this summer until I buy my serval Quote Link to comment Share on other sites More sharing options...
fastbanshee8 Posted March 25, 2012 Report Share Posted March 25, 2012 Check the gap between the pickup coil, and the nubs on the flywheel. It should be .020. Quote Link to comment Share on other sites More sharing options...
jayboy Posted March 26, 2012 Report Share Posted March 26, 2012 I had the same problem on mine... the positive wire for the coil was freyed at the connector...would run at idle and mid, hit wop throttle and not..some spit and sputter or nothing. Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted March 26, 2012 Report Share Posted March 26, 2012 was it fine previously and just started to run like this ?, did you buy it like this or has anything been changed on the bike prior to it running shit WOT ? Quote Link to comment Share on other sites More sharing options...
mhoksch Posted March 26, 2012 Author Report Share Posted March 26, 2012 Ran ok when I bought it. It originally had 32mm round slide Mikunis that were shit. One of the tops was stripped and the slide spun around and would stick open. That's y I picked up the cheap 2-1 w/ 38mm PWK. After putting on the new single carb is when it started running bad at WOT. This is why I'm guessing i has something to do with the jetting. And I know alot of people dont like the 2-1 intake setup. My plan is to ditch it when I build my cub, this is all just a temporary setup to get me thru this summer. P.S. Due to all of the current problems, the cub build may be getting ordered this Friday when I get paid... Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted March 26, 2012 Report Share Posted March 26, 2012 ah ok, i dont have a clue where to start with 2n1 jetting, i heard that the needle plays an important part on a 2n1 setup, do you know what needle it has in it ?. its prolly carb/jet related as you say. hopefully some 2n1 peeps chime in on jetting, Quote Link to comment Share on other sites More sharing options...
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