B22 Posted June 16, 2015 Report Share Posted June 16, 2015 Hey guys, I'm having an odd issue with my 4mil stock cylinder. Last year it was running fine before it was put away for the winter. It was previously dyno'd with the setup I'm running and ran great for a small motor. At idle and about to 1/2 throttle the right side seems to be loaded up but clears out at higher RPMs. It misses/pops with low revs but cleans with higher RPMs. What I don't understand is that it didn't do this last year before I put it up, and I haven't changed any jets or carb settings. I've soaked both pilots and mains with carb cleaner as well as thoroughly sprayed the rest of the carbs down. To no avail. The carbs I'm running are Keihin PWK 35s. When dyno'd one carb took a 155 main and the other took a 165, which seemed odd at the time to me but I didn't argue with the way it ran afterwards. Compression test was 155 in both sides. I run pump gas with 21cc domes. Does anyone have any clue what this issue could be? I'm at a loss. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted June 16, 2015 Report Share Posted June 16, 2015 Check your reeds, swap your pkug wires, new plugs. Report back Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 Check your reeds, swap your pkug wires, new plugs. Report back I've swapped the wires and it stayed on that side. And put probably 5-6 sets of plugs in it while trying to fix this issue. What am I looking for in the reeds? Broken petals or what Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted June 16, 2015 Report Share Posted June 16, 2015 Yes or frayed tips of pedals. Could try swapping them Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 (edited) Is it true that sometimes broken reeds will cause it to suck air through the exhaust...cause at about 1/4 throttle there's no exhaust coming out of the affected side Edited June 16, 2015 by B22 Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted June 16, 2015 Report Share Posted June 16, 2015 Uhmmmmmmmmmmmmmm Have you done a leak test? Your dyno "guy" don't know shit, two different jet sizes, WTFIH? Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted June 16, 2015 Report Share Posted June 16, 2015 Only time it may suck air through ex is if it isn't sealed well between flange and pipe, reeds have nothing to do with it. Chipped, frayed, broken, not sealing (laying flat) are reed problems. Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 Only time it may suck air through ex is if it isn't sealed well between flange and pipe, reeds have nothing to do with it. Chipped, frayed, broken, not sealing (laying flat) are reed problems. Yeah the 2 different jet sizes confused me as well...anyways, I'll pull the reeds tomorrow and see what's up with them... After checking up on bad reed symptoms I'm almost convinced that's where the issue is. I'll check back tomorrow and update Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 Thanks for the help guys, I'm not the greatest when it comes to troubleshooting these things...I really appreciate it Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted June 16, 2015 Report Share Posted June 16, 2015 IMHO, good reason to do a leakdown test. Go through every aspect of carbs, no matter how insignificant it may seem Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 (edited) IMHO, good reason to do a leakdown test. Go through every aspect of carbs, no matter how insignificant it may seem I'll check reeds first thing tomorrow...if I can't see any issue with them I'll THOROUGHLY check carbs and follow up with a leak down. Thanks for the advice!! Edited June 16, 2015 by B22 Quote Link to comment Share on other sites More sharing options...
sheerider11 Posted June 16, 2015 Report Share Posted June 16, 2015 Do the leak down first. You want to see if the boots are sealed before you pull them. Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted June 16, 2015 Report Share Posted June 16, 2015 cylinders mismatched in some way, one pipe restricted (dent?) , oddity with one carb (bored?) Quote Link to comment Share on other sites More sharing options...
B22 Posted June 16, 2015 Author Report Share Posted June 16, 2015 No dents in the pipe...both carbs were brand new from keihin...all I know is he said it could have been a little difference in the porting in the cylinders..does that sound like it would call for that? They were dune ported by wildcard racing about 2 years ago, I just figured like he said it may have been a little better flow on that side than the other. Not sure though. Quote Link to comment Share on other sites More sharing options...
dankengineering Posted June 16, 2015 Report Share Posted June 16, 2015 I doubt that. I have wildcard cylinders an there identical, also 2yrs old, he wouldnt have mismatched them. How does the tuner know one cylinder needs more fuel then the other? sent from somewhere Quote Link to comment Share on other sites More sharing options...
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