ICULOKN Posted December 2, 2008 Report Share Posted December 2, 2008 Guys, Need some help here. Setup: 4mm Crank 65mm Bore Weisco Pistons Shaved Stock Head .020 Ported Jugs T5's K&N Pods V-Force Reeds NGK BR8ES Gapped at .035 Stock Carbs No TORS K&N Jet Kit with Needles on 4th Clip, Air Fuel Turned out 2.5, and 340 mains Stock Electronics Sunoco 112 mixed at 40 to 1 The Bike Starts Great Idles Great Part Throttle Runs Geat in any gear Trying to go to half or full throttle bike lieks to break up and die down I have read some posts and wonder if I may have a stator problem or jetting problem? Should I try some smaller jets first? Any Thoughts on what to check?? Quote Link to comment Share on other sites More sharing options...
brian Posted December 2, 2008 Report Share Posted December 2, 2008 Thats a pretty big plug gap. A little more info please. What jets do you have in now ? What is your temp and elevation ? Was the bike running fine with this setup or did you change some things and are now getting this problem ? Quote Link to comment Share on other sites More sharing options...
ICULOKN Posted December 2, 2008 Author Report Share Posted December 2, 2008 Thats a pretty big plug gap. A little more info please. What jets do you have in now ? What is your temp and elevation ? Was the bike running fine with this setup or did you change some things and are now getting this problem ? This is a new setup Richmond,va not to sure of elevation? 340 main jets 52 degf outside Whats normal plug gap? Quote Link to comment Share on other sites More sharing options...
brian Posted December 2, 2008 Report Share Posted December 2, 2008 Factory calls for .028-.031. With higher compression you need to run a little bit closer. I have seen people run as low as .015. I run .020 on my 4mil with 170psi compression. Have you done a leakdown test ? Check for air leaks. Sounds like you may be a little leaning out on top. Breaks up and noses over on power. You are at about sea level. Alot of air and it is getting cooler. Try jetting up your mains a couple sizes. (360-370) Do a plug chop and see what the plugs look like. Quote Link to comment Share on other sites More sharing options...
ICULOKN Posted December 2, 2008 Author Report Share Posted December 2, 2008 It feels to me way to rich, even from a dead start it wont take full throttle under load. I will rev up fine, just not while trying to move the bike. Think the neddle clip needs to be changed? I cant get it to go good enough for a plug check. Quote Link to comment Share on other sites More sharing options...
brian Posted December 2, 2008 Report Share Posted December 2, 2008 Ok, you said break up tho. If it is bogging then it is too rich. I cant believe it is that rich with that setup and sea level ???? Is the needle on the 4th clip position from the blunt end or the point end ? Quote Link to comment Share on other sites More sharing options...
ICULOKN Posted December 2, 2008 Author Report Share Posted December 2, 2008 (edited) Ok, you said break up tho. If it is bogging then it is too rich. I cant believe it is that rich with that setup and sea level ???? Is the needle on the 4th clip position from the blunt end or the point end ? I Can feather the gas to make it go, just dosent seem like enough air or something. Guess its to much fuel or to quick of fuel. But once I get it going it breaks up when I try to give it full gas. I guess its bogging back out. Its on the 4th clip down from the top heading towards the needle. I think I may try the 3rd to lean it up some right? On my old motor I always ran the same setup with 290 jets. It wasnt a 4mm and had a stock head though. Never had a problem. These are a used set of reeds, Dont see any damage on them but what does a bad set of reeds do? Edited December 2, 2008 by ICULOKN Quote Link to comment Share on other sites More sharing options...
2001Stroker Posted December 2, 2008 Report Share Posted December 2, 2008 I also had that problem a couple times. First time, the carbs were outta sync. The other time, the secondary jet was clogged on the left carb. A torch tip cleaner works good for cleaning trash out of jets. Quote Link to comment Share on other sites More sharing options...
brian Posted December 3, 2008 Report Share Posted December 3, 2008 Its on the 4th clip down from the top heading towards the needle. I think I may try the 3rd to lean it up some right? yes On my old motor I always ran the same setup with 290 jets. It wasnt a 4mm and had a stock head though. Never had a problem. Exact same cylinders/porting ? Were those cylinders ported for 4mil stroke ? These are a used set of reeds, Dont see any damage on them but what does a bad set of reeds do? Unless you have big gaps between reeds and cage or chipped/broken reeds they are probably good. Quote Link to comment Share on other sites More sharing options...
ICULOKN Posted December 3, 2008 Author Report Share Posted December 3, 2008 yes Exact same cylinders/porting ? Were those cylinders ported for 4mil stroke ? Unless you have big gaps between reeds and cage or chipped/broken reeds they are probably good. No they are not the same bottom end or top end. I changed the clip position and it seemed worse. I didnt ride it down the rode yet though. I think I may try my 290 jets and see where I am, I dont know. Quote Link to comment Share on other sites More sharing options...
BellicoseBanshee Posted December 3, 2008 Report Share Posted December 3, 2008 Make sure the pickup coil gap is within limits. An excessive gap can cause a break-up on the top. Quote Link to comment Share on other sites More sharing options...
ICULOKN Posted December 3, 2008 Author Report Share Posted December 3, 2008 I think I found the problem.... 115lbs on the left and 95lbs on the right... Way to low for the setup. Jugs are on the way to FAST as we speak! Quote Link to comment Share on other sites More sharing options...
Badapwned Posted December 4, 2008 Report Share Posted December 4, 2008 Factory calls for .028-.031.With higher compression you need to run a little bit closer. I have seen people run as low as .015. I run .020 on my 4mil with 170psi compression. Have you done a leakdown test ? Check for air leaks. Sounds like you may be a little leaning out on top. Breaks up and noses over on power. You are at about sea level. Alot of air and it is getting cooler. Try jetting up your mains a couple sizes. (360-370) Do a plug chop and see what the plugs look like. I don't mean to steal anyone's thread but I want to confirm something...... If it breaks up at 3/4 throttle its a lean condition? I get engine break up right before the powerband. Before the break up and during the powerband it runs great.....its just at that certain rpm range before the power band it starts to break up. What I have tried is move the needle clip to the top position. Thought maybe it was trying to clear itself out, it didnt change anything. I will move it to the bottom and see if that helps. As long as your saying a break up is from a lean condition. Is this correct? Quote Link to comment Share on other sites More sharing options...
LS1Inferno Posted December 4, 2008 Report Share Posted December 4, 2008 I don't mean to steal anyone's thread but I want to confirm something...... If it breaks up at 3/4 throttle its a lean condition? I get engine break up right before the powerband. Before the break up and during the powerband it runs great.....its just at that certain rpm range before the power band it starts to break up. What I have tried is move the needle clip to the top position. Thought maybe it was trying to clear itself out, it didnt change anything. I will move it to the bottom and see if that helps. As long as your saying a break up is from a lean condition. Is this correct? breaking up can be either way. either too rich or wayyyy to lean. at 3/4 just typically means its a needle postion problem. but the main will also effect the jetting at that postion. whats you main, and your entire setup? Quote Link to comment Share on other sites More sharing options...
Badapwned Posted December 4, 2008 Report Share Posted December 4, 2008 breaking up can be either way. either too rich or wayyyy to lean. at 3/4 just typically means its a needle postion problem. but the main will also effect the jetting at that postion. whats you main, and your entire setup? Pods with outerwears Boyseen reeds FMF fattys port and polish on the jugs +4 timing 380 Main, 35 pilot. Like I said, the bike runs great before the break up and after the break up. I thought maybe the bike was trying to clear itself out before it got into the powerband, but I moved the c clip to the top position and didn't change anything. I am thinking that the bike wants more fuel. Quote Link to comment Share on other sites More sharing options...
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