adeezy9183 Posted May 20, 2004 Report Share Posted May 20, 2004 yea i just rebuilt my top end due to piston detonation and the guys on here say that it was caused due to a lean mizture. the jets i had in the car before were a 172 and a 48 and i replaced the 172 with a 185 and left the 48 alone. i was wondering if this would be enough to fix the problem. also, my carb doesn't idle for nothing. before the piston got a hole burnt in it, it didn't idle neither. i was wondering what caused this because i have tried turning the idle screw and it seems to have no affect on it. pleez help guys. thanks a lot. andrew Quote Link to comment Share on other sites More sharing options...
J..J. Posted May 20, 2004 Report Share Posted May 20, 2004 Looking at your other posts, not ALL the guys on here agree with the lean mixture theory, some of us are leaning towards detonation. Are you still running 15cc domes? If you are, what is the compression with the new pistons fitted? Sort that out first and then come back to the carb. Quote Link to comment Share on other sites More sharing options...
sredish Posted May 20, 2004 Report Share Posted May 20, 2004 You need to run a compression check. If it's over 155 or 160 you need to run a race fuel mixture, and how much fuel depends on how high the compression is. With 20cc domes, you could be close and be on either side of the line, if you have 15cc domes, guaranteed you'll need some race fuel, unless your at 5k or 6k feet. 185 main is a decent average. that should get you close for a good start. honestly, if it was mine, I'd start at 200, so I know that I've got it somewhat rich, 185 could be good, or a little lean, or a little rich. Your 48 pilot is not bad, you could try a 50 and see if that help some. You should probably run a leakdown test before you run it also. That way you've eliminated an air leak inside the case, which will help you after you get her up and going if you come into lean mixture / detonation problems. Plus, it's easier to do out of the frame. Let us know if you need something, or if you want to run your compression amount by us. Keep us posted. Scott Quote Link to comment Share on other sites More sharing options...
adeezy9183 Posted May 24, 2004 Author Report Share Posted May 24, 2004 i just rode the banshee with the fresh top end rebuild and WOW is all i can say. before it was resleeved to standard and now it's bored .60 over with a 185 jet in it. i still have the 48 pilot and i may change that to a 50 and possibly move up some clips on the needle. which way do i go on the clips of the needle to richen it? i am not quite at 1000 sea level. what would you guys recommend, because i know it's WAY better to be rich than lean. Quote Link to comment Share on other sites More sharing options...
adeezy9183 Posted May 24, 2004 Author Report Share Posted May 24, 2004 sredish, i see that you have the same carb setup as me and we're about the same elevation. i may put a bigger main in because i see you have a 230 in there. what pipes are you running? i have fmf fattys. i'll get a 200, 210, 220 and 230 and see how that does. should i just swap out the 48 pilot and put a 50? what is your opinion? thanks Quote Link to comment Share on other sites More sharing options...
adeezy9183 Posted May 24, 2004 Author Report Share Posted May 24, 2004 hey guys, i just found out today that my elevation is 457 to be exact, so hopefully you guys can work from that. i need to know exactly what jets i need to run, because i want this thing to run the way it should. just to be safe, i'd like to run her a little on the rich side. thanks guys. Quote Link to comment Share on other sites More sharing options...
sredish Posted May 24, 2004 Report Share Posted May 24, 2004 Hey man, was gone for the weekend. Keep in mind that not all banshees jet the same. While I'm running a 230, you might be at 190, or 210, or whatever. Your plug will tell you where it needs to be. I'd concentrate on getting the main jet set right, then move on to the pilot later. One at a time. If you move both and it runs funny, you might have trouble figuring out what caused what. Now, regarding the main. You might throw in a 210 and see what color your plugs are. If they're black an oily wet, then you need to go down one size and try again. Once you get the main where you want it, then play with the pilot. If your at 48 and it doesn't hesitate, then your good, if it hesitates then goes, you might move up to a 50. I'd suggest putting your needle in the 4th clip down from the top/blunt end. Down (away from the blunt end) is richer and up (towards the blunt end) is leaner. Just remember, take it slow and be patient, and your plugs will tell you everything. For more info on reading plugs, BenBB's jetting FAQ is a good place to look. Good luck. Later, Scott Quote Link to comment Share on other sites More sharing options...
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