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How Much Will Porting Make Ur Jetting Go ^^


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I also have a 12 port motor from Jim and am running stock carbs (they suck I know). I have 25 pilots, as the bike wouldn't idle with anything larger and it constantly wanted to load up and blubber when trying to putt around. The needle is a dynojet needle in the 3rd notch from the top. Mains are 370. My problem is that when in fifth or sixth just cruising along at say 1/3 throttle and nail the throttle, it takes forever for the motor to come on the pipe. I'm thinking that it is running too rich in the midrange and can't pull itself on the pipe. My reasoning for this is, it was worse when the clip was in second notch from bottom. I know, I know, raise the f#@&ing clip idiot! Heres the clincher though, my friend has the exact same port job with the exact same pipes,(FMF Fatties) andexact same gearing, he was so frustrated that he stuck his stock needles back in and its still too rich. So where o where do I go from here? It runs fine when putting around in 1-3 and nail it, it will jump on the pipe rather quickly and is a load of fun. It runs like a scalded hog when its on the pipe and it will keep scalding him if you're raping it through the gears, its just that the roll on power sucks balls. I was hoping not to resort to spending another $500-$600 on gdamn carbs already. Someone help.

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well, it all depends on how much porting, but easily 2 or 3 sizes, and often more than that, like maybe 5, because your flowing much more air in and out.

Best thing to do is throw in mains that are a couple sizes bigger and run a plug check. There is no way any of us are going to be able to tell you what to use. Not only are all shee's a little different, but porting amounts are different, flow air different, and there are so many variables that it's impossible.

 

You are going to have to run a plug check and perform a little trial & error to get it right.

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yeah, just start high, and go from there. also i have a Q, right now im running 360 mains @ sealevel, needle in 3rd or 4th position (i forget, 4th i think), i have t5s, milled head, carbon techs on ported cages, 1/2" reed spacers, k&n clamp ons, boost bottle (some say doesnt work, but i took it off and noticed a loss in bottom end, so im leavin it on) and lightly polished ports. i want to get a stage 4 port job, but am curious, where do u find 400+ main jets??? cause if im 360 now, then i just might be 390-400 right? just curious cause i've never seen anything higher than 390..

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I have Jim's 12 port also and i'm running a 32.5 pilot and I can idle All day and all night...So long as the choke is not pulled...now if only I could get the bike to run at WOT I would feel young again :dance:

 

I have tried 340-380 mains and toomy needles in various positions with no luck (exact same problem)...but I can idle all damn day with 32.5s

 

I think you need larger Pilots...Of course I went the new carb-air filter-intake-reed route can'twait to see if I can finaly go WOT again...

Edited by Justintoxicated
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