william r Posted July 11, 2008 Report Share Posted July 11, 2008 so i have a heavily modded shee with fmf fatty pipes, fmf silencers, k&n filter, cool head with 21cc domes, standard plugs, 4 degree key, vito's pwer pistons, 2 stage reeds, ported reed cages, and trail ported cylinders. the problem i am having is at idle and just off idle. at idle it is running super rich. so much that my idle screws are almost all the way in. it is not fouling plugs, but breaks up badly when at part throttle. yes i know a shee is supose to be driven wide open, but i do like to slow down and cruiseevery now and then. the pilots are stock 25, the needle is stock and middle, and the main is a 330. when pulling the chock half way the wide open is a little sluggish. so as far as i can tell with the feeling and plugs(killing after wot running for a few min) the mains are perfect. they might be a little rich if nothing else. 1/2 throttle is awsome too, no real bogging. so only at idle and in the pilot circut. so the smallest pilot i found has been 25 which is stock and thats what i have. so how do i correct this. does every one with ported cylinders have the same problem. all and all the bike is awsome. it lifts the wheels in 1-2-3 when shifting. i dont get traction, but it sure is fun to super powerslide turns. also my budies hate me. they are always eatting my dust. also i have a spare engine i just built, with near the same set-up. the only exception is aftermarket stock style reed cages, and a 4mm stroker crank. would the jetting be totaly differnt for that engine? Quote Link to comment Share on other sites More sharing options...
Erwin8r Posted July 11, 2008 Report Share Posted July 11, 2008 so i have a heavily modded shee with fmf fatty pipes, fmf silencers, k&n filter, cool head with 21cc domes, standard plugs, 4 degree key, vito's pwer pistons, 2 stage reeds, ported reed cages, and trail ported cylinders. the problem i am having is at idle and just off idle. at idle it is running super rich. so much that my idle screws are almost all the way in. it is not fouling plugs, but breaks up badly when at part throttle. yes i know a shee is supose to be driven wide open, but i do like to slow down and cruiseevery now and then. the pilots are stock 25, the needle is stock and middle, and the main is a 330. when pulling the chock half way the wide open is a little sluggish. so as far as i can tell with the feeling and plugs(killing after wot running for a few min) the mains are perfect. they might be a little rich if nothing else. 1/2 throttle is awsome too, no real bogging. so only at idle and in the pilot circut. so the smallest pilot i found has been 25 which is stock and thats what i have. so how do i correct this. does every one with ported cylinders have the same problem. all and all the bike is awsome. it lifts the wheels in 1-2-3 when shifting. i dont get traction, but it sure is fun to super powerslide turns. also my budies hate me. they are always eatting my dust. also i have a spare engine i just built, with near the same set-up. the only exception is aftermarket stock style reed cages, and a 4mm stroker crank. would the jetting be totaly differnt for that engine? The main seems a little fat, and your pilot seems a little lean... I'd try stepping down to 310 or 300, and step up to a 27.5 pilot. You have enough mods that it might be a good idea to setp up to a nice set of Keihins or Mikunis... A set of Keihins would be a lot easier to tune and give you added performance. Quote Link to comment Share on other sites More sharing options...
brugal Posted July 11, 2008 Report Share Posted July 11, 2008 Adjust the air screws. Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted July 11, 2008 Report Share Posted July 11, 2008 If you're rich off idle then turning your air screws in is only worsening the problem. On stock carbs in is rich out is lean. Good rule of thumb is if your air screws are behind the slide turn them in to richen the mixture, if they are in front of the slide turn them out to richen the mixture. One other thing to consider if it's bogging and choppy in the bottom end is your carb sync, make sure youre slides are set at the same height and open at precisely the same time. Do a search on here and learn to do a plug chop to dial your jetting in. As for the 4mill, it will depend some on your port durations. But, If it has all the same bolt on mods it may require a little more jet, but should be fairly close to the same. Quote Link to comment Share on other sites More sharing options...
william r Posted July 12, 2008 Author Report Share Posted July 12, 2008 my air screws are almost all the way out. right now they are at 2.5 out, which is max. do you all think my mains may a bit too fat causing too much of a low end problem? i will start with the mains and see what happens. if it gets better i will try my 27 pilots Quote Link to comment Share on other sites More sharing options...
Wildcardracing Posted July 12, 2008 Report Share Posted July 12, 2008 Like I said in my earlier post, do a search and learn how to do a plug chop!!! dial your mains in first, then your needle position and then your pilot. 330 seems a bit large on the mains for fmf's with a trail port. Quote Link to comment Share on other sites More sharing options...
william r Posted July 12, 2008 Author Report Share Posted July 12, 2008 Like I said in my earlier post, do a search and learn how to do a plug chop!!! dial your mains in first, then your needle position and then your pilot. 330 seems a bit large on the mains for fmf's with a trail port. alrighty. ill try a 310 and see what happens. although it feels really great on wot/ even with choke out Quote Link to comment Share on other sites More sharing options...
william r Posted July 12, 2008 Author Report Share Posted July 12, 2008 so i put the 310 mains in it, and had to readjust the air screws. they are now 1.5 out and withthe 310 its alot better. there is still a little problem with it though. idle is great, mid is great, but when comming out of a turn there is a little bogg right b4 the engine picks up speed. although i herd this is completely normal for a 2 stroke. Quote Link to comment Share on other sites More sharing options...
sandman Posted July 12, 2008 Report Share Posted July 12, 2008 so i put the 310 mains in it, and had to readjust the air screws. they are now 1.5 out and withthe 310 its alot better. there is still a little problem with it though. idle is great, mid is great, but when comming out of a turn there is a little bogg right b4 the engine picks up speed. although i herd this is completely normal for a 2 stroke. When I had a clean up port & fmf pipes I was running toomey needles which seemed to work pretty well. I would not advise a stock needle with your mods. Just my .02 Quote Link to comment Share on other sites More sharing options...
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