rejetting a 4mil stroker with stock carbs

[oih8u2]

hello people. i am looking for some help to properly setup machine. i've got an 03 banshee with pro curcuit pipes and silencers, 4mil long rod crankshaft, .040" over 795 wiseco pistons, a spacer plate, k&n pod air filters and stock 26mm carbs. no porting has been done. elevation is around 800 feet. current carb setup is as follows: 27.5 pilot jet, air screw 1.0 turn out, stock air jet, stock needle on 3rd position(center), and 440 mains. to me the midrange feels rich but the top end still seems lean. ive looked up other posts on this site for help, but my searches come up with posts where people have gone to other carbs or have done alot of porting. any help to get in the ballpark of where this should be jetted would be greatly appreciated.

[oih8u2]

i forgot to add that i have boyseen reeds installed also.

i'm surprised to see that no one has replied that has similar setup machines to say which way I would have to go to jet my quad.

[pr0blumz]

hello people. i am looking for some help to properly setup machine. i've got an 03 banshee with pro curcuit pipes and silencers, 4mil long rod crankshaft, .040" over 795 wiseco pistons, a spacer plate, k&n pod air filters and stock 26mm carbs. no porting has been done. elevation is around 800 feet. current carb setup is as follows: 27.5 pilot jet, air screw 1.0 turn out, stock air jet, stock needle on 3rd position(center), and 440 mains. to me the midrange feels rich but the top end still seems lean. ive looked up other posts on this site for help, but my searches come up with posts where people have gone to other carbs or have done alot of porting. any help to get in the ballpark of where this should be jetted would be greatly appreciated.

 

440 is way too big, try a 300 main and take it from there. What's your elevation? Did you snyc the carbs?

Edited August 20, 2009 by pr0blumz

[oih8u2]

the carbs are synchronized. again, elevation is around 800 feet above sea level. I had started off at 320 mains after i removed the air box and added the stoker crank, and just went up in mains from there to where i am now and the porcelain on the plugs still looks grayish.

Edited August 20, 2009 by oih8u2

[captainhowdie]

I may be wrong, but i thought you had to have cylinders ported for the 4mill.

[KEVSWS6]

You don't have to port it to use a 4 mil crank. It will drop right in and run just fine.

 

Get a leak down tester and check for air leaks.

I would guess your mains should be 300 to 320. Stock needle middle clip, the pilot and air screw are correct.

[robert0762]

I have been trying to figure out my jetting for a long time now. I was always rich even when i dropped to a 270 so I leaned the needle one clip went back to a 320 and now she hauls ass like never before. Still got to do a plug chop though . I'll be doing that this weekend

Edited August 21, 2009 by robert0762

[decon]

440 mains too big on a stroker? that sounds odd. or is it the fact that he doesnt have any porting done? My buddy is running a 440 main in his banshee and all he has is a dune port and lrds with stock carbs and his bike runs pretty okay... well sometimes... not trying to thread jack or anything just putting in my .2 cents

[oih8u2]

hey guys. i got a leak down test done and passed. 6 psi for 30 minutes. id say thats good. here are the specs to where i've stopped tuning the stock carb to: 310 mains, 35 pilots, needle on 4th clip down from the top (rich), air screw 1.0 turn out. its still a little bubbly on the mid range but at least its not backfiring anymore. but thats as much as im gonna tune it this year unless i start setting it up for ice racing again.

later.

Edited December 14, 2009 by oih8u2

[AKheathen]

oh, man, how did i miss this? 440 is not far fetched at all.... i would've done a plug chop and make sure. the fact that you are using a spacer plate on the bottom and not domes or a head spacer will put your port timings out from the pro-circuits, and it could sound lean. i would first change that this winter, and pring your peak rpm timings back down. either get a coolhead and domes, or track down a head spacer...... go from there with your jetting, and once you get the wot sounding right, do a proper plug chop and then mess with the needles to get it tuned. porting will greatly help, however.