PLEASE HELP WITH JETTING?

[KBaca]

Ok here is the problem that I am having I have a 99 shee with toomey t6 pipes, toomey 2 into 1 air filter, bored 40 over boysen reeds with stock cage and a 4 degree key. we are at just under 5000 feet. I have kept on going up in main jet size and am not at a 380 main jet needle is aftermarket with 6 positions. I have it set 3rd from the bottom. 25 pilot jets. Pulled plugs after wide open throttle run and plugs are almost white. Any suggustion on where i should go from here thanks in advance.

[C&B]

Ok here is the problem that I am having I have a 99 shee with toomey t6 pipes, toomey 2 into 1 air filter, bored 40 over boysen reeds with stock cage and a 4 degree key. we are at just under 5000 feet. I have kept on going up in main jet size and am not at a 380 main jet needle is aftermarket with 6 positions. I have it set 3rd from the bottom. 25 pilot jets. Pulled plugs after wide open throttle run and plugs are almost white. Any suggustion on where i should go from here thanks in advance.

Fire it up let it idle. You have an air leak somewhere. spray carb cleaner/ eather around the cyls carbs. If it doesnt rev up round the base of the cyl, or carbs, do a leak down. Let us know.

[KBaca]

I sprayed all around and found no air leaks, I do not have the tools to do leak down test but it is a fresh rebuild so is it possible to have a leak somewhere else???

[KBaca]

One other thing this is the 2nd rebuild in a week, the first time I went to wot with the last rebuild it burned a hole in the top of the left piston and melted the plug on the right with 270 mains so now I started with 360s to be on the rich side and still found it running lean.

[dragbanshee]

One other thing this is the 2nd rebuild in a week, the first time I went to wot with the last rebuild it burned a hole in the top of the left piston and melted the plug on the right with 270 mains so now I started with 360s to be on the rich side and still found it running lean.

 

Are you doing a plug chop or just pulling the plugand checking it, alot of times one wot run wont turn the plug colors, Ive tried that and would of thought it was lean also untill I found out about plug chopping. Since your on your 2nd rebuild you better get more input from others on here, good luck!

[Wildcardracing]

Sounds to me like you have an air leak in your crank seals or between your cases, you should have to run no more than 280 mains with that setup at your altitude.

[rubberneck]

Did you check your float height? Also, pull the petcock out of the tank and make sure the screens are clean. Are you running inline fuel filters? If you are remove them. if you dont have an air leak, then somehow the bike is being starved for fuel. I had a similar set up and ran 290 mains at sealevel. At 5k feet something deff seems fishy.

[KBaca]

Is there any other way to find a leak between the case halves or crank seals besides doint a leak down test? Thanks for all the input it has helped alot. I checked my transmission fluid and the level has not changed. I heard that if the case halves are leaking that it would draw the trans oil into the crankcase?

[KBaca]

Is it possible that I went too high in main jet size to start and the carbs are not able to keep up with that much fuel, because at wot in 1st through 4th the bike bogs but on the top end in 6th wot it seems to run out of fuel. if I drop to maybe a 310 main to where it is not using as much fuel before max rpm maybe the carbs will be able to keep up. Its just me thinking outloud let me know if this could be possible?????

[dajogejr]

That is WAY more than enough jet for that bike, especially at 5000 feet.

You have an air leak. Buy a leak down test kit to confirm it...

 

Remove the top end, replace the crank seals and re seal the cases, use rtv thin on the reed cage gaskets.

 

Going from 270 which is about what it should be to 380 mains...and it's still lean. You have an air leak. Period.

You'll be rebuilding it again in another week if you keep riding it.

 

It's not the jetting....guarantee. Your bike will flow any size jet you throw in it. 270 to 380 is a DRASTIC change...you have other issues.

 

Bob @ R&B Racing in Michigan sells a nice leak down tester...he normally has them up on ebay, but I don't see one now. Tell him I sent you.

 

517-388-3662

[KBaca]

I dropped my needle down one position and installed a 290 main jet bike is running great and no more power loss on top end. I also removed in line filter performed a plug chop and plugs are looking perfect. I guess it was a fuel delivery problem after all. Thanks for all the help!!!!!