Jetting for T5's is WAY off....why?

[80overShee]

Ok, this doesn't seem right to me because of all the jetting posts I have read. I have an 87 with the following;

-.080+ fresh bore

-matched/balanced Wiseco rods & pistons

-welded/trued crank

-Boyesen 2-stage reeds

-Toomey T5's

-K&N w/ Pro-Flow

-Air box lid removed

-stock carbs

-stock cages

-stock head

-32:1 Yamalube w/ 94 octane

 

My jetting is set at 280's on the mains and it is STILL rich. I am at 900 ft + sea level and I have seen that everyone has suggested between 300-330s for this setup. What could be the reason for this low of a main? I know its rich because I have done the "ride and pull the choke 1/2 way" and a plug chop after a 6th gear topped out engine kill. The plug is still dark and wet. When I bought the Shee it had the air box lid on, stock pipes, stock crank and was .060+. It had 190's in it when I got it and was running a little lean, but nothing horrible. I went up to 210's and it was just a bit rich. I know bone-stock is supposed to be 220's and this already had the K&N and 2-stage Boyesens. I am pretty sure the carb settings are all completely stock but I know the floats need to be adjusted (leaks from bowl overflow after sitting)

 

Right now it bogs out horribly in 3rd gear from time to time and it feels dead in the top 7/8 of the throttle. My friend with the same setup (.050+ though) and FMF Fattys absolutely smokes me in short races and top end drags. I should atleast be keeping up with him and I would think, beating him in the top end drags.

 

When I pulled the jugs off to do the rebuild last week, I noticed that the ports had been cleaned up a little, doesnt look like any real port work was done, just very half-a$$ polishing on the intake side. The other thing I have noticed is that I have a mild spark, it seems a bit weak, I tested the stator and it is fine. I just ordered a new ignition coil and am looking into a FS CDI (the adjustable timing one). I am just tryin to give as much info as possible to help me fix this problem. Its embarrassing to have a 400ex almost be able to keep up with me! WHERE SHOULD I START?!

 

I want to get some porting done, advance the timing, add a coolhead and some pod filters but I want to fix what wrong first!

[wesw]

i suggested 320 with the needle in the 4th clip. if you have it in teh 5th you will probably need a smaller main cause of the fuel in the mid.

 

might look at your needle and clip

[race-a-holic]

I had the T-5's,Toomey needles,and no air box.I was using a 420 main jet.I was using a dyna ignition also.Some of your problem may be the needle.If the needle is too high it will try to drown out in the mid-range keeping it from revving quickly to the top end.It should have no problem with the 280.Try raising the clip on the needle.This will lower the needle.You should be spanking the 400's.The Dyna ignition has alot hotter spark,and you have to jet it fatter for the added spark.Might also want to consider the clamp-on style K&N filters.This will allow you to get rid of the air box.

[80overShee]

Thanks for the heads up on the clip. I was already planning on tearing the carbs down tomorrow. I have the Vito's needles (repacked Dynojet needles) and was going to throw those in anyway. I think my weak spark has a lot to do with the low mains, not burning all the fuel up so it looks rich...I'll know more tomorrow. Thanks

[bigboybanshee]

I think my weak spark has a lot to do with the low mains, not burning all the fuel up so it looks rich...

381728[/snapback]

 

That could definitely be a factor...

[dave95.1]

If you are leaking fuel from your overflow you need to fix that first. If your bowl is too full you will suck way too much fuel into the motor. Until that is fixed you are wasting your time messing with needles and jets.

[80overShee]

If you are leaking fuel from your overflow you need to fix that first.  If your bowl is too full you will suck way too much fuel into the motor.  Until that is fixed you are wasting your time messing with needles and jets.

382554[/snapback]

 

 

I adjusted the floats and cleaned the carbs out very very well. I am sure nothing it sticking or adjusted incorrectly now but the jettin situation hasnt changed. I am STILL rich with 280s. I havent checked the needle yet but if it were off by 2 positions could it really have that much of an effect on the mains? I just got it all back together after I thought I had a huge problem, ended up I completely destroyed a reed (only 2 week old Boyesens too) but its back to same ol' same ol' dead acceleration in the low end and very top end. My friends Shee with Fatty's is stomping me and its pissin me off!