New pipe and Tboost

[MeanMax]

I have recently installed a Marks performance full exhaust and have a K&N filter with the "T" on the air box spaced about a 1/4 of an inch and im useing the factory jets. my problem is that when i have my tboost on and do a quick start (launches over 4000 rpm) it falls on its face and allmost dies. then about 2 seconds later it rockets off like normal. Same thing happens when the throttle is applied at any speed over 4000rpm. this has only started sence i installed the new exhaust. with the Tboost off it performs perfectly and doesnt miss a beat when it hits the factory 6000rpm vboost. could my stock jetting cause a stumble in the mid range with the boost on but not in the top end? the carbs were cleaned this winter and i have just synced them today. any thoughts/ideas would be appreciated.
Zak

 

[lankeeyankee]

Yes
You have a lean condition.
If you dont want to buy a jet kit, try the following:
First put the y back to stock postion see if this helps the stumble or makes it worse.

What is going on is seems like the slides arent lifting quick enough.
If I were you I would buy some spacers (small shims / washers and raise the needles start off about .030 (must have a micrometer)
Also tie about 3 coils off on the diaphram springs.

Or just buy a jet kit. (depending on your tuning ability)
:cheers:
There is plenty of expierence and knowledge here to get you back screaming with no flat spots hang in there.

 

[maleko89]

+1 to what Lankee said. Tboost decreases intake velocity and shimming your air box lid makes it worse. Insure the Tboost is installed correctly and a short circuit doesn't exist. Put your lid to stock position and see if that helps. Otherwise you'll probably have to shim your needles to compensate.

 

[MeanMax]

i should have guessed it. im an automotive technician so tuning is no problem. only thing is the last car with carbs was built probably 10 years before i was a tech so its a new skill to learn. Are dynojet kits any good or would you reccomend somthing else? Thank you guys for the help.

 

[maleko89]

I don't think I would try DJ jet kits with stock air box/carbs. Try shimming your needles with little washers first. If you're really gung-ho in getting tboost to work with a stock bike you may have to get some DJ stage 1 needles. http://www.dynojet.com/pdf/4116.pdf Part number is DNT306 and can be ordered through this DJ website.

With stock bike stock vboost works best. Bike feels stronger with tboost at midrange because it accelerates fast with smaller throttle angles. When comparing stock WOT with Tboost WOT stock wins. You loose torque from 3-6000 rpms.

 

[MeanMax]

I see, its more of a "seat of the pants" thing rather than a performance upgrade. im going to leave that switch off for now. its more fun to wick it up anyway. thanks for the info, i greatly appreciate your help :thumbs up:

 

[maleko89]

You're welcome, anytime!