I'm putting a K&N filter and a full Big Gun exhaust on my son's 04 TRX 90, the boy's ready for a little more than the stocks' puttin out. Should be here monday or tues. Question is, anybody upgrade this bike yet, and how'd your jetting experience go? Any recomendations that could save some trial and error?
Big Guns web site suggested moving the needle, but with the K&N jetting will be needed. Thanks KB
Full Version: Jetting For A Trx90 Upgrade
For my son dinli 90 i put on a pipe and k&n, had the main jet drilled out to a 98( dealer wanted a 100), you need to go up 1 or 2 sizes on the main jet or get drilled and up one clip on the needle jet. If it pops on decelaration then you need to go up one on the piolet jet, and do a plug check. hope this helps 
| QUOTE (8sumsand2 @ Feb 6 2005, 10:09 AM) |
| If it pops on decelaration then you need to go up one on the pilot jet, and do a plug check. hope this helps |
That's interesting- hadn't heard that before. Are you talking 4-stroke? If so, I'll have to try that on my ATC350X. It makes all kinds of racket when you're decelerating...
When i added the k&n to the 450(Dr D,needle jet up 2clips,zip-tye idel screw at 1 1/4s turns) it poped on deceleration.When i went up 1 on the piolet jet,the fuel/ air mixture is equel when the throttle returns to closed.Theres no excess fuel to pre denat in the carb.NOW i know im missing something or its bin a month or two since i read the info from the zip-tye that turned that light bulb on but PLEASE any one confer or deny cuz i know immmmmm missen sumtin 
.HEY 24V what ya think?
.HEY 24V what ya think?
Thanks for your input guys. Guess not to many mini upgrades on the board. When I find the combo that works, I'll let ya know. 
| QUOTE (8sumsand2 @ Feb 6 2005, 09:03 PM) |
| When i added the k&n to the 450(Dr D,needle jet up 2clips,zip-tye idel screw at 1 1/4s turns) it poped on deceleration.When i went up 1 on the piolet jet,the fuel/ air mixture is equel when the throttle returns to closed.Theres no excess fuel to pre denat in the carb.NOW i know im missing something or its bin a month or two since i read the info from the zip-tye that turned that light bulb on but PLEASE any one confer or deny cuz i know immmmmm missen sumtin .HEY 24V what ya think? |
If you are running a k&n with no lid, and a pipe, you should be somewhere near the following.
172-175 main jet
45-48 pilot jey
4th clip on ncvq needle(yz dirtbike needle)
1.5-2.5 turns on the air screw
Also, be careful with that zip type screw. I went back to stock because mine fell out.
| QUOTE (az350x @ Feb 6 2005, 01:17 PM) | ||
That's interesting- hadn't heard that before. Are you talking 4-stroke? If so, I'll have to try that on my ATC350X. It makes all kinds of racket when you're decelerating... |
Another cause of poping on decel could be bad packing in the silencer, or an exhaust leak. Rule those out before changing jets.
O.K. Pipe and filter got here tues. Install went well, after taking the rear fenders off. The complete pipe just did'nt want to snake through without it off. Runs pretty snappy with the new stuff on it even pre jetting, riding wheelies up the driveway! Go to ECC this morning for larger jets, not in stock, in fact it's hard to find anything mini these days locally. Stock was 80, ordered 85, 87, 90 to be safe( these were #'s the mech. & my sales rep suggested I try) Ill see them in 3-5 more days. 
and the beers were good during install
and the beers were good during install
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