Regearing a 90

[dads400ex]

After this weekend of riding at the dunes I got to thinking if it would be possible to put a smaller tooth on the front of a 90 as it seems like they could use a little more low end. Is this possible and what other things might be able to be done for a little more power? Not looking to make it like a 250ex but just a little more umph for the little guy.

dads400ex

[Lil90man!!]

hey, well if annyone does make different sized countershaft sprockets for the 90 let me know cuz i have one(for the little cousins now that i have my 300ex):D ) but at the dunes isn't speed more important??? i dunno i have never riddin at the "dunes" i just always hear more topend for the dunes does that mean powerband or gearing??

[quadfamily]

I took the airbox lid on my sons 90 and cut the snorkle piece off of the front making the hole alot bigger than it was. You did take the restrictor off of the snorkle didn't you? Then I had to re-jet it. It made a difference in power for sure. It was too much air with no airbox lid. If you want to change gearing to help bottom end then you could get a larger rear sprocket if you can't find a smaller front one. Or you could get smaller diameter rear tires like 18"s. I also reversed the front wheels on his quad and it is so stable now because it made the front around 5 inches wider. It messed up the valve stem a little but not too bad. I had to use some washers under each wheel stud to space out the wheel so it would sit flat on the hub. It's been that way since around January and no problems yet. His front shocks were beat so we got Works for it and they're great. He's almost 8 years old now and just yesterday he cleared over 27' on a jump near our house on his little 90! He was flat out in 4th gear when he hit it.

[dads400ex]

quadfamily, yes I did remove the snorkel restrictor and something I forgot to mention was that with the air box lid off it makes a girgiling sound when you bring it up off of idle any ideas as to that? Also that is the size of Skat Trac Gliders he has, 18 inchers and that is another reason for wanting to lower the gearing to help with the pull of the paddles.

dads400ex

[250EXcited]

dads400ex,

I just bought a trx90 for my daughter. Where did you get your wheels and paddles? We'll be going back to Little Sahara for spring break and I need to get her quad ready. Also, I don't know if you want to spend the money for some power, but Big Gun makes an exhaust for the 90.

[quadfamily]

Dads400, The sound you heard is just the air being sucked into the engine. It's normal, the airbox lid muffles this sound. As 250EXcited said you can get exhaust for the 90. Powroll also has an exhaust system for it. They also have a piston for it to make it 95cc. Nobody makes a high compression piston for it because it would be too hard to pull start with the rope. That's as big a piston you can get. There is no sleeve in that engine from what I'm told. The cylinder is one piece.

[dads400ex]

250EXcited, got the paddles and wheels from Rocky Mountain, the Gliders are a little hard to find since everybody does not carry them in that size and they are a little high compared to your common sizes. I paid around $160.00 with shipping and have also considered an exhaust for the 90.

dads400ex