Here is what you can do to the 90. A pipe is the first thing along with a air filter. To make it run up over 60, you have to change the sprocket ratio to 19 front, 25 rear. Change teh CDI box to a digital cdi or a 9500 rpm cdi. To get to 60 fast, you need a new head, 24mm or 28mm carb, Some like 20mm but I recommend 24 or 28mm. A ported cylinder, transmission kit(have to have with pipe).
As far as suspension, +3 A-Arms, 2.5 wheels spacers, works shocks, Tomco rear swing-arm(+3), aluminum handlebars, (Have I spent enough of your money yet?), Double A-Arm kit if you want, douglas wheels and tires.

 

You will not get anymore top speed out of this machine unless you allow the engine to rev higher or change the sprocket ratio. The 53mm cylinder kit will give you very limited power gain, but it is an excellent top end rebuild.

 

Tommy's right. The cylindar upgrade on mine did produce some noticable power, the kids can get up hills better, etc, but there was no change in top end speed.

Tommy, my 90cc is a 2001, does it have a CDI? And where would such a thing be? Also, before I tear the carb out and dig around in it, is there a restrictor in the carb? There was NOT one in the exhaust intake or on the muffler. I'm not yet ready to drop any real money into this thing, but keep thinking there are some smaller things I might be missing.

 

Pechmial,
The sportsman doesn't have any physical restrictors that I am aware of. It is limited by the sprockets and CDI. THe CDI you have is a 8300rpm CDI.(Don't quote me on that but it is low.) The real solution for power is a pipe. the solution for speed is sprockets. Be careful about getting a unresticted CDI. This machine will not hold up to 10k rpm for very long. You can cut every other fan blade out of your fan. This will help the power some. Take off the oil injection and pre-mix with good oil (BelRay H1r) at 40:1 will help a little, plus it is better for your engine.

 

Whats jetting and what do u do? I getting a filter and a pipe. And im going to premix do i need to jet? Or could i re jet to make it have power/speed?

 

Also do i need a trans kit with the pipe ? Or i could just get the pipe?

 

For the most part, If you stay with the stock carburetor and get a Tomco exhaust system with Air Filter, then you will need to take the float bowl off the bottom of the carb and replace the main jet with a biogger one. WRH Pipe=.95mm Ex-Pipe=1.10mm PP=1.25mm main jet. THe needle will have to be moved up one notch.
The stock clutch springs are set up for the power of the stock engine. If you change the pipe, you have to change the clutch springs, variator roller weights, and teh torque driver spring to get the right power delivery out of the machine. That is were you need to buy performance parts from a minni quad performance dealer.

 

YO MR sportsman 90 that litle Quad is not ment for speed wait about 3 years then with all that money you saved you can buy a real bike!! Know what I am saying here!! AM 14
and I ride a SP 90 I might put bigger tires on it but thats IT!!!! DUDE I have broken my arm on mine!! IT hurt!!

 

hey prechmial, i looked at your pics of your son raelly splashing through the mud and water, did you build a sort of snorkle for the 90? i was working on ours and the 2 breathers, ( air intake and crank case) are so low im afraid to let my son even go near the water. if you did what size pipe did u use or was it just something like a large dia hose.

 

Foneguy,

A air filter off of a DRR raps around and goes under the set. It is a great set up for trail riding in the mud and stuff.