LTZ90---need more speed

[ccdhowell]

I recently bought a very nice '08 LTZ90 from a board member. It's list of mods are: CT Racing pipe, CT racing clutch mod, Dynatek ignition(running is at unlimited RPM setting), Durablue spacers on all 4 corners, Works shocks all the way around. My daughter loves the quad and is racing much better than she ever did on her Typhoon. The LTZ90 handles much better, but she is getting eaten up by Apex and Kasea 2strokes and is slower than even a stock Raptor 90.

Help, what can I do to increase the speed of my LTZ90? I was thinking I'd like to change to a bigger carb, anyone have an idea of which carb I can run on this little quad? Does anyone know of a piston and cam I can install? How about a big bore kit? Our series rules allow 4strokes to run up to 125cc, it would be great to bump up a few cc to compete better with the 2strokes.

She races XC and I will say that the Z90 does better than the 2strokes on muddy tracks. It is much more water proof than the Apex and Kasea.

[airmobile101]

You need a starting point before you start tossing more money at it. You need a baseline to work off. If you have all the stock parts, I would put it back to stock form and get some baseline times. Setup a 100-200 ft. strip and time that bike in stock form. Do multiple runs with it and take the average. That way, you know exactly what your dealing with. Then you can start adding the mods back on one at a time. Each mod you add, send it back out and get some times on it. Yea, its a pain in the butt, but it works. That bike might already be setup wrong with that CT racing stuff. Thats why you need to start over with a stock bike and get a baseline to work with. If I remember correctly, that CT Racing clutch kit only comes with one set of rollers. Now how the hell can you dial that in with only one set of rollers?????? And who is to say that that clutch is setup right???? You see where Im coming from????

Sorry to drag this out,but I have been thru this already. Myself and my son race XC in Missouri.

Depending on the course she runs, that Z90 should be killing those Apex/drr's/Kasea's in the tight,technical, wooded areas. Thats just the nature of the beast. But don't worry, the 2-strokes returns the favor in the wide open areas.

Make darn sure that the restrictor band has been removed from the cvt!!!! Yes, people have overlooked this simple restrictor and tossed money to make it faster not realizing that the ring was still installed!!!!!


:D

[ccdhowell]

I appreciate the input and you called it, she does well in the tight stuff, and mud, but gets left in the open. Unfortunately, most of the PeeWee tracks she runs are predominately open areas, with little in the way of tight terrain.

The bad news here is that I don't have the stock parts to go back to. I hear you on the clutch, I don't have a lot of experience with CVT clutching, but it is a strange setup IMO. The engine revs to maybe 4K RPMs before the quad moves at all, and then it gets going pretty quickly.

If I pull the CVT cover, what would I look for when I'm looking for the restrictive band? I've read about them being on the Z90, but don't know what to look for.

This thing just seems like it should be revving faster. Like it needs a bigger carb, or maybe it it restricted in airflow. It has the stock air box on it with the stock filter. What mods can be done to the air box?

Does anyone make a cam for this engine?

How would I adjust the rollers in the CVT? Is some info on the web I can read through on this CVT and how to improve it? I am clueless on them. I can change a belt on one and that's the extent of my knowledge.

[airmobile101]

The restrictor would be located in the front pulley. The belt would be sitting on it. I doubt if its still in there, but its worth to take a look. That CT Racing pipe isnt doing crap for yea if you still are running the stock intake setup. Get some more air to it and re-jet it !!!! I dont think there is a cam for it. I think your main issue is that cvt. There is alot of good info on cvt's on here. Just do a search and you'll find them. I do know this, if it takes forever and a day for the quad to move , then you need lighter clutch springs. I would call CT Racing and see if they can help yea or at least give yea the specs on the stuff you have on it now.

[ccdhowell]

Thanks man, I'm off from work the week of Thanksgiving. I'm gonna give it a good going over and see what I can see. I'll check the CVT band then and look at the air box. Don't want to remove it altogether, she XC races and does enjoy an advantage in wet and muddy races over the DRRs and Apex quads because of the airbox.

[jetta75]

You can add some of those 1" Uni filters to the lid. See if you could open up the intake hole. You may have to buy some stuff from the hardware store to make an extra air intake tube or two. Like one on each side of the stock tube. For the filter you could clamp a tube into the airtube on the inside of the box, then clamp a k&n onto the tube if there is enough room. Luckily I had enough room to fit a soda can in the airbox so I just measured and went to k&n website to find one that would work. If you don't hae enough room you could get some uni filter material and cut it to fit that will flow better than stock filter.

[airmobile101]

Depending on where its located, I would just run a straight pod filter with no airbox. Granted, if its hanging off the intake tube near the front wheel like the 2-strokes, then there might be a concern. Our carb on the Kawi tucks in nicely above the engine.

[quadnana7]

Sent you a pm

[ccdhowell]

Wanted to post an update on my Z90. I took the airbox off and put on an UNI pod in it's place. Rejetted the carb to a 95 main and a 22.5 pilot. Jets seem to be about right, but haven't tested good yet. A little frustrated that there is no air screw on this carb to adjust the idle.

I also added a 12 tooth front sprocket which seems to really help the speed. My daughter took to the changes right away and should race faster when we race again in January. I have a 13 tooth front also, haven't tried it, but I'm afraid it would take too much bottom end away.