Need Help

[ryan 83]

we need help getting our polaris 90 off the line. It currently has a stock bore/new piston and rings,hetrick pipe,no rev cdi,31 tooth rear sprocket, tried 16 an 18 inch snow hogs on the rear, 24 grams of rollers-1500 ztr torsion spring-2000 shoe springs.

I have changed the rollers from 30 grams down to 24 grams with no change on take off. Does anyone know where to direct me next?

my son is drag racing, but he is getting beat off the line. Most of tracks we are racing on is no more than 190 to 250 feet long. If they were any longer we could run them down and have caught a few at the finish,but we need help getting the quad rolling off the line. It usually takes about 4-5 feet before it really takes off by that time its too late.

It still has the stock carb on it I know this probably wont help on take offs, but will there be a noticeable difference in performance? I have also heard of advancing the timing. Does this help that much?

Any help would be appreciated. I need to get this fixed before june 19 our next race.

Does anyone out there know of any sponsorships available for this type of racing. We will take what ever help we can get.

Thank you in advance,Keith (ryan 83 dad)

How old is your torque spring?

[ryan 83]

10 months old

[ryan 83]

could it be the torsion spring?

[ryan 83]

no one out there has ever had this problem?

[airmobile101]

IMO, and Im not a 2-stroke guy, but some advise is better than no advise. 24grams is too light for that torque spring(ZTR). Go try to find just a average 1500 torque spring(koso,hoca) and try it.
Also, you could have your son ride the quad for a short time and yank the cvt cover off. Put your hand on the clutch bell. if its too hot to keep your hand on it, then you having a slippage issue.

Not saying Im right, just an idea for you to work with.

[nordic quad]

It doesent matter how old the torquespring is,what matters is the hrs.of ridingtime on it.IMO if your previous set up was working,change back and try replacing the torquespring first.This link may also have some usefull info.
Stein A

http://www.apexatv.com/2009%20Apex%20Site%20by%20488/Tech%20Suport.htm

[ryan 83]

Thanks for the help. I have never been able to get the quad to launch off the line hard. It has always been about 4-6 feet before it comes to life and then its moving good. I read the article you suggested and it also mentioned jetting the carb. Do you thank that would help that little sputter at the beginning? I am still running the stock carb and air cleaner.

Thanks again

[dericsdad]

Okey, now we are getting some where. It "SPUTTERS" off the line?

If you simply bolted on the pipe, and did nothing with the carb. or intake/reeds then that is where you need to start.

A good 24mm or 28mm keihin or OKO carb and a better intake to match it will wake it up greatly.

At minumum put a set of Boyseen reeds in it and rejet the carb. Probably lean on the pilot, which is why it sputters.

Hope this helps.

Dan

[ryan 83]

It has a 82.5 main jet in it now. what size should I start with? and where can I find jets to fit the stock carb? I have a k & n clamp on filter I can use. where should the pilot jet be?I am not to familiar with the jetting process but with your help I think I can get it.

THANKS FOR YOUR HELP

[dericsdad]

well, you can start by removing the carb. slide, then remove the needle and move the clip in the slide needle down (to raise the needle) one or two spots and see if it helps at all. BUt most likely you will have to get a larger size pilot jet.

That size main is way too small for a pipe. I'm guessing you'll need a 90 or 100 main jet.

Maybe others on here who have run a stock carb with a pipe will know exactly what jets work best.

[nordic quad]

The jet kit we got for the pipe kit on our Polaris came with #27,5 and #30 pilot #110 and 115main for the stock carb to be used with K/N style filter and Boyesen reeds.
Stein A

[ryan 83]

I got a 115 main jet. would it be alright to try without adding a larger pilot jet? do I still want to move the stock pilot jet up along with adding the 115 main jet?

Thanks again for everyones help - Keith

[nordic quad]

Yes it may be alright to try this but i am guessing your midrange is lean to,try raising the needle a clip or two.Use a new sparkplug and shut down your engine while going full trottle and read the color on your plug you are looking for a light tan chokolate color.These places should have jets for your 16mm Mikuni Sunworld carb.

Lakes motorsports
Hetrick racing
G-force powersports
And i am shure there is others too.Make sure you have a few to chose from both main and pilot.
Stein A

[ryan 83]

I put the 115 main jet in and the pilot is on the middle notch. Hesitation is still there. Removed plug and color is tan . bike runs perfect on top end. I put the bike up on a stand and it has a hesitation even with no load on it where before I changed the jets it reved quick with no load. What next?

Thanks again, Keith

[nordic quad]

Ok if the jetting is good on the top end you may try playing with your rollers again go lighter and and use a markerpen on your front pulley to check your belt travel,the clue here is to try make the jetting and clutching to work as a unit.
What rollerweights do you have to alternate with?
Stein A

[ryan 83]

I have 4,4.5,4.75,and 5 gram rollers and the stock rollers not sure the grams of them. I currently have 24 gram total in now. Can I take every other one out if I need to to get to the proper weight?

Thanks for taking the time to help, Keith

[o4twinpeaks]

I switched to the 787 belt and it seemed to help his hole shot.

current set up is red mallosi torque spring 2000 koso small clutch springs and 4.25 koso rollers gearing is 21 27 18"snow hogs

we too had the soft holeshot and all i did was change to the 787 belt from the 780 belt.

[o4twinpeaks]

I dont know about just removing every other one but you can use 4 and 4.5 to get an overall 4.25

[ryan 83]

what is the difference in the belts? I still have the stock belt and the bike is a 2003 model.

I have a ztr 1500 torsion spring 2000 small spring gearing is stock on front I believe it is 19 and 31 on rear have tried 16 an 18 inch snow hogs. seems about the same with both.

thanks for your time and info, Keith

[o4twinpeaks]

Originally posted by ryan 83
what is the difference in the belts? I still have the stock belt and the bike is a 2003 model.

I have a ztr 1500 torsion spring 2000 small spring gearing is stock on front I believe it is 19 and 31 on rear have tried 16 an 18 inch snow hogs. seems about the same with both.

thanks for your time and info, Keith

The 780 was the stock belt on our eton and the 787 is 7mm longer. This IMO allows the belt to come up a little higher on the rear pulley/clutch to give you a little more on bottom end and if you are set right it also allows the belt to go a little higher on the front for some more top speed. You and I have been chasing the same problem this year. I have gone nuts trying to tune this for my son. All he does is drag race. The reason for the different gearing is yours has 90cc gears in the tranny and ours still has the 50cc gears in there. different overall final drive ratio for the 2 gear sets.

[nordic quad]

Twinpeaks may very well be right about the 787 belt.You can alternate roller weights,as an example:our Apex 100cc has
3-3g rollers and 3-4.5 rollers and stock clutch with stock springs and a ZTR 1500 torque spring,pulls hard from bottom to top end with stock pipe.20-30 gearing.
The Access 100cc (DRR) is only running 3-6g rollers with a stock Apex vario and clutch with stock springs but it has a custom pipe.19-30 gearing.
The Apex 70cc has 6-2,5 rollers and 1500 Koso springs and 2000 rpm ZTR torque spring with stock pipe and Polini Evo 2 top end.What set up that works best may vary with altitude and humidity.
Stein A

[ryan 83]

Thanks nordic quad and twin peaks for all the help. I am going to look for a 787 belt and try that and maybe change a few rollers around again. I hope to have this ready by the 19 of june our next drag race.

Thanks again, Keith

[o4twinpeaks]

Bedford pa. Nationals on the 19.

We were planing on going but looks like we will be a little short on fundage:( bedford is a 500' track so gear for the moon and let him run them down!!

Have fun and good luck. Wish we were there to race with ya.

Tom

[o4twinpeaks]

Just checking up and wanted to see how rayn did today.

[ryan 83]

we did not go,but thanks for asking. Keith