Today I picked up my sons 2003 Helix 90 from the shop. Prior to taking it in it did 30 MPH. I had them replace a 13 tooth sproket with a 16 tooth sprocket. I also had them add carbon fiber reeds and a "power up" clutch kit all both from Maximum RPM the performance side of Dinli. All of these things were done in an attempt to increase the top end of the machine. Upon test riding the unit it now has a top end of only 20 MPH. Why? Is it possible that they did something wrong? What should I do to get the 35 MPH I was looking for. I do not want to get rid of the oil injection or risk any decrease in reliability. Please help.

 

I would wonder if the engine would have the power to pull the extra teeth on the front sprocket. Do you know some one who did this and it worked?

 

They'll do 35mph with the stock gearing if you'd do some motor mods. I'm guessing you could've bought a pipe for what you paid for the sprocket, clutch reeds and labor. Hard to have your cake and eat it too. You want more performance, you need to add a pipe and alter the intake at a minimum. And that may mean chunking the oil injection (which you won't regret once you do it).

 

Does the engine still sound like its revving as high as before the mods?I would say either the engine doesn't have enough power to pull that gearing(3 teeth sounds like quite a bit?) or the variator roller wieghts in your kit are too light so your clutches are not shifting up to top gear.If this kit is for a modified engine they may need the extra rpm of a modified engine to work properly.

 

It sounds like it is hitting rev, it is slower out of the hole (as I knew it would be), then it pulls for a very shot while and just stays there. They said that it was for stock or mod motors. Right now I'm attempting to get the the 16t tooth off and and put the 13 back on to see what happens. I have the chain off now... what is the trick for getting the sprocket off?? Is it a reverse thread bolt? How can I keep the sprocket from spinning?

 

I spoke the guys at Maxium before I ordered the parts. I told them what I was attempting to achieve and this is what they told me to do...so far this has been a huge waste of $$. As I stated not only didn't I get the top end I wanted but the bottom end is far worse than before. I'm attempting to put the 13 tooth back on to see what happens.

 

Removing the oil injection will do nothing for performance. Leave it on. Going up 3 teeth is a huge difference. The motor may not have the power to deal with that much of an increase. You can keep the stock gearing and just do motor mods to achieve your goal.

 

Ok...I got the 16 off and the 13 back on. I'm back up to about 25 MPH which is still 5 less than where I started from. It doesn't appear to be much quicker off the line (if any), and it sounds as if it is winding out much quicker. It used to pull up to about 25 then work its way upto 30. Now it pulls to about 20 and works it way up to about 25. At this point I will be happy to get back to 30 MPH (where I started from) with a bit quicker out of the hole...where do I go from here?[img]i/expressions/face-icon-small-disgusted.gif[/img]

the clutch kit I had installed is as follows:

CLUTCH POWER UP KIT
Install this complete kit for greater top end speed, smoother shifts and better holeshots.
This is an absolute must for racing!
Kit includes:
Front Clutch Varieter
Clutch X-Power Rollers
Rear Clutch Shift Springs
Rear Clutch Compression Spring

The reeds are as follows:
CARBON FIBER REEDS
Lighter for better throttle response.
Durable to withstand higher RPMs.
Use with stock OEM intake or Koso racing intake.

Where do I go from here?

 

I'm assuming you have kept the stock air box? With the stock air box and pipe, there's not too much you can do to increase the performance. The clutch kit says it is an absolute for <u>RACING</u>, the reeds were a plus but without any additional air flowing through your motor, you are stuck with about 8000 RPM geared at 2.46, your 2.0 (16T front speocket) will only drag the engine down. Remember this is a 2 stroke engine and it takes RPM to create HP unlike the 4 stroke.

As for your speed loss, it is because of the roller weight. Stock rollers generally weigh between 9 & 11 grams each. Your kit included 6 gram rollers which require higher RPM to spin the rollers as high as the 11 gram rollers once rode.

Here's my .02, leave the clutch kit and reeds on it, replace the stock air box with a K&N or UNI style filter and see what you get or put the stock rollers back into the variator. The Koso variator will allow the rollers to go higher, thus giving you more top end. If you replace the air box, remember you'll need to go larger on your main jet. If that doesn't give you the performance you want, you'll have to replace the pipe to allow the engine to breathe thus giving you the power you seek.


Wish I could help more.

 

A lot of performance pipes require the removal of the oil injection. It also alows you to "fine tune" your mixture which can reduce smoke and carbon build up. I'd recommend the removal for anybody.