Struggling for 40mph?

[Kieren]

I've had my 6 month old Kymco Super 8 50cc 4stroke a few weeks and have since fully de restricted it.
I've changed the boss for a de-restricted one, put a size 84 jet in the carb, cut the 2 purple (with red highlights) wires on the CDI and swapped 3 of the rollers (was told this was ok by a bike mechanic) for 4.5g rollers and kept the 3 originals (in an attempt to get good pull on hills and still have a decent top end).

But the bike goes above 30mph but then struggles to get into the high 30s.

Is there something im missing here?
I don't expect super speeds out of a little 50cc but my last scooter (unreliable thought it was) made 40mph (45 if you really pushed it) so for a higher quality and higher priced scooter i would like it to do 40 easy.

Thanks in advance for any help...

EDIT:
According to another website I've found i need to remove a restriction in the air box and there is a restriction underneath the carb / on top of the inlet manifold

[zombie]

You should be getting better speed! The first obvious trouble is the rollers. They must all be the same weight for long term stability. The heavier (stock) rollers will be doing all the work, while the lighter ones will float. It seems 5.5 gram rollers work the best w/ the 4t engine. you will have a total of 33 grams. Also changing the clutch fly weights will give back the low end torque. You will want to install a heavier set of these, (stiffer). Being a new scoot I believe your trouble is in the set up of the cvt more so than any other cause. Have you also changed the main friction spring in the clutch? This will also give a smoother overall feel to your scoot. Also pull off your muffler, and take a look into the manifold end of it. You are looking for a 1/2 moon re-stricter that must be filed/ dremeled out. I may have missed something but these are the basics.

[Kieren]

You should be getting better speed! The first obvious trouble is the rollers. They must all be the same weight for long term stability. The heavier (stock) rollers will be doing all the work, while the lighter ones will float. It seems 5.5 gram rollers work the best w/ the 4t engine. you will have a total of 33 grams. Also changing the clutch fly weights will give back the low end torque. You will want to install a heavier set of these, (stiffer). Being a new scoot I believe your trouble is in the set up of the cvt more so than any other cause. Have you also changed the main friction spring in the clutch? This will also give a smoother overall feel to your scoot. Also pull off your muffler, and take a look into the manifold end of it. You are looking for a 1/2 moon re-stricter that must be filed/ dremeled out. I may have missed something but these are the basics.

So basically go back to the standard rollers, i may have to buy new ones as they all seem to have flat spots (if anyone could let me know if this is good, bad, normal or what causes it i would really appreciate it!)
Change the clutch springs? I think that's what you mean? If so something like these 'http://www.centralscooters.co.uk/product_info.php?cPath=514_657_677_497_626&products_id=3820' ?
Then get one of these? 'http://www.centralscooters.co.uk/product_info.php?cPath=514_657_677_497_626&products_id=3832'
Check the exhaust and for the cvt i assume that all falls under the rollers and clutch springs?

Thanks for your help, i know im asking a lot of questions 

[Shaka]

Those are the clutch parts your are looking for.  I'm gonna take up with Zombie and say the different rollers are probably the culprit.  Flat spots are normal wear, also the cause of not hitting top gear.  Flat spots will also occur much quicker when using different weight rollers!  I have had real good luck with the Dr. Pulley sliders, they don't wear nearly as fast as rollers!  The clutch springs will give better overall performance, but not really effect top speed.  Definitely check the exhaust for a restricting washer.  I think I have heard about super 8's having that restriction as well.

[Kieren]

According to my dad when we had the exhaust off (to get the wheel off to get a new tyre fitted) he checked and there was no kind of restriction in the end of the exhaust.
Also i was running it before with just the 4.5g rollers and then only really made around 30 (not much higher). May well try just the original rollers but then may not make it as well up a long hill i have to go up once a week.
If all else fails it's still under warranty so there must be something wrong with it if it doesn't go much above 30 with the original rollers.

[Shaka]

Something is going on, you should be getting a higher speed than 30mph!  I have also heard of some exhaust having a restriction in the middle of the pipe, that there is no easy way to remove.  For those you just have to get a replacement exhaust.  You may have to do some research and find out which exhaust you have.  I'm not sure of any restrictions in the air box or intake manifold.  You probably have to take those parts off and check. 

[zombie]

If you go back to the dealer, perhaps you could "persuade" them to install the springs, and new rollers/ sliders for you. A good shop can do the whole thing in about an hour. If you explain your driving route, and "how unhappy you are" they may just help you out a little! You mentioned your rollers are getting flat already! Even though the stock rollers are not very good, they should not be wearing soo quick. If you go ahead, and set it up correctly, the difference will be worth it. Keep posting so we can see the outcome!

[Kieren]

If you go back to the dealer, perhaps you could "persuade" them to install the springs, and new rollers/ sliders for you. A good shop can do the whole thing in about an hour. If you explain your driving route, and "how unhappy you are" they may just help you out a little! You mentioned your rollers are getting flat already! Even though the stock rollers are not very good, they should not be wearing soo quick. If you go ahead, and set it up correctly, the difference will be worth it. Keep posting so we can see the outcome!

I didn't buy it from a dealer, might be able to get a Kymco dealer who does warranty work to have a look at it though?

[zombie]

It sure couldn't hurt! If there is a problem that is causing the rollers to wear too quick they may put in the good parts for you, or at least you will have a clean slate to work from! Good luck.

[Kieren]

Went to my local dealer today but the mechanic wasnt there.
The other guys tried to help me out but didnt have any ideas either!
They are supposed to be getting the mechanic to phone me back, if not il arrange to get them to look at it friday (hopefully under warranty so no cost?)

I took the little restriction out of the air filter today but still no luck!
I ran it on the stand and gave it full throttle it when to what seemed like full rpm then died down a bit then came back again :S
I think this was just because it was cold but who knows!
Hopefully they'll look at it Friday

[zombie]

Now I'm not SURE about this but the de-restriction on the cdi is supposed to be cutting ONE of those wires (purp/r). I have never looked into exactly what the circuit is so I don't know what cutting both will do. To be on the safe side I would use a butt connector to put 1 back. Good luck w/ the dealer/ mechanic! Please let us know how you make out...

[Kieren]

Now I'm not SURE about this but the de-restriction on the cdi is supposed to be cutting ONE of those wires (purp/r). I have never looked into exactly what the circuit is so I don't know what cutting both will do. To be on the safe side I would use a butt connector to put 1 back. Good luck w/ the dealer/ mechanic! Please let us know how you make out...

This was one of the things i was thinking, I'll re-solder one if no difference try the other.
If everything fails i think i'll just re-restrict it...

[zombie]

Na!!! Don't give up so soon. Those wires make a loop. They are going to something inside the cdi. I have talked to Suitai about the failure rate on their cdi's, and their explanation is the 2 stroke model is shorted to de-restrict, creating more current (heat) to the cdi. The 4 stroke is a loop that when de-restricted, eliminates a circuit that in turn forces other circuits to work harder (again more heat). Suitai has engineered their stuff to work pretty well, and can program a cdi for you, if you find yourself getting into tuning. For now stick w/ it. One step at a time is best. You'll get there!

[Kieren]

I'll give it a blast Friday then (day off), just borrow someone elses soldering iron and solder then take it for a whizz.

What have i got to lose?
I'll also try only 6g rollers and.. well if that is no help Kymco i shall phone!
They never seem to respond to emails so maybe they are better with phone calls...

[zombie]

No doubt!