Mods

[Jmills41]

yeah leo vince zx but everything ran fine until the polini hi speed variator.. Using after market tachometer if its off not by much its running way to hard... carb been 19 dellorto clone jetted for this set up.. Had a hard time w polini bbk just put on but even ran fine(for a little while) after that it seems to be variator issue.. Is it possible a damaged piston could make it run at this high of a rpm?

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[Jmills41]

and yeah i was just sayn ive tried all weight rollers between 6 and 9 grams

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[Jmills41]

JP glue ?


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[dan v.]

You're not telling us something.  What do you mean by " Had a hard time w polini bbk just put on but even ran fine(for a little while) after that it seems to be variator issue"?

So is it a Malossi BBK, or did you change to a Polini BBK?  A cast iron one?

If cast iron - NO WAY you are spinning 14 to 20 rpms.  Your tach is set up incorrectly.   With the Leo vince exhaust, it probably should cruise at 8500 -9500 rpms.

I think you changed out the clutch springs, and contra spring, correct?

Not understanding why the change in variator would have made such a difference.  Is your Polini variator the six roller one, one the nine roller one?

What happens if you would re-install the stock variator?

[Jmills41]

Your right alot happened since malossi ended up buying a polini  bbk because idiot put the molassi in arrow facing wrong way... Ended up getting a 70cc polini sport  bbk which he then couldnt get to lubricate right so ended up ruining as well ended up buying a 2nd Polini which also had a hard time lubricating so now the piston is a little scuffed but seems the rings are sitting fine so its still in... Yes on 3rd 70cc kit embarrassing but its what happened... While all that was going on(3 months) installed polini hi speed vario changed everything springs  ,torque ,rollers.. I knew by this point bad idea but i had it and my supposed scooter guy did it as it was left at his house anyway... But im back to stock variator stock toque spring 9 gram sliders and blue 1000rpm clutch springs runs better but still high rpms... Was getting 50mph stock w 8 gram sliders before everything(should have left alone).. Now i barely get 40 but accelerates better revs high but doing way better w stock vario back in... Would shimms help w polini vario? it looks like polini sits back further than the stock so would longer belt help w the issue? and gonna try and adjust tachometer in a little while but its def running alot harder than it should especially w polini vario in it...

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[Jmills41]

oh and he used a wrench of some sort to hold back clutch when changing small clutch springs... I now have small chunks missing out of my clutch shoes.. I got rid of him a while back but just realized what he did to the shoes so im guessing thats probably part of the problem. Correct? maybe shoes  arent catching bell until higher rpms because of that.. Im by far as u can tell new at this so please let me know any suggestions you may have would be greatly appreciated..

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[dan v.]

The "mechanic" is the problem.  This stuff is not that difficult.   Three cylinders gone?

"which also had a hard time lubricating"   ?   I believe you mean seized.  That happens from improper jetting, improper installation (sucks air), or oil pump inop/ wrong fuel/oil mix.   Two strokes are lubricated from the fuel, so if there were "which also had a hard time lubricating" issues the crank and bearings MAY be shot.

Really sounds as if most issues are from poor wrenching.  Breaking the clutch shoes from installing the springs - the mechanic owes you a new clutch.   No way of telling what is going on with the variator of the carb.

Did you get a copy of the service manual for this scoot?  The aftermarket parts are not that different from the stock parts as far as installation and inspection.

I don't know what else to offer.  I wish I could help you find a decent mechanic who knows how to install the parts properly and tune your scooter.

Where are you located?

[Jmills41]

The "mechanic" is the problem.  This stuff is not that difficult.   Three cylinders gone?

"which also had a hard time lubricating"   ?   I believe you mean seized.  That happens from improper jetting, improper installation (sucks air), or oil pump inop/ wrong fuel/oil mix.   Two strokes are lubricated from the fuel, so if there were "which also had a hard time lubricating" issues the crank and bearings MAY be shot.

Really sounds as if most issues are from poor wrenching.  Breaking the clutch shoes from installing the springs - the mechanic owes you a new clutch.   No way of telling what is going on with the variator of the carb.

Did you get a copy of the service manual for this scoot?  The aftermarket parts are not that different from the stock parts as far as installation and inspection.

I don't know what else to offer.  I wish I could help you find a decent mechanic who knows how to install the parts properly and tune your scooter.

Where are you located?

yeah i know shenandoah county virginia... The variator was most of the problem im having now the boss on the polini kit was too long have to use the oem... Some of this stuff has been hard to find on the internet im now doing it all myself...

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[Jmills41]

and yeah of course siezed is what happened..

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[dan v.]

When learning how to do the hotrod thing it is best to install one one aftermarket part at a time, and get it dialed in.  Then when the next part is added you have a good baseline to work from.

Polini makes very good parts.  I have their variator in most of my 2 strokes.  It should be fine in yours.

Perhaps you ordered the wrong one.  I see a lot of Kymco engine parts listed a fitting Honda.  That should throw up a red flag for you, as they will not work on the Super 8 engine.  The ones listed as fitting Honda are for the engine in the ZX50, the Honda "Dio" engine, which is a way different design.

I am not aware of any tuners in your area - sorry i can't help you out there.

good luck.

[Jmills41]

really i thought the super 8 and 9 were almost identical to the dio? thanks thats definitely a big help..

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[dan v.]

Not even close.  The Super 8 and 9, and most Kymco 50cc engines are horizontal cylinder designs.  I think they are Kymco designed SF10? designated engines.  Pretty certain no relation to Honda.

Now the engine in the ZX50 Super Fever is the clone of the Honda AF16 vertical cylinder "dio" engine.  Completely different design.

Question is, and I don't know for sure if parts such as clutch, torque drivers, and variators are interchangable between the two designs. Some may fit, some not.

Best to check with the parts manufacturers or knowledgeable suppliers as to what will fit.  Like I said, be careful if you parts are listed to fit Honda.  You have to make sure they fit the Kymco Horizontal engines.

Confusion also arises  from scoots having different names in different countries.   Be careful 

[Jmills41]

Any idea w polini 70cc and leo zx exhaust where my power band may lie? Just a guess 8,000 rpms? I know like 7500 before exhaust and kit plus variator.. I think..

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[Jmills41]

and how could i tell if i have a rear pulley restriction im still only going 50 and was hitting that before w just exhaust.. Or is my belt too short?

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[dan v.]

There are no restrictions in the torque driver.  Typically when you hotrod a two stroke scooter you need to change out the torque spring and clutch springs to take advantage of the higher power output and the change of powerband.  You need to do this before tuning the other components.

Common way to tell if the torque driver and variator are running through their full range is to draw a sharpie line from the "axle" to the outer edge.  As the transmission operates it wears away the line.  The line should only be visible on the very outer edge.

Your Polini cylinder - do you have the sport or "contessa" or the race "corsa" version?   The powerband of the sport cylinder is 8 to 8.5 k rpms.

https://www.pedparts.co.uk/blog/sports-exhaust-testing-50cc-and-70cc-sports-mopeds-part-two