CMG (Chinese Motor Group) GTR 150 CVT Engage RPM

[fastrider]

Haven't posted here before, but here's a crying hope that i've followed the rules and done what i'm meant to do...if not, shoot me and tell me what i did wrong and i'll fix it.

I've just been 'gifted' a 2007 CMG GTR 150 to get road worthy for my daughter. Random yes. Cheap yes. Google information no.

Before you all fall over laughing, yes it's a sewing machine on wheels, but it was free (good reasons). So we move on...

The CVT drive in the thing engages at 4000RPM and despite my limited skills i've figured out that there's no adjusting the point at which this engages as it's based on the standard scooter centrifugal force to engage the drive wheel - so i assume spring tension to throw the wheel out and engage into the outer drive wheel. Proven in pulling the thing apart and seeing how it works.

My questions are:

1. Is this the RPM point where it's meant to engage?
2. Can it be changed?
3. If so, how do I change it?

My challenge with this is that at 4000RPM on a corner, speed dropping under 30km/h, the thing hits neutral and shoots you into a freewheel corner manoeuvre - somewhat interesting to say the least. Applying accelerator at this point simply makes you appear like you can't turn a corner in a smooth curve, or better yet starts a wonderfully chaotic drift in the wet. Not so good for the daughter on a learners licence.

Any answer is helpful, but i'm a stuck goose with this thing at the moment and can't figure out if i can change it.

Cheers!

[imdying]

Lighter springs will lower the engagement point.

[haydes55]

Lighter springs will lower the engagement point.

Or what I tried on a mini moto bike, pull the springs out and stretch them and use a butane torch to heat it up. Make them weaker and or longer.

Another idea (to really maori it up) make the plates that grip the basket thicker, so add a cut up brake pad to each one. I haven't tried that, but no reason why it wouldn't work?

[fastrider]

Lighter springs will lower the engagement point.

Thanks, now for the real question - where on earth does one get those from? Tried Red Baron, Motorad, and a few others in NZ - nobody wants to play...

[fastrider]

Or what I tried on a mini moto bike, pull the springs out and stretch them and use a butane torch to heat it up. Make them weaker and or longer.

Another idea (to really maori it up) make the plates that grip the basket thicker, so add a cut up brake pad to each one. I haven't tried that, but no reason why it wouldn't work?

If i'm understanding you right, making the springs 'looser' (cut to memory of that girl we all know from college...ahem) they will move out at a lower RPM? But of course that assumes the three would be equally stretched/heated...can't think how to make that work? The other thing is that these springs live in a basket casing that is sealed with wonderfully factory assembled press bolts with no replacement i can think of (they are end spot welded/pressed?) so i don't even know if i could get them out if i wanted to...then there's the obviously stupid move of stretching them too far, starting the bike, and finding that it's trying to ride away without me...Am I just kidding myself thinking this is a modification that can, nay, needs, to be made?

[Akzle]

Thanks, now for the real question - where on earth does one get those from? Tried Red Baron, Motorad, and a few others in NZ - nobody wants to play...

try somewhere that sells chainsaws or other toys.

[fastrider]

try somewhere that sells chainsaws or other toys.

Thanks, I think...

[SS90]

I suspect that someone may have "modified" the clutch springs already, as it is doubtful it came from any factory working like that.

Most (almost all) 125 and 150cc chinese CVT scooters use the GY6 engine (which was originally a Honda engine from 20 odd years back.

In all truth, there are several qualities of these clone engines about, some are in actual fact extremely reliable and fast, and others, just OK, and for all intents and purposes, suitable for the job.

The cheaper ones (from my limited auto scooter experience) seem to wear transmission components out faster than the better quality ones (variator drive faces and therefore belts)
Followed by clutches.

From what you have written, it would not be inconceivable that someone has either inadvertantly or possibly intentionally replaced either the springs or complete clutch assembly with a "performance" clutch, designed to engage at a higher RPM (such as on highly tuned engines revving significantly higher than standard, losing bottom end power and therefore needing to engage drive at a higher RPM.

If you are able time out what model of engine you have, you could then start to assertain if you have the correct components fitted.

You could also check to see if your rollers are the correct weight as well.

[imdying]

Thanks, now for the real question - where on earth does one get those from? Tried Red Baron, Motorad, and a few others in NZ - nobody wants to play...

I believe that Canterbury Brake and Clutch were unable to secure a reliable supply of all the odd springs that have to replace in the course of their daily business, so they purchased a spring manufacturing business. They could be worth a call.

[imdying]

Or what I tried on a mini moto bike, pull the springs out and stretch them and use a butane torch to heat it up. Make them weaker and or longer.

Another idea (to really maori it up) make the plates that grip the basket thicker, so add a cut up brake pad to each one. I haven't tried that, but no reason why it wouldn't work?

Sure, or drill the shoes to insert some lead into them.

[Ribit]

Not so good for the daughter on a learners licence....

I hope that idea is put under heavy consideration when debating the cost of the bike vs the "cost" of the daughter getting injured or worse...

[fastrider]

I suspect that someone may have "modified" the clutch springs already, as it is doubtful it came from any factory working like that.

Most (almost all) 125 and 150cc chinese CVT scooters use the GY6 engine (which was originally a Honda engine from 20 odd years back.

In all truth, there are several qualities of these clone engines about, some are in actual fact extremely reliable and fast, and others, just OK, and for all intents and purposes, suitable for the job.

The cheaper ones (from my limited auto scooter experience) seem to wear transmission components out faster than the better quality ones (variator drive faces and therefore belts)
Followed by clutches.

From what you have written, it would not be inconceivable that someone has either inadvertantly or possibly intentionally replaced either the springs or complete clutch assembly with a "performance" clutch, designed to engage at a higher RPM (such as on highly tuned engines revving significantly higher than standard, losing bottom end power and therefore needing to engage drive at a higher RPM.

If you are able time out what model of engine you have, you could then start to assertain if you have the correct components fitted.

You could also check to see if your rollers are the correct weight as well.

That is an epicly outstanding response. Thanks! I note that i do have the CY6 engine, and i've discovered also that my scooter is a direct (re-badged) copy of the CPI GTR 150 of which there seems to be a wealth of information around for

I've checked what you've said, and i think you're right on the money - so thanks again, once i was pointed to the engine, yes i found google was my friend once more

Cheers much, thanks for taking the time

[fastrider]

I believe that Canterbury Brake and Clutch were unable to secure a reliable supply of all the odd springs that have to replace in the course of their daily business, so they purchased a spring manufacturing business. They could be worth a call.

Thanks heaps, I'll give them a try! Cheers

[fastrider]

I hope that idea is put under heavy consideration when debating the cost of the bike vs the "cost" of the daughter getting injured or worse...

Absolutely agree wtih you - hence why if it's not up to standard, she won't be riding it. I guess my only challenge is trying to find out how I can ensure the safety of my family with this thing, if I can't it will absolutely be gone. Thanks for the comment