A demon on highways, a shy turtle going uphills

Senior Rider

Currently Offline

Pura Vida!

Posts: 1,592

Likes: 281
Joined: Oct 31, 2014 8:42:52 GMT -5

A demon on highways, a shy turtle going uphills by: ricardoguitars - Apr 27, 2015 15:00:15 GMT -5

Reply Quote

Post by ricardoguitars on Apr 27, 2015 15:00:15 GMT -5

I'm trying to figure out how to balance better my scoot to perform good on highways as well as going uphills; today I had to visit a customer on the other side of the city, I took the main highway and the scoot behaved like a champ, I was able to overtake some cars and several motorcycles with higher displacements (including a 150cc Vespa bm1

); I have no complaints on highway performance, the problems begin when I come across a hill, is like hitting a wall, like kryptonite to my poor 125cc scoot

Aside from a BBK (which I'll be installing soon), what else should I do to may scoot to beat hills without losing too much highway performance? I already have the basics on (blue CDI, hotter coil, Iridium spark plug, 12g sliders); change gears perhaps? it has the factory gears still, I have no clue what is the size. The engine is a 1P52QMI GY6.

I'm a Land Rover enthusiast, that's why I ride a scooter.

Senior Rider

Currently Offline

Posts: 3,041
Likes: 471
Joined: Feb 25, 2013 3:03:01 GMT -5

A demon on highways, a shy turtle going uphills by: oldchopperguy - Apr 29, 2015 0:45:53 GMT -5 ricardoguitars likes this

Reply Quote

Post by oldchopperguy on Apr 29, 2015 0:45:53 GMT -5

Ricardoguitars,

I had the same problems with my first 150. There's only so much you can expect from a 125/150. At around 10 cubic inches, they're doing really well to put out 10 or 11 hp even when tweaked.

My old Xinguye 150 had the same basic mods as yours, with upgraded CDI, coil, plug and UNI sock filter. The engine mods that did the most were the CDI and coil, and the UNI filter with richer main jet. The engine mod that improved tuning and general performance (but not much power gain) was to install a full-diameter exhaust header and free-flowing muffler.

However, the mod that made most improvement in acceleration and climbing, but still retained good top speed was the installation of a good variator (I used a "Prodigy") and careful experimentation with roller weights. The roller weights made MONUMENTAL changes in performance. For example, using 11 gram rollers gave me "crotch-rocket" acceleration and ferocious hill climbing... BUT... A dismal top speed of 45 mph at 9,000 rpm.

Moving up just one gram, to 12-gram rollers gave me a good top speed of 62 mph, but "snail-like" acceleration and dismal hill-climbing.

Finally, an alternated mix of three 11-gram, and three 12-gram rollers was "perfect" for my particular scooter, giving me strong acceleration and hill-climbing (even with a passenger) and a great top speed of 65 mph.

The Xingyue would finally cruise 55 mph, but a strong headwind, OR a steep hill would still slow it down to 48-50 mph. Back on level road with little wind, it would do 60 to 65. Unless it's a 4-valve, fuel-injected, watercooled 150, that's about all I could ask for from a 150.

I weigh 235, and a lighter rider could nudge a couple more mph from the same scooter. Newer designs with more sophisticated engines will top 70 mph, but I believe mine was as good as a Chinese carbureted GY6 is likely to do. With yours, especially with a BBK, I would expect similar performance.

When I traded mine in on a used Kymco 250, I had a new set of Dr. Pulley 12-gram SLIDERS but had not tried them. I've been told that SLIDERS offer major advantages over rollers, in that they provide COMPLETE OPENING of the variator for acceleration, and COMPLETE CLOSING of the varitor for absolute top-speed. I've also heard you can go a half-gram, or even a whole gram heavier with sliders than rollers.

I can't speak from experience, but from what others have posted, I'd skip rollers all together and go with sliders even with a stock variator. Weight changes in rollers, or sliders, seem to offer more performance increase for the money than most any other mods.

Each scooter is different, and individual mods on one will not always perform the same way on another, but from my experience, I'd pay a lot of attention to the variator, and the whole CVT setup.

Hope this may help,

Leo in Texas

Last Edit: Apr 29, 2015 0:51:43 GMT -5 by oldchopperguy

Senior Rider

Currently Offline

Pura Vida!

Posts: 1,592

Likes: 281
Joined: Oct 31, 2014 8:42:52 GMT -5

A demon on highways, a shy turtle going uphills by: ricardoguitars - Apr 29, 2015 17:37:51 GMT -5

Reply Quote

Post by ricardoguitars on Apr 29, 2015 17:37:51 GMT -5

Apr 29, 2015 0:45:53 GMT -5 oldchopperguy said:

Ricardoguitars,

I had the same problems with my first 150. There's only so much you can expect from a 125/150. At around 10 cubic inches, they're doing really well to put out 10 or 11 hp even when tweaked.

My old Xinguye 150 had the same basic mods as yours, with upgraded CDI, coil, plug and UNI sock filter. The engine mods that did the most were the CDI and coil, and the UNI filter with richer main jet. The engine mod that improved tuning and general performance (but not much power gain) was to install a full-diameter exhaust header and free-flowing muffler.

However, the mod that made most improvement in acceleration and climbing, but still retained good top speed was the installation of a good variator (I used a "Prodigy") and careful experimentation with roller weights. The roller weights made MONUMENTAL changes in performance. For example, using 11 gram rollers gave me "crotch-rocket" acceleration and ferocious hill climbing... BUT... A dismal top speed of 45 mph at 9,000 rpm.

Moving up just one gram, to 12-gram rollers gave me a good top speed of 62 mph, but "snail-like" acceleration and dismal hill-climbing.

Finally, an alternated mix of three 11-gram, and three 12-gram rollers was "perfect" for my particular scooter, giving me strong acceleration and hill-climbing (even with a passenger) and a great top speed of 65 mph.

The Xingyue would finally cruise 55 mph, but a strong headwind, OR a steep hill would still slow it down to 48-50 mph. Back on level road with little wind, it would do 60 to 65. Unless it's a 4-valve, fuel-injected, watercooled 150, that's about all I could ask for from a 150.

I weigh 235, and a lighter rider could nudge a couple more mph from the same scooter. Newer designs with more sophisticated engines will top 70 mph, but I believe mine was as good as a Chinese carbureted GY6 is likely to do. With yours, especially with a BBK, I would expect similar performance.

When I traded mine in on a used Kymco 250, I had a new set of Dr. Pulley 12-gram SLIDERS but had not tried them. I've been told that SLIDERS offer major advantages over rollers, in that they provide COMPLETE OPENING of the variator for acceleration, and COMPLETE CLOSING of the varitor for absolute top-speed. I've also heard you can go a half-gram, or even a whole gram heavier with sliders than rollers.

I can't speak from experience, but from what others have posted, I'd skip rollers all together and go with sliders even with a stock variator. Weight changes in rollers, or sliders, seem to offer more performance increase for the money than most any other mods.

Each scooter is different, and individual mods on one will not always perform the same way on another, but from my experience, I'd pay a lot of attention to the variator, and the whole CVT setup.

Hope this may help,

Leo in Texas

Thanks Leo, I'll try with lighter sliders, right now it has 12g, compared to the stock rollers it was a night and day difference upgrade, I will try 11g and see how it goes; perhaps a combination like you mentioned will work with my scoot as well.

I'm a Land Rover enthusiast, that's why I ride a scooter.

Senior Rider

Currently Offline

Posts: 3,041
Likes: 471
Joined: Feb 25, 2013 3:03:01 GMT -5

A demon on highways, a shy turtle going uphills by: oldchopperguy - May 1, 2015 13:23:52 GMT -5 ricardoguitars likes this

Reply Quote

Post by oldchopperguy on May 1, 2015 13:23:52 GMT -5

Ricardoguitars,

You will definitely see major differences when changing weights. With rollers, I could barely believe 12's were too heavy to the extent that they literally "killed" my acceleration and hill climbing. Then, dropping only one gram down to 11's, brought ferocious acceleration yet "killed" my top end.

It just doesn't seem like one gram should make THAT much difference. I was definitely frustrated until mixing 3 11's and 3 12's. Suddenly it was a whole NEW scooter! It now had a near-perfect mix of acceleration, climbing and top speed. I suspect the smaller the displacement of the engine, the more the weights affect the performance but I have no proof of that.

The only problem with sliders is that they are a little more expensive than rollers. Not a biggie for most riders, but on a fixed income, I have to watch every penny. Fifty bucks will buy a lot of ground beef... LOL! I was fortunate that when I bought the Prodigy variator, the seller included 10, 11, 12 and 13 gram rollers free of charge. So I had "unlimited" choices to experiment with. For two weeks, I left the belt-cover and kick-starter off and fiddled with the rollers all I wanted to.

Your scooter seems to already have very good performance, so I would probably first try 12 gram SLIDERS. If they prove too heavy, then try 11's. If a "mix" is needed, I doubt there would be any problem mixing 11 and 12 gram sliders (be SURE to alternate them...). I really do wish I'd have installed my sliders before trading the Xingyue 150 in, just so I could have seen what difference they'd make. In addition, if you install a BBK you may be able to go a tad heavier then with the 125 cc mode.

I do plan to try sliders in my Kymco 250 when I get a chance. The old scoot has 19 hp and a lot of torque, and runs SO well as-is that I hesitate to "fix something that ain't broke"... LOL! But, as good as it is (I LOVE this old scoot!) if sliders would open and close the variator only a shy 1/16" more than the stock rollers, the difference in acceleration and top-speed would be VERY noticeable with more "jackrabbit" off the line, and probably "comfortable cruise" increased from 70 to maybe 73-74 mph. That's a worthwhile improvement. Worth a try anyway.

I'd recommend checking the Internet for videos on installation of Dr. Pulley sliders to see how you feel about them.

Please do keep us posted, as % of 125/150 GY6 riders are anxious to obtain that elusive "nimble grocery-getter but still OK to sneak onto the freeway" ride!

Ride safe,

Leo in Texas

PS: Somehow my lost ability to access type mods, give bones etc. on the site has "magically" returned... So... Have a bone on the Old Chopper Guy!

Last Edit: May 1, 2015 13:33:24 GMT -5 by oldchopperguy

A demon on highways, a shy turtle going uphills By ricardoguitars (Read 713 times)

Post by ricardoguitars on Apr 27, 2015 15:00:15 GMT -5

Post by oldchopperguy on Apr 29, 2015 0:45:53 GMT -5

Post by ricardoguitars on Apr 29, 2015 17:37:51 GMT -5

Post by oldchopperguy on May 1, 2015 13:23:52 GMT -5

Shoutbox