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Post by raq1025 on Nov 21, 2011 19:32:03 GMT -5
I have a Vento 150cc scooter with a GY6 motor. Engine code from left side of case near drain plug = VE157FM2A. (Any idea what specific GY6 motor this is? lol) Here are the mods that are currently done to the motor & CVT. Unless otherwise stated all parts came from MonsterGY6.com. Carb rejeted (can't remember if it's a 120 or 130) Exhaust Uni Filter Performance Coil Performance CDI Iridium Spark Plug 115mm Variator & fan Yellow Clutch Springs & Torque Spring in OEM Clutch Dr. Pulley weights (12 g) 842-20-30 Belt. I've also had roller weights of 14g (stock) & 12g (round not slides like the Dr. Pully) and a factory belt of 835-20-30. The belt was changed from 835-20-30 to 842-20-30 at the suggestion of Steven (I believe) at MonsterGY6. It appears to me that the belt never rides to the upper ~ 1/4" of the variator. My goal was to get a little more top speed out of the scooter, but with all I've done, I have not seen any increase in top speed from stock. The motor seems to be getting to about 8k rpm. The speedo/tach on this thing is a terrible LCD unit so it's hard to see. I pulled the plug and it's a dry, dark gray. It doesn't appear to be running lean or too rich (probably a touch rich.) Any ideas on what I need to do? Attachments:
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Post by dyoung1167 on Nov 21, 2011 21:47:23 GMT -5
try going back to oem springs in the clutch, OR put the 14's back in the variator and see what the difference is. there is a fine balance between the clutch and variator and they can counter each other. stronger springs usually require heavier weights in order to compress them and get your highest gear ratio, but also need more hp to accomplish .
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Post by skuttadawg on Nov 21, 2011 22:22:42 GMT -5
Try putting the airbox on in place of the uni . Being open it does not create as much vacuum as the airbox . Try whistling with your mouth wide open instead of having your lips together to get an idea of what I am talking about . Stock heads are restrictive try a HP head of the 4 valve head to get most of of the uni . HP heads are ported better thus increase airflow .
I put a BBK on my 50 and top speed was the same but I got there faster and went faster uphill than before .
You can change the final drive gears for a higher ratio . Try the 14g vs the 12 or mix to have 13g and see what works best since you already have the parts handy .
If you are a big guy it will have a slower speed than it will for widdle guy
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Post by edfr on Nov 21, 2011 23:06:39 GMT -5
Put the OEM belt back on that will pull the belt down further in your REAR Clutch Pulley. A longer belt will usually result in lost to end due to the fact that MAYBE it will climb to about 1/8 from the edge of the Variator BUT since it is LONGER and here is the BUT the belt is NOT BEING pulled DOWN as far as possible in your CLUTCH PULLEY, so you loose top end.
I have tried just about every possible combo you can think of I EVEN CUT down a BOSS that also lost me top end tried it with a longer belt and orginal. What it did do is get my CVT hotter than sh!t to much pressure on the belt.
Why the heavier springs? That does nothing for speed all that does it require MORE RPMS before you scoot starts to move and that is all. A heaveir CONTRA spring you then need heavier WEIGHTS or a lot of RPMS to open the CLUTCH PULLEY to bring the belt down IF your Belt climbs up the Variator.
I only recommed 1000 rated springs for either of them and no more UNLESS your drag raceing and you want to have your rpms around 4000 before the scoot starts to move. Lefty
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Post by 2wheels4ever on Nov 22, 2011 2:32:29 GMT -5
Another notch on the parts seller's belt, no pun intended. 4Ts aren't going to give a favorable return of speed for dollars, I've even read in several MC trade magazines that 'racing' cams are being sold at a healthy markup and measuring less lift than stock.
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Post by imnts2 on Nov 22, 2011 9:19:14 GMT -5
And watch your tire pressure. anything you can do to reduce rolling resistance will help. At 8 grand you are well past your peak torque so acceteration will be slow. Have you read the long long thread on the 150 to 170CC upgrade? Lots of good guidance there. Lots of work and more than a buck of two to get 5 mph on top. It is easier to lose performance than to gain. But typically, it takes improved air flow, increased displacemnet and camshafts to get more power and more speed. Most of what you have done - I would have waited to last and then only done if I had evidence they were really needed. Unless you are after a short fused bomb . Good luck. Keep us posted Cheers lefty2
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Post by edfr on Nov 22, 2011 9:46:11 GMT -5
The other possiblity is that the tranny is geared low and your running out of gearing. Some scoots do that to give the scoot really good take off and mid-range gets up to 40-45 real quick but then you are out of gearing. Best bang for the buck for more top end and what you have already got is get taller gears in the tranny they run from around 40-50 bucks or so. First you need to count the teeth on the short shaft that turns the big gear and count the teeth on the big gear. Since it is stock do not go more than 2 MORE teeth on the Short Shaft and 2 LESS teeth on the big gear that the short shaft drives. That should get you anywhere from 6-10 mph on the top end depending on the power of your motor. Lefty
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Post by raq1025 on Nov 22, 2011 13:42:52 GMT -5
Ok, A lot of information here (not complaining ) I'll try address the responses in the order posted. I'm terrible about quoting, so I'll do my best. ok, so either go back to stock rollers or go back to stock CVT springs? If I'm putting the CVT springs back, do I put the clutch springs and the torque spring back? Any suggestion as to which to do first? Rollers are much easier. Airbox is a no go. I tossed that 2 years ago along with the exhaust. lol Why go with the 1500 springs? They're High Performance, they must be better. lol Rookie mistake. So no going back on intake or exhaust, but it sounds like I should undo most of what I've done tranny-wise. I'm going to go the easy route first and leave the clutch together and put the14g weights back in. (This may be the only combination I haven't tried.) If that doesn't do it, I'll take it all the way back to stock then do one item at a time, starting with the weights. I'm gonna hold off on messing with the gearing for now. I've thrown in too many variables already. I'll definitely read that 150-170 article too. I'll try to be a little more scientific this time & post my results. Thanks
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Post by sprocket on Nov 22, 2011 13:43:10 GMT -5
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Post by DanK on Nov 22, 2011 15:41:35 GMT -5
In stock form it should hit 50mph no problem. Why do we always see modified motors that don't run as well as from the factory?.... You could put $1000 or more of upgrades on it and if you get more than 10% boost in horsepower I'd be surprised.
Anything with the electronics won't make you go faster. Changing intake without a calibrated exhaust change, will negate that effect. Etc.
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Post by RandyT on Nov 22, 2011 17:37:01 GMT -5
In stock form it should hit 50mph no problem. Why do we always see modified motors that don't run as well as from the factory?.... You could put $1000 or more of upgrades on it and if you get more than 10% boost in horsepower I'd be surprised. Anything with the electronics won't make you go faster. Changing intake without a calibrated exhaust change, will negate that effect. Etc. I agree with the in stock form it should hit 50 mph, but mine came with a 5k rpm limiter on the cdi, so before I changed mine out I don't think it would have hit 50 or barely. I changed to an unlimited cdi, the coil, and iridium plug, and had no problem reaching 60 mph on the scoots speedo and turned about 6k I think, but no idea how fast it goes. Now with 10 gram rollers it just gets there quicker. Turns about 7.5K rpm. I was going to change out the torque spring to get a little more jump, but couldn't get the clutch bell nut off. Have to heat it with a torch, and try again this weekend
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Post by sprocket on Nov 22, 2011 18:38:24 GMT -5
Adjust the valve gaps in the last 1000 miles?
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dodie
New Puppy Dawg
Posts: 1
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Post by dodie on Nov 22, 2011 19:23:03 GMT -5
I have the same problem, top speed 50-52. Ifyour running this high of RPM after putting on a larger belt thats normal. What I found was a 125cc cylinder on a 150cc motor. good luck
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Post by dyoung1167 on Nov 22, 2011 21:09:32 GMT -5
you can try the heavier weights first and see what happens but i think the clutch springs(including the contra) are your bigger problem. as was stated the three clutch SHOE springs won't affect top end just the rpm needed for take off, which is not needed for the average scoot, meaning it's harder to putt through a parking lot without burning up the clutch shoes, but the contra spring does affect top end. it squeezes the belt in the rear and the weights have to ever come that pressure to get the higher ratio and reach top end speed. as was stated your rear gears may be to low, but if you used to get the speed your looking for then they are probably ok.
for the most part you can expect get to speed a little slower and keep (most of it) on hills, or reach speed faster, but not both.
more speed, not so much.
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Post by psikiguy on Nov 23, 2011 2:58:59 GMT -5
How much do you weigh?
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Post by RandyT on Nov 23, 2011 3:24:28 GMT -5
Are you sure your stock rollers weigh 14 grams~? You say with 12 grams your turning 8K rpms..you should be able to get the scoot over 50 mph. 8K is redline on mine, even though some say it's more like 10K. I have 10 gram rollers, and get 7.5k rpm's. I know scoots are diff, but I would have to think if your turning that many RPM's, even if your not at max ratio, you should be able to exceed 50 mph. Only other things is like dyoung said, but that high a rpm should throw even a lighter roller out to the edge of the variator, and overcome the torque spring. Good luck
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Post by Doug in San Diego on Nov 23, 2011 11:20:14 GMT -5
A few questions
1) Did you do all these mods in one fell swoop? or did you put them on 1 at a time?
Problem is, if you put them on all at once you can't tell which is causing the problem.
2) How are you checking your speed? The stock speedos are crap
3) Are you using a 130? That is very rich.
4) what was it getting to before? Did you have any speed gains?
I hate to say it, but I would go back to stock and start over one thing at a time.
If you don't want to do that (and who would?) check those weights and that jet.
Good luck
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Post by raq1025 on Nov 23, 2011 13:39:05 GMT -5
I weigh about 175 lbs. I did all the cvt mods at once almost a year ago. I didn't get what I expected & kinda abandoned the scoot. That's why I'm a little unsure of things. To get he jets I'd have to pull the carb. I've checked my speed with a gps. The speedo isn't so far off that I can't use it until I start seeing a difference. I just checked the weights of all my rollers with a food scale, so it should be accurate. I'm going to put all springs back (which will put the cvt back to stock.) I already put the 14g rollers and the shorter belt back but haven't been able to give it a good run.
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Post by sprocket on Nov 23, 2011 14:42:53 GMT -5
>>>I already put the 14g rollers and the shorter belt back but haven't been able to give it a good run.
Probably the engine... put the stock air box back on and try a #112 main jet
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Post by tour96se on Nov 23, 2011 22:29:02 GMT -5
or 110
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Post by raq1025 on Nov 25, 2011 14:13:58 GMT -5
Ok, good call on returning the CVT springs to stock. I returned the CVT basically to stock. The only difference from stock was the 115mm variator. 835 belt, 14g rollers, & stock springs: 54mph Changed to 12g sliders still only got 54mph on the same stretch of road as above but on a longer stretch saw 57mph for a brief moment at about 7500rpm. I changed the belt to the 842 belt and only saw 54mph on the longer stretch of road. I put the 835 belt back on and tried 3 12g sliders & 3 14g rollers I only managed about 52mph. So of the parts I have on hand, the 12g Dr. Pulley sliders & 835 belt gives me the best results. I haven't pulled the carb yet to check my jet, nor have I looked into checking my gearing. It still doesn't appear that my belt is reaching the edge of the variator. I don't want to throw good $ after bad on this scoot. What direction should I be looking with this? Should I be looking at 11 or 10g weights? Going lighter seems counter intuitive (I thought heavier weights got more top speed.) Should I be looking at a different variator? (This is one from MonsterGY6.) Remember stock intake is a no go. I will still be pulling the carb to check the jet. I don't know how to get to the gear yet, but I will research it.
Update: The carb jet is a 127.5 in 24mm carb.
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Post by sprocket on Nov 25, 2011 16:44:36 GMT -5
If your jet is #127.5 it is HUGE...for a GY6 engine you should be in the #110 to #115 range...
I didn't know they made a 127.5 for a CV carb.. I thought they went for #125 to #128 and #130...
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Post by tour96se on Nov 25, 2011 17:29:54 GMT -5
^^^thats what my jet kit has, 120-125-130. for just a uni filter you should prob be running a 110 or 112 jet....all depends on your climate, elevation. 120+ if you have an exhaust.
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Post by sprocket on Nov 25, 2011 17:57:21 GMT -5
The rule of thumb is to go up two sizes for an oiled UNI or K&W.. if your stock air filter is paper... if your stock air filter is foam you may not have to change the jet...
If you go with a free flow exhaust.. then you go up two more sizes
So if your stock jet is a #108 and you put on a UNI and an exhaust the you go to a #112 jet as a starrting point. I usually would go to a #115 because I like the engine to run rich...
However, if you put on any type of 'pod' air filter you should brace the front of the carb to the engine or you will be replacing the intake elbow because they will stress crack from the flexing caused by the throttle cable pulling on the carb...
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Post by RandyT on Nov 25, 2011 20:06:55 GMT -5
I guess also, what do you want your scooter to get to~? It's only a 150cc, and the need to go 70+ mph is unneccesary, let alone probably not safe on these inexpensive scooters. If you want a freeway ready scooter..buy a name brand one, that you can at least risk your life on~!
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Post by car6car on Nov 25, 2011 21:38:48 GMT -5
It is a 150 cc toy! Live with it or buy something else. I rode mine yesterday and couldn't understand why I didn't feel acceleration I used to. Well, I realized, that I just sold Kawasaki Vulcan 1500, there had to be difference! Price is not a big deal, couple years ago I bought 83 GoldWing for $350. If you want to ride faster, you have to watch Craigslist. December is the best time to buy a bike.
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Post by quest4fire on Nov 26, 2011 6:41:40 GMT -5
It is a 150 cc toy! Live with it or buy something else. I rode mine yesterday and couldn't understand why I didn't feel acceleration I used to. Well, I realized, that I just sold Kawasaki Vulcan 1500, there had to be difference! Price is not a big deal, couple years ago I bought 83 GoldWing for $350. If you want to ride faster, you have to watch Craigslist. December is the best time to buy a bike. I agree. For more speed, get a faster machine. Brakes and chassis are matched to the engine. More power by modification means faster wear and more breakdowns.
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Post by algears on Nov 26, 2011 6:59:36 GMT -5
It is a 150 cc toy! Live with it or buy something else. I rode mine yesterday and couldn't understand why I didn't feel acceleration I used to. Well, I realized, that I just sold Kawasaki Vulcan 1500, there had to be difference! Price is not a big deal, couple years ago I bought 83 GoldWing for $350. If you want to ride faster, you have to watch Craigslist. December is the best time to buy a bike. I agree. For more speed, get a faster machine. Brakes and chassis are matched to the engine. More power by modification means faster wear and more breakdowns. Hotrodding 101: When you add more "go" power, you need more "whoa!" power. The brakes on scooters are NOT over-engineered. Nothing on them is.
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Post by warriorboxerdog on Nov 26, 2011 10:17:46 GMT -5
I think 55 or 60 would be the max for a 150 scooter. My roommate has a 200cc motorcycle and max speed is like 70mph stock. Now he has 50 more cc's then you! If it was a 2 stroke you would have no problem going faster. 4 strokes are slower then 2 strokes and heavier. If you want more speed go with a big bore kit. There is no replacement for displacement!
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Post by sprocket on Nov 26, 2011 12:32:26 GMT -5
yeah... and the CVT transmissions are cool because they are a mini-automatics but they just sap away the horsepower from these little engines... because they are inefficient.
Put a gear box, clutch and a chain drive on a GY6 engine and you would see a remarkable difference both in acceleration and top end....
My point is everything is a compromise in life. These scooters are designed for urban use in town...if you are heading for the highways get a motorcycle... 250cc-400ccs are a nice power to weight ratio.
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