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Post by yourgevidge on Jul 2, 2017 16:51:08 GMT -5
I have 2016 YIBEN CHALLENGER, 3000K+, that is my ONLY transportation. I live in the mtns and struggle with hills (10mph-20mph on steep grades). I can get 50mph on the flats at around 9200rpm, but desperately need more torque. Any advice on free to cheap DIY mods that would help me get on up these hills would be awesome.
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Post by yourgevidge on Jul 2, 2017 16:53:19 GMT -5
I have a high flow air filter($5) and drilled out the plug to get to the air/fuel screw, but it's otherwise stock.
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Post by lostforawhile on Jul 2, 2017 16:57:51 GMT -5
pictures, I also have a 2016 Yiben, but it was missing the model name as the dealer stuck their name on it, what carb do you have? mine had the Keihin which is the better carb, you can take out the restrictor ring from the variator and get a unrestricted CDI, I just paid 6 bucks for one from ebay, also look in the end of your air cleaner inlet, and see if there is a restrictor plug with four holes in it,
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Post by lostforawhile on Jul 2, 2017 17:00:35 GMT -5
I wont know how much a difference the cdi will make as I have a hole in the carb diaphram, and I'm down waiting for parts,but make sure you run at least 93 and use non corn gas if you can find it
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Post by lostforawhile on Jul 2, 2017 19:24:35 GMT -5
there is also a throttle stop screw on the carb on some of them, that won't let the butterfly open fully, if you back off the screw until the butterfly opens fully you will be good, most carbs have a throttle stop, but sometimes they adjust it to prevent full throttle opening
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Post by badpumpkin on Jul 4, 2017 9:09:17 GMT -5
Welcome, before doing anything, watch 90verts videos on upgrades. You will save money and headaches. Now, I do highly recommend a 72cc kit, sliders,a9 cam, and carb jets. Also look at the bottom left of what other rider's setups are.
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Post by yourgevidge on Jul 14, 2017 14:05:29 GMT -5
As I said earlier, I have a high flow air filter "cone shaped w 3" 90°rubber elbow turned up to keep everything kinda dry",and I do have the kelihn carb. and unrestricted CDI(I can get 10,000+rpm on a downhill run). I drilled out the plug to get to the air/fuel screw because I was running WAY too lean after removing the entire factory air box/filter/and pipe. Definitely want to go with a BBK/big valve head/and A9 cam when my budget allows. But working on getting my license back and cheap is the name of the game right now. How big should I go upjetting the carb without upgrading the exhaust?
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Deleted
Deleted Member
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Post by Deleted on Jul 14, 2017 15:12:00 GMT -5
If this is your only transportation, I would suggest riding it. Big guys+50cc+hills=10-20mph going up hills. The only mod to get up the hill faster is more power(cylinder kit). Some CVT tuning will help(lighter roller weights+1k torque spring), but only marginally
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Post by yourgevidge on Jul 16, 2017 19:49:49 GMT -5
Can anyone tell me what gear ratios are on gy6's with 10" and 12" wheels.
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Post by dan50 on Jul 16, 2017 20:52:22 GMT -5
Welcome. My 139QMB has a gear ratio of 11.1:1 with 10" wheels. The best mod for hills is tuning the CVT. I did mine for just under $50. Buy a 1k (blue) and a 1.5k (yellow) contra springs for the clutch, this gives you a choice. Hoca brand Contra springs are $14.99 each. Link; www.partsforscooters.com/169-207_QMB139_Torque_Spring?sc=34&category=132705Also get rollers for the variator, 4 gram, 5 gram and 6 gram. You can mix 3 of each set to get 1/2 gram weights. For example, 3 of the 4 gram and 3 of the 5 gram will get you the same as 4.5 gram. Alternate the weights in the variator to keep it balanced (4g, 5g, 4g, 5g, 4g and 5g). Hoca brand rollers are $8.99a set. Link; www.partsforscooters.com/169-149_QMB139_Roller_Weights?sc=34&category=132705I tuned my CVT so the variator doesn't reach full travel until 24mph to 25mph. This gives me more power up hills and into the wind. What I ended up with for a stock 50cc 139QMB was the 1k contra spring with 5 gram rollers. That also allowed the engine to be in it's powerband for acceleration. I still slowed down up a steep hill, but not under 25mph. My top end speed also went from 36mph to 42mph with stock motor. I recently installed a 47mm BBK (Big Bore Kit). This gives great hp gain and power to go up hills. The stock head and crank will work well with a 47mm BBK (which is 72cc's). An A-9 cam also helps out on power. These are inexpensive mods that are easy to do (watch videos in the Tech Section). Also, download the 139QMB manuals (the link is on the left side of the screen), these have exploded diagrams of the engine and CVT alongwith torque specs and a bunch of good info. A tool that you'll need to make life easier is a 4t variator locking tool. I bought mine for about $15 from ebay, but I can't find one from an American seller. |
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Post by jeff84 on Jul 16, 2017 21:26:27 GMT -5
the first thing I would do is install a stiffer contra spring. its cheap and easy. you will surprised just how much of a difference that one little change will make
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Post by yourgevidge on Jul 17, 2017 6:01:39 GMT -5
Yea, I've noticed a gradual but dramatic drop in rpm when accelerating and pulling hills. Did a little research and I figure my contra spring is to blame. Could the heat inside the case cause the spring to lose some of it's stiffness? I plan to vent it because it gets pretty hot, almost too hot to touch.
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Post by dan50 on Jul 17, 2017 22:45:05 GMT -5
CVT's do get very hot. There is a lot of friction with the clutch shoes, variator rollers and ramp plate and the belt rubbing on the pulleys. The heat will weaken the force the spring has, after awhile the spring can fail due to metal fatigue. A name brand contra spring like Hoca, is made of better material than the stock Chinese springs and will hold up better. Same with the drive belt, Don't go cheap, cheap belts break really quick, I've read that sometimes they can fail in as little as 5 miles. Bando or Gates are the most common quality belts that are available.
A good vent is to find a PVC fitting for the flywheel timing hole on the right side fan cover, then run a hose (3/4" to 1") to the CVT and use a metal fitting the same size, drill a hole in the front top of the CVT cover with a hole saw, hook up the hose and the fan pumps cool air through the CVT.
I'll be doing that mod soon myself.
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yeska
Scoot Member
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Post by yeska on Sept 23, 2017 16:06:22 GMT -5
CVT's do get very hot. There is a lot of friction with the clutch shoes, variator rollers and ramp plate and the belt rubbing on the pulleys. The heat will weaken the force the spring has, after awhile the spring can fail due to metal fatigue. A name brand contra spring like Hoca, is made of better material than the stock Chinese springs and will hold up better. Same with the drive belt, Don't go cheap, cheap belts break really quick, I've read that sometimes they can fail in as little as 5 miles. Bando or Gates are the most common quality belts that are available. A good vent is to find a PVC fitting for the flywheel timing hole on the right side fan cover, then run a hose (3/4" to 1") to the CVT and use a metal fitting the same size, drill a hole in the front top of the CVT cover with a hole saw, hook up the hose and the fan pumps cool air through the CVT. I'll be doing that mod soon myself. have u done it ,, more idea's for stock cvt , am traying to find more so materials ,that will allow air and protect and the same time |
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