|
|
Post by slicknick4811 on May 25, 2016 20:42:58 GMT -5
Qmb 139, installed full bbk "80cc" exhaust, carb, filter, piston, cylinder, valvles, all done 100% to spec. Infact it's the second kit I tried due to me being at a loss here. The bike runs absolutely great, but I'm stuck hitting 6k rpms. Before I put the new variator on it would hot would hit 8k rpms. Which I'd like to be back in that range. I've tried from 5g to 9g rollers. Started high with the kit and worked my way down. And I just can't get over 6k.... I have 2 brand new cdi of different brands. Neither make a difference. Now if I put the bike on the stand with no load it'll hit hit 12k I believe. I let off 3/4 throttle at 10 rpms. I weigh 165. I've also tried a range of torque and clutch springs. Nothing has made a difference except my acceleration has bounced from crazy fast to shitty... I'm hitting 53 gps verified which I'm more than happy with, but why on earth can I not hit just a bit higher rpms?
Also, on to my second variator trying to figure this out aswell, I keep getting huge detrimental flat spots on my rollers.
What gives!?!?!?!?
|
|
|
|
Post by arkie on May 25, 2016 21:05:22 GMT -5
Have you ever entertained the notion that you are getting over 6k rpm? I for one find it very dificult to belive that you could get anywhere near 50mph only turning 6k rpm.
|
|
|
|
Post by 90GTVert on May 26, 2016 8:17:11 GMT -5
Stock gearing? 53MPH at 6000RPM would be really good for one of these engines.
If the rollers do let it rev higher, you can keep going lighter or put a stiffer contra spring in with the lightest rollers. That should get RPM up. If the sound and performance changes, but the tach doesn't, something is probably going on with the tach.
Try sliders. They don't wear so bad like rollers.
|
|
|
|
Post by slicknick4811 on May 26, 2016 9:10:43 GMT -5
I've entertained that notion yes, but I'm pretty familiar with rpms lol I've been racing quads and dirt bikes since I was 5. I know the tach isn't correct, but I get almost 6k higher according to the tach when it's not under a load. And when hitting a hill I lose around 10mph. I've rebuilt plenty of motors and this is my 2nd rebuild of this engine. Just trying to figure out what's going on here. I've installed 1k 1500 and 2k clutch and torque springs in diff variations same problem. Also when the bike is not under load it sticks at 6k then hammers to 12k and I feel while I'm riding I'm stuck is point.everything is brand new 2nd time again with same issue.
|
|
|
|
Post by slicknick4811 on May 26, 2016 10:43:52 GMT -5
Stock gearing? 53MPH at 6000RPM would be really good for one of these engines. If the rollers do let it rev higher, you can keep going lighter or put a stiffer contra spring in with the lightest rollers. That should get RPM up. If the sound and performance changes, but the tach doesn't, something is probably going on with the tach. Try sliders. They don't wear so bad like rollers. That's the thing I know I have this bike performing about to its max lol. But I'd just like to regain some rpms. I know it can run higher than it is and I know the stock tach isn't right, but the rpms go a hell of a lot higher with no load. |
|
|
|
Post by arkie on May 26, 2016 11:17:58 GMT -5
Ok so you said on the stand it sticks at 6k then will go higher. do you happen to have a grove worn in either your variator or clutch drive sheave? If not may I suggest a drive belt change.
|
|
|
|
Post by slicknick4811 on May 26, 2016 14:22:05 GMT -5
Literally everything is brand new. When I did the first build it was all new about 2 months ago, so I decided to go all new again to see if the problem was something stupid I missed. But it's not.. no grooves worn anywhere at all.
This is why I'm at such a loss here.
|
|
|
|
Post by 90GTVert on May 26, 2016 14:46:03 GMT -5
I don't suppose you'd be able to post a vid of this for us, would you? Sounds strange that it "sticks" at that RPM on the stand momentarily too. Vids have to be hosted on YouTube or another host and embedded or linked BTW.
If that's a no-go, then does it do anything when it sticks at 6K on the stand? Does it sputter, does it bog... anything other than normal operation (aside from obviously hanging in one spot)? If it's struggling to pass that RPM on the stand, I can imagine it won't want to under load.
|
|
|
|
Post by arkie on May 26, 2016 14:49:36 GMT -5
Well the only other thing I can conceive of would be a worn notch on your torque driver where the pins go through the slots. At any rate a 53mph qmb139 that can accelerate crazy fast and only turns 6k rpm, I wish I had those problems.  |
|
|
|
Post by slicknick4811 on May 28, 2016 9:17:53 GMT -5
Well the only other thing I can conceive of would be a worn notch on your torque driver where the pins go through the slots. At any rate a 53mph qmb139 that can accelerate crazy fast and only turns 6k rpm, I wish I had those problems. I'll try and get a video today, sorry it's been a couple days. 4mo old daughter has had all my time. And yes I'm very impressed with how it's running, I just want my 7500 rpms and to stop wearing out rollers in 200 miles! |
|
|
|
Post by humanshield on May 28, 2016 10:03:20 GMT -5
More and more "GPS verified" 50mph + QMB139's. Those Chinese are really upping their game it appears. My 150cc can barely top your little 80cc scoot with almost double the motor  What's gets me is my 50mm scoot with all those mods and more, and tuned to perfection doesn't stand a chance next to my 150. I need to attend your school of scooter modding bro. |
|
|
|
Post by slicknick4811 on May 28, 2016 10:25:27 GMT -5
youtu.be/dq4C1UvX5BgHere's the link, no I'm not hammering the trotted or running wot either, u hit it slow to show the rpms stick better... the mentioning of the guide in the clutch pulley made me think, that's the only thing I haven't looked at. I'll run down to my local shop and see if I can slap a used one on there to see if it makes a difference..
|
|
|
|
Post by niz76 on May 28, 2016 10:52:04 GMT -5
Seems like it's "shifting" at around 6k. The torque driver has a dual angle and it shifts like that. Seems kinda normal??
|
|
|
|
Post by slicknick4811 on May 28, 2016 11:33:40 GMT -5
Seems like it's "shifting" at around 6k. The torque driver has a dual angle and it shifts like that. Seems kinda normal?? Ok with that being said, how do I achieve that sooner while still keeping my top speed? If I drop weights it does the same thing just loses a couple mph... |
|
