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Post by madirishman on Apr 1, 2015 22:32:11 GMT -5
New to scooting and have been reading posts for months trying to fine tune my 49cc taotao. It has about 1,500 miles on it. When I bought it, it was running about 35 mph. I adjusted the valve clearance from i/e .001/.001 to. 002/.0025. I knocked the centers out of 1/2 of the rollers. Got speed up to 43 mph. Then the spark plug blew out of the socket (I probably tightened it to much and stripped the head threads). I bought a new head and was back down to 35 mph. Two days later, at about 1000 miles, the drive belt broke at full speed. After I put the new belt on, my new top speed was 30. I have bought a new carb and moved the clip up one from center and down one from center. I put a new jet in (89 I think). I've bought the multi pack of rollers and have put several different weights in. I put a 'high performance' variator and clutch on. I changed the head gasket. I have changed the valve clearances up and down, but can't get speed up over 30. Any advice would be greatly appreciated. Thanks.
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Post by madirishman on Apr 1, 2015 22:36:19 GMT -5
Sorry, I also bought a tachometer. Starts out @8000 rpm, jumps to 20mph pretty quickly, revs drop to 7000,and acceleration slows, then at about 26 mph, the revs drop to 6300,and acceleration just dies.
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Post by humanshield on Apr 1, 2015 23:08:25 GMT -5
43 is amazingly fast for a stock 49cc scooter. My 100cc Big Bore scoot tops at about 42. Unless going downhill or with a good tail wind, then almost 50. Your valves are a bit looser. That .001 and .0015 makes a difference the motor can feel. But running them too tight is risky. The exhaust valve cant cool as well. Also, is possible the new head does not flow quite as well as the old head. Hard to tell.
I think your biggest issue right now is getting the carb adjusted right.
You may be too rich and it wont reach peak power if it's too rich
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Post by madirishman on Apr 2, 2015 0:01:41 GMT -5
The data plate says valve clearance i/e .003/.006. I have it at .0025/.004 right now and the carb pin in the center position with 7 & 8 gram rollers in it. An thinking about getting the 72cc upgrade, but want to exhaust all other avenues first. How does the flow change between heads. Is it a different shape in the combustion chamber?
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Post by scooterpimp on Apr 2, 2015 5:58:52 GMT -5
Did you put in same size belt? Sometimes a belt needs to breakin /stretch a bit to ride high on pulley.
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Post by runningbuck on Apr 3, 2015 22:59:42 GMT -5
ok IMO you have too heavy of weights for a stock it should be around 5 to 7 also recheck the weights as the kit weights don't last long they just to get you the weights you need to buy a good set if you keep using the kit rollers they will flat spot and wear quick and give you loss of performance like what you are talking about if it runs great with 7 and 8 gram rollers buy a good set and install them
cheap set = cheap parts = replace often
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Post by madirishman on Apr 4, 2015 22:45:27 GMT -5
Belt had about 500 miles on it. Is that long enough to break in? None of the package of weights had been on longer than 2 or 3 miles (just long enough to test drive for speed). I took the 'high performance' clutch and variator off. Now I've screwed the pooch. Was changing to lower weights and when I hit the nut with the impact wrench, it impacted a couple of times and then started spinning. How hard is it to change the drive shaft? ?
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Post by madirishman on Apr 7, 2015 16:16:39 GMT -5
OK. Drive shaft want destroyed, just needed a little work. Valve clearance set at I/O .003/.005, have 4 & 6 gram weights with stock variator and clutch. Revs up to 8000, gets to 25 quickly, but a little slower than before. Revs stay over 80 0 0 and climb to nearly 9000 with a top speed of 38 mph. Should I raise both variator weights or maybe just go to 4 & 7? Thanks.
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Post by 90GTVert on Apr 8, 2015 8:43:14 GMT -5
You shouldn't need to do all of this fiddling with valve clearances. Pick one... most commonly 0.002"-0.003", and leave that alone. Or just leave it as is if the current setting isn't making the valvetrain noise loud.
Your current avg is 5g per weight so I think the 4+7 mix for 5.5g avg would be good to try. It takes some fine tuning to get them just right. There's a point where the stock gears won't let you get much faster without high revs too.
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Post by madirishman on Apr 9, 2015 16:51:38 GMT -5
Thank you all for the advice and direction. I'm going with the 4/7 rollers and maybe later this summer do the 72 or 80cc upgrade. Human shield, I prefer cruisers over doughnuts if you don't mind. Thanks.
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Post by madirishman on Apr 11, 2015 12:47:15 GMT -5
Crullers, not cruisers.
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