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Post by bones113 on Nov 1, 2012 15:12:07 GMT -5
My Linhai main street 300 scooter has developed a bad vibrating, pulsating problem. It happens over 35 mph and increases, decreases with throttle. I have checked the muffler connections and all are tight. What could it be?. There is plenty of power and I have no lag in acceleration. There is a shudder on take off up to about 5-7 mph after that it goes away. I have finally got the demon outs of the motor worked out with the intake manifold being the culprit in the end. After I replaced the manifold and the fuel pump with a mikuni high flow pump the motor is running like it ought too. Now this pulsating problem has reared its ugly head. I now have 5100 mile on the scoot. I can feel the pulsation, vibration under the seat and even in the grips at times. The bike handles very well and is true to the road. I thought I finally had all the problems fixed. I have also checked the motor mounts for tightness and they appear fine. It is driving me nuts. Any ideas?.
Thanks.
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Post by jlee on Nov 1, 2012 16:20:17 GMT -5
It sounds like the crankshaft counterbalance weight may have shifted or broken.
Bent or misaligned forks might also cause some of these symptoms...
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Post by bones113 on Nov 1, 2012 18:09:16 GMT -5
It sounds like the crankshaft counterbalance weight may have shifted or broken. Bent or misaligned forks might also cause some of these symptoms... Thanks for the input. How does one check the crankshaft counterbalance weight?. How about the forks?. Is there any how to's or videos on those?. |
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Post by xxbenjamminxx on Nov 1, 2012 23:53:48 GMT -5
Mine Sid the same thing at higher speeds and changing the belt took it away.. old belt was stretched. Will do it again if I put the old one back on.
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Post by jlee on Nov 2, 2012 0:40:19 GMT -5
It sounds like the crankshaft counterbalance weight may have shifted or broken. Bent or misaligned forks might also cause some of these symptoms... Thanks for the input. How does one check the crankshaft counterbalance weight?. How about the forks?. Is there any how to's or videos on those?. I'm afraid it's a complete engine teardown to get to the crankshaft. There are several methods to check the forks - easiest is with a long straightedge - it's not really bike-specific, so check out any motorcycle video on youtube dealing with fork alignment. I admit it's a longshot though, based on your symptoms. |
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Post by prodigit on Nov 2, 2012 3:28:19 GMT -5
Suppose the wheels are balanced?
Sometimes it could be a resonant frequency with one or several things in the motor (say, cables hitting the walls, or a screw came somewhat loose, and parts are vibrating)...
Just saying...
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Post by cheapeto on Nov 2, 2012 8:27:28 GMT -5
I will get a weird sound when my final drive oil is low, as there is only about a cup or so in there.
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Post by jazzman on Nov 3, 2012 1:07:46 GMT -5
Shudder on take off sounds more like your clutch is slipping. The pad arms may be binding and hanging up. Also the pads will glaze pretty bad on a heavy scoot pulling the weight and if so it will pulsate unless your on the throttle. Maybe take the clutch off and lube the pivot points on the arm pads as well as where the arms fit between the metal plates.
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Post by jlee on Nov 3, 2012 1:11:27 GMT -5
Shudder on take off sounds more like your clutch is slipping. The pad arms may be binding and hanging up. Also the pads will glaze pretty bad on a heavy scoot pulling the weight and if so it will pulsate unless your on the throttle. Maybe take the clutch off and lube the pivot points on the arm pads as well as where the arms fit between the metal plates. Ah, good call jazzman! That fits much better than anything else so far. |
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Post by oldkid on Nov 3, 2012 9:49:21 GMT -5
Bones, I've never had that on my Mainstreet, but my 150cc had a vibration on takeoff at low speed and holding the rear brake a relving up the engine a few times fixed it. I suspect clutch dust had balled up in the system and I wore it off. The vibration at speed is probably tire related or belt related. I don't know, but I would try to ride it to a down grade and let up the throttle and see if you still have it with the coasting engine. However with everything still turning it may not help. AS you know the clutch releases at about 5 mph and I also wonder it you could stop at the top of a hill and just let the grade take you up to 35 mph with out the engine. I really believe you have something dirty or a bad tire but.... ??
Let us know what it is when you find out.
Good luck,
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