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Old 02-29-2008, 10:20 AM
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Norman Norman is offline
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Join Date: Jan 2008
Location: pampa texas
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Default re: Motorized Bicycle Take a Tip...Leave a Tip

I found this on my 70cc Dax engine. Which has needle bearing on both ends of the rod.
The base gasket on the cylinder is 0.070 (2) 0.035 gaskets I removed them and replaced it with a 0.055 thick gasket and it helped the performance now it runs better. I went a little too far and used a 0.032 gasket and found that the piston will tap the machined lip on the head at higher rpms. I ground off the lip about 0.020 all around the head sealing lip and that took care of the tapping and I went to the 0.055 base gasket just to play it safe.
I was surprised to find that even with the needle bearings on the wrist pin the piston can wobble or rock in the same direction or parallel to the wrist pin just like the bushed one can which its not supposed to do anyway on other engines its not supposed to. So there you go. I might try the 0.032 base gasket again but for now it runs a heck of a lot better.

Last edited by Norman; 02-29-2008 at 10:23 AM. Reason: cause I can
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