Engine Crankcase Replacement! ARG...

alienboy366 · Oct 17, 2011

So, I got a two stroke 66cc motorized bike with the shifter kit on it. When I installed everything about 3 months ago, I stripped one of the two bolts holding the shift kit jig to the rear of the engine. Now, one of the bolts is coming off and the whole thing is severely whack out of align. This has damaged my shift kit sprockets and constantly derails my chain from the freewheel to the engine.. Can someone tell me how hard it is to replace the crank case so I can reinstall my shift kit? And what should I do...(looking for permanent fixes)
THANKS, WANT TO BE BACK RIDING MY BIKE ASAP.!

Goat Herder · Oct 17, 2011

Witch side bolt did you strip? A Helicoil is likely very do able. Harbor freight sometimes has them. The whole thing might cost you 20 bucks..

MotorBicycleRacing · Oct 17, 2011

alienboy366 said:
CRAP, I have been looking forward to this race/meet up but shift kit has separated from motor. One of the two bolts attaching them stripped the motor mount. SO.... NO IDEEA WHAT TO DO. I heard replacing crank case is quite hard, HELPPPP MEE!!!!

Don't panic!

No need to replace the crankcase.

Do you have a 1/4" x 20 tap?
Replace the 6 mm bolts with 1/4 -20 bolts.

If the 6mm bolts holes are not too badly stripped out all you
need to do is run a 1/4 20 tap in to make new threads.

1/4 - 20 is just a bit bigger than 6 mm so the hole doesn't need
to be drilled first.

Another option is using a heli coil insert.

Give me a call and if you bring the case over today ONLY I will
retap it for you.

rohmell · Oct 17, 2011

Another option is to use Alumaloy/HTS-2000/Alumiweld to restore the hole and threads to original dimensions.

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Engine Crankcase Replacement! ARG...

alienboy366

New Member

Goat Herder

Gutter Rider

MotorBicycleRacing

Well-Known Member

rohmell

Active Member