crankshaft play

Fuji Moto

Fuji Moto

New Member
After I mounted my engine for the first time i shook it side to side ad i could hear something knocking back and fourth and i found out it was the crankshaft it has about an 1/8 of an inch of play and when the motor is running ut automaticall pulls it to the side with the gears, hard to explain but if you've seen this before you will know what i mean, i tried shimming behing the magnet with rubber but it onl fixed it temporary as it gets pulled to the one side like i explained. Also I cant seem to get my motor to run consistenly it always seems to run different and never really wants to wind out properly and i've tried lots of things like, different oil ratios differnet carb(s) configurations and a bunch of stuff , but i cant get it to run consistent, sometimes it will rev up and do around 45 50 km then i slow down adn hit the throttle again and it will just bog and barely power up any thoughts?
 
I've never seen any spec for crank end play on these engines. End play needs to exist but how much on these engines I don't know. I do have one that was built from parts it has pretty close to 1/16" end play. I shim the crank behind the roller bearings ,to do that you need to split the crank case.
As for it running crumby is the engine fairly new?
 
yes, it is fairly new i only ran about 4 or 5 tanks so far I broke it in pretty slow the first 3 were mixed rich and I figured that's why it wasnt running too good I may also have weak igniton, the spark used to be blue then the wires shorted out because of where I installed the cdi and i blew the mag, replaced it and the wires on the cdi only have two little threads of copper left to them so it might be a weak spark now it looks more yellow when i check it , I still am waiting for a new cdi. how long does it take to break in usually?
 
and i;ve checked for leaks and i dont think there are any, i've made new gaskets with quality paper and i didnt move the needle on the new carb yet , i might try different oil or something , not sure what else to check or change or try
 
check the color of the spark plug if it's oily and black that tells you its running rich or too much fuel
it should be tan or a chocolate brown. could be you will need to lean it out some.
If your wires are getting bad on the cdi or breaking off right at the spot where they go into the cdi it would be hard to repair it. So the easiest thing would be to change out the cdi.

Sometimes you can use a soldering gun that will put out a lot of heat to carefully melt the plastic resin around the wires. The resin will crumble with heat making it to where you might be able to get to good wire. Then you could solder on new leads to make a poor boy repair. to rebed the leads 5 min epoxy will work to seal it back up.
Norman
 
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