doesn't idle?

[Goat Herder]

The gouge in that cylinder is a huge problem. You don't know if the debrees that caused it or any related shrapnel is still inside the motor block unless you disassemble the whole thing to clean it out and look. This implies taking the entire motor apart. You will totally mess up a new jug kit other wise. The result will be what you have now!

 

[motorizedmatt]

well I pulled the jug off and one of the piston rings was cracked. How do I get the piston off so I can throw another one on? Or is it kind of required that I take the motor apart and look for that little pice that broke off.

 

[motorizedmatt]

Is it possible to remove the piston with out taking apart the bottom of the block? If I have to take apart the bottom of the block can someone link me to a how to, I looked but the search on this site is really crappy.

 

[Goat Herder]

http://motorbicycling.com/f39/bicycle-engine-tear-down-391.html

china engine tear down - Google Search

 

[2door]

So you guys think that gouge in the cylinder is not the problem? What if I just swapped the jug over from another motor (I have a few busted ones)

This is interesting news. What is the problems with your previous engines?
What oil/gas mix are you using? If you've had problems in the past, what were they? There's usually a reason for "busted".
Tom

 

[motorizedmatt]

This is interesting news. What is the problems with your previous engines?
What oil/gas mix are you using? If you've had problems in the past, what were they? There's usually a reason for "busted".
Tom

I have 3 broken engines lol. They're broken becaus I have spent soo many hours trying to figure out whats wrong with them but none of them run. I use 32:1

 

[motorizedmatt]

Update - I fixed it! (for now at least) I put a different jug on it and switched the piston out to one I had from another engine and it runs great now, Idles fine and pulls all the way to top speed. Thanks for all the help guys!

 

[GearNut]

I am concerned that any remaining debris that was in the bottom end is still there. If even the teeniest bit of metal winds up in the bearings it will cause one of the rollers or balls, depending on what type of bearing is affected, to lock up and skid in the bearing race. That will lead to an early grave for that poor bearing.

I do wish you the best of luck with your repair. Sometimes one does get lucky and the bearings remained clean throughout the initial top end failure.

 

[motorizedmatt]

Well it blew again today. I have one more spare piston and jug left what do I need to do when I rebuild it so this doesn't happen?

 

[GearNut]

What brand of pre mix are you using? What ratio?
And break it in properly before running it all out for extended lengths of time.

 

[motorizedmatt]

What brand of pre mix are you using? What ratio?
And break it in properly before running it all out for extended lengths of time.

im using maxima with 32:1 and I always break it in correctly.

 

[MotorBicycleRacing]

Well it blew again today. I have one more spare piston and jug left what do I need to do when I rebuild it so this doesn't happen?

What blew?
Please be a little more specific.

 

[motorizedmatt]

What blew?
Please be a little more specific.

Well I havent had time to pull it apart again but I'm assuming there is something in there that messed up the side of the cylinder wall so it doesn't have good compression. If I take all the screws out of the sides of the motor will it come apart so I can make sure there isn't any peices of metal in there?

 

[GearNut]

How about step by step instructions?
Norman is awesome!
Click this ->http://motorbicycling.com/f39/bicycle-engine-tear-down-391.html