Engine stuck/ Piston not moving

[RollingStones]

Hello eerbody,

So I took apart the top end of my engine so I could clean it and the piston and once I put it back on I was able to get it running for a few yards until it came to a halting screeching stop.

I realized that the bike would ride when I had the clutch pressed but as soon as I let go it would stop and the engine would be stuck.

I took it apart again and realized that the arm that connects to the piston which makes it go up and down is stuck and the rotating parts of the engine will not rotate.

Something may have fallen in there while I was monkeying with the piston and I didn't see.

My question is, how can I troubleshoot this to see where the issue may be coming from? is there a video anyone can point me to on taking apart the bottom end of the engine and troubleshooting for engine rotation issues?

Thanks for your help in advance.

RS

 

[crassius]

there's a set of those pics on this board

no troubleshoot needed - you got a piece of debris caught in your mains

 

[dougsr.874]

You say you took it apart again...what does that mean??? If you haven't pulled the cylinder off the piston you need to do that first to make sure the cyld. wall & piston are not pitted & ruined....If those items are good the only other thing to do is what's called splitting the case.....that's a major undertaking. you will need a gear puller, a large screwdriver. a gasket set or sealent, and a lot of time and infinite patience...depending upon your mechanical ability, sometimes replacing the entire engine is a better option...If the piston or cylinder is bad and you don't find what caused it you still need to split the case.

 

[RollingStones]

so do I basically take the whole thing apart and attempt to get whatever is in there out?

Ive never taken it apart further then the piston so I am a little nervous about doing so.

 

[RollingStones]

I just meant the engine head and piston. the piston looks pretty Fxxxed up now yea. Im moving out of state and the movers come to grab my stuff 7/23 so I doubt ill have the time to go through all that trouble. I'm thinking of just striping the engine apart so I have extra parts if needed in the future and riding it as a regular beach cruiser until I just buy a new engine....

 

[Fabian]

It's one huge f*#kup. You now have to take the whole engine apart to install a new crankshaft.

If you have f*#ked up the engine just by taking the cylinder off, i can't begin to imagine the f*^kup that will be created when you attempt to install a new crankshaft.

It might be best to simply purchase a replacement engine.

 

[Big Red]

To do a proper top end rebuild cost me $70 or $80 bucks last time I did it, An ENGINE ONLY is $100, Trust me, Its worth the extra 20 or 30 bucks to just order a new engine, And you have spare parts.
Big Red.

 

[crassius]

agree with both posts

 

[HeadSmess]

was it running before hand?

if so, why did you pull it apart?

to clean it? why? does a bit of carbon on the piston really upset you that much?

you reaped what youve sown... you stuffed your engine.


if you had to post this question, save yourself the time and effort and just buy a new engine, and leave it alone this time.

there is no reason to pull an engine apart unless it needs it. serves you right. ha ha and other vindictive comments po' lil engine

my guess is you were completely unaware that the rings have little pins and notches that stop them rotating, and you just jammed the thing back in, possibly with a hammer.

you know that rings "bed in" to the cylinder, and once you pop the cylinder off you have to re-hone the cylinder and replace the rings or it will always be a son of a pig forever after? possibly not.

a pro engine builder wont even turn them over until its time to start them.


what else? the circlips that hold the gudgeon pin in need the tags either removed or lined up in the direction the piston travels, or they snap off eventually.

um, the piston has to go around a certain way or the rings tend to try to jump out the exhaust port, and then break. the lil pins are there to stop the rings doing this. as all two strokes do, other than the odd exception... 4 strokes dont need it, they dont have great gaping holes in the cylinder walls.

once again, ha ha. congratulations


im being nasty at the moment just so you get the point...dont fix what isnt broken!

well, now you do have something to fix. giggity

 

[Fabian]

does a bit of carbon on the piston really upset you that much?

you reaped what youve sown... you stuffed your engine.

I agree.

The only time i look inside my engine is when it makes so much internal mechanical noise that my ears can no longer put up with all the rattling and clunking sounds, and these engines are able to make a heck of a lot of noise before they'll stop running.

A bit of carbon on the piston (even a lot of carbon on the piston) makes no difference in the operation of the engine from my experience.