Brand new to gas bikes.

[Tyler6357]

I took of the cylinder head and gobbed oil in there, rocked it back and forth and the engine unsiezed. There's no cylinder wall damage.

However after spinning freely for a while the engine will seize again and has to be rocked back and forth to unsieze.

Oh really? wow, I'm sorry, I'm not an expert on these engines. It's possible that the piston rings are not lined up properly. I would try pulling the cylinder off and checking the piston rings. There should be 2. Make sure they are each in their grooves on the piston. Slowly rotate each one until they won't spin anymore (are stopped by a small piece of metal on the piston). Make sure that you can squeeze them together with your fingers against the piston. Now try to put the cylinder back over the piston. Squeeze the top ring with your fingers and slowly slide the cylinder down over it, do the same with the second one then slide the piston down against the gasket on the engine case. Now try to engage the clutch and see if it still gets stuck. If it still gets stuck it's possible that something fell into the engine case. Try taking the cylinder off and turning the engine upside down and shaking it, maybe something fell in there.

 

[Ludford]

Ok so the siezing at a certain point isn't the engine. For some reason when the master link gets to a certain tooth on the engine sprocket it stops and wont go allow the sproket to turn any more.

 

[Tyler6357]

Actually, the more I think about it the more I think that something has fallen into the crank case (lower end) and is causing the crank to get stuck. Take off the cylinder and pull the piston up to its maximum point (closest to the head location), then turn the bike upside down and slap the engine, shake the whole bike if you have to and see if anything falls out. It could be that a piston ring broke off and part of it fell into the case, check the piston rings for any breakage, they should be totally round except for a small gap in each one. They should each be the exact same.

 

[Tyler6357]

Ok so the siezing at a certain point isn't the engine. For some reason when the master link gets to a certain tooth on the engine sprocket it stops and wont go allow the sproket to turn any more.

Oh, ok, forget what I said---haha, It sounds like the chain is your problem, thank goodness! Try to take the master link off and put it together again. If you can't get it to stop getting stuck you probably need a new chain. The chain has to flow over the engine sprocket smoothly without getting stuck.

 

[Ludford]

I don't think there is anything wrong with the engine. It will freely turn without seizing with the chain off.
The problem is that it seizes with the chain on, when the master link gets to the engine sprocket

Should the master link clip have it's open end towards the direction of travel or away?

 

[Tyler6357]

I don't think there is anything wrong with the engine. It will freely turn without seizing with the chain off.
The problem is that it seizes with the chain on, when the master link gets to the engine sprocket

Should the master link clip have it's open end towards the direction of travel or away?

The open end of master link clip should point away from the direction of the chain.

 

[Tyler6357]

Also, make sure the clip is not bent or sticking out in some way. If it's bent try to straighten it out with pliers or in a vice. If you have to lightly grind of the bent metal that sticks out but don't take off too much or it won't stay in place.

 

[Tyler6357]

If you can't get it to stop getting stuck you will need a new master link.

 

[Ludford]

Got the chain spinning semi freely, Went out to try and start it, wouldn't start again and my master link clip flew off and is now AWOL. That's be buggered for today then.

Are these "420" sized chains? Need to order the right size master link.

 

[Tyler6357]

Got the chain spinning semi freely, Went out to try and start it, wouldn't start again and my master link clip flew off and is now AWOL. That's be buggered for today then.

Are these "420" sized chains? Need to order the right size master link.

I'm not real sure, I am using a 1/8" regular sized BMX bicycle chain that is extra strong, that I find it flows through my engine socket smoother and works better than the one that came with the kit. But I think they are 415. Sorry you lost the master link clip but it sounds like it wasn't working correctly anyhow.

 

[rossrider]

Yeah mine is a 415 chain, you can find them on ebay for pretty cheap brand new!

 

[Toadmund]

Most of these two stroke engines are low compression so that they're easy to crank. So unless you've up the compression to around 15:1 don't run premium.

The problem I have is that I used to use regular, but I have been using high octane. Why?
Because the lower octane stuff has ethanol in it and people say that is bad for our engines.
Damned if you do, or don't.

 

[Toadmund]

I got a KMC HD 415 chain, problem is it's not long enough, so my brother wanted one, so we got two and split the third for links.
We also broke two chain tools!

 

[Toadmund]

The only real solution is to shave my head.

If I can't change the gas, I'll change the compression.
(sometime)

 

[Ludford]

I'm going to have to get a new chain because this one is fowling up as it goes round the sprocket, I think one of the links doesn't turn as much as it should.

Is there any way to tell what size chain I need?

 

[Toadmund]

Size is here, but if you get this you will need a few more links, and don't use your crappy chain for links
I have a lifetime supply of extra links.