110cc 3v motocross bike make and model???

[Daniel D]

Hi all. Just wondering if anyone knows what sort of bike/engine this is? I've never worked on one before. Thanks.

 

[Daniel D]

So this is where I'm at.
Bike has spark but has basically no compression at all. I can easily turn kick starter by hand. Makes no difference if spark plug is in or not.
I'm thinking the piston rings are gone or one of the 3 valves are stuck. Can the valves cause lack of compression or just the rings?
Question is, should I bother checking valves or should I remove head and check piston and rings.
Any help would be much appreciated.
Thanks

 

[AntNZ]

more than likely your rings are buggered, take the head and cylinder off to change the rings, if you think its a stuck valve just take the valve covers off the head and turn the motor over to see if the valve's are moving in and out.......do that first.
If they all move both ways then new ring's it is! good luck.

 

[motodevo]

Maybe give the clutch an adjustment before you rip off the top end. The kicker drives through the clutch, if its slipping it will feel like it has no compression. Also make sure the valves are closing 100% by doing a valve adjustment, a valve thats not closing will give no compression. The old lifan 3v 110s were a good thing in there day, but if you need a new piston i doubt you'll find one with the correct reliefs for the 2 intake valves. The cylinder and head are also unique to this motor, meaning the head wont bolt a regular 110 cylinder and this cylinder wont bolt to a regular head. Might have to give the cylinder a hone and a set of rings from a regular 110cc motor. The difference is the 3 valve 2 bolts on the side of the head joining it to the cylinder, where a normal 110 only has one in the middle.
Alot of guys used to buy high compression pistons for regular 110s and dremel the reliefs into the piston when they wanted to hop them up.
If you can fix it, it's worth the effort if only for the fact it's an unusual motor, like i said they were a good thing back in the day

 

[Daniel D]

Maybe give the clutch an adjustment before you rip off the top end. The kicker drives through the clutch, if its slipping it will feel like it has no compression. Also make sure the valves are closing 100% by doing a valve adjustment, a valve thats not closing will give no compression. The old lifan 3v 110s were a good thing in there day, but if you need a new piston i doubt you'll find one with the correct reliefs for the 2 intake valves. The cylinder and head are also unique to this motor, meaning the head wont bolt a regular 110 cylinder and this cylinder wont bolt to a regular head. Might have to give the cylinder a hone and a set of rings from a regular 110cc motor. The difference is the 3 valve 2 bolts on the side of the head joining it to the cylinder, where a normal 110 only has one in the middle.
Alot of guys used to buy high compression pistons for regular 110s and dremel the reliefs into the piston when they wanted to hop them up.
If you can fix it, it's worth the effort if only for the fact it's an unusual motor, like i said they were a good thing back in the day

Thanks motodevo.
Is it possible to adjust clutch when bike is not running as it's a semi automatic? If so, how would I go about doing this for this type of engine?
Thanks for your time.

 

[Daniel D]

After some investigation it turns out my timing chain is off as pictured. Any ideas as to where to go from here?

 

[Daniel D]

Turns out that the timing chain is broken. This is getting interesting.

 

[motodevo]

That would explain it! Only one thing for it, OFF WITH IT'S HEAD! If the timing chain snapped then you're gunna need to see whether the piston has kissed a valve/s and if so whether or not you have bent a valve or two (or 3). If the heads still good and valves are sealing it should be an easy fix