Smaller head on larger case?

[tig5]

Hey guys, I'm wondering if I can put a smaller jug and head on my Zongshen 140cc?

I have a CT110 engine and I want to know if I could put the piston, jug and head on the Zonger temporarily for "legal purposes". If not, would another smaller capacity Zonger (110,125cc) head setup work? Are the stroke lengths the same or would I have collisions?

Any thoughts would be appreciated. Basically I want to reduce the capacity of my engine without changing the engine block itself.

Cheers

 

[unit1]

Buy a set of number stamps grind the 140 off ya cylinder and restamp 110

 

[tig5]

Yep that's cheap and easy option B, anyone know if option A is possible?

 

[my67xr]

Buy a set of number stamps grind the 140 off ya cylinder and restamp 110

The number's are raised on the cylinder though, and it's not too legal either.

You could compare the cylinder's side by side, check the height of each cylinder from base to top, and check the head stud pattern too.
Then you need to check the gudgeon pin size's etc
I'm 75% sure it won't work though

 

[unit1]

The number's are raised on the cylinder though, and it's not too legal either.

You could compare the cylinder's side by side, check the height of each cylinder from base to top, and check the head stud pattern too.
Then you need to check the gudgeon pin size's etc
I'm 75% sure it won't work though

are the numbers raised on the ct110 cylinder
My z155 came with fresh grinding marks and 155 stamped over it was restamped at the factory

 

[tig5]

The Zonger has 140 raised on the cylinder. The Ct110 head has a different hole pattern so that won't work. Anyone know if a Zongshen 125 or 110 head would fit? It would only be temporary and wouldn't have to run well.

 

[motodevo]

Might want to do some investigating, most states will allow for a 20-25% increase in capacity without the need to have it engineered or approved which is mighty close. The ct110 brakes are also used on higher capacity models to (xl175,etc) so even if you did have to get it checked there shouldn't be an issue as the brakes, suspension, etc are more than up to job with the extra capacity. I'd be talking to a clued up motorcycle mechanic/roadworthy tester, you could be worrying for nothing. Hell, there's heaps of guys running 190s in Z50s. Also be aware most china engine numbers have the bore diameter in the first few numbers (57mm) so anyone inspecting it that is savvy with pit bikes will know its a 140, that and the fact a 110 bore will still end up around 120cc with the extra stroke of the 140 crank

 

[tig5]

Thanks for that info.

I decided to go the legit way and filled in forms and emailed structural engineers. After speaking to the "Top Dog"safety officer he said I could do it as a basic mod, just take it to the test shed and get them to change the numbers No engineers, no TAC meeting, no probs.

He's even given the guys at the shed a heads up so I don't have any drama. Dream result.

 

[motodevo]

Good result, atleast now if anything happens you know you're 100% legal. Sounds like it would be fun to rip up the streets on