Puch big bore kit.

[DieselTech]

I've been doing alot of reading among 2 stroke engines, why is no one using the puch big bore kits on these CG engines? CG engine is 63mm diagonal across studs & puch big bore is 65mm diagonal across cylinder studs. So why is nobody using them say over a minarelli? Surely a puch kit makes better power than a CG cylinder kit. I think it would be a faily straight conversion minus drilling stud holes to 8mm. Can anybody chime in on this? Reasons why or why not this would work?

 

[Karl Snarl]

Prob because they have to fill and drill new stud holes. Which makes me wonder why they have never made a spacer like with the minirelli kits.

 

[GreasyChris]

I think it has to do with the rod length and the stroke on the puch. The minarellis are already using a 40 mm stroke so it works out for the port timing. Trust me once you try a minarelli you will never bother with a China cylinder again.

 

[DieselTech]

Yeah puch does have a 43mm stroke instead of 40mm like the minarelli.

 

[GreasyChris]

I believe the length of the rod is also different. On the minarelli you end up using a low hole piston on a high hole crank and rod and then with the 10mm spacer plate. The port timings work out

 

[Street Ryderz]

Prob because they have to fill and drill new stud holes. Which makes me wonder why they have never made a spacer like with the minirelli kits.

The Minarelli vertical that those cylinders are intended for have the same/similar stud spacing but are 6mm so when you drill out the jug for 8mm stud holes you can account for any slight variances and not have to mess with the case, when going to bigger bore's like the saws or the Puch you will need to relocate the holes on the reg case type, the newer yd style cases I believe have the larger stud spacing but most require the spacer as Chris said to get the timing right or at least be able to bring the piston flush with the deck. The longer stroke being still under square should be ok rpm wise but will make the spacer thickness needed different again as to what is commonly available.

 

[DieselTech]

Thanks guys that's the answer I'm looking for, the cdh 110 cases look more like they would facilitate a minarelli better if I fill stud holes & drill & tap case to preferred stud pattern. You guys put a bug back in me like when I raced go-karts. Lol now its bicycles!!!

 

[Cannonball3]

You should be able to use a Minarelli horizontal cylinder on the 110cc spacing if you still want to build a case reed.

 

[DieselTech]

Yeah that's what I want to do, I just dont know if the horizontal minarelli has same stud pattern as minarelli vertical, plus stud spacing on cdh110 is 82mm diagonal across studs. I think minarelli vertical is 72mm diagonal across studs.

 

[Cannonball3]

The Minne horizontial has a 50mm square pattern with a 70mm diag. Its the same as a YD.
You will have to build it on a YD. You can get wrist pins/pistons in both 10&12mm for the Minnie. With the newer
bigger engines coming out Im seeing YDs drop a bit in price. My gut is aYD/Minnie will easily out do all but the stoutest modded CGs. And is cost effective too. Buy a engine only YD, a horizontal cylinder kit, a G2 reed set,
and a carb and you are basically there. Throw in a jog pipe and build away. I will do this at some point in the future.