Hawk Rebuild

[Megadan]

Just my opinion on the big nore cylinder. Being "worth it" is a matter of opinion. Will it provide a gain? Absolutely. On it's own without some head porting and/or a cam upgrade, it likely wouldn't be a whole lot. Plenty more torque on the bottom end to take advantage of, but no real top end improvement.

The other real issue being cost. Motocult offers a machined and decked 70mm bore jug ready to install with the piston and new gaskets for $250. If the supplier in Aliexpress ever gets them in stock again, there is a source there that runs about $150 that already has the sleeve machine, ready to bolt on. It's not decked.

A regular bore cylinder can be had on ebay for as little as 60 to 70 bucks.

[Brook]

Originally Posted by Megadan

Just my opinion on the big nore cylinder. Being "worth it" is a matter of opinion. Will it provide a gain? Absolutely. On it's own without some head porting and/or a cam upgrade, it likely wouldn't be a whole lot. Plenty more torque on the bottom end to take advantage of, but no real top end improvement.

The other real issue being cost. Motocult offers a machined and decked 70mm bore jug ready to install with the piston and new gaskets for $250. If the supplier in Aliexpress ever gets them in stock again, there is a source there that runs about $150 that already has the sleeve machine, ready to bolt on. It's not decked.

A regular bore cylinder can be had on ebay for as little as 60 to 70 bucks.

https://www.ebay.com/itm/250cc-Cylin...5-e0bc64292688

Will this one do? its a link from the good ol boys youtube channel but mine is a 2021 so i dont know if these engines have changed at all.

[Bill Hilly]

Originally Posted by Brook

https://www.ebay.com/itm/250cc-Cylin...5-e0bc64292688

Will this one do? its a link from the good ol boys youtube channel but mine is a 2021 so i dont know if these engines have changed at all.

I think that's the stock size bore. The kits can be deceiving. The 300 kits with a 70 mm pistol is actually going to equal 250 cc on these motors, and if you do buy one,it either has to have the outside diameter of the "sleeve" to be at a 73 mm, if I remember right, and it has to have a 16 mm wrist pin.