One of the best methods is to make a slug that fits the cylinder. Use a piston position calculator to determine how long it should be. As an alternate, measure from the spark plug seat to the top of the piston with the piston pressed to the top of the cylinder. Set the piston to the port opening position with a degree wheel. Measure the distance to the piston again and subtract the first measurement. A dial indicator held by a modified spark plug works well for this. Make one slug for the exhaust and one for the transfers. Cut the ports to the slug.

Lohring Miller

Hello,

First off id like to say thank you for the write up! Its very informative! One question I have is for the turbo crank mod, do you "sand" down all 4 corners of the crank? Or just the 2 sides (as seen in the picture you posted)?

Thank you for your help & time!:drinks:

Only done on the outside corners of the leading edge of rotation as shown.

Thank you for Zen porting tech,
i made the same porting . i run motor With WT-990 . after first run the engine need a while to get first throttle response , just first run when motor cold, the motor sound totally different , but i guess the motor is lean , for this reason i didn't get performance, i dont know which Carb i can use for this ported motor , Kindly help scott

So much ground to cover ????

First off generally a mod engine is going to have less torque than a stocker, so if running the biggest prop engine would run before you very likely may be over propped now ?
Pipe length generally SHORTER on a stock engine and LONGER once engines modified.
* This due to exhaust open duration being greater and the wave activity entering pipe sooner and returning as a boost signal to soon not optimized to later closing of the modified exhaust ports roof.

WT257, *WT771, *WT929 are currently IMO the best carbs to use these days (* personal choice)

Dear scott

Thank you for the zenoah porting info
Do you now where i can buy our order the frees tooling for the dremel

Regards
Guillaume

Get my cutters from: www.procarbide.com (Order SINGLE cut profiles)

Cylinder top size ??

scott, what is the squish and intake timing you use?

After a long time , still usefull to show the 'youngsters'

Will save me hours of discussing

Thanks Scott