tuning a dr kit

[ducksta]

well the time has come for me to get the dremmel out, never tuned a cylinder/piston/cases before, got a new dr kit +descent exhaust 24/24 carb so any advice before i go too far

[paul d]

Before any creativity I'd file the edges off all of the ports in the barrel, DR's have sharp edges! Also a quick hone to give 4thou clearance helps to stop piston seizure. Don't worry about the piston slap. BBQ painting the barrel black helps with cooling. 21 tooth clutch helps with top speed. Take your time breaking it in!

[fastfrog]

Plenty of work to do on a DR barrel.
Lots of power outta it...

[fastfrog]

before with small combustion chamber

After:

[paul d]

What a work of art! Am I looking at bridged exhaust ports? If I was the owner of DR I'd hire you on the spot!

[fastfrog]

many thanks mate. lots of meat to grind.... And absolutely no risk of passing through...

[ducksta]

spot on do you have a port map for the barrall

[fastfrog]

unfortunately not. Engine has had different owners by now. Still running great.

[fastfrog]

Pmax at 7600 rpm.

timing:
T:130°
E:185°
I: 195°

[fastfrog]

this one shows the main difference between opened ports and the shut ones.