Update: tested with a 15x8 and 18x5, scroll down to the props for results.

I looked at all your guys conversion so I had to try one for my self,

The engine is out of a Featherlite FL1500LE 23cc leaf blower, this has the long shaft and the small transferports (low performance version) I was disappointed!

Bore 34.44mm
stroke 26.40mm

Displacment is 24.6cc, the box says 23cc??

Stock port timings are:
Exhaust port duration 139 degrees
Transfer port duration 92 degrees
Intake duration 120 degrees
Head clearance stock is .044

Mods that I did to the engine were:

Machined .020 off the bottom of the cylinder

Machined .020 off the top of the intake port (no other mods to the intake port were done)

I skirted the piston for better flow the the transferports

For the transferports I did not widen them, I increased there duration only
Primary transfer ports were increased to 124 degrees duration
Secondary transfer ports were increased to 128 degrees duration

The exhaust port duration was increased to 155 degrees

The intake duration was increased to 124 degrees resulting from lowering the cylinder .020

And the new head clearance is .024

I stuffed the crankcase by adding a piece of .300 thick nylon plastic to the back cover

The muffler and prop hub are from wackerengines.com (excellent service from them BTW)

The carburetor that I used is a walbro WA 167A

Fly wheel was lightened

I machined some of the excess cooling fins off the cylinder to save some more weight

The engine weighs 3 lbs. 5 oz. with everything on it ready to run

Perfomance so far after about 1/4 gallon through it of regular gas mixed at 32:1 of Klots R-50 synthetic is:

15x8 @ 8600 rpms
16x8 @7600 rpms
16x10 @6900 rpms
18x5 @ 7300 rpms
18x6 @7100 rpms
18x8 @6400 rpms


Frank B.