ORIGINAL: Pat Roy

Not much to it really. Mix your oil at a ratio from 32 to 40-1 for the first couple of gallons. I prefer a good synthetic but a good natural oil will do. Say Pennzoil Air Cooled (natural), BelRay MC1 (synthetic), Bel Ray H1R (synthetic), Motul 800 (synthetic), Redline Two Stroke Racing Oil (synthetic), Stihl two stroke (natural), or the like. Do not use Lawnboy Ashless. There are a lot of great oils out there and all you have to do is pick one. I use 3W engines at work so there's been tens of thousands of hours of testing using some of those oils. Once the first couple of gallons have been run you can change over to a 50 to 70-1 mix, preferably with a synthetic. The hotter the day the more oil. 87 to 92 octane pump gas is just fine. There's no benefit to using higher octane gas.

For the ignition use a 4.8v battery with at least 800mAh of capacity. That will provide a bit more than an hour of running time for the ignition. Tom makes connecting the ignition leads easy by providing the connectors you might need. You have two leads coming from the ignition. One end of the ignition leads goes to the switch of your choice. One end on the switch leads go to the battery. A standard radio switch works just fine. The other ignition lead plugs into the lead coming off the engine. Mount the ignition and ignition battery somewhere they will not be next to the receiver, receiver battery, or receiver switch.

Here's a copy of somthing I had in another forum that covers the tuning process:

Basic Engine Tuning:

My tuning method doesn't really care which needle is set first. Either way, let the engine warm before you start twisting on the needles. You will not have an accurate needle setting if you start with a cold engine. The idle setting will be higher when it warms up if you start with a cold engine. Using the low range for a starting place the following works. You can use the high needle for a start as well if you want, just start at max rpm.

Set both needles to 1-1/2 to 2 turns open. That should be enough to get the engine started and running reasonably well. I like to bring the engine up to about 3,000 rpm or a little less and peak the rpm at that level using the low needle.

Now go to max rpm and tweak the high needle to max rpm and back off an audible skosh. I've never needed a tach so I can't provide a specific rpm drop amount. Go back to the low and peak it again at that lower rpm level. Leave the low needle peaked. Check the high one more time by going to max rpm and back it off that little skosh.

Now go fly.

Does the engine falter (sound like it's going to suddenly quit) when you go from low to high? The low needle is a little too lean. Does the engine sound like it's blubbering going from low to high? Then the low needle is a little rich. In the upper mid range does the engine sound like it's blubbering? Lean the high just a tiny amount. Can you hit max rpm in level flight? The high needle is a little lean if you can. Pull straight up vertical and see if the rpm sags any. If so the high end is a little lean. When you can go straight up at max rpm and not hear the rpm drop off you have it close enough. You may have to play with both needles for a bit to get it as close as you can. It's a trial and error process. Don't be surprised if the mid range does not become what you want it to until you have a few gallons of gas through it.

Remember that unlike a glow engine tiny movements of a gasser's needles have big effects. Often turning a needle the width of a small screwdriver blade is all you need once you're close to the right place. There's no need to bench run the engine nor is there a need to run it rich for break in. Set the needle to a point that it will be flown at all the time. All gassers made with cast components benefit greatly from heat cycling during the break in. The best heat cycling you can do with an engine is that performed in the air.
That means you fly at varied power settings to raise and lower the running temperature while keeping the temps within the normal operating range.

Note: If you change props to a different size or manufacturer you may (read should) have to tune the engine slightly again. Especially if you went to a larger prop from the one you originally tuned with.

ORIGINAL: paul5992

Check this cowl cutting job. I went back to my stock pipe. What do ya think guys? Just got it done.

ORIGINAL: cygnet

If you make it shorter it will get even more peaky I would make the header longer or use more prop.