Chainsaw Repair

How often do you go outside your recipe papers?  Or do you generally stick to building them exactly the same

That's a good question Andrew. I'm glad you brought that up.

When a model is something new, like this one was last year, I'll stay close to the original timing numbers. I'll add compression, set the squish in the .025" range, try some ignition timing advance, etc. Then when I put a few tanks thru the saw, I'll try to decide if it needs more exhaust, transfer, intake, and so forth. After that first saw, then I'll vary just the transfer, or intake timing a couple of degrees to see if it makes a difference. I'll vary a few degrees over ten - twelve saws, trying a little different numbers. When I see that I've gotten that model running the best I can make it, I'll stick with those numbers.

My worst fear is making a turd. It would really look bad if a couple of guys with the same saw, built by the same builder showed up at a GTG, swapped on new chains and one saw just waxed the other one's ass. That's why I'll only made small changes over many saws.....

Now to match the muffler shell to the cylinder. Again we use the heat shield as a template.





We use a mesh screen that is more open in mufflers that will still accept a screen after the mods.



I didn't have a good picture of the side outlet......I will get a better one when the muffler is complete.

The timing numbers. ATDC

Intake...



Exhaust...



Transfers...