ignition timing how to?

[joshnnh]

I'm new to modding and have a timing question about altering the key. On my saw the key sits in the keyway on the crankshaft when the flywheel is removed. To properly remove material am I filing the entire surface half way down to the shaft? Or am I taking half the width of the key along the length? I have a timing light as I have done timing on automobiles. But when I read that altering the key on a saw can advance as much as 10 degrees that seemed like a lot. Is that normal for a small 2 stroke? Any help would be greatly appreciated. My practice saw is a 455 that was givin to me. If that helps. I know it's no ones favorite but it was free and I can chop it up at no loss

 

[ncfarmboy]

8* is normally max advance. File width. Key is only for ease of installation. Taper is what keeps flywheel from moving.
2* adv. 1.5% power gain 3.5* plug temp. increase
4* adv. 1.9% PG 5.5% TI
6* adv. 2.1% PG 7.0% TI
8* adv. 2.2% PG 9.25% TI
10* adv. 2.0% PG 11% TI
12* adv. 1.7% PG 13% TI
Found this info don't remember where.
Shep

 

[joshnnh]

Thank you

 

[CanadianCarGuy]

Every saw is different. If you are gonna go through the trouble of advancing timing at least keep doing it till you hit the sweet spot. Keep going til it pings pops or sounds like it is missing under load, then dial it back til it quits. Pretty darn simple no need to complicate things with measuring with a degree wheel, if it works on my 383 stroker Camaro it should be good enough for a single cylinder chainsaw. Don't forget to richen the crap out of the low speed jet, if you go limiter caps in your carb, you might need to get rid of em. The more timing you got, the more heat and vibration is soaked into the cylinder and piston; meaning the saw will run hotter.

 

[trappermike]

If you have the ability to modify or advance your saw engine's timing then you should first be able to establish where the factory timing is to begin with! Altering ignition timing without knowing what it is to begin with is not something I would do. I would use a degree wheel to make timing marks on the motor to check with a timing strobe light,then make alterations at about 2 degrees at a time.
No one should be altering timing without first knowing where it is...
Most other engines have timing marks to begin with,like the Camaro,or most other engines.
I hear lots about how much changing a keyway advances timing,but not where it actually is. Just keep advancing it until it melts I guess...
Look at the timing advance of known high output 2-strokes to start in the ballpark.
Too much ignition advance can actually hurt power.