Ignition timing in degrees

[muskrat]

G'day Fellas.
I'll throw my two bob's worth in.
As Rob say's about higher compression the flame is faster so less advance is needed (31-32 BTDC). Then if using higher octane fuel the flame is slower so more advance is needed (34-35 BTDC).
It's all a bit "suck & see" as each motor/owner is different (combinations of above and riding style). I just keep advancing the timing till it pings then back it off a degree or two.
Cheers

[limeyrob]

I was chatting to a guy with a race stock car - a Ford Galaxy. I asked him about timing: He said the only way to tune it was advance until it pinked then back off a gnats.  That gave a timing of 45 deg advanced! He said that was because the combustion chamber was such an awful shape, it wasn't a hemi, and the plugs were right over one side.

[Rex]

Add in the fact that it's very old machinery (Galaxy or A10) that has suffered God-knows-what mods from standard over the years, and that method is the best way rather than trusting to arbitrary figures (possibly) set decades ago.

[RichardL]

Orabanda’s Dynamometer testing is more recent than decades ago.

Richard L.

[Rex]

Of course, but how many engines would he have tested to reach those figures? As previously said, all engines differ, so try and tune to the individual engine.

[orabanda]

Seven A10's were run on the dyno.
Also Yamaha two and four strokes; slight retardation (around 2 degrees) was the optimum setting for engine performance.

Cheers,
Richard

[Sakura]

Well, there's no point in asking a question and then ignoring the answers. If I say so myself, I'm an extremely experienced fitter/mechanic but not an experienced tuner. I generally just follow the manual. I'm going to start with 33 degrees. It's manual adv/ret so I can monitor pinking easily. Thanks for all the input but don't stop if you've got something extra to add.

[berger]

why not just do what i did with my manual mag on a bit of a hot shooter, set it at 3/8ths full advance 36 degrees and there is plenty of retard to stop mine pinking if i force it labouring in gear, in fact there is enough to blue the exhausts.

[sean]

berger
same with my super rocket 3/8th ... which is basically the same as the RGS motor starts first kick 9 times out of 10 with a slight retard on the manual lever and crap 10% ethanol gas