Timing a 400 G3LC ?

[Clankrod]

I read some time ago (poss on this forum) that bored 350's require slightly more advanced timing ? Does anyone here know
how many degrees btdc is recommended for a 400 comp or maybe post up a web link/ phone no for someone please ?
- Running an NR1 mag

Thanks - ART

[Colin F]

I would think that this would very much depend on the engine and how it is set up.

As you are running a N1 mag with manual advance retard this should be easy to work out.

Set the mag to fully advanced and time the bike 10 or so degrees before the recommended point for 350's, now ride the bike adjusting the mag until you get the optimum running position, do not move the lever! Stop the bike and measure the piston position when the points are just opening, this is then the timing position (degrees or travel distance BTDC) for your bike, take a note of it then retime your bike to this figure and off you go.

[Clankrod]

Thanks Colin, I did ad a couple mm to the bog standard & it runs ok, just could do with a little more. Didn't
want to chance my luck before consulting those more experienced on the comp front. Your suggestion of adding
a fair wack to the standard btdc is def the way to go. I guess that's just one more advantage to running manual
mags, the fact that you can work out the optimum performance for a tuned motor far more easily than other
ignition types. Hate to think how many nipped & holed pistons in my mx bikes over the years, just trying to
let that last horse out.....you know it's in there somewhere

Cheers - A.R.T