timing key

[quadrider11]

My friend has a 05' 400ex and he was thinkin about getting a Curtis Sparks Timing Advance Key. Do they help at all? are they hard to install?

[GPracer2500]

They're pretty easy. You remove the left side cover, remove the flywheel, replace the "key" and put it back together. An impact gun might be needed to get the flywheel bolt off. Also, you will need a flywheel puller. The Sparks key may include that tool?

The gains will be small. Probably quite hard to detect without a dyno. This is the only dyno graph I can recall seeing that shows the affect of additional ignition advance on a 400EX. Note that this EX is not otherwise stock, so take it for what it's worth. On a stock(ish) EX additional ign adv may make more, less, or the same difference--I really don't know. I wouldn't expect much though....

http://www.geocities.com/gtthunder.geo/400cdi.jpg




my $0.02

[guinness77]

I receintly installed one, I noticed a slight increase in Mid range performance. They're weak and should definitely NEVER be used on anything larger than a stock piston set-up. Next time I'll install a rev box. they advance the timing without being a weak link. I also noticed the motor would knock and ping with 87 octane. That's called detonation and will ruin the motor. With 92 octane I cannot detect any detonation. So I run 99 to be sure.