I originally posted this in the "What's your latest purchase" thread, but it comes up fairly often, and it's hard to find there, so I thought I'd repost it here:
Innova Equus 3551 timing light
I started out looking at Snap-On timing lights, which are rated for 10,000 rpm (5,000 for a 2-stroke). Those are the better part of $200. Then I found that Innova sells one that looks the same and has the same features, as far as I can tell (maybe same manufacturer). It's model 5568, and can be had for a little over $100 delivered. Then I discovered their whole line of timing lights, including three less expensive models. I finally got down to the basic version, the 3551, which is just a timing light, still rated for 10,000 rpm, for $26.54 and free shipping from Amazon. [note that price is slowly rising since this post] The more expensive ones have things like digital rpm display, advance setting, and dwell measurement.
I tried the 3551 on the bench, up to about 7,000 rpm and it worked great. Unlike my old light, this one doesn't start doing odd things at high rpm to make it appear that there's timing jitter where there isn't. It behaved perfectly to 7,000, which is equivalent to 14,000 for a 4-stroke. It seems to handle the higher speeds by skipping sparks. For example, at idle it sparks every time, then when you speed up, it lights every 2nd spark, then every 3rd or 4th, etc., so it never has to actually flash at ridiculous speeds. Note that setting the timing at 4,000 rpm as the manual specifies requires a timing light rated for 8,000 rpm, and most aren't.
