Formulating a timing curve?

[CARBONX2]

A question for the gurus. How do you setup the right timing curve on a MSD digital TL without a dyno or detonation sensor? Are there any good guidelines?

 

[Waternut]

Most people run around 30° static timing give or take a few depending on the users aggresiveness. Depending on which digital TL you have, you'll back off the timing differently. If you have dual channel you can run a more aggressive static timing and back it off faster for higher rpms. With a single channel, the timing "curves" are really just straight lines. My single channel is 30° static, max rpms is something like 7750, and I back off 15° starting at 5500. That basically means at 5500 you're still running 30°, at 6600 you're running 23°, and at 7750 you're running 15°.

Hope that makes sense. Maybe it'll give you a good starting point.

 

[CARBONX2]

Thanks, I have the dual channel. I know how to set the basics, I'm looking to find out if there is a certain 'feel' or sound to the ski that tells you when you are going over the correct timing for the particular setup

 

[chrisdoc0608]

yea when it goes BOOM

 

[CARBONX2]

Naturally that is what I'm trying to avoid
In a 4-stroke you can hear the pinging easily without doing real damage, wondering what a hi-perf 2-stroke sounds like.

 

[Matt_E]

The best guideline would be to talk to the pro that built your engine. :bigok:


Short of that, I believe a builder told me a couple of years ago (FOR PUMPGAS) to start with 28-32 degrees static, then pull back starting at 3500-4500 so that at 6000 RPM, you're below 19 degrees.

 

[Pablo]

I thought the MSD directions that you can download give a basic timing description/set up/curve and gives a little help with fine tuning. I remember MSD having an area to post questions and get answers from MSD experts.

 

[CARBONX2]

Thanks
MSD Powersports has lots of info, long time since I've been on their site. Also hauled out all my books and went through the ignition chapters. Going to start at 28-static and 15 at 6000rpm.

 

[waxhead]

that sounds like a good safe curve that will still make good power