Ignition Timing help/ Timing light help

[750SX]

I have just purchased a Jetinetics flywheel, and I want to set the timing at idle so that I don't melt my pistons. I have never checked the timing on a two stroke before, so I don't even know if my timing light will work as expected.

Equipment: I have a nice snap-on timing light with a digital rpm readout, and I can also put a set timing advance in it.

Process: I plan on finding TDC. Do I find it in the front or rear cylinder, or doesn't it matter?

After finding tdc, I will make a mark on my flywheel, and cases that line up.

Next I will set my timing light at the desired advance for idle.

I will start the engine, and observe how far off the marks are, and which way the stator should be moved.

I think this sounds right, but I could be very wrong. I would like to hear your input on this process. Also what is the stock advance at a certain RPM?

I also tried calling Jetinetics, but they weren't in.

 

[Crab]

Use a dial indicator in front cyl to find tdc, with 650 electrics you can shoot into the inspection hole and align marks, 750 electrics have no adjustment unless you get the a/m advance kit. Its possible to check it however if you were to mark the coupler at the rear to a mark on the cases at TDC, then use your fancy timing light to check advance.

 

[750SX]

Ooops I forgot to mention that this is for a superjet with 61x electronics

 

[SUPERTUNE]

Yes, your on the right track, I always use #1 cylinder with a dial gauge, use a pointer (mount from the coupler mount) and a scribe your TDC mark on the rear coupler as it's easy and will give you a distance reading, (how much your timing is off, move the stator plate the same amount) set the timing light for 21 degrees and make sure you bring up the RPMs to get full advance for a stock CDI, If you have an MSD enhancer, you can check it at much lower RPMs as the curve advance is on early then retards a little at high RPMs.

 

[750SX]

Yes, your on the right track, I always use #1 cylinder with a dial gauge, use a pointer (mount from the coupler mount) and a scribe your TDC mark on the rear coupler as it's easy and will give you a distance reading, (how much your timing is off, move the stator plate the same amount) set the timing light for 21 degrees and make sure you bring up the RPMs to get full advance for a stock CDI, If you have an MSD enhancer, you can check it at much lower RPMs as the curve advance is on early then retards a little at high RPMs.

Thanks Chuck!

I do have an enhancer. Should I check the timing at 21 deg at around 1800-2000 rpm?

 

[750SX]

Well I got a chance to put the flywheel on last night. I am having some trouble using my timing light. It is not giving me the correct rpm reading. At idle it was reading anywhere from 3500 to 8000 rpm, and I know that can't be correct. I'm not sure if i need a special timing light that can be set for the number of cylinders or not.

I am wondering if i can still use this light to check the advance, if I use another method of obtaining a rpm readout like a mychron, or if even the timing flash is messed up, because the rpm's are messed up?

Anyone have any input?

 

[#ZERO]

Your CDI is triggering the coil to fire for every 180 degrees of crank rotation.

You need a 2-cycle timing light that's has the 180 degree trigger feature.

 

[750SX]

Your CDI is triggering the coil to fire for every 180 degrees of crank rotation.

You need a 2-cycle timing light that's has the 180 degree trigger feature.

Can I just divide the rpm's and advance by 2, or will my programmed advance be screwed up as well?

 

[Crab]

This is the one I plan to get. http://www.iequus.com/product_info.php?product_id=5568&category_id=1_20

 

[750SX]

Can I just divide the rpm's and advance by 2, or will my programmed advance be screwed up as well?

anybody?

 

[#ZERO]

If your idle readings are fluctuating between 3500 to 8000 rpm I'd say your advance features are going to be way off too.

Your best bet would be to find TDC on your front cylinder and make you own timing marks on either the flywheel or coupler.

If you don't have a bendix holder the coupler method will probably be the easiest.

 

[Crab]

anybody?

I think you will need to divide by 4 since it fires at 180. The marks might work the same, just try it and see what it shows for advance.

 

[750SX]

If your idle readings are fluctuating between 3500 to 8000 rpm I'd say your advance features are going to be way off too.

Your best bet would be to find TDC on your front cylinder and make you own timing marks on either the flywheel or coupler.

If you don't have a bendix holder the coupler method will probably be the easiest.

Yep, I made the marks on the coupler, after finding TDC.