2 Stroke Timing

[Sobo2k5]

I recently purchased an SBT motor for my Polaris SLT780. Is there a simple way of setting the timing on a 2 stroke motor? I realize it is totally different than a 4 stroke, just never had to tune a 2 stroke before. Thanks for any info....

[Technical Support]

Re: 2 Stroke Timing

Some have minor adjustment possible at the stator, some are non adjustable, some only through a dealer computer. In any case, there is no need to do so when you swap blocks.

[Sobo2k5]

Re: 2 Stroke Timing

Thanks, I was going through some of the SeaDoo timing threads on here, figuring timing would be somewhat similar? Where, for my polaris, there are 2 marks on the magneto back plate, the advance mark and retard mark. Should I just align them so that the mark on my flywheel is centered between them?

[Technical Support]

Re: 2 Stroke Timing

That's fine.

[Polaris_Nut#1]

Re: 2 Stroke Timing

I just put my stator in my SBT 780 the other day. It is adjustable. Seeing how I don't have a mark on my old block to go off. I followed the procedure for installing a new stator. I think it is were the old one was anyway. You line the mark on the stator plate up with the line where the two case split. That is generally where they go. Hope it is good enough cause it looks like it is impossible to adjust later without pulling the engine or at least the gas tank.

[douglee25]

Re: 2 Stroke Timing

I just put my stator in my SBT 780 the other day. It is adjustable. Seeing how I don't have a mark on my old block to go off. I followed the procedure for installing a new stator. I think it is were the old one was anyway. You line the mark on the stator plate up with the line where the two case split. That is generally where they go. Hope it is good enough cause it looks like it is impossible to adjust later without pulling the engine or at least the gas tank.

There are actually two marks on the stator that could be used to line up with the cases. One mark is advanced and the other is retarded. Use the retarded mark for the 750 and 780. The 650 uses the advanced mark.

Doug

[Sobo2k5]

Re: 2 Stroke Timing

Thanks guys for your responses. So did either of you guys use a Timing Degree Wheel? or do you just eye it? I dont have the manual with me, but I think the Mag Cyl is supposed to be BTDC. Thanks again for your all's help!

[douglee25]

Re: 2 Stroke Timing

Thanks guys for your responses. So did either of you guys use a Timing Degree Wheel? or do you just eye it? I dont have the manual with me, but I think the Mag Cyl is supposed to be BTDC. Thanks again for your all's help!

Eye it up!:emoticont

Doug

[Polaris_Nut#1]

Re: 2 Stroke Timing

yes the mag

"NOTE:1993 stator plates have to two marks. When installing a new stator on an 650, align the upper mark on the stator plate (more advanced) with the crankcase parting line. On an 750, align the lower mark on the stator plate (more retard) with the crankcase parting line." RIGHT from the manual. My 1996 only has one mark.

http://www.sbtontheweb.com/forum/sho...+timing+stator

This is the base line for installation.
I'm just eye balling it and use the base setting.
You need a dial indicator and degree wheel to make timing adjustments.
There is an entire chart to go off if you're gone really go all out.The chart goes from 10 to 28
Degree BTDC (mm/Inch)
10 = 0.62/.024
20 = 2.47/.097
28 = 4.77/.188

[Polaris_Nut#1]

Re: 2 Stroke Timing

specs
650, 18 degrees +/- 2 = .079 (2.01)
750, 24 degrees +/- 2 = .139 (3.54)
780, 28 degrees +/- 2 = .188 (4.77)

[douglee25]

Re: 2 Stroke Timing

yes the mag

"NOTE:1993 stator plates have to two marks. When installing a new stator on an 650, align the upper mark on the stator plate (more advanced) with the crankcase parting line. On an 750, align the lower mark on the stator plate (more retard) with the crankcase parting line." RIGHT from the manual. My 1996 only has one mark.

http://www.sbtontheweb.com/forum/sho...+timing+stator

This is the base line for installation.
I'm just eye balling it and use the base setting.
You need a dial indicator and degree wheel to make timing adjustments.
There is an entire chart to go off if you're gone really go all out.The chart goes from 10 to 28
Degree BTDC (mm/Inch)
10 = 0.62/.024
20 = 2.47/.097
28 = 4.77/.188

That's where I remember reading it from as well. I had no idea the '96 had one mark. Thanks for the tip.

Doug

[Sobo2k5]

Re: 2 Stroke Timing

Awesome, thats what I like to hear :emoticonc . I'm trying to do this without spending more money to have the dealer do all this stuff for me. After all, you dont learn anything by having someone else do it for ya :D , especially after awhile its going to be hard to find anybody that'll work on polaris's. Guys, you kick azz! Thanks a bunch!