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1986 Formula MX Attempting to add Electric Start

548 Views 17 Replies 6 Participants Last post by  chriswy27
I'm attempting to perform an electric start retrofit on my '86 PRS sled. The parts seem very hard to come by but at this point I think I've collected most of them. Mostly want to ask, is there anything I am completely overlooking? Below is the parts I've acquired. I think I have pretty much everything minus the battery. My only question is which ring gear to use.

From a couple different '91 PRS Sleds:

* Clutch Part# 417202100 : My '87 clutch didn't have the posts to mount a ring gear. Looks like despite having the posts that this one never had a ring gear installed either as the holes are not tapped. I was worried at first but then read the screws are self tapping.​
* Ring Gears Part #414807500 & Other Part# 414604300 (maybe)?: Below are two different styles and I'm not sure which one I should use. The right one looks like images I've seen online and comes with the Phillips head self-tapping screws which I believe are part# 309903100. The left one I think was the newer replacement once the right was marked NLA by skidoo and looks to use hex head screws part# 732601120. Any idea which gear I should go with?​
* Startor & Engine mounting bracket:
* Wire Harness from a 91 sled with E-start: I believe the missing "pins" marked 1, 3, etc. from the large 8-pin connector are the ones coming from my stator but I'll have to compare my'87 harness there.​
* Ignition w/ E-Start
* Voltage Rectifier
Just want to say that I wouldn't have been able to get this far without Hudson's Sled Salvage awesome parts diagrams w/ oem numbers. Anyhow, am I nuts to attempt this? Will something I've purchased not work the way I think it will? Thanks!​
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1 - 3 of 18 Posts
Looks like a good start.
What's your plan for drilling out the ring gear mount holes? I would think this would have to be done perfectly for balance purposes.
Here's an 86 shop book on pdf.
The holes are already on the clutch
Got it. Missed that part.
Now just have to decide which ring gear I should be using.
I agree with your earlier comment that the 7500 is simply the replacement for the earlier ring gear. Looks like it was used into the late 90's at least. I would go with that.
As for the fasteners I believe either fastener will work with either gear but given the choice I'd use the hex head.
Good luck.
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