well i thingk i found out what i have

think its an 1985 formula plus
found the vin plate
vin # 3721 00928
sep 1984
3721 is an formula plus in skidoos codes

Yep, if it has a build date of Sept '84, its an '85. My '91 had a build date of Oct '90.

Not sure if you'll have the square gaskets (1 per cylinder) or if you'll have the "gasket steak" like I have on my 617. Its 3/16" thick NBR gasket 1-piece and covers both jugs. Hence my nickname "gasket steak", lol.

Is the Engine a type 537 but 521cc? Seems like there's a few 85-87 Formula Plus gasket kits on evilBay for $36-to-$60.

I replaced all the top end gaskets, seals, pistons, and rings in my 470 before dropping it in the buggy.

Separate gaskets

Where did you get your pistons ? Did you go oem?


I'm very pissed at my self I broke an ring when removing the cylinder I barley turned the cylinder and herd an pop

The pistons and cylinders look great just going to replace the rings


Anyone know where to get rings for oem pistons ?
Pistons say: aus. 7194. 1784

This Engine had an big air leak and water leak

Photos coming soon

Nope, I bought a set of SPI pistons/rings. Little birdie in my head keeps shaking its head and telling me to GO OEM though.

I have heard good things about SPI pistons/rings, most use them as stock replacements they are not using them for modified engines where they induce more stress on the parts.

I would just schedule a top end tear down and inspect them for wear and cracks every 40 hrs use or so.

Your running stock compression and close to OEM RPM specs?

the pistons have L shaped rings

Picks

These elko?

Yep, I believe that is an OEM Elko piston.

Stock bore was 72mm, so with the 71.94 stamp on there, she looks to be a virgin.

Seeing the AUS on the top my guess is its a ELCO probably says it on the bottom, your head gaskets looks like same type used on my 440 they are reusable if not damaged.

previous owner said it was rebuilt onCe

the Pistons have light use on them not much
whoever rebuilt it put the one gasket in wrong has a big damn air leak
and can't reuse the head gasket as its bad one cylinder had water in it
it just for me starting the Engine up and idling and revving an little

Do both jugs have the same piston?

Check the wall clearance and the ring gap. If they're fine and comp is good, just get yourself a seal kit and be done.

I broke an lower ring

Already ordered the gasket kit

I just need to find a set of rings
bouth jugs have the same piston in it

Got the steering working no bump steer that I can see
Not done yet Still need to Make the other mount for the pivot I

Still can't find any 72mm elko rings
Any one got one lying around
Hell an used will be fine for me if I can't find a pair of nos ones

Need to get an New steering bushing as this one is warn out.
guy on Ebay any good?

Where can I get an line lock for these metric brake fittings?


Need to find an ring gear and starter
still most the ring gear
As the starter I will order from Farr offroad sconce every one I look at has an fat solenoid on the side of it

More

this the starter i need?
looks like the one farr sells

http://www.ebay.com/itm/Starter-Fits-Sk ... be&vxp=mtr" ."..


will this ring gear work?

mine is an 6 hole clutch
my clutch is off an 1985 formula plus 537
http://www.ebay.com/itm/Ski-Doo-Snowmob ... 9a&vxp=mtr" ."..

or do other ski doo clutches fit this 537?

That starter will be a lot easier to mount and work with than the gigantic stock one I used. Just needs to be the same gear pitch for them to mesh. And make sure it spins/engages in the right direction so that the starter can reside within the Engine bay (not outside of it).

Ring gears...as long as the clutch the ring gear is off of is the same as the one on your donor sled, it will fit your clutch. Is it a TRA clutch? No one seems to let those ring gears go for cheap!

Tra?

Here's mine

Looks like you've got an RSSR clutch, which SkiDoo used in the early-to-mid 80's. They switched to the TRA clutch on most models in 85-86.

RSSR stands for "Roller Square Shaft Ramped". It should have (3) adjustable ramps and rollers in the cup. Its predecessor, the RSS, was not very tune-able and I believe it was orange (vs. black). Check the 'Doo forums for more info (dootalk.com).

You might want to just pick-up that TRA you PM'd me about for [1] a clutch upgrade, [2] parts availability upgrade, and [3] for the ring gear. That price or 'best offer' for a TRA w/ ring gear is a STEAL!

I replaced a roller in my TRA when it was still in the sled, right before it became a donor. Just had to buy a set of TRA button retainers and a puller shaft for it (Denis Kirk http://denniskirk.com). Extreeeeeeeemely easy to disassemble and service these TRA's! I may even have a thread on it ever in the tech section. There must be a reason SkiDoo switched and never looked back.

what pistons did you install in your Engine ?
weisco?

need 72mm kit
really don't want to but might have to

i cant find one damm ring found the part # i need
420915850 RECTANGULAR RING, 72.0 MM DIAMETER




also do rotax Engine cases weld easily ?
thinking about pulling the complete Engine apart not totally sure yet to weld the hole in the underside of the mag casing

What are some radiators that are the smallest in size that will work ?

The pilot radiator won't work will it?


Ordered an starter
Just need to get the clutch and an ring gear
Working on the steering today hope fully getting it finished up today
Sould I go with grade 8 bolts?

I'm running a factory banshee radiator on my 570 exciter odyssey. doesn't cool quite as well as I would like. I personally would go for the civic rad like in my pilot on my next build.

running a little hot?
i just need the smallest one i can get that will work

well won my clutch
happy with the price
http://www.ebay.com/itm/140931885405?ss ... 1439.l2649

got my starter ordered also found out its the exact one that farr uses



got some work done to the front didn't finish the steering like i wanted to

made a new steering stem bushing so happy about that rather make one then spend $30 i don't want to

Even if you paid the full $99 + $20 shipping, that's a great score on a TRA clutch!!