Thread: Crankshaft sizes
01-08-2010, 08:23 AM #1
Could someone explain the differences between the 650,750,780,1010 1050 785 700.900,1200 cranks.
650- basic fugi crank for 3 cylinder
750-same as above-same rods different bore
780-same as above- different bore and porting?
785? (domestic-red ? or is it a fugi crank in a domestic case?)
1200? (SLX and PRO-) The same crank?
It's a little confusing. Thx
Can any of these be Modded? like lightening the rotating mass on the counterweights? or shaving the weights into knives? and of course wearing ceramic bearings!
01-08-2010, 09:41 AM #2
01-08-2010, 10:38 AM #3
01-08-2010, 01:36 PM #4
- Join Date
- Jul 2007
- near Toronto, Canada
Polaris PWC engine sizes, engine families, bore and stroke
service manuals, parts manuals, Polaris cross reference, Polaris PWC model chart, and elsewhere
Note that in many cases the actual engine displacement is not exactly the same as the model code
(Bore x Stroke)
Fuji engines (painted blue, except Pro 785)
650 (647cc) 3 cylinder (65mm x 65mm) SL650
750 (744cc) same rods different bore (69.72mm x 65mm) SL750, SLT750
780 (779cc) same rods different bore (71.3mm x 65mm) SL780, SLT780, SLX780 different exhaust manifold bolt pattern
785 (779cc?) Fuji crank in a Fuji case (69.705mm x 68mm ) (750 size pistons, longer throw and rods, exhaust valves) Nikasil cylinder plating
1010 (or any Fuji engine larger than above) - Heavily worked Fuji engine (bored, stroked, ported, massaged)
Domestic engines (painted red, except MSX 140)
700 (700cc, 701cc) twin cylinder crank (81mm x 68mm) - Hurricane, SL700, SLT700, carb'ed Virage (two-thirds of a 1050 engine)
777 (aka 800) twin cylinder crank (84mm x 70mm) - carb'ed Octane & Virage i (fuel injected Virage twin) two thirds of a 1200 (1165cc) engine
900 (889cc) three cylinder domestic SL900 (74.5mm x 68mm)
1050 (1050cc) three cylinder domestic (81mm x 68mm) SL1050, SLX, SLTX, SLXH
1200 (1165cc) - three cylinder domestic (84mm x 70mm)
(Genesis and Genesis i/FFI, Virage TX and TXi, X-45, SLX and PRO 1200)
1200 (1192cc) MSX 140 only (85mm x 70mm ) Nikasil cylinder plating
1450 (or anything else above 1165/1192cc) bored, stroked, ported, massaged
Weber 4-stroke two cylinder turbocharged, inter-cooled engine
750cc MSX 110 and MSX 150
01-08-2010, 02:10 PM #5
01-08-2010, 02:50 PM #6
- Join Date
- Jul 2007
- near Toronto, Canada
01-08-2010, 03:22 PM #7
K-447 you amaze me! U can find everything and anything on these skis! Wow. All in order too. I see theres a few I didn't list.
I thought the 785 pro cases were a little different inside, someone said they had work done(ported cases possibly) to them in some way. So that means you can put a 785 crank in a 750 case or a 650 or a 780? If there the same cases.
Then why did jkindt use the bottom of a 785 case on his sleeper then? if it's no different than a 750 bottom case.?
Well does a 750 case have 2 pulse line outlets on it? Like the pro has? No, I don't think so. Maybe thats the only difference? But thats done easy enough.
So that also means you could build a 785 motor with 750 cases then, and just use the jugs from a 785 then and the longer stroke crank. correct?
01-08-2010, 03:38 PM #8
785 cases have different porting than the 750, the 785 crank has a larger stroke, so I dont think it would rotate inside a 750 case, that is just a guess though,I should have tried my rebuilt 785 crank in my 750 cases before i installed it.
01-08-2010, 03:41 PM #9
That would be interesting to find out if that can be done. Maybe someone has already.
Well after sanding the ruts out of the rods path in these cases, I could go with even longer rods now, The center rod took out a few thous at least where the rods spun n hit. . Lots of clearence now!
Come to think of it, that wouldnt work, it would throw the port timing off.
01-08-2010, 03:44 PM #10
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