Summit 670

[glengine]

Beer is good when it's HOT out like it's been tha last few days.. Man did we ever have a wicked thunder & lightning storm in the city lastnight.. It went right over our place, thunder very loud, you could actually feel it.. That rocked!!!!!

 

[Modman]

Ken has ran P85's on his triples and and other sleds for alot of years and know's them well.. But these are just issue's that we have found.. And we just dont like usung them in a situation wher they have been known to create premature crank bearing failure.. But that is just our opinion and decision...

Interesting comment. How many have you seen them take out? I've run with 1200's, 1085's and a "few" other mods with P85's (the 1500 had a quad cam), never heard this comment before. Was/Why is it just on the Doo's?

P85 - easy to tune, lots of parts, cheap to tune and easy to replace (as Deano stated). Lighter than the older TRA meaning faster revvvvvvving motors (think flywheel re: rotating mass)
TRA - (the better clutch for the mountains IMO - due to its mass and ability to hold lower RPM torque better) pulls like a freight train on the bottom and holds the torque better, harder to tune, but has more tuning options (ramps, pins, rollers, arms, springs) and yes you need a small Snap On tool truck with you to take it apart. Oh, and have you tried to buy a TRA clutch? Even the oil sheiks with gold palaces can't afford one....

With the proper venting, they will stay cool enough to touch. If they are getting that hot, clutching/gearing needs to be adjusted possibly.

Same for the secondary's. The enclosed TRA's required removal and disassembly for tuning, and its kinda hard to see what the clutch is doing through a 1/4" thick layer of aluminum, whereas other secondaries are external and can be tuned easier, and if there is a problem with the clutch or you want to see it working, you can take the hood and clutch cover off and look at it while you ride (yes I'm one of "those" guys).

A lot of other factors need to be considered before switching clutches, primary and secondary tapers, clutch outer diameters (clearances and larger/smaller diameters, etc.,) type of riding and riders tuning ability.

Anywho, those are just my thoughts, not important either way. Back to the real topic (and yes Deano, I'm in full agreement on the 670 - pipes, port and polish and throw the oil injection in the trash Also, there are some air intake mods IMO that really wake this motor up (you kinda have to be willing to throw the headlight in the trash too though):

Hey Deano got a couple questions for ya, we'll get this 670 thread back on track. Ok so I'm getting jugs bore 1mm over to total 686CC,s and having the head milled down, Mac's Machine in Sicamous is doing it and I will put it back together. How do I get the fuel mix figuared out, is there a chart for compression / fuel mixture? And will heat be a issue? One more thing I need a clutching guru as I should redo them now while eerythingis tore down and time is availible. Any other budget ideas ?

Calculators - Wiseco Piston Inc.

Download the excel spreadsheet with the automatic calculators. All you need is the measurements listed, input them and determine the compression ratio. The compression ratio will determine what type of fuel you need.

 

[glengine]

I agree on the fact that the P85 works on alot of sleds.. Alls i know is that the harmonics just don't ssem to work from i've seen and been told.. It's like the old VMAX700's with psi pipes clutching was fine but with slp pipes it'd take out the bushings in the primary every 200km's.. it's just harmonics's.. On the Vmax's we tried switching pipes from sled to sled and the issue followed.. But if someone has info that can solve the problem glad to hear some idea's that might work..

 

[TABSTER]

Not to try and rock the boat, but is the crank bearing not a issue with the 670? I have had a couple 670 summits and ...... yup pulled them out of the mountains with the engine siezed... both of them the crank bearing on the PTO side chit the bed.....I replaced them with Adrian Bernard cranks with the roller mod on them ... rode them... never a prob. after mod...... Just MO.....So all that being said... I still love the 670... you can do lots with and to them....

 

[Deano670]

Not to try and rock the boat, but is the crank bearing not a issue with the 670? I have had a couple 670 summits and ...... yup pulled them out of the mountains with the engine siezed... both of them the crank bearing on the PTO side chit the bed.....I replaced them with Adrian Bernard cranks with the roller mod on them ... rode them... never a prob. after mod...... Just MO.....So all that being said... I still love the 670... you can do lots with and to them....

I have yet to see any 670 crank fail due to a p85 on the crank. Keep in mind you cant just through ANY unbalanced clutch on any engine. Ive seen stock out of the crate engines fail with the FACTORY clutch on them due to an improperly balanced clutch. So imo to say using an aftermarket clutch on an engine is going to destroy it is foolish.

 

[Modman]

I have yet to see any 670 crank fail due to a p85 on the crank. Keep in mind you cant just through ANY unbalanced clutch on any engine. Ive seen stock out of the crate engines fail with the FACTORY clutch on them due to an improperly balanced clutch. So imo to say using an aftermarket clutch on an engine is going to destroy it is foolish.

What he said^^^^. To be honest with you, I can't remember if I have ever seen a 670 crank bearing fail. They were one tough motor, just like the 583.

 

[Deano670]

well ive seen them with rough bearings that should be replaced, but again cant say ive ever seen them fail to the point that they seize, regardless of what clutch is on the crank. speaking of a 583 i have a modded 583 forsale if you know anyone whos looking:d sorry to highjack the thread

 

[TABSTER]

I have yet to see any 670 crank fail due to a p85 on the crank. Keep in mind you cant just through ANY unbalanced clutch on any engine. Ive seen stock out of the crate engines fail with the FACTORY clutch on them due to an improperly balanced clutch. So imo to say using an aftermarket clutch on an engine is going to destroy it is foolish.

Both sleds were stock. Both had approx. 2400 km on them and they had factory clutches. So what your saying is that the clutches must not have been balanced right from the factory to cause this crank bearing issue then? Would you feel lots of vibration if it were not balanced proper? I know that i am not the only one to have this happen to, infact when the wife was riding out of Renshaw a gentleman stopped because she was stopped with the hood up and checked it over for her as i was still uptop. He told her after looking the sled over that it as most likely the crank bearing that was gone..... It had happened to him three different times and on differant mchines. We must have got the friday afternoon builds i guess.
Bythe way ski-doo has a crank exchange program set up. ship your old to them and they send you one back with the spacers and bearings all pressed on... ready to drop in the lower end. The dealerships have the number to phone them for availability....... Its usually 3 to 4 weeks for the 670 cranks.. they go through them more than any other ones..... right from the service counter guys mouth.....

 

[Deano670]

Both sleds were stock. Both had approx. 2400 km on them and they had factory clutches. So what your saying is that the clutches must not have been balanced right from the factory to cause this crank bearing issue then? Would you feel lots of vibration if it were not balanced proper? I know that i am not the only one to have this happen to, infact when the wife was riding out of Renshaw a gentleman stopped because she was stopped with the hood up and checked it over for her as i was still uptop. He told her after looking the sled over that it as most likely the crank bearing that was gone..... It had happened to him three different times and on differant mchines. We must have got the friday afternoon builds i guess.
Bythe way ski-doo has a crank exchange program set up. ship your old to them and they send you one back with the spacers and bearings all pressed on... ready to drop in the lower end. The dealerships have the number to phone them for availability....... Its usually 3 to 4 weeks for the 670 cranks.. they go through them more than any other ones..... right from the service counter guys mouth.....

Dont get me wrong im not saying that it cant or hasnt happened, but as a generalized statement that 670's have crank issues i say NO they dont. A good friend of mine is still running 96 summit 670 its got 12,000km on it and has NEVER been rebuilt. But i will say this the BIGGEST reason for a pto side crank bearing failure is an unbalanced and heavy azz clutch hangin on that end of the crank and the old tra's were just that.

 

[SLEDBUNNYRACING]

When my 670 was rebuild I had the crank trued and the bearings were fine at about 5800mks. I replaced them of course...just because...but they were still in good shape.

Just my 2 cents worth...