Correct jetting on 1999 Polaris 700 RMK

[DCJ]

Hello,
I bought a 1999 Polaris 700 rmk with a blown engine, I believe the rings failed, damaging the piston and cylinder(see pic),
I have the engine rebuilt, but know I think the carbs are wrong, maybe why the engine failed?
Their is no ACCS one this sled, nor a primer system (Polaris part catalog shows one, I never seen a primer on a Polaris?)
Except for the VIN #, it loos like a 1998 700 set up., air box has no spot for a ACCS, if its the original.
This is what I got going on, 700 engine, no ACCS, Keihin carbs, PTO Card air screw was set at 1.5 turns out from seated, pilot jet #48, Main jet 165, needle jet is a R1371g set to top slot,
Mag side card, air screws was set at 1 turns out from seated, pilot jet #48, Main jet 165, needle jet R1331G set at top slot.
What would be the correct jetting for this 700 with no ACCS?, I search this forum, the web, found several answers, but non that fit my sistuation it seems.
Also I want to see , if these carb setting could of cause the piston on PTO side to fail, All crank seals where in good shape.
I would appreciation any suggestion on how to set up these carb correctly,
Sled will be in 2000-6000 feet, 10-35 degrees
Thanks,
DCJ

 

[DCJ]

Typo in first one:
Both Needle Jets are R1371G

Hello,
I bought a 1999 Polaris 700 rmk with a blown engine, I believe the rings failed, damaging the piston and cylinder(see pic),
I have the engine rebuilt, but know I think the carbs are wrong, maybe why the engine failed?
Their is no ACCS one this sled, nor a primer system (Polaris part catalog shows one, I never seen a primer on a Polaris?)
Except for the VIN #, it loos like a 1998 700 set up., air box has no spot for a ACCS, if its the original.
This is what I got going on, 700 engine, no ACCS, Keihin carbs, PTO Card air screw was set at 1.5 turns out from seated, pilot jet #48, Main jet 165, needle jet is a R1371g set to top slot,
Mag side card, air screws was set at 1 turns out from seated, pilot jet #48, Main jet 165, needle jet R1371G set at top slot.
What would be the correct jetting for this 700 with no ACCS?, I search this forum, the web, found several answers, but non that fit my sistuation it seems.
Also I want to see , if these carb setting could of cause the piston on PTO side to fail, All crank seals where in good shape.
I would appreciation any suggestion on how to set up these carb correctly,
Sled will be in 2000-6000 feet, 10-35 degrees
Thanks,
DCJ

 

[retiredpop]

Sounds like previous owner used some jetting info from 1999 specs and some from 1998. 48 pilots were on the 1999 ACCS, 1998 used 42 pilots. 165 mains were from 1998. R1371G jet needles were from 1998 and running on #1 is pretty lean in midrange. In 1999 Polaris put a primer on them because the choke circuit on the Keihin carbs was pretty poor to say the least. You can find out for sure which year your carbs are from by the slides. In 1998 they used a 5.5 cutaway. In 1999 they used a 6.0 cutaway. Anyway I have attached some info for you which should get you headed in the right direction on jetting. Follow the 1998 specs although they were a bit rich but on the safe side.

 

[DCJ]

Retiredpop,
Thank you for the replay and help,
It's looking like the carbs are from a 1999 700.
I also being researching, and with the information you posted, this is what I'm thinking:
Jet needle R1371G in #3
Pilot Jet 42
Main Jet 164
Air Screw 1 turn out
It seems the charts are showing to use the same Main Jet on both Mag and PTO carb.
Should I have them both at 165, or bump up a little on the MAG side? 168?
I haven't got in to the clutch yet ( figure that I should see if it will start and run before moving on to clutched), but it have have a blue spring in it.
DCJ

 

[retiredpop]

165 mains should be okay but if you have the 168 jets maybe put them in both sides to start with seeing as how you don't know at what throttle position and circumstances the engine blew up. I think the 42 pilots are good. You can play with the air screw for best idle and throttle response off idle. The 99 carbs had a leaner slide cutaway than the 98 but had a richer needle so with the 1371G needles you may have to put the clip in #4 or even #5. It's just a matter of setting and testing at all throttle positions. If you find you are lean in the midrange you may have to change the needles to richer ones.
I don't know if you have come across the following but it is one of the best write ups I have seen on Keihin carbs.
Keihin Carb Jetting

 

[retiredpop]

I just had another look at the picture. Was the other piston showing signs of detonation as well?

 

[DCJ]

I just had another look at the picture. Was the other piston showing signs of detonation as well?

No,
The mag side piston, cylinder and head were in good shape , I replace both piston, reused Mag cylinder and replace the head with a good used one.
I dont have a pic of the piston, but the attached pic is of the cylinder head.
This is my first time going this deep in to a snowmobile engine, so Thank you for the advise,
So I should start of with 168 mains, 42 pilots, and start with needle in #4

DCJ

 

[retiredpop]

Yes, I would start with that just to be on the safe side. As you ride it you can do plug color checks or check piston wash to see how it is.

 

[Jay]

All good advice, the keihins were infamous for being lean in the midrange. Most guys ran staggered jetting, mag side? richer, I'd have to check notes. Also check the towers that hold the pin the plate for the floats pivots on, they pound out and cause issues.

 

[TRS]

Float setting can be off also. They are set differently than a Mikuni carb.
It’s also a good idea to pull the brass pin(float stop) out of the bottom of the bowl.

 

[DCJ]

Thank everyone for the advise and tips,
I hope to have this ready for a test start in a few weeks,
DCJ

 

[polrmk]

I had a 2000 700 rmk that the ACCS was taken off of. I used the jetting chart from the 700 SKS as a starting point.