'13 Pro RMK 800 low on RPM?

[Nyheim]

Hi,

Does anyone know what top RPM should be on the 13 Pro RMK 800?

I went WOT across a big lake and the sled maxed out on 8000-8100 then went down to 7850-7900 RPM and stabilized there. Is this normal? If I had a little bit more time on the WOT I think it would have rose up to 7950, but not sure.

Was about 6-7 inches of snow
Sled has about 1350 miles on it, current belt is only 1 year old and has about 250 miles on it, looks brand new, rest of the sled is completely stock.

Read on another thread that it should be 8250 +- 50 rpm?

Thanks

 

[skibreeze]

drop a couple grams in the clutch weights.

 

[Nyheim]

drop a couple grams in the clutch weights.

So this is normal and happens to most Pro's?
If not, I'd like to find out what is causing the RPM drop

 

[Toad face killah]

what elevation were you riding at? it is normal for all sleds to pull less rpms at high elevation. There is less oxygen in the air for the motor to generate power so dropping clutch weights a couple grams brings rpms back to where you want them. I change clutch weights regularly depending on where I am riding.

 

[Nyheim]

what elevation were you riding at? it is normal for all sleds to pull less rpms at high elevation. There is less oxygen in the air for the motor to generate power so dropping clutch weights a couple grams brings rpms back to where you want them. I change clutch weights regularly depending on where I am riding.

About 1200 feet.
Is that enough to bring the rpm down by 300?

And does it matter if I did the test up a hill or not? Where I tested it was flat.

 

[NapaMatt]

How many miles on sled


after 500 miles they drop a little power

 

[Nyheim]

How many miles on sled


after 500 miles they drop a little power

Says on top 1350 miles.
More people are saying to put in 10-66 weights and toss the 10-68.
But still, if Polaris is saying that RPM should be about 8250 +- @ Stock clutching, Id like to find out what's wrong with the sled, if something's wrong with the sled. That's why I'm asking what other Pro RMK riders are getting

 

[NapaMatt]

Is sad. but ur Top End could use some new slugs.. New pistons!

Bet ur down on compression a bit...

 

[Nyheim]

Is sad. but ur Top End could use some new slugs.. New pistons!

Bet ur down on compression a bit...

No, my compression is 120 PSI on both cylinders. Brand new they are 125, so my pistons are good.
But I'm throwing in a set of Wossner's after this season

Just talked to a friend of mine, he said he got the same RPM as me (7900) at WOT on a 2015 Pro RMK with only 190 miles on it. He changed from 10-68 to 10-66 weights and suddenly it was up to 8300 rpm.

 

[NapaMatt]

well yes!!

Less weight... it should be seeing higher RPMS!

Go with 10-66 weights or maybe u can find a 67 gram weight that pulls 8,250 rpm

 

[Nyheim]

well yes!!

Less weight... it should be seeing higher RPMS!

Go with 10-66 weights or maybe u can find a 67 gram weight that pulls 8,250 rpm

Yup! Gonna do that!
Thanks

 

[Nyheim]

Is it possible that my throttle cable isn't correctly adjusted?
I just took of a 2" inch handlebar riser. Maybe the handlebar coming down 2" is causing the throttle not to fully open?

 

[sledheadd]

If you need 67 gram weights you can easily grind/file your 68 down to 67.

 

[Nyheim]

If you need 67 gram weights you can easily grind/file your 68 down to 67.

Thanks for that info!

 

[sledheadd]

Thanks for that info!

Just be sure that the profile is the same on all 3 weights.
Take the same amount off at the same place?

 

[Nyheim]

Just be sure that the profile is the same on all 3 weights.
Take the same amount off at the same place?

Ya!

 

[Jaynelson]

Before changing any parts...yes, it could be the throttle cable, they stretch over time. Easy adjustment - no tools required, just peel back the sheath on the cable near the bars and it'll make sense.

Also, check your primary rollers for wear...could have one that's gone flat. clean clutch faces and belt, of course. Other than all that, yes you may need to drop some primary weight.

 

[spark2]

Try a new primary clutch spring. They get weak.

 

[Nyheim]

Before changing any parts...yes, it could be the throttle cable, they stretch over time. Easy adjustment - no tools required, just peel back the sheath on the cable near the bars and it'll make sense.

Also, check your primary rollers for wear...could have one that's gone flat. clean clutch faces and belt, of course. Other than all that, yes you may need to drop some primary weight.

Checked the throttle cable, needed to be tightened a little bit, but not much. RPM was the same (7900). I dont think there's any problem with the rollers, but not sure. Ill check 'em.

Clutch faces and belt was cleaned carefully about 200 km ago.

Try a new primary clutch spring. They get weak.

Ya, will do that.

 

[Buchholz56]

I was just experiencing same thing on a 15 pro 800 at both 1500' and 8500'+, would shoot to 8050 for a second at most and stabilize at 7850, changed the primary spring and it goes to 8300 for a few seconds before settling in at 8200. The old spring looked fine, was at most an 1/8" shorter compared to the new one.