04 RMK 800 not pulling revs in Powder!

[Taylzee]

I'm new to this forum but not to sleds or other forums. So Hi there to everyone!

I do quite a bit of wrenching on friends sleds for friends and locals here.
Right now I have an 04 RMK 800 Vertical Escape in here that is not pulling RPMs in the powder. On trail it is hitting 7800-7900 which is still a little low but in the neighborhood.

We are at 2000'
Current set up is:
Almond primary with 10-66
Team secondary with Black/red and stock helix
Running 430 mains

I looked through all the clutching and to me it appears it is all ok.
EVs were cleaned and inspected (all Good).

My friend just bought this sled a couple weeks ago and so far not impressed.

When this thing gets into powder on the flat we can only get 7000 out of it. So to me it is a backshift problem but I am not a Polaris expert by any means especially not with the Team secondaries!

So anyone that might have any ideas, I would sure appreciate it.

 

[Vertical Asshauler]

Have you tried replacing your drive belt? A 1080 or 115 would be preferrable.

 

[wellfed777]

the two things that come to mind are jetting how are the plugs and wash looking 430s with a stock pipe (or slp single) seem big/fat (they came stock with 350s-360s)
the other is the secondary spring i really like the black/purple better back shift
hope this helps
garth

 

[Taylzee]

I thought about the jetting. It doesn't appear to be real lean by any means but we are at 2000'. The polaris chart calls for 450 at our elevation. Again I'm not a Polaris guy so I am not sure where to start on this for jetting.

We are going to through a belt on it, maybe try some 420 or 410 and see what we get. If that doesn't provide good results, I think we'll look at the secondary next.

Question:
This thing should be able to pull those 10-66 at 2000' Yes or NO?

 

[itsallgood]

my escape has 10-62's @ 9-12k so yours should pull 10-66 no problem.

 

[CO 2.0]

Your exhaust outlet isn't getting plugged up in the pow is it? What color are your plugs?

 

[Taylzee]

I have been doing alot of reading! Had a sick kid today so I had the time. I think I'm going to be looking into the carbs a little better. I am used to triples that when a little fat don't seem to have as big of an effect on RPMs. I knew this thing was on the fat side with 430s but I never would have thought it could bring it down that much. I am going to through the 410s in and see what that does. Going to do it tomorrow night so I'll let yas know what I find. Going to have a closer look at the EVs too. I'm starting to think that the spring or bellows could be pooched!

 

[wellfed777]

cool let us know how it goes
like said above should be able to pull 66s
i'll bet jetting makes big diff. i got 380s in mine with slp single bored carbs and gutted air box @ 5000'-8000' and i think i could go leaner
good luck
garth

 

[theultrarider]

I ride 0-4000 feet here in Ak. Even at 0-2000 400's are safe down to about -15f on those motors! Fat for sure. I also second the black/purple secondary spring. Makes a big difference in the backshift. When you do that, make sure to put delrin washers in there as well if someone has not done so already. I would have to look at my notes, but I am thinking we were running 64's when they had the stock exhaust. I am running 66's with twins. Anymore q's just ask.

 

[ec148]

Take the secondary apart and check the spring. I have seen a fair amount break. May even be sacked out. Have seen a broken spring cause your exact problem

 

[Taylzee]

I have had the secondary apart to look at the spring. All seems OK but I couldn't get the spring out without a press. Have to take it into work for that!

 

[Vertical Asshauler]

Check your exhuast vavles to make sure they are working. Lift the track off the ground and take the sled to WOT. Look at the little holes in the middle of the black exhaust valve caps at the same time. A little nipple will pop out to show that they are working. A stuck valve or blown bellow will cause under revving like you have due to exhuast port not opening completely. This is a pretty common issue.

 

[Taylzee]

So we ended up at 430s for mains. The wash was getting quite lean at 410s.
FOUND the problem!!!
Bad EV bellow. Ripped all around the shaft. She's going good now. Hits 7900 and climbs to 8100 or so in the powder. And yes, it does pull the 10-66s.

Thanks to everyone for the ideas!

 

[Taylzee]

Update

So... had this thing dialed in and about 200 miles later...Crank SNAPS! Holy moly!!!
But Thanks to IndyDan we have a Torque Master coming...and a new top end is going on it! Should hopefully be back up by next weekend providing shipping works out!

 

[this1ultraflyz]

I know where there may be a torque master in Sask. brand new from Indy Dan.
Where you from?

 

[Taylzee]

Regina area...We have one of Dan's bottom ends on the way! Thanks for the thought though.

 

[this1ultraflyz]

So whats Indy Dan Crank worth these days?

 

[Taylzee]

Close to stock and I'm sure it's worth every penny!

 

[this1ultraflyz]

Hopefully it don't get stuck in customs for a week of two. When ever I order anything that I need fast that is what happens.

 

[quality time]

I have an 04 800 and just had similar issues.
have an SLP single pipe and Air box kit. Jetted down to 360 to make it run and just ran it at 3400 feet all week end. Ran great. also got rid of almond spring and went back to stock black/ red in primary. running stock secondary.
Check the bushings in the primary weights to make sure they are't rubbing in the sides and go to 10 64 weights. also check the rollers while you're checking the clutch.
I am running 19/ 41 gears with a 159 track.
I pull 8200 RPM with 42 MPH track speed while hill climbing in wet snow.
Hope I helped.