• Don't miss out on all the fun! Register on our forums to post and have added features! Membership levels include a FREE membership tier.

03 RMk wont hold RPM

J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
Looking for ideas on why my 03 RMK 800 will hit 8000 RPM at WOT on the trail and then slowly drop RPM till I let off the throttle.
If the Deep fluffy powder it will only pull 7200-7400 RPM.


Ideas???

Ride 7-10k
Crankshop twins
UBR head
159 polaris track
19-41 gears
390 mains(too rich, will try 380 later this week)
10-58 weights, 140-330 spring (Team Green )
TSS-04. 58-38 with red/pink (140-260 ) with 3 delrins
Yellow exhaust springs
I weigh about 260 with gear.

Thanks for your ideas
 
M
Sep 4, 2007
568
317
63
Minnesota
It's shifting too fast and dragging your RPM's down.
Could run 10-56 weights and try it. If your engagement is right though you could try a heavier secondary spring instead. I'm not a clutching pro. Just some thoughts.
 
J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
Yea the 10-56's crossed my mind but that just does not seem right for a 800 with twins:confused:

Higher start or finish for the Spring?
 
M
Sep 4, 2007
568
317
63
Minnesota
Couldn't tell ya for sure.
I would think you'd be close on clutching to new 700's
10-58's with a 140/330 spring in the primary.
56/42/36 helix with a Black Team spring 155/222 (I think) in the secondary.
 
Last edited:

omernikski

Well-known member
Lifetime Membership
Nov 26, 2003
651
78
28
43
Minocqua, WI/ Foxboro, WI
I have the identical sled setup for the same alt. running CPI Twins with twin stingers. I will let you know tomorrow what I'm running for a setup, I'm not sure at this time because I bought the sled this way. It about pulls my arms off and engages at 3500 rpm and tachs out at 8800 give or take a couple hundred rpms. the sled did come to me with 390 mains, and a speedwerx high alt. domes running 50/50 race gas
 
T

theultrarider

Well-known member
Nov 26, 2007
3,311
890
113
Soldotna Alaska
I'm running an 03 159 with slp race twins and also weigh about 260. Last week I finally dropped to 19/43 gears and that made a big difference on just what you are describing. I also went to a 160-240 secondary spring, black/purple. That worked better than the 140/260 also. Good luck, Please let us know what you figure out.
Tim
 

indydan

Well-known member
Lifetime Membership
Nov 27, 2007
1,245
3,301
113
Custer, South Dakota
www.indyspecialty.com
Air Box & vents

Looking for ideas on why my 03 RMK 800 will hit 8000 RPM at WOT on the trail and then slowly drop RPM till I let off the throttle.
If the Deep fluffy powder it will only pull 7200-7400 RPM.


Ideas???

Ride 7-10k
Crankshop twins
UBR head
159 polaris track
19-41 gears
390 mains(too rich, will try 380 later this week)
10-58 weights, 140-330 spring (Team Green )
TSS-04. 58-38 with red/pink (140-260 ) with 3 delrins
Yellow exhaust springs
I weigh about 260 with gear.

Thanks for your ideas

Jonny, Tell me about your air box and carbs vents.........

Are they completely stock or have they been altered ???

1 thing - Your Helix is to flat, I would go right to a 64/42 .46 and gear it down.
 
Last edited:
A
Nov 26, 2007
1,512
810
113
Elko, NV.
I'm not following Indy's clutching advice. How is a steeper helix going to help this sled gain RPM's. Gearing down is generally good for another loss in RPM's without going lighter in the primary. Hmmm!
 
T

theultrarider

Well-known member
Nov 26, 2007
3,311
890
113
Soldotna Alaska
I'm not following Indy's clutching advice. How is a steeper helix going to help this sled gain RPM's. Gearing down is generally good for another loss in RPM's without going lighter in the primary. Hmmm!

I'd like to hear Dan's explanation as well. A steeper helix will usually drop r's and slow down backshift, so if it isn't backshifting now, how will a steeper helix help?
 
J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
Jonny, Tell me about your air box and carbs vents.........

Are they completely stock or have they been altered ???

1 thing - Your Helix is to flat, I would go right to a 64/42 .46 and gear it down.

The air box is gutted with a SLP air horn kit, carb vents are just the stock ones that go to the front of the air box.
I also have plenty of Flow-Rites.

What kind of gear down, Like 19-43 or lower?
 
M
Sep 4, 2007
568
317
63
Minnesota
I would say your gears are fine. Try a heavier starting secondary spring. That will slow the shifting (keeping your RPM's up) and improve the backshifting. There only like $20. That would be the cheapest place to start. I don't agree with a steeper helix in the elevation your in. Would also like to know how that would help.
 
J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
I have a Black/Red (155-222) kicking around, What would the lower finish do different than the Red/Pink (140-260) ???

Or would I be better off trying a Black/ Purple (160-240) ?
 
R
Aug 30, 2008
1,438
151
63
Rocky Mountians
Had a similar thing happen when I first rode my sled (04 800). Turns out I was running the ignition switch in the secondary position not the premium. It was cutting down the timing.

Just a thought, I know there are other circumstances
 
J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
So what will I notice if I have either too high of a start or finish with a secondary spring?
 
0
Feb 18, 2008
40
2
8
If it was me I'd spend a little more time and get the jetting set spot on. I ended up dropping my jetting down 5 jet sizes last year to get the perfect color on my plugs. And it changed the RPM's big time and then I dial in the last couple R's with the weights dropping to a 10-56 and may go lower yet.
Get some good info on plugs there's more to it than just looking for Brown on the plug. It took me some time but I have it perfect now.
 
J

JohnnyH

Well-known member
Nov 26, 2007
528
116
43
SL,UT
If it was me I'd spend a little more time and get the jetting set spot on. I ended up dropping my jetting down 5 jet sizes last year to get the perfect color on my plugs. And it changed the RPM's big time and then I dial in the last couple R's with the weights dropping to a 10-56 and may go lower yet.
Get some good info on plugs there's more to it than just looking for Brown on the plug. It took me some time but I have it perfect now.

What is your elevation, sled and setup?
 
0
Feb 18, 2008
40
2
8
I run at 9000-11500.
My sleds 02 700 Ported and piped, Wiseco pistons
Primary stock Black/green 120-340 10-56's
Secondary SLP yellow/purple (don't remember rate)
SLP mountain helix 44-46/34 1 shim #3 hole

I have a friend that use to work for Xtreme and compared these specs to there kits and it's real close, except they run a 10-57.5 weight. (they grind their weights) I was having the same problem when I talked to him and he told me to dial in my jetting so I did and it helped. I dropped to a 290 from a 330 and could probably go down one more size if I pushed it. I'm pulling 8200 RPM's but I'm still a little under full shift out. I know the motor will pull more R's. My big thing now is I think I need to just clean up my clutches real good and see.
Plus I did find that my throttle cable was starting to frey so I wasn't getting WOT alot of the time when I was tuning last year, so that problems fixed now I just need to get out at check it out.
 
Premium Features