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View Full Version : 03 RMk wont hold RPM


JohnnyH
12-21-2008, 06:18 PM
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

mad1818
12-21-2008, 06:32 PM
Is this the same set-up that worked last year?
Have you replaced your clutch springs lately?

JohnnyH
12-21-2008, 06:44 PM
Is this the same set-up that worked last year?
Have you replaced your clutch springs lately?

Last year I had a 151 and POS!!!! Dial-a-jets.

The spring was new last Jan.

mad1818
12-21-2008, 07:13 PM
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.

JohnnyH
12-21-2008, 07:19 PM
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?

mad1818
12-21-2008, 07:37 PM
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.

omernikski
12-21-2008, 07:46 PM
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

theultrarider
12-21-2008, 08:38 PM
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
12-21-2008, 09:39 PM
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.

AdrenalineAddict
12-22-2008, 12:16 AM
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!

theultrarider
12-22-2008, 12:22 AM
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?

JohnnyH
12-22-2008, 07:07 AM
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?

mad1818
12-22-2008, 04:03 PM
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.

JohnnyH
12-22-2008, 04:21 PM
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) ?

Rprecision
12-22-2008, 06:11 PM
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

mad1818
12-22-2008, 08:10 PM
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) ?



Try them both and see what works better.
Would think the 260 would backshift better?

JohnnyH
12-23-2008, 10:36 AM
So what will I notice if I have either too high of a start or finish with a secondary spring?

02RMKer159
12-23-2008, 10:45 AM
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.

JohnnyH
12-23-2008, 10:49 AM
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?

02RMKer159
12-23-2008, 11:03 AM
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.

theultrarider
12-23-2008, 02:58 PM
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.

I think you are way fat on your 390's. I am running 360's at 1-3000 ft with slp race twins and am still fat. I think I should be down around 330's. Get your jetting dialed in first, then the clutching.

winter brew
12-23-2008, 03:31 PM
I think you are way fat on your 390's. I am running 360's at 1-3000 ft with slp race twins and am still fat. I think I should be down around 330's. Get your jetting dialed in first, then the clutching.

I agree...jetting is fat, try 360's, needle in the middle, should still be plenty safe. I would keep your clutching the same, bring some 10-60's or 10-62's.....should pull them once things are running strong.

mad1818
12-23-2008, 03:57 PM
Take it to someone who knows what their doing or your going to end up burning your motor down.

JohnnyH
12-28-2008, 06:47 PM
I agree...jetting is fat, try 360's, needle in the middle, should still be plenty safe. I would keep your clutching the same, bring some 10-60's or 10-62's.....should pull them once things are running strong.

I dropped down to 370's needle in the middle.
World of difference on the trail.
On the hill with the new 3-4' of powder slowly gets loaded up and R's fall off fast.

Will check plugs and piston was tomorrow.

Will plan on some 350's maybe 340's for next week.

I think that I am heading in the right direction. . .

theultrarider
12-28-2008, 07:06 PM
Good to hear! You are defintely headed the right direction. Just start paying attention to your plugs and wash now. You'll get it cleaned up and then hang on for the ride lol.

IceCap
12-28-2008, 07:08 PM
Sounds like your running fat, However you mentioned that it hits 8800 rpm then drops off.......tells me that you have secondary problems not shifting out properly then not backshifting under load.

theultrarider
12-28-2008, 07:22 PM
I just reread your first post and at 7-11000 you are still way fat. Did you try a different secodary spring or just the jetting? Lean it out quite abit more and try the black/purple spring. It should start coming alive for you. Someone gave you his set up for an 02 at your elebvation, bear in mind the 02's must run BIGGER jets than the 03-05's so with his 290's you should still be rich! I believe it since a m running 330's at 1000-3000. Don't be afraid to go leaner, just make sure to read your wash when doing it so you don't learn an expensive lesson.

JohnnyH
12-28-2008, 07:34 PM
I just reread your first post and at 7-11000 you are still way fat. Did you try a different secodary spring or just the jetting? Lean it out quite abit more and try the black/purple spring. It should start coming alive for you. Someone gave you his set up for an 02 at your elebvation, bear in mind the 02's must run BIGGER jets than the 03-05's so with his 290's you should still be rich! I believe it since a m running 330's at 1000-3000. Don't be afraid to go leaner, just make sure to read your wash when doing it so you don't learn an expensive lesson.

I did not change anything in the clutches, I ordered a blk/ppl (160-240) and a blk/white (160-260).

I wanted to only make changes to one system at a time so I know what changes do what.

How does the saying go. . . . . . . "if in doubt lean it out" :confused:

mountainhorse
10-25-2009, 06:01 PM
ttt

JohnnyH
10-25-2009, 08:50 PM
So after messing around all last year with different clutch setups and jetting I worked all the way down to 280 (Yeah not a typo 280's) mains before my plugs started to lighten up and the EGT's to get hot. I checked the choke cable and it is not adjuted too tight or sticking. The sled still runs like a 500 jetted way too rich in the powder but on hardpack runs hard and fast.

I checked the compression-160ish +or- 3 psi
TPS is 4.1V @ WOT
The timing was 2* or 3* off (retarded)

I bumped up the timing to 32*-33* (Spec is 29*)

I dont want an other year of the sled running like Poo:mad:

Ideas. . . .

Mtn Escape
10-26-2009, 10:22 AM
When your sled starts to bog, is your hood covered in snow? My 03 Escape, when I was in deep powder, hood covered in snow it would bog like it was jetted fat. Found around the head light the foam seal had pulled away and was letting snow and being sucked into the carbs.

I would look there. For a whole year I spent messing with jetting trying stop the bog and found that.

JohnnyH
10-26-2009, 10:49 AM
When your sled starts to bog, is your hood covered in snow? My 03 Escape, when I was in deep powder, hood covered in snow it would bog like it was jetted fat. Found around the head light the foam seal had pulled away and was letting snow and being sucked into the carbs.

I would look there. For a whole year I spent messing with jetting trying stop the bog and found that.

It will do it with no snow on any of my vents, and does not matter if the right side (exhaust exit) is totally out of the snow either.

The headlight has been resealed.

JohnnyH
10-27-2009, 02:39 PM
Ttt

RottenScummyTroll
10-28-2009, 03:23 PM
Just throwing this out there, but have you checked your exhaust valve diaphragms?

I had a similar problem where it would lose RPMs on the trail after initially taching up fine, and it turned out I had a ripped diaphragm that was allowing one of my exhaust valves to creep closed. Worth checking.

JohnnyH
10-28-2009, 03:27 PM
Thanks, both exhaust valves, springs and diaphragms are A OK.

What could be going on that I could run 280's and not burn down ???:confused:

whoisthatguy
10-29-2009, 11:44 PM
Those main jet sizes, scare the hell out of me. They are not even close. I love the smell of burned up pistons in the morning. About a mile out of the snowpark. 1 to 3000 feet should be about 450's at 20F to 35F. The engine will starve itself of gas if the suction hose gets hot from a hot engine that is being wound out. The hose softens up and cuts off the suction at the hose bends. Particularly the new and improved Red Hose from Polaris. If your polaris dealer sold you the O-rings that are not high temp like mine did, you will start sucking coolant into the pistons and burn up everything as well. He had to do a lot of begging to get those outdated O-rings from Polaris, just so he could screw up my sled.

shortstop20
10-30-2009, 02:18 AM
I think you are way fat on your 390's. I am running 360's at 1-3000 ft with slp race twins and am still fat. I think I should be down around 330's. Get your jetting dialed in first, then the clutching.

How in the heck are you running 360's at 1000 ft? That is NINE sizes lower than stock for that elevation and that's on a stock sled.

JohnnyH
10-30-2009, 07:14 AM
Those main jet sizes, scare the hell out of me. They are not even close. I love the smell of burned up pistons in the morning. About a mile out of the snowpark. 1 to 3000 feet should be about 450's at 20F to 35F. The engine will starve itself of gas if the suction hose gets hot from a hot engine that is being wound out. The hose softens up and cuts off the suction at the hose bends. Particularly the new and improved Red Hose from Polaris. If your polaris dealer sold you the O-rings that are not high temp like mine did, you will start sucking coolant into the pistons and burn up everything as well. He had to do a lot of begging to get those outdated O-rings from Polaris, just so he could screw up my sled.

So. . . . I think that you are saying that the fuel lines to the fuel pump and from the pump to the carbs will restrict flow to the carbs and lean out the motor and sieze :confused:

Are you talking about the cylinder head o-rings:confused:
I dont have a coolant problem

whoisthatguy
10-30-2009, 09:41 PM
The problem with the fuel pump for some years is caused by the bends and ensuing kinks in the SUCTION HOSE ONLY, that attaches to the bottom rear of the crankcase. The fuel pump stops working and shuts the engine down so fast that it doesn't have time to burn the pistons up. The original stock black rubber hose with a fiber cross weave, has a far less tendancy to kink when it gets warm. The Polaris update that was sold to me was a red plastic hose. Of course, the dealer may have deliberately sold me the wrong hose for that as well.

The hi temperature o-rings that I was referring to, sit on top of the cylinders and below the cylinder head.

Defective hi-low beam switches also cause RPM problems, believe it or not. Defective CDI boxes will also cause RPM problems. I have a new one for sale that is guaranteed to be fully functional, for $50. Polaris will gouge you about $340 for the same item. Never hurts you to carry an extra around for an old sled.

Thermistor wires may be wearing out. Some Polaris dealers like to bend the wires over as they come out of the top of the thermister, in order to sabotage the sled and cause premature engine failure. Which may then kill you when you break down 30 miles from your ride home, in a snow storm.

A stator that is going out may miss now and then and may have trouble idling at the same RPM's.

JohnnyH
10-31-2009, 08:01 AM
The problem with the fuel pump for some years is caused by the bends and ensuing kinks in the SUCTION HOSE ONLY, that attaches to the bottom rear of the crankcase. The fuel pump stops working and shuts the engine down so fast that it doesn't have time to burn the pistons up. The original stock black rubber hose with a fiber cross weave, has a far less tendancy to kink when it gets warm. The Polaris update that was sold to me was a red plastic hose. Of course, the dealer may have deliberately sold me the wrong hose for that as well.

The hi temperature o-rings that I was referring to, sit on top of the cylinders and below the cylinder head.

Defective hi-low beam switches also cause RPM problems, believe it or not. Defective CDI boxes will also cause RPM problems. I have a new one for sale that is guaranteed to be fully functional, for $50. Polaris will gouge you about $340 for the same item. Never hurts you to carry an extra around for an old sled.

Thermistor wires may be wearing out. Some Polaris dealers like to bend the wires over as they come out of the top of the thermister, in order to sabotage the sled and cause premature engine failure. Which may then kill you when you break down 30 miles from your ride home, in a snow storm.

A stator that is going out may miss now and then and may have trouble idling at the same RPM's.

The CDI,Stator and ignition coil had crossed my mind but I dont want to start throwing parts (I might have to) at it on a WAG.

Where are these thermistor wires located and what is their purpose ???

whoisthatguy
10-31-2009, 08:41 AM
The thermister screws into the top of the cylinder head. It measures coolant temperature. It completes the electrical circuit when the wires are good and connected, like a kill switch. When the wires break, the engine won't start or run. Then in an emergency you need to fashion a little wire that you can connect the two ends of the wire harness plug that attaches into the thermister connector plug. The thermister pigtail wires are supposed to extend straight up out the top. The polaris dealers around my parts will deliberately kink that pigtail wire, break the plastic wire insulation and weaken the now bent copper wiring. Use a zip tie to make a nice gentle loop in this wire to double back on itself, and tie it too itself. All without breaking or kinking this pigtail. If it is already kinked, then you need a new one.

Mtn Escape
10-31-2009, 06:50 PM
My 03 Escape had a problem with running out of fuel. Especially on long hills. Found out to be the the pulse line to the fuel pump was being kinked by the air box.

indydan
12-04-2009, 10:24 AM
I have been out of the loop for to long..........

Ok I have to do some reading to catch up on this thread.

and then I will explain a few things that i said......I can understand why some would be confused as to why I said go up in angle it it was not pulling RPM. I will expalin after I read everything so I am up to speed with everyone.

indydan
12-04-2009, 10:27 AM
JohnnyH what elevation are you riding at ???

lowest to highest and average.

Dan

JohnnyH
12-04-2009, 03:48 PM
Unload around 7,000 ish and up to close to 11,000 ish

indydan
12-04-2009, 06:26 PM
Ok, this threads to long to read everything.

I skim read enough to see whats up.

And yes I said a bigger helix, 60/40-.46 is or 60/42 .46 is a great 800 TEAM helix the 150/250 area spring depending on conditions and rider weight. 140/240 to 160/260 should be the low and the high.

58/38 is borderline to flat depending on the rider weight and gear ratio in the chain case.........IF the ride is heavy enough and the gears are a little to tall the driven will pull against the drive clutch when you hit the deep stuff to back shift and will not upshift fast enough and drag the motor down and or over heat the clutch or clutches depending on which one is most unhappy at that point.

Johnny I believe someone has touched on whats wrong with our sled aslo and that sounds like jetting to me........Also the 2003 Escape needs a OEM Polaris fuel pump relocation kit because the impulse line is to long and the pump needs to be moved from the oil bottle to under the air box they have a cool little bracket that makes this simple.

Your jets are to big........If you have an SLP intake on that thing you should be running right around 300 mains.

If you are a lite weight guys and have low gears you can get by with the 58/38 no-problem.

Keep in mind that center center distance has alot to do with what helix and what drive weights you can pull.

a long center to center will tend to like - lighter weights and steep helix

and a short center to center will tend to like - Heavier weights and pull like a frieght train with a slightly flatter helix.

Center to center distance is the very reason why to sleds that may appear exactly the same can and will not perform the same with the exact same clutch set-ups.........I.E. Belt length.....& belt shear have a unbelieveable effect on clutching.

example..........Lets say all is performing well with an old belt AND then after the install of a new belt that lets just say that it is a little short........( in effect the sled will act like it has a long center to center ) the the sled will have a hard time pulling RPM.

And all these effects tend to be a little different depending on what driven clutch you run some driven are much more sensitive to this then others.

Johnny H theres a few things to chew on for now.

Dan