RPM Problem

[modded93xlt]

I tried this on an old thread, but got no assistance, so I figured i would try a new one. Here is my problem

My sled wouldn't rev over 7k all the time below 45mph. it was intermitent at first so I have started the task of tracking down the problem, the first thing I did since I was rich, was drop jet size from 490-470. this did not correct the reving problem and it was doing exactly what it did before. However it did lean out the engine(possibly too much) I swapped out the old plugs to new plugs(NGK) and immediatly did another test, but then all the sudden it wouldn't pull over 6500rpms until i got over 40mph, after two 1 mile test hits I pulled the plugs and they were white(but no piston wash i could see. Also on this hit the sled seeme to want to idle around 3500 and start to creep. I stopped and started turning down the idle screw and got the idle down to 2500, but then the sled died, so i turned it back up.

As for the sled here is where it sits now:

2005 RMK 800
-single SLP Y-pipe, pipe, and can
-SLP Air horn kit
-SLP flow-rite intakes
-SLP powder sno pre-filters
-470 jets
-needles at position 3.5(SLP needle shim)
-Steel guillitines
-orange VES Bellows
-Pink VES Spring
-Black green primary spring
-10-66 primary weights
-team rapid reaction secondary(reverse)
-Black secondary spring
-58-42-36-ER Helix
-Running NGK Plugs

I have not opened up the chain case yet, to look at the gears or looked at the drivers, but I'm assuming both are stock and when I bought the sled I was told it had the wide bearing kit installed. I also pulled the reeds and they arein great shape.

I Ride in North dakota mostly (900 feet) and at temps normally ranging from negative 10 to 25 above.


I have been looking around and have seen others had this problem and saw suggestions to fix it running the full gambut ranging from dimmer switch(yeah not sure where they got that) to head temp sensors, clutching, VES, CDI and so one, basically everything short of saying it's the brake light causing it.


I am looking for help from anyone that has dealt with this condition before, I'm adjusting things one at a time until I get it fixed. I started out with jetting since it was rich, I am going to swap to 480 jet next and see what that does, after I get the engine set, I am going to try MXT 68g weights(SLP's suggested weights for the pipe) and keep adding inserts until I can't make 8k at all.

Well that is unless someone has a very confident fix to try first. I must admit I am at a loss at this point and am basically taking educated stabs in the dark.

Thank you in advance for any help you can offer.

 

[BB454]

RPM

I would hose it down on all the seal surfaces with brake cleaner while it is running, including carb adapters. If you have an air leak the idle RPM will change. Then look to the clutches. Sounds like one of the springs may be weak. Allowing the clutches to load the motor too much. They are relatively inexpensive. What is the max RPM that you can get out of it if under 8100 on the single pipe then go lighter weights not heavier, 64s sound more like it to me at your elevation. Has it run good last year? If so then something is worn out not a calibration thing so helix and weights and jets should be fine but maybe primary needs rebuilt and carbs cleaned. If it dies under 2500 RPM, that says idle jets are plugged. May be just that simple. Will it idle down with the belt off?

 

[modded93xlt]

I hope you are right! I'm going to go through everything again this weekend, clean carb, clean VES, check clutches ect... Hopefully this sees some change. The sled is new to me, but I got ahold of the guy I bought it from and he said it ran perfect last year on the stock pipe, I only have his word to go by, but I have no reason to doubt him..

I'm hoping it is something dumb, since I've checked most everything else

 

[modded93xlt]

I finally got it fixed, turned out to be a bad oil pump, over oiling.

 

[blueyoda]

How did you diagnose the bad pump?