I lost 200 RPM over the summer?

[Gianni_CRX]

'17 ASSAULT RMK

I did a few mods, and maintenance or the summer. Seems I've lost 200 rpm. Sled would pull 8250, now maxed out @ 8050.

I cleaned my power valves (in the sled) I did not touch actuator, or cable... no codes on screen.

Added a JAWS pipe
Changed plugs
Tensioned chain
Added 3 delrin washers to secondary
Cleaned both clutches
Changed hyfax
Swapped bumpers & arms..

Same belt being used as last season... no pulled strings... deflection looked OK..

I was expecting to gain rpm w/ the JAWS pipe... not sure where to look... I'm hoping for 8350 - 8450...

 

[cascadesnowjunky]

I guess I will say it before others, try your stock pipe and see if it comes back to life. Report back after.

 

[Robbie]

Change your primary spring. It took a set over the summer

 

[Perk]

8050 seems to be the magic number. I have done everything possible and still cant pull 82-83 like a lot of my riding buddies. Sled has about 580 miles and has never pulled 8300. Over the summer had the clutches gone through, added slp pipe, new motor mounts, new belt, checked power valves (at dealer). Clutch was balanced, new weights and spring (for SLP pipe add). Sled out runs stockers in a drag race, but I know I am leaving some on the table. Frustrating. TPS was also checked by the dealer, but I expect it was done with DW. Maybe I'll go down that road.

 

[alexkravets]

lost rpm

change your motor mounts. I change mine every 800 miles
that would bring rpms back

 

[EBartling]

Bad Ethanol gas? Or nest in air box?

 

[WAsledder]

How are you checking your deflection? Looks ok vs adjusting and being spot on is a huge difference. Checking and adjusting deflection is one of the best "performance mods"

 

[Wheel House Motorsports]

Fresh primary spring is cheap insurance, and while the cover is off verify all your rollers are moving smoothly. Little corrosion on things can go a long way. Scotchbrite sheaves, make sure your filled up with fresh fuel.

Not sure how/where you store your sled but stupid stuff can cause issues. If none of this fixes it I would throw the stock pipe on to verify. Process of elimination. It worked, you changed something, go back to square one and verify.

 

[HECKS]

Are you running the stock can or aftermarket ?
Motor mounts and make sure you set your deflection on a track stand or track in the air.

 

[Gianni_CRX]

Thnx for the suggestions... gonna try a few things...

Gonna swap back to the stock pipe to test...

Pull and inspect primary... Probably replace spring.

I cleaned the p-valves. .. no issues. .. no codes.
New plugs...

I didn't check.. but I doubt there's a nest in there.. sled was in garage all summer.. ran it a few times... no signs of animal activity..

I'll recheck... and set belt deflection.... what's the procedure..

 

[Gianni_CRX]

I swapped my motor mounts this summer.. I'm running 4x #3290's from the '18 Pro... pto side

Ggb mountain can on it.. same as last yr... I don't have the stock can...

 

[Gianni_CRX]

Fresh tank of 91 octane... Ethonol free... I siphoned out last yrs...

 

[WAsledder]

Suspend the sled so the track is in the air. Start the sled...Back off the adjuster on secondary(7/16 wrench and 1/8 allen) until track starts to creep, tighten adjuster slightly until track stops. There are a few detailed threads on belt deflection on this forum. I run mine as close to creeping as possible.

 

[AdrenalineAddict]

I know a few guys who lost 100 -200 R's by just putting on a horsepower robbing can.

 

[HECKS]

I swapped my motor mounts this summer.. I'm running 4x #3290's from the '18 Pro... pto side

Ggb mountain can on it.. same as last yr... I don't have the stock can...

Try and get a stock can or buy the Jaws can.
Reason I asked about the can, as I had a GGB on as well with stock pipe and ran fine 2 seasons ago.
Then purchased a Jaws pipe last fall and it was hit & miss with the RPM's being very inconsistent and stumbled on the bottom end quite often.
Then went back to the stock can all of last year and ran flawless ! This year I bought the Jaws can to shed some weight, and I would say it is a bit more responsive now over the stock can. Running 8400 - 8500rpm

 

[Gianni_CRX]

Hmmm... I can't see how the pipe or can is costing me power.... I ran the Ggb problem free last season.. it would jump to 8050 then gain to 8250 .. my bud is running the same exhaust set up Jaws & Ggb. .. he pulls 8500 all... different track/gear/clutching....

I'm working till christmas... so testing will have to wait..

 

[Gianni_CRX]

Back at it...

Swapped the Jaws pipe back on... as the stocker did not fix my loss or rpm...

Installed a New Ultimax belt.. (it came with the sled) I set it by feel.. and creep... it seems to sit lower.... so I opened/loosened the clutch a bit...

Tightened the track to 1.75" droop w/ 10lbs hanging from "the mid" point of the skid... I had 2.75"...

New plugs... again... BPR9ES I didn't check gap, but both looked good... Old plus were wet when removed... I haven't ran the sled in atleast 10 days... idk?

Re-checked chaincase tension... it was good... but i backed it out 1/4 turn...

Temps were higher today... 0C 32F.... snow was sticky maybe 1.5' deep... other spots a bit packed.... I was able to pull a few 250 -- 300'' WOT pulls... not the best test location!
Lol... .. pretty much the same results... 8050 RPM..

What should I b checking next?

 

[Matte Murder]

Did you ADD the delrin washers or change them out for new?

 

[Gianni_CRX]

I added 3 delrin washers this fall... either end of the spring... and 1 under the spring cup.... everything else in there looked kosher....