M8 Not reaching full RPM's and It's not the clutching!

[06m7]

i'm glad to see this post my 2011 m8 sno pro is doing the EXACT same thing i have 2 different primaries and 2 different sec dont matter what i do it will not go over 8050 untill it reaches gear out at 85 mph then it will climb but last year in cooke i tried everything to get rpms up never happend. came back home to 1000ft asl and with stock clutching for 9000 and up ft it still would not go over 8000 it should be screaming at the crack of the throttle. this jan in revy i tried all different kind of things and no luck
got new motor mounts installed still nothing all the little nornal stuff like power valves are clean and good not sure what else. i'm 95% sure its not clutching because i have 4 of them and nothing helped i have about 1000 miles on this thing

 

[WyoBoy1000]

Thats why I'm asking about added electronic, and unplugging every thing to the bars and brake light wires next to brake rotor. Ohm coils, new plugs, wouldn't hurt to find someone to test the TPS setting (dealers can get tools), try changing pipe sensor.
maybe something out of balance, might want to check crank run out and rod throw/timing.

 

[offroadmatt]

I found at least one GIANT problem
67 p.s.i. Fuel Pressure.

 

[Rixster]

I found at least one GIANT problem
67 p.s.i. Fuel Pressure.

WOW, yeah, that will make it a little rich !!

 

[WyoBoy1000]

Does it have a regulator (aftermarket) the stock one should not be able to go that high unless something is stuck in it or the reg is stuck, you may want to make sure the gauge is good. I've seen a lot of differences in gauges, but usually if they go from 0 up and return to 0 they will be within a few lbs.

If stock try tapping on the reg while running and see if it drops.

 

[1]

what is the fuel pressure supost to be? i would like to check mine as well

 

[WyoBoy1000]

43-47psi

 

[AKboondocker]

Maybe its a conspiracy. Arctic Cat tachometers are programmed to read a max of 8050 after the 750 mile mark to cause you headaches and many trips to the dealership to buy clutch parts, clutches, etc. Plug in a tach from a new sled. If it goes to 8200, you may have yourself a nice lawsuit. Just a crazy thought when thinking about those crafty japanese engineers...hahaha

 

[offroadmatt]

Does it have a regulator (aftermarket) the stock one should not be able to go that high unless something is stuck in it or the reg is stuck, you may want to make sure the gauge is good. I've seen a lot of differences in gauges, but usually if they go from 0 up and return to 0 they will be within a few lbs.

If stock try tapping on the reg while running and see if it drops.

Gauge is fresh out of calibration. Blew some compressed air back through the gage and regulator. Stuck at 67 for a second then started opening fine at 42. Plug it back into the sled and started it ran fine at 42 for a minute then climbed to 50. Took it for a test run tonight was clear up at 65+ as soon as I punched it.

Have a aftermarket one coming from BDX. Hoping this will solve all my problems.

 

[windsock]

O.k. how does one check one's fuel pressure? Where is this located? I believe I might have this issue also (losing RPMs, clutches seem good) Would Reflashing or using a new ECU clear up this problem of the fuel pressure being too high or is it separate from that?

 

[WyoBoy1000]

You have to buy a gauge and plum it in.

 

[offroadmatt]

I just used a tee and a couple chucks of hose to plum a little gauge in. Right where the line comes out of the fuel tank.
But you could buy the gauge and adapter from Black Diamond extreme if you wanted a cleaner permanent installation.

 

[windsock]

Offroad Matt, so have you put the fuel pressure thingy in yet? Any improvement?

 

[offroadmatt]

Offroad Matt, so have you put the fuel pressure thingy in yet? Any improvement?

Installed it Thursday and got to ride it Friday and Saturday. This thing helped out TONS!! Fixed most of my problems. For the first time this year I really thought I was getting my moneys worth out of this sled. Here are the things it fixed.
Lower EGT and RPM at idle.
No more bog coming off idle
No more surging, cruising at 5000-5500 at 20% Throttle
EGT's are finally leaning out on top which is giving me gobs of more power.
Hitting 8300 on hard pack. Still working on clutching for the pow.
I don't feel that this was or is the only problem but it was for sure 90% of the problem. Now I can focus on the smaller things like clutching and skid setup.

 

[Frostbite]

It's good to hear that you figured it out.

It makes me want to buy a BDX fuel pressure regulator.

I have no idea what my fuel pressure is....

 

[windsock]

I ended up solving most if not all of mine. 2000 miles on the sled. New spring and rollers in the secondary and a new belt and now I'm getting the proper RPMs, Not getting any 8300 type of stuff but performing where it should be 8050 in the deep powder at elevation. I'm not messing with my fuel pressue (don't know what I'm doing) but if it comes up again, perhaps I'll have to look into it.

 

[offroadmatt]

Sent my Secondary out for rebuild. BDX said it was pretty bad .010" bad. Machined it and made it so a double row of bushings will fit hopefully it will last a little longer. Also added a set of Rock Rollers to it while it was apart.

Sent my primary to SLP to have it Shimmed for the MTX weights. Either the spider was broke or it broke coming apart. But either way now I have the STP billet spider on a 09 sheave. Plus rebalanced and bead blasted. Going to ride 3/10. Will see if there is any significant change.

 

[cumminshp]

Racinstation rebuilds primaries and secondaries.

Do you know how much they charge for each ?

 

[cumminshp]

Sent my Secondary out for rebuild. BDX said it was pretty bad .010" bad. Machined it and made it so a double row of bushings will fit hopefully it will last a little longer. Also added a set of Rock Rollers to it while it was apart.

Sent my primary to SLP to have it Shimmed for the MTX weights. Either the spider was broke or it broke coming apart. But either way now I have the STP billet spider on a 09 sheave. Plus rebalanced and bead blasted. Going to ride 3/10. Will see if there is any significant change.

How much was it to get each done ?