m7 wont rpm past 7000

[jasn179]

i have a 2006 m7 has 4100 miles went riding today started out great now wont rpm past 7000 on wide open deep barely holds 6500. Exhaust valves are clean clutch is new with 68 gram weights and a new stock yellow and original white spring primary and white in seconsry. Have two idears do the exhaust valve servos fail these are same symptoms that i have when a exhaust valve sticks or do secondary springs loose there abilty to hold secondary closed over time?

 

[WyoBoy1000]

You should be able to put it on a stand and watch the powervalves open, put a mark on them where they should be all the way open. have you pulled on the cables to make sure a cable isn't bad.

 

[jasn179]

cables are good will try running on stand problem is that it will be hard to see the servo because on the m7 its under the pipe what a bad place for it thought of moving it to where my m8 one is at

 

[High Country]

ditto

have a look at the servo/cable ends the 2006 has no clip to hold the cables in place...and they pop out...i had one do that...exact signs and symptoms described...about 6500rpm on my 2006...local cat dealer tell them you need a clip from a 2007 or newer.if its not that it could be your stator....ouch better sit down...just saying...good luck check those cable ends first

 

[jasn179]

i have had those cable ends fall out before i put a bead of silicone across them a couple years ago which stopped that problem. Ya i sure hope thats not a stator problem just replaced one on my older sleds when it failed it just died right in its tracks. Part of me thinks that it is a problem with the servo motor.

 

[jasn179]

well checked the servo motor and it is working fully opening valves the only other thing i can think is the secondary spring might be weak for age and miles is this possible?

 

[W A O]

I had a different problem but one of the sugested fixes or things to check was make sure your power valve cables have not streched on you. Pull your pipe and look up the wye pipe and see your power valves then take off your cover and manualy stroke and or twist the servo motor all the way and then look at your power valves again, they should be completly out of sight or all the way up. Just a thought?

 

[jasn179]

I had a different problem but one of the sugested fixes or things to check was make sure your power valve cables have not streched on you. Pull your pipe and look up the wye pipe and see your power valves then take off your cover and manualy stroke and or twist the servo motor all the way and then look at your power valves again, they should be completly out of sight or all the way up. Just a thought?

Very good point i did check that earler i am just so stumped dont know what to think i have checked everything i can think of. I even checked compression and shes just like a spring chicken

 

[W A O]

One more possible problem to check. I had a can on my sled that ran just fine for almost a full day and then my sled just would not peak much like yours. I checked everything( including the polaris sticker I had on it) and could not find anything wrong as well as three rideing trips wasted trying, what a pain. Now my point, My no name can had come apart inside not letting all the flow exit out the exaust, put on a new can and suprize it ran like a raped ape. Check the flow on your exaust and make sure it flowes freely. Any restrictions and it will run just the way you described it.
Hope you find it soon good luck
Sean

 

[High Country]

things

yeah check those cables...service manual is like 35.4 mm or something like that.
also check your primary...stuck weight or something binding???? pull it off and inspect real good

 

[jasn179]

One more possible problem to check. I had a can on my sled that ran just fine for almost a full day and then my sled just would not peak much like yours. I checked everything( including the polaris sticker I had on it) and could not find anything wrong as well as three rideing trips wasted trying, what a pain. Now my point, My no name can had come apart inside not letting all the flow exit out the exaust, put on a new can and suprize it ran like a raped ape. Check the flow on your exaust and make sure it flowes freely. Any restrictions and it will run just the way you described it.
Hope you find it soon good luck
Sean

I have a snow stuff can on there been on there a long time had to weld the mount back on a while ago m7 sleds have lots of vibration could be broken inside i will inspect it carefully i bet you are onto something i appreciate all your help makes alot of sense

 

[W A O]

No problem bud Im sure you will help me out one day soon.

 

[jasn179]

well took can off and cut end off no restrictions but the packing is mostly gone could this cause the flow to be restricted enough to make sled not run right?? have to go over to my other house and get the old muffler out of the shed and try it again so weird. If it still runs crappy guess got a lil welding to do may as well repack it while i have it apart though.

 

[IShartd]

So the one thing barely anyone has touched on is your clutch, this is the one thing you just screwed with, Id check that first. Weights are to tight, maybe not getting a full swing, Belt deflection is out of adjustment, possible alighnment issues, did all the washer go back on the DD after reinstalling the secondary? check the power valves and be done with it, ive run my sled with both cables off just to see what it would do, lost a couple of hundred Rs but not 2000 rpm, thats sounds like clutching. Happy Hunting.

 

[jasn179]

when i put the new clutch on a last year was working perfectly first ride out this year rpms slowly depleted and this is where i am now puzzled know exhaust valves are working perfectly know the primary clutch is new all rollers, o rings and weights perfect. Still scratching my head.

 

[WyoBoy1000]

Still go through the clutches, mainly rollers and springs and new belt. maybe check your DD fluid maybe something is going out.

 

[jasn179]

i have been working hard at it again took primary apart weights are free rollers are good on primary. I am really thinking that the secondary spring is shot i find it too easy to open the clutch up got a new one coming from cat hope this is it out of options primary good exhaust valves are working great got to be secondary watched it cruising the yard and the little bastard opens up as soon as you mash the throttle hope its the spring way frustrated.

 

[WyoBoy1000]

Where do you ride, there may be better option than the stock spring.

 

[jasn179]

i ride normally between 8-10k feet in somewhat bottomless snow i normally ride a 09 m8 but this m7 used to be my primary sled my wife rides the m7 when she rarely goes and i use it now and then cause its just a plain ol good and fun sled untill i took it out the other day.

 

[jasn179]

stole the secondary spring from my m8 its the orange put it in m7 top rpm at 7000 feet at the house here 7620 just for a micro second then drops down to 6800 and wont pull any harder well beyond puzzled patience is long gone about ready to give it away now is entirely stock except a orange spring in secondary will pull 7900 off the ground exhaust valves are working properly what is the deal