2012 Pro RMK down on Rpm

[corpeleven]

I searched but couldn't find much so ill ask: sorry if its been posted and I missed.

12 pro 163, 1700 miles, stock. When i punch it, it seems sluggish and jumps to 74-7600 the creeps up topping out at 7900 in flat meadows in a foot of fresh. 7400-7600 on inclines with fresh, and 8050 on hard pack.

I Ride at 10,500.

Also idles low at 10k, 1000-1200

New clutch springs, new 58g weights, clean ves valves, new plugs, pistons look great looking in from ves ports, compression tests at 105/105 at 4800 feet.

Has been flawless until now, always pulling 8200. Did not change clutching, just replaced worn parts from last 2 seasons.

Any injector issues with the 12's? Have not changed fuel filter, could it be restricted?

Thanks guys.

 

[jeremyp111]

Yes, the fuel filter really could cause those problems, especially at 1700 miles. I'd change it if I were you. 105/105 is even compression, which is a very good thing, although a tad low. At 4800' maybe it's not too bad, could be your gauge reading low. And you're sure that you put in the exact same clutch parts as what you took out?

 

[corpeleven]

Same clutch parts.

Is it difficult to change the filter?

 

[BILTIT]

Not hard but you will want this cheap tool set.

http://www.harborfreight.com/6-piece-fuel-line-and-a-c-quick-disconnect-tool-97576.html

 

[jeremyp111]

No, not really. You just need to pick up an inexpensive fuel line removal tool. Do a search here on the forum and you'll see what I'm talking about.

edit - BILTIT beat me too it...Yeah that's the tool.

 

[800poodragon]

Make sure bellows are good and installed right on exhaust valves. That could be part of the problem. I agree that is a lot of miles on a fuel filter which will cause problems as well.

 

[towny]

Check Power Valves

My 2012 pro did as yours.
Check your Power valves. The Port from the cylinder to the Valve gets pluged and the small ports under the bellows in the Valves get really pluged.

You can quickly check to see if there pluged by pulling the hose off the solenoid valve on the Power Valve side. Carfull not to break the barbed fitting!
Start your sled, watch to see if there is exhaust flowing out the tube. Should be a noticable amount! Works best to do the check when the sled is cold. Smokes more!

Do a search on "Power Valves" for more info.

 

[BILTIT]

Just a little story about fuel filters.

I purchased my '11 pro with a blown motor this past march. I replaced everything (filters, reeds, injectors) since i didn't want the same problem happening to my new engine. When i went in to order the fuel filter (the only polaris dealer in town), they said that part had never been ordered in before.

So here in spring of 2013, no one has ever ordered a fuel filter for an '11-12 Pro?!?!?!

Goes to show how a lot of people don't think of these maintenance items.

 

[jdw1]

Had some what of the same issue with my 12 pro rmk last year, at approximately 1700 miles it was hesitating, I have put a new fuel filter on this summer and have not tried it out yet.
So I am subscribing to your thread to see what happens on your end.

Thanks

 

[OuraySledder]

Just a little story about fuel filters.

I purchased my '11 pro with a blown motor this past march. I replaced everything (filters, reeds, injectors) since i didn't want the same problem happening to my new engine. When i went in to order the fuel filter (the only polaris dealer in town), they said that part had never been ordered in before.

So here in spring of 2013, no one has ever ordered a fuel filter for an '11-12 Pro?!?!?!

Goes to show how a lot of people don't think of these maintenance items.

I have never replaced a fuel filter on a sled in 20 years of riding. My M7 is bone stock, 2700 miles on it, 8 years old. Runs great. Cars go at minimum 30k miles on a fuel filter. Why is it my new Polaris seems to need a massive amount of extra maintenance compared to any sled I have previously owned? Doesn't surprise me one bit they haven't sold any filters, changing them used to be unnecessary.

 

[Reg2view]

Doo etec's get fuel and oil filters every 3700mi (6000km). This is high pressure direct injection. Poo's CFI says fuel filter every 2000mi. Low pressure semi-direct injection. I've assumed the HPDI is why, in part, doo has a higher mile maint schedule. Regardless, DI and SDI injectors like clean fuel, and won't tolerate junk going through them for long. The poo fuel filters can get plugged in my experience. Change them if you ride them.

Poo's CFI system is more cludgy. Running quality on an etec is better, more consistent than CFI, period. Own both. There is no doubt, etec is a much better engineered system, performance-wise, then CFI. If you want the chassis, you gotta put up with CFI.

AC's throttle body EFI is comparable to a jetted carb as far as fuel quality requirements. Pretty low. Less maintenance. And why AC's fuel mileage is the lowest in the industry, and 2S emissions are the highest. There's a reason AC finally came out with SDI - TB EFI won't meet their fleet EPA requirements, and 4S credits won't cut it anymore. Yep, fuel system maintenance is more critical on DI, SDI. You'll find that with AC's SDI now, too.

 

[BILTIT]

Todays fuel is getting worse and worse as well. I run premium in my race/street car and i put a brand new carb (clean as a whistle) on in the spring, pulled it apart in the fall and it was full of white crap.

 

[flying frenchman]

I've changed fuel filter at 1900 miles and performance do not change. This is a sales gimmick to sell you one expensive filter. I think your best bet would be to check or replace your TPS.

 

[800poodragon]

I usually change mine about every thousand miles...It is a pretty fine filter and catches a lot of crap. Changed mine last March and could turn the old one over and fine black crap would come out....it could have come from anywhere....gas can, fuel tank I bought the fuel from...who knows. I do not think it would take much on one of these 2 stroke motors to lean it out on a long pull and burn down...then it gets expensive.

 

[corpeleven]

New fuel filter installed, and valves double checked, double cleaned. I know the valves opening when they should.

Blew through the old and new filter to see if any difference. Yes, it was harder on the used one, but not dramatically. Really like to put this to bed. We will see. Riding tomorrow.

 

[corpeleven]

Fixed!

Rode today, and sled is back to ripping like it used to.

Also, was having some low idle issues before and it would sometimes want to die after long, hard pulls, I'd have to hold the throttle open a bit to get it to idle.

Well, none of those symptoms today and power was back. Jumping to 8100-8200 and holding. Man it's fun to ride like this!

Thanks to all for your input. The Polaris fuel filter is expensive (excessively so) but in my case it seems to have been worth it.

I plan on cutting the old one apart and will post a pic of what I find.

 

[Scott]

Glad you are running better.

But while people have brought it up...go have your TPS checked in addition.
Can't hurt.

 

[xc6rider]

Just wondering... I see you're running 58's up to 10,500 or that your median elevation?
Just wondering as I'll pull 60's up to almost 12,000. I'm running all stock though, with exception of Indy Specialty primary balance/machining.

Other clutching changes?

 

[OuraySledder]

Just wondering... I see you're running 58's up to 10,500 or that your median elevation?
Just wondering as I'll pull 60's up to almost 12,000. I'm running all stock though, with exception of Indy Specialty primary balance/machining.

Other clutching changes?

I know your weren't asking me but... My '13 has 58's and was pulling 8300 on the trail pretty easily at ~10k ft. I have not had the seconary off the see which spring is in there but the dealer who set it up knew that the original owner lived at 11,000ft. Those guys do alright, I suspect it is the high alt spring. Mine is all stock with just 84 miles on it after this weekend.

I was wondering about adding a little wieght...

 

[corpeleven]

Ride zone is 10000-11,500. 60's have never worked for me, nor anyone else I ride with.