850 still Bogging and fouling Plugs after Break in

[MDEVO]

Hi
Looking for suggestions to a bogging/fouling plug issue on my friends 850
It is well past the 10hr break in and still struggling to run clean.
Anyone else seeing this type of issue?

 

[XFIRE800]

@goridedoo


Sent from my iPhone using Tapatalk

 

[TRS]

Hi
Looking for suggestions to a bogging/fouling plug issue on my friends 850
It is well past the 10hr break in and still struggling to run clean.
Anyone else seeing this type of issue?

10 hrs isn’t past break in. I think it’s 10hrs above 5000 rpm gets you past breakin.

 

[MDEVO]

19.6 hrs Figure that’s got to do it??
Always PTO plug that fouls (10 plugs so far)
I’m trying to post a video of it.

 

[Mp3performance]

My rmk 850 has 45 hours on it and will still foul a plug every now and then always on the PTO side, it runs to rich, especially when runing in low rpm's comming down a long decent or side hilling in technicle tree ridding it will load up with fuel bog out and sometimes foul a plug. There needs to be some sort of reflash in my opinion.

 

[TRS]

I thought this article was interesting.

 

[Timbre]

I thought this article was interesting.

So . . . run 91 ethanol fuel in the tank and put the gauge on non-ethanol setting.

 

[TRS]

So . . . run 91 ethanol fuel in the tank and put the gauge on non-ethanol setting.

I’m not recommending anything. I thought it was interesting that the article states run eth fuel on the premium setting.

 

[revrider07]

Trs have you got yours broke in yet and have had any plug trouble?

 

[TRS]

Trs have you got yours broke in yet and have had any plug trouble?

Can’t ride for 6 weeks. So I’m “keyboard” sledding.
With that said mine runs like a scalded dog.
What would be interesting is to check an ill running 850’s timing. Dial indicate the flywheel or clutch per cylinder, mark it, and check it with a timing light. Not with digital wrench.
Wondering if the keyway was indexed correctly. Someone should check it. While your at it check the crank phase. If most are losing PTO plugs I’m leaning towards crank phase, miscut flywheels or maybe just mis adjusted pickup coils. Checking timing of both cylinders will relieve the question.

 

[Solarguy]

Ours and the guys we ride with are not having bogging issues and have not fouled any plugs? We are riding from 4-9,000' and riding them hard. Non eth 91 and set in non eth mode. I did have belt slip (squeal) one day after a couple hours in 21/2-3' fresh snow, clutch side had moisture from snow in engine compartment.
Curious why this is happening to some and not others (bogging issue)?

 

[revrider07]

Thanks trs mine has been great. Hopefully leaving here on Friday. Going for an extended trip somewhere. Get well soon we need a na clutch set up.

 

[SRXSRULE]

So . . . run 91 ethanol fuel in the tank and put the gauge on non-ethanol setting.

Ive done this several times. Its a great way to lean down an overly rich stock tune.

You can also do the reverse of this if you have a slight det issue. Run 91 NON-ethanol fuel with the sled in ethanol mode.

 

[TRS]

Thanks trs mine has been great. Hopefully leaving here on Friday. Going for an extended trip somewhere. Get well soon we need a na clutch set up.

Thanks, I’ll be back as soon as they allow.
I have a few NA setups out. Reports have been good. Running 82-8250 here.
42-32F and 125-175 spring
66g TRS weights and stock primary spring.
3211216 belt.
I believe the .....16 Polaris belt is a harder compound and needs more fly weight compared to a Gates carbon to maintain RPM. Testing that soon.

 

[Scott]

10 hrs isn’t past break in. I think it’s 10hrs above 5000 rpm gets you past breakin.

Tony, I've heard several people say this, but I've heard conflicting information from the engineers.
They told me 10 hours TOTAL, with 2 hours above 5500 rpm.

 

[connojo]

I changed my plugs at 4-Hrs, the sled ran flawlessly for about another 4-Hrs then the bogging came back. I will picking up more plugs today to change them out. I was talking to another guy in the mountains and he told me he brings lots of plugs with him because his 850 is constantly fouling them. I hope this gets better, got around 10-Hrs on my 850 now.

 

[indydan]

If you foul more then 2 sets of plugs after 2 hours the most important thing you can do is a leak down test.

Walking around in circles waiting for Polaris to solve the problem is as close to insanity as you are going to get.

Mid to high leak down.......Weird and bad symptoms always loom around.

Low leak down numbers ....... Only complaint ( My Arms hurt ) from hanging on.

Stop whining and order a leak down kit..... Read the directions and do the procedure.

If you own a 2 stroke and don't have a leak down tester you should not be allowed to ask questions about performance.

Pretty much end of story.... You cannot accurately speak about your own motor until you present the leak down numbers.

Sorry..... To be harsh.

But this thread in useless without leak down numbers.

We have not seen one fouled plug on our 850's

Dan

 

[indydan]

Can’t ride for 6 weeks. So I’m “keyboard” sledding.
With that said mine runs like a scalded dog.
What would be interesting is to check an ill running 850’s timing. Dial indicate the flywheel or clutch per cylinder, mark it, and check it with a timing light. Not with digital wrench.
Wondering if the keyway was indexed correctly. Someone should check it. While your at it check the crank phase. If most are losing PTO plugs I’m leaning towards crank phase, miscut flywheels or maybe just mis adjusted pickup coils. Checking timing of both cylinders will relieve the question.

always a good check to make sure they have this stuff right if you have weird things happening to only one cylinder

 

[indydan]

If everyone listed their ( leak down numbers ) we would already know if some or most of the 850's have a cylinder finish problem.

No one is happier then polaris that almost no one properly trouble shoots their motors.

Next thing you know it will be spring..... and some will have motors they are still unsure of.

MAKE sure you keep the pressure on Polairs.....

If your leak down numbers suck there is only one thing you need to do...

drop it off at the dealer and get it fixed.

And pray you don't get a box full of ( a cylinder ) with the same old 80 grit finish.

Polaris.........if your listening.........I will give you a little tip...........( 600 grit Super abrasive stones are WAY to course ) and i mean WAY TO COURSE !!

These are not cast iron cylinders that can sneak by with the wrong 220 grit stones and still survive.

600 grit is a death sentence..........800 grit is a death sentence..... 1XXX might be a death sentence. ( done giving hints. )

Dan

 

[TRS]

If you foul more then 2 sets of plugs after 2 hours the most important thing you can do is a leak down test.

Walking around in circles waiting for Polaris to solve the problem is as close to insanity as you are going to get.

Mid to high leak down.......Weird and bad symptoms always loom around.

Low leak down numbers ....... Only complaint ( My Arms hurt ) from hanging on.

Stop whining and order a leak down kit..... Read the directions and do the procedure.

If you own a 2 stroke and don't have a leak down tester you should not be allowed to ask questions about performance.

Pretty much end of story.... You cannot accurately speak about your own motor until you present the leak down numbers.

Sorry..... To be harsh.

But this thread in useless without leak down numbers.

We have not seen one fouled plug on our 850's

Dan

Hey, get to work.?