Det Issue with '16 Axys and BD Sidekick

diamonddave · Dec 5, 2018

How many miles on this sled?

Can you pinpoint when at what point Det is triggered?

What exactly happened to the crank? Failure? Rod bearing by chance? I’d like to know more about the motor failure. Was the motor failure from detonation or the result of something else?

Have you replaced your motor mounts? If not, I’d do this first.

Solving Det in a Polaris can be tricky. There can be instances of false set Det from poor clutching, worn motor mounts, something rubbing, something loose and vibrating. Pipe rubbing the lower overstructure has been the most common.

diamonddave · Dec 5, 2018

Hmm. After watching your videos I have to wonder if this thing is loading the motor enough with clutching? Overboosting?

You could plum a boost gauge cheap enough to verify.

Or try running 100% av gas just for testing.

I would also tighten up spark plug gap to 0.015”. Could be flaming out.

Octanee · Dec 5, 2018

nater24 said:
Thanks a ton for the follow up post on this and I'm glad to hear that you found the issue. I haven't had any luck yet. I bought a new fuel pump as I was convinced that it was failing due to det issues and the whining noise. Went up to test and it still detonates. I'm completely frustrated and burned out at this point so I just left it at the dealer on the way home. They said they can't touch it for 2 weeks so I'm stuck for a while. Maybe I should just go get it and put new injectors on it and go test it. Or can the mechanic test the actual injectors somehow?

I would honestly go get some used fuel injectors from a "known good sled" to try. I watched your video again there and it detonated just like how mine was as well, on off the throttle, for my sled when I took my knock sensor off it revealed a very lean spot where if the sled didn't limp mode it I got a back fire practically/bog until the turbo kit started its fueling again. I added A boost gauge, and air fuel to my sled to be able to better see whats going on and also noted how after the sled got warmed up It was going way lean down the trail. 19:1 and out of range, basically 1 cylinder lacking fuel. I started to have a weird soft idle happening periodically.

on my 2011 changing injectors wasnt bad, because the stock airbox is gone I had plenty of room to reach in from the exhaust/turbo side and pop them in and out. probably took no more than 2 hours.

nater24 · Dec 5, 2018

die hard poo said:
My guess is the injectors. I personally would try those. If that doesn't fix it, maybe consider removing the turbo and trying stock to see if its something to do with the turbo or something stock...

Thanks for the reply and input. I'm thinking injectors are the next move

nater24 · Dec 5, 2018

diamonddave said:
How many miles on this sled?

Can you pinpoint when at what point Det is triggered?

What exactly happened to the crank? Failure? Rod bearing by chance? I’d like to know more about the motor failure. Was the motor failure from detonation or the result of something else?

Have you replaced your motor mounts? If not, I’d do this first.

Solving Det in a Polaris can be tricky. There can be instances of false set Det from poor clutching, worn motor mounts, something rubbing, something loose and vibrating. Pipe rubbing the lower overstructure has been the most common.

Thanks for the reply!! The brand new motor has about 80 miles now. The Det is happening when i'm on and off the throttle and probably between 6k-7k RPM if I where to guess. I had a motor guy tear the old motor down and the crank seal and bearing were just fine. One piston was just fine but the other showed major signs of detonation. I've made sure that the pipe is not touching and that everything is tightened up as much as possible. Yes, I've replaced the motor mounts.

nater24 · Dec 5, 2018

diamonddave said:
Hmm. After watching your videos I have to wonder if this thing is loading the motor enough with clutching? Overboosting?

You could plum a boost gauge cheap enough to verify.

Or try running 100% av gas just for testing.

I would also tighten up spark plug gap to 0.015”. Could be flaming out.

I've wondered the same thing ever since I dropped it off at the dealer if maybe putting a little heavier weights in would help. Boondocker suggested that it might be overboosting and had be turn the boost down by turning the push rod for the wast gate out 1/2 turn or more. I've gone a total of 2 full turns and still get the same result. I've also mixed up to 97 octane but I could do 100% av gas for testing. I'll also tighten the spark plug gap as suggested on a set of plugs to test that the next time I go up.

Thanks again for your input. I really appreciate it.

nater24 · Dec 5, 2018

Octanee said:
I would honestly go get some used fuel injectors from a "known good sled" to try. I watched your video again there and it detonated just like how mine was as well, on off the throttle, for my sled when I took my knock sensor off it revealed a very lean spot where if the sled didn't limp mode it I got a back fire practically/bog until the turbo kit started its fueling again. I added A boost gauge, and air fuel to my sled to be able to better see whats going on and also noted how after the sled got warmed up It was going way lean down the trail. 19:1 and out of range, basically 1 cylinder lacking fuel. I started to have a weird soft idle happening periodically.

on my 2011 changing injectors wasnt bad, because the stock airbox is gone I had plenty of room to reach in from the exhaust/turbo side and pop them in and out. probably took no more than 2 hours.

I’m glad you watched the video again and saw some commonality in how yours was also detonating. I’m gonna try injectors as a next step. Will probably just get new ones since I don’t have access to good used ones. Thanks again for the input.

revrider07 · Dec 5, 2018

Cheap thing to try is let sled idle and spray either around any seals and boots could have a leak. Also check that slides are equal and open all the way also check intake track for obstruction. Just guessing maybe something easy over looked.

diamonddave · Dec 5, 2018

nater24 said:
I've wondered the same thing ever since I dropped it off at the dealer if maybe putting a little heavier weights in would help. Boondocker suggested that it might be overboosting and had be turn the boost down by turning the push rod for the wast gate out 1/2 turn or more. I've gone a total of 2 full turns and still get the same result. I've also mixed up to 97 octane but I could do 100% av gas for testing. I'll also tighten the spark plug gap as suggested on a set of plugs to test that the next time I go up.

Thanks again for your input. I really appreciate it.

Easy quick thing would be try the 100% avgas, tighten spark plug gap and test.

What weights, springs, helix are you running?

It's interesting you didn't see a change in boost, I'd be real curious what actual boost really is?

I am not a fan of the location of the injectors in this motor but I'd hold off running out and buying injectors. And if you go that route, I'd certainly only buy new. Injector location lends these things to prematurely accruing carbon deposits. I used to have them flow tested and ultra sonic cleaned, I just replace them now with every top end since they are wearing out mechanically.

modit · Dec 6, 2018

We have experienced this issue in the past if you would like to call me I will explain and help trouble shoot would be much easier on phone. Rod 208-589-1665.

Track Man · Dec 7, 2018

Did you try new spark wires. We had two that did this and the wires fix them. got the SLP wires.

sumtinwong · Dec 8, 2018

not to get off topic but are you referring to the slp high performance ignition wires? and if so past fixing the problem did you see any throttle response/top end improvements?

polarisboyc · Dec 11, 2018

Any update on this issue? My 17 is doing the same thing and I'm also trying to pin point the problem with mine.

tjards · Dec 11, 2018

Have you tried running just straight 91 and not mixing any race? As weird as it sounds the minute I stopped mixing fuel and started running straight 91 out of the pump all my DET issues went away. Called VOHK directly and he said the tuning on these sidekicks is optimized for 91 and once you start mixing it messes with things a bit.

nater24 · Dec 11, 2018

tjards said:
Have you tried running just straight 91 and not mixing any race? As weird as it sounds the minute I stopped mixing fuel and started running straight 91 out of the pump all my DET issues went away. Called VOHK directly and he said the tuning on these sidekicks is optimized for 91 and once you start mixing it messes with things a bit.

I started out running only 91 non ethanol pump gas without any issues. Slowly overtime it started detonating more and more. I tried octane booster (which never helped) and then went to mixing just a little race fuel until the Det went away. Eventually it started detonating again even with mixing a little race fuel so I had mix more and more and you know the rest of the story.

There were times that I wondered the same thing about just going back to pump gas so I tried it and still detonated.

Spaarky · Dec 11, 2018

just for kicks.. throw a set of EYA plugs in it.

Also what year is your kit? if sled is 16 does the controller match?

nater24 · Dec 11, 2018

UPDATE

I finally picked my sled up from the dealer. They tested using the digital wrench and the only issue they could come up with was that it was telling them that the octane was too low. I didn't know the DW could tell them that!!?!

So I picked up the sled yesterday afternoon and removed the mixture that I had in it (a mix of 100 race fuel and 91 non ethonal) and picked up a 5 gallon jug of the only race fuel I could find that was close enough for me to be able to go up and test. The race fuel was Sunoco leaded 114. I dumped the whole thing in and went up to test and it never deontated even once. I tried everything I had done before to get it to detonate and it ran great. This was obviously a big deal cause it seems to eliminate the question of if it could be due to electrical parts or even fuel injectors causing the issue. I'm thinking now that it may be overboosting. However, I do believe that these "Pump Gas" kits are set up so close to the line that most sleds eventually start to detonate if they only run pump gas. Because the new motor that I have has the Mtntk "Fix Kit" in it that could have increased the chances of detonation on top of a kit that was already prone to detonation thus requiring a higher octane level to keep it from detonating.

At this point I'm going to get a boost gauge and then test different levels of octane figure out....
a. If I'm Overboosting
b. What is the least amount of octane that I can run and still not detonate

I REALLY appreciate everyone's suggestions and input on this as it has definitely helped to narrow this down. If anyone has any other thoughts or suggestions at this point please to hesitate to let me know.

Any suggestion on a good Boost Gauge? I'd love one that data logs so I can go back and see exactly what my highest boost level is instead of trying to watch it while i'm riding. Or maybe that kind of gauge becomes very pricey if it even exists.

Spaarky · Dec 11, 2018

it could be when you installed the fix kit you picked up some compression too. maybe you got a shim that was off, or something crazy.

again I would try the br9eya. seems to mellow the motor out without loss in performance.

nater24 · Dec 11, 2018

Spaarky said:
it could be when you installed the fix kit you picked up some compression too. maybe you got a shim that was off, or something crazy.

again I would try the br9eya. seems to mellow the motor out without loss in performance.

Thanks Spaarky. I will pick up some BR9EYA plugs to try. I believe I tried those a couple of seasons ago (on the previous motor) and it didn't make any difference but won't hurt to try again.

Someone else suggested to tighten the spark plug gap from .025 to .015. I did this on my spare set of plugs and was going to try them yesterday if the higher octane didn't work. I'm still planning on trying those as I continue to test.

nater24 · Dec 11, 2018

Spaarky said:
it could be when you installed the fix kit you picked up some compression too. maybe you got a shim that was off, or something crazy.

again I would try the br9eya. seems to mellow the motor out without loss in performance.

Yep, I'm sure the fix kit did increase the compression slightly. For the record, I wouldn't have done the shim kit but it was the only new fully built motor that I could find at the time last year and it was built by a dealer using the fix kit. Before the motor was installed in the sled I almost swapped out those piston with Polaris ones which would have gotten rid of the shim. Hindsight is 20/20!!

Det Issue with '16 Axys and BD Sidekick

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