Need help with diagnosing my sleds sickness

[Shum]

I have been having electrical issues (and more) and I only have 1 more idea and am nearly at the end of my rope, any advise will be appreciated.

2005 RMK 900

Was riding and lost all power, lights and MFD went off, the sled would just idle (very roughly), would stall when the throttle was touched, but would start back up, but would simply idle rough with a stall if I touched the throttle again. We towed it home, and I tore into it looking for the problem, Capacitor check, relay check, fuel pump check, stator all checked out except the charging coils ohmed at .30 not .13. Adjusted the TPS (it was in spec but did it anyhow) I put it all back together and it started up and ran, but was missing power (I had not changed anything). It would hit 7500 rpm (60 mph) on our lake, but would take a full 25-30 seconds to get there. Had less snap than my buddies 550 fan cooled trail RMK.

I ordered a stator, it got here and I replaced it (it ohms at .3 as well on the charging coil) is the manual .13 incorrect or do I have 2 bad stators? Started it up after the stator replace and it fired up and ran and seemed fine. Turned it off to toss on my gear (3 minutes), backed it out of the garage and MFD went off with the lights and bad idle problem is back (this time 20 ft from the garage). I unplugged the Relay this time and it ran strong (not sure if it is full cuz it is dark and full throttle across a lake in the dark... well I'm not 18 any more).

So I think the only thing I have left to replace is the regulator (don't say ECU), could this cause these symptoms? I know if the regulator is flaking out it could cause the electrical issues for sure, I suppose that could make for the ECU to function badly as well if it was getting bad power? I assume the ECU is in the loop when the relay is unplugged??? Is the regulator bypassed in this state? Is there a test for the regulator?

Other things, Compression 125 & 127, new plugs, no check engine lights. I have searched for shorts, see no rubbed wires, or bare wires, how does one tell if the sled has a short?

This forum has proven very informative to me since I bought this sled, Thanks in advance for helping me out in figuring out how to get back to riding it instead of just working on it.

 

[sloan188]

My guess is the manual is wrong with the stator charge coil resistance problems as I got the same measurements you got on 2 different stators as well.

Wrt MFD, did you check the output of the VR? I had a similar issue (but no idle issues) and I'm in the process of replacing the VR as soon as it comes in. I checked the output and and saw nothing. In order to check it, I put the meter probe down in behind the clutch side foot well with the ground on it and probed the orange wires coming out of the white connector connected to the VR. I know these should have 12V on it for the brake light due to other troubleshooting.

Wrt rough engine, did you check your spark? I had a similar issue with mine last year and found that one of the coil connector wires had a pushed pin. If you look closely into each end, you will see a black grommet. if it isn't in the connector, the pin is pushed.

 

[Shum]

My guess is the manual is wrong with the stator charge coil resistance problems as I got the same measurements you got on 2 different stators as well.

Well then that makes 4 of them showing .30 I'd have thought I'd have seen that in the forum somewhere (may have missed it)

Wrt MFD, did you check the output of the VR? I had a similar issue (but no idle issues) and I'm in the process of replacing the VR as soon as it comes in. I checked the output and and saw nothing. In order to check it, I put the meter probe down in behind the clutch side foot well with the ground on it and probed the orange wires coming out of the white connector connected to the VR. I know these should have 12V on it for the brake light due to other troubleshooting.

I did check voltage when it was running badly and was getting numbers all over the place. The motor however was barely spinning, so I would not have expected full or consistant voltage. I am going to try the regulator, my concern is they normally don't come and go, when they bust they stay busted (don't they)... I'm afraid I have a short somewhere that my digging is causing a temporary fix till I reintroduce vibration.

Wrt rough engine, did you check your spark? I had a similar issue with mine last year and found that one of the coil connector wires had a pushed pin. If you look closely into each end, you will see a black grommet. if it isn't in the connector, the pin is pushed.

I have pulled both ends of the wires clipped them and reset them (screwed them back in). All the connections seem fine. How does one check spark? I have spark on both plugs, not sure how to go about telling if it is good spark at full throttle. Again a coil either works or does not correct? I'll diagnose this issue after I get the first figured out. My gut says they are 2 separate issues unless someone has a scenario to explain both.

Thanks for the reply.

 

[sloan188]

I'd think that when they go they go but my buddies came and went before it was down hard. I'll let you know if the new VR fixed the problem. Wrt short, you can try the lights test jack (white jack with red/white wire and brown wire I think) centrally located along the steering shaft. Put 12 volts to it and if lights/mfd come on with no issues then it's likely not a short.

When I said check the the coil connector wires I didn't mean the plug wires but rather the connectors to the coils themselves. Mine were coming apart. I believe you can ohm the coils to check them (at least I did on my xlt when I had a coil issue). Would agree that spark shouldn't come and go. When I diagnosed mine, I simply removed the spark plug cap off one, replaced it and the removed the other and replaced it. I knew I had an issue when the engine sound didn't change upon removal of one of them.

 

[Shum]

I'd think that when they go they go but my buddies came and went before it was down hard. I'll let you know if the new VR fixed the problem. Wrt short, you can try the lights test jack (white jack with red/white wire and brown wire I think) centrally located along the steering shaft. Put 12 volts to it and if lights/mfd come on with no issues then it's likely not a short.

I have a regulator coming (none local so won't be here till mid next week).
I'll try the lights test jack as well...

When I said check the the coil connector wires I didn't mean the plug wires but rather the connectors to the coils themselves. Mine were coming apart. I believe you can ohm the coils to check them (at least I did on my xlt when I had a coil issue). Would agree that spark shouldn't come and go. When I diagnosed mine, I simply removed the spark plug cap off one, replaced it and the removed the other and replaced it. I knew I had an issue when the engine sound didn't change upon removal of one of them.

I'll check the back side as well... I have not looked there close... But when it is running bad I have removed plugs and both sides have the same result, so I think both sides are still sparking.

 

[Shum]

Voltage Regulator came in yesterday, I replaced it and still have the rough idle and no power(HP) issue. The lights and MFD did stay on, but I only ran it for about 10 minutes.

Next theory? I guess mine is fuel pressure related... Fuel pressure drops causing bad running, causing the voltage to drop??? Would explain the no power(HP) as well...

Anyone other theories? I'm about to let the Dealer try to figure it out... Speaking of the dealer... I see talk on here of the digital wrench... I assume this is a dealer only item that I cannot get my hands on?? What does it do how much diagnostic information does it provide?

 

[Shum]

Wow was I way off (electrical problem...) Dealer Called today to let me know that the Clutch Side Cylinder was scored... I went and got it and they showed me with the scope. I brought it home and retested compression and it was at 125 (just like I tested the other day). Took it apart and found the c-Clip in 2 parts ground into the cylinder wall in 2 different places, no idea how it pushed 125 PSI with the damage...

So I am doing a top end rebuild. I read that 2006 stock pistons are the best to use (it was an older set of posts is that still the case or is there a better option now?) I know this cylinder needs replaced, the other looks fine, feels fine, do I need to have it honed to put a new piston into it, or is it ok to use as is? Anything else I need to do/look at while I'm in there?

Thanks for any advise...

 

[Danbot]

Wow was I way off (electrical problem...) Dealer Called today to let me know that the Clutch Side Cylinder was scored... I went and got it and they showed me with the scope. I brought it home and retested compression and it was at 125 (just like I tested the other day). Took it apart and found the c-Clip in 2 parts ground into the cylinder wall in 2 different places, no idea how it pushed 125 PSI with the damage...

So I am doing a top end rebuild. I read that 2006 stock pistons are the best to use (it was an older set of posts is that still the case or is there a better option now?) I know this cylinder needs replaced, the other looks fine, feels fine, do I need to have it honed to put a new piston into it, or is it ok to use as is? Anything else I need to do/look at while I'm in there?

Thanks for any advise...

You are correct, 2006 Polaris pistons are still the part of choice.

A plated cylinder can be "de-glazed" not honed. While your in there, it might be best to have it measured to make sure it's within specs. I would be hesitant to assemble a twin engine with one new cylinder and one heavily used. My choice would be to have the mag cylinder re-plated to match the new one.

A side note... a re-plating company may consider that damaged cylinder repairable... worth checking into.

Good luck, and let us know how things progress on this build.

 

[hammerman]

Last weekend my 05 900 was running like crap. It was like when I lost my bellow. I fouled right plug out, getting way to much fuel.
Bellows where fine,Found wiring harness going to the hood was rubbing on aluminum. Repaired wire ran like it always did. awesome

 

[Shum]

A plated cylinder can be "de-glazed" not honed. While your in there, it might be best to have it measured to make sure it's within specs. I would be hesitant to assemble a twin engine with one new cylinder and one heavily used. My choice would be to have the mag cylinder re-plated to match the new one.

I found another used Cylinder locally with similar miles to the one I have so I had both de-glazed, and the pistons will be here Friday... They should be similar enough usage on the cylinders. I did find a place locally that would replate them (swap them out for replated ones), but I did not want a new and a used (and I didn't want to pay for 2 replated ones)...

Can you describe "within Spec"? I assume feeler gauge in both the front and back with the new piston in place (no rings). What clearance am I looking for? What is too much?

I sure hope once I get it back together all my issues I have been having this year go away... I'll let you know what happens next, thanks for the info.

A side note... a re-plating company may consider that damaged cylinder repairable... worth checking into.

Everyone I spoke to at repair shops said as long as it is not into the water jacket it is still good to replate...

 

[GKR]

Yes use the 06 pistons. Clearance spec in manual is 0.0045"-0.0098". Ideally you buy the pistons and the size the cylinders to get 0.0050" Make sure you check ring end gaps too, 0.016-0.022" This all goes to long way to longevity of the engine, consistent performance too.

 

[Shum]

Clearance spec in manual is 0.0045"-0.0098".

Thanks, I looked through the deep snow manual but didn't see that...

Make sure you check ring end gaps too, 0.016-0.022" This all goes to long way to longevity of the engine, consistent performance too.

I'm new to engine rebuilds... Didn't know I needed to do this, but reading up on it makes complete sense,Thanks for pointing that out.


Break in Question, I read that I should use "real" oil for breakin because synthetic is too "slippery"... But I also read to add that "real" oil to my tank and keep the injected oil running as well... In my mind this means I'll have 2X the oil and 1/2 of that oil is the "slippery" kind, doesn't that defeat using the "real" oil if the "slippery" synthetic is in there too? Do I need to drain my synthetic out of my reservoir and replace for breakin? I'm a bit confused and realize everyone has their own procedure, but hopefully there is a simple answer to my confusion.

 

[Shum]

Rebuilt everything Friday Night, broke in a bit on Saturday, then Sunday headed on a 98 mile easy trail ride to the Iditarod to finish up my first break in tank... Fouled some plugs at the end of my first tank, but at the beginning of my second tank all seems well, peppy like it should be... Still have not hit WOT, but that will come this weekend.. Thanks everyone for the advice. Now to fix my wifes 700 Issue, always something to work on.