Ok yall so I had a bit of a doozy today .... A little background - Sled is a 2018 RMK 800 with ~200 hours, 2600 miles. Stock pistons were replaced at ~160 hours (2200 miles) with a MTNTK Drop-In kit. Sled has run FLAWLESSLY since it was new, and has run flawlessly since doing the MTNTK kit on it before last season. EG, ran perfectly tip top peppy all last season and just fine so far this season until today. Sled has no power adders and only mods off stock are the MTNTK piston kit, an SLP trail can, and an MTNTK tunnel kit .... All of which were on the sled all last season with no issues whatsoever.
So what happened - We're riding a really cool drainage, not one you want to have a sled sh*t the bed in, because it can be really difficult to tow out. Sled was running peachy keen, try to follow a track up a hill with a lot of snow on it, so was WOT then got bumped towards a tree, let off the throttle so as to not crash into other tree. Sled is sitting at an angle on the slope, its steep enough a rollover is the quickest easiest way to get it pointed down hill again. So, buddy shows up on top, we decided to just drag the front end on its side a little and then set the sled upright ... AKA, all standard operating procedures, nothing out of the ordinary here, done it on this particular sled literally hundreds of times and other sleds just like this hundreds of times. So, start it up, head back down the hill and I notices something isn't right .... Sled is vibratey, has no power ... wow, golly gee seems like its only running on one cylinder. So, stop .... let it sit for 5 minutes or so, and restart it again .... Same thing, seems like its only running on one cylinder. Ok, so lets get back to the standard procedures here ...
Pull the plugs, looks like the mag side is a bit fouled, PTO side is your normal EFI-tune chocolate brown just like you want .... So for good measure, I swap both plugs with the new ones. Try to start the sled .... Same thing, brand new plugs. At this point I'm kind of getting worried about how to get the sled out of where we are since its only running on one cylinder. So, we do a little bit of troubleshooting - We check for spark, both plugs have spark when the rope is pulled .... We swapped the MAG and PTO side plug cable to see if the PTO side cable would fire the MAG side cylinder and vice versa .... No go on the MAG side trying to fire it with either ignition coil, but the MAG side coil worked find firing the PTO side .... So at this point I'm relativley sure its not a coil/wire/plug issue ...
So, I pull the plugs again ... the brand new PTO-side plug looks fine, the MAG side one looks like it hasn't fired at all, but its a got a little bit of a sheen on it ... However it wasn't like it was dripping wet. So, we decided to limp the sled on one cylinder back out of the drainage in case we have to tow it, and then remove the MAG side plug again and yard on it for awhile trying to blow anything in the cylinder out and get it dry .... So we spend about 45 minutes doing this and put the brand new plug back in, nothing. For good measure, we even tried the old PTO-side plug we knew was good ... still the same thing. So at this point I have no idea whats going on and whatever it is I can't fix it on the trail. So, we set off for the trucks ....
So I'm riding the sled down the trail on 1 cylinder, and on two separate occasions on the 12-mile trail ride, the MAG cylinder fires up again but ONLY for about 2 seconds, then it was dead again ... so I'm sitting here going "Ok so this thing has gotta be dumping so much fuel into the MAG side it can't fire" .... so, I pulled the scratchers up and tried to heat the motor up a little on the way back to the truck thinking maybe it would clear itself out, but it never did. Got back to the truck, pulled the MAG plug again and it had a sheen on it, PTO side plug looked great - Did the swap-a-roo with the ignition cables again just to see if anything would change, and no, so I'm about 100% certain at this point this is something fuel rail/injector related, but I don't know what ...
Got the sled back in the garage now, put it on the track stand, and its still only running on 1 cylinder ... Won't pull over 6800 RPM on the track stand and after doing a run like that the MAG side plug still hasn't fired and has an oily sheen on it.
So .... at this point .... I'm stumped. What is causing the sled to dump fuel on the MAG side like this? Is this something electrical or mechanical like the injector is physically broke? For all practical purposes the PTO side seems to be ok, so I don't think its a fuel rail pressure issue? *shrug* IDK .... What could cause this? Let me know yalls thoughts
So what happened - We're riding a really cool drainage, not one you want to have a sled sh*t the bed in, because it can be really difficult to tow out. Sled was running peachy keen, try to follow a track up a hill with a lot of snow on it, so was WOT then got bumped towards a tree, let off the throttle so as to not crash into other tree. Sled is sitting at an angle on the slope, its steep enough a rollover is the quickest easiest way to get it pointed down hill again. So, buddy shows up on top, we decided to just drag the front end on its side a little and then set the sled upright ... AKA, all standard operating procedures, nothing out of the ordinary here, done it on this particular sled literally hundreds of times and other sleds just like this hundreds of times. So, start it up, head back down the hill and I notices something isn't right .... Sled is vibratey, has no power ... wow, golly gee seems like its only running on one cylinder. So, stop .... let it sit for 5 minutes or so, and restart it again .... Same thing, seems like its only running on one cylinder. Ok, so lets get back to the standard procedures here ...
Pull the plugs, looks like the mag side is a bit fouled, PTO side is your normal EFI-tune chocolate brown just like you want .... So for good measure, I swap both plugs with the new ones. Try to start the sled .... Same thing, brand new plugs. At this point I'm kind of getting worried about how to get the sled out of where we are since its only running on one cylinder. So, we do a little bit of troubleshooting - We check for spark, both plugs have spark when the rope is pulled .... We swapped the MAG and PTO side plug cable to see if the PTO side cable would fire the MAG side cylinder and vice versa .... No go on the MAG side trying to fire it with either ignition coil, but the MAG side coil worked find firing the PTO side .... So at this point I'm relativley sure its not a coil/wire/plug issue ...
So, I pull the plugs again ... the brand new PTO-side plug looks fine, the MAG side one looks like it hasn't fired at all, but its a got a little bit of a sheen on it ... However it wasn't like it was dripping wet. So, we decided to limp the sled on one cylinder back out of the drainage in case we have to tow it, and then remove the MAG side plug again and yard on it for awhile trying to blow anything in the cylinder out and get it dry .... So we spend about 45 minutes doing this and put the brand new plug back in, nothing. For good measure, we even tried the old PTO-side plug we knew was good ... still the same thing. So at this point I have no idea whats going on and whatever it is I can't fix it on the trail. So, we set off for the trucks ....
So I'm riding the sled down the trail on 1 cylinder, and on two separate occasions on the 12-mile trail ride, the MAG cylinder fires up again but ONLY for about 2 seconds, then it was dead again ... so I'm sitting here going "Ok so this thing has gotta be dumping so much fuel into the MAG side it can't fire" .... so, I pulled the scratchers up and tried to heat the motor up a little on the way back to the truck thinking maybe it would clear itself out, but it never did. Got back to the truck, pulled the MAG plug again and it had a sheen on it, PTO side plug looked great - Did the swap-a-roo with the ignition cables again just to see if anything would change, and no, so I'm about 100% certain at this point this is something fuel rail/injector related, but I don't know what ...
Got the sled back in the garage now, put it on the track stand, and its still only running on 1 cylinder ... Won't pull over 6800 RPM on the track stand and after doing a run like that the MAG side plug still hasn't fired and has an oily sheen on it.
So .... at this point .... I'm stumped. What is causing the sled to dump fuel on the MAG side like this? Is this something electrical or mechanical like the injector is physically broke? For all practical purposes the PTO side seems to be ok, so I don't think its a fuel rail pressure issue? *shrug* IDK .... What could cause this? Let me know yalls thoughts
