Join Date: Jun 2013
Location: Nova Scotia Canada
800 EFI Engine problems
I recently had the Camshaft and lifters go in my 2011 sportsman 800 EFI at 151 hours and a little over 2k KM it (about 1000 miles). The machine was of coarse out of warranty so I decided to do the fix myself, I have been working on small engines all my life rebuilding many motorcycles snowmobiles and ATV's so it was not a big deal to me.
Of coarse i purchased a service manual before taking on the task.
First I will tell you that you CAN do this without pulling the motor but the 2 head bolts will give you a bit of a problem to get out. I wont go into the details oh doing the job but I wanted to let everyone know what I am going through with this machine.
When installing the CAMSHAFT the service manual clearly states to use the dots stamped on the gears for timing, there is no other way to do this and if the dots are lined up then there is no way it could be out of time. well in my case they were WRONG .. in going by the dots the engine ran like crap back firing through the intake. I then tore it down again to double check the mark alignment and doubble check the service manual, I put it back together again with same result. the third time I took it apart i noticed a spot of red paint on one of the teeth on the crank gear. I decided to try that tooth instead of the one with the DOT on it and it ran perfect.
After going through that it worked like a new one again .. but that was short lived .. I ran the engine 5 hours and changed the oil and filter .. then again at 15 hours (to make sure there were no filings left in the engine anywhere)
Now I have an issue that the first start of the day (after setting all night) it will start up and idle normal .. however if you touch the throttle at all it dies immediatly .. then the engine had 0 compression in both cylinders . after setting for 15 min or so it will start up again .. this process will repeat unless you let the engine idle and warm up for at leaf 15 min (way too long). then it will Work like a new one all day long with no issues and has 180psi compression in each cylinder.
I have sense taken the head off again and checked all the Valves and springs, there are no bends and they all move as normal . I would say it seems like the cylinders are washing out but the plugs are dry when this happens and if you leave it idle until the fan kicks in then it doesn't do it.
Anyway im still troubleshooting this (next step is maybe planing the head) I think it might be leaking a bit of Antifreeze in the jugs from the head gasket when it sets.
Oh and by the way ... Polaris claims to not have any issue with the CAMS in these engines .. yet I know of another machine like mine within 10 miles that had the same issue and the CAM was on back order for 4 weeks when I ordered it.
Last edited by neal860; 06-03-2013 at 08:43 AM.
Reason: Adding Photos