So my 2005 800 just started this small backfire at high RPM's, under load in High gear. When in low gear, it does it worse and I can feel a loss of power.

This JUST started but after I did some work on the machine. So let me give a little background.

Just did fluid changes including Oil, Coolant, Hub fluid. Changed spark plugs. I also performed the 3-headlight mod and fan override switch mod.

When I did the 3-headlight mod I cut into the WRONG yellow wire. I cut into the Yellow wire coming from the ignition to the 20amp fuse. When I figured this out I tapped into the correct yellow wire. I removed the pigtail and resoldered the original yellow wire I had cut.

The troubleshooting I performed is:
- Put old plugs back in (one at a time): still same results. Put new plugs back in
- Disconnected power lead to relay for 3-light mod (thereby bypassing it): same result

The wiring harness has NOT yet been reconnected to the POD. The only reason is that I have yet to cut the hole for the fan override switch. Is it possible something NOT being plugged in there is causing an issue?

Trust me guys, I'm open to any suggestions. Sometimes talking this stuff out helps.

Let me know if anyone has any suggestion. OH, one more thing. I did hook the POD up to get the error codes. Only one: 54 (overheat) which happened last trip out...

 

Did you check the wires to the t bap harness for wear or breakage...Sometimes the wire will break off inside plug and it isn't visible...

John

 

how did the plugs look when you took them out? does it show it running lean or rich?

 

The plugs actually looked great. I didn't grab a chart but clean with a slight light/med brown tip. I changed them since I just bought it and was doing a bunch of other things.

I will need to look it up b/c I have NO idea what a T-Bap even is...let alone where to look!!

Btw, getting to the left side plug IS possible. But you will need a $100 ratchet to do it!! My mechanic buddy talked me into buy the Snap-on 3/8" rachet with the swivel head ($20 a week). I'm not talking the kind with the swivel NECK. The head has a pivot point on each side so it pivots on center. That wrench alone makes it possible to get to that plug. Also, I used a 16mm deep well and NOT the spark plug wrench b/c the rubber inside those sockets makes it nearly impossible to line everything up just right.

After seeing all the crap on the sides of the plugs I wondered if any of it fell into the cylinders when I pulled the plugs out as well.

Also, the machine starts up fine, but not QUITE as easily as it did before if that is a clue for anyone!!

 

Ok, been thinking about this one. I would actually describe the problem as more of a loss of spark - it feels like a cylinder drops or like a misfire is taking place.

It doesn't really backfire in the normal sense, just feels like a plug isn't firing. But it didn't do that before and I put the old plugs back in just to eliminate that (same result).

I hate troubleshooting stuff like this...ugh!!!!!!!!!

 

Also check maybe your coil wires...Your t bap sits between your throttle body and your airbox on the rubber hose......You will see a plug with 4 wires going into it and that is the harness...just ask if you have any other questions...

John

 

On the T-bap wiring, check the Brown wire for damage and or broken