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Discussion Starter #1
My F5 has a strange problem and I cant figure it out. Sometimes it only runs on one cylinder-used to be once in a while but last weekend it did it almost the whole time.

I will be cruising along and all of a sudden it will drop a cylinder and run like crap-no power and a max of 35mph. If I keep riding it it will try to pick up the other cylinder and will run better but not great. If I put snow on the exhaust manifold it only melts on one side so I know the cylinder isnt firing. I've changed the plugs thinking they were fouled but it makes no difference.

I checked the APV cables (even though I know they have nothing to do with spark) just to make sure they were connected. They were.

The weird thing is when it was -12 degrees at night it ran perfect.

I'm wondering if it is the coil breaking down and not providing enough juice at high rpms.

Anyone else experience this?

I took it to the shop today and there is a 2 week backlog of repairs but I have no choice. It will probably be the end of the season when I get it back which really bites.
 

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id check all your wires for the ignition sytem sounds like you have one or more grounding out ? could also be the magnetic pick up system/ trigger system failing? strange, let us know !!!!! :blink:
 

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Could it be as simple as poor connection between the plug cap and plug wire? Screw cap onto the wire to reseat the connection. Pulling the plugs a number of times can loosen that connection causeing loss of spark. Frustrating problem, easy and cheap fix. It doesn't cost anything if it is not the problem.
 

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I would check a few things before you bring it in.

Check to make sure your plug WIRES are tight. (they are threaded if you didn't know).

Check you spark plug gap. I have seen squashed gaps cause a cylinder to dryp at high R's.

Pull the plug out and pull the rope to see if you have spark. If you don't check the plug wires first.

This doesn't sound like your problem, but you may have a frozen gasline going to one cylinder. (this happened to me earlier this year).

I am no electrical expert. If it goes beyond that it goes to the dealer.

Hope I can help.
Cat S.
 

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My sled did the same thing when I first bought it. Mine turned out to be the fuel line was getting caught between the engine and the chassis and was stopping fuel flow at times.
 

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Discussion Starter #7
Thanks for the Ideas. I did unscrew the plug wire ends and then reattached them. I changed plugs several times with the correct gap and it made no difference. I checked for spark- it had spark laying on the head but when it was running only one side of the exhaust manifold got hot. This tells me the cylinder isnt firing or not firing right. It should'nt be frozen lines because I use isopropyl alchol. Plus the plug comes out wet and oily.

The weird thing is sometimes it runs perfect and then the next time it runs like crap.

I will upadte with what the dealer finds.
 

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Check out the post "F5 problems - please read" on this forum... he had a pinched fuel line which was causing a similar problem. Good luck!
 

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Discussion Starter #9
Just got the good news from my dealer. My sled had a shorted ignition wire rubbing on the steering post. Simple fix and now it sounds awesome again- especially with the MBRP silencer!

I still wonder why it would run sweet when very cold out but I have faith that it's fixed and ready to rock.

Thanks Kenningston Motorsports in Michigan. :lol: :lol:
 
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