2005 Harley sport xl1200Runing on back cylinder front kicks in while riding on high rpm
 

Hi all

Please forgive me for bad grammar and newbie questions.
So I have a 2005 hd sportser 1200 with about 16000 17000 miles on it just bought it for $2500 might of screwed my self on this one for sure. When I bought it I couldn't ride it or hear it idle more than 2 minutes as I bought it at late night and bike is loud as hell. Come home take it for a ride I notice bike is runing like shit. When I took it for a ride down the street at 1/4 bike barely moved then anything after that the other cylinder kicks in then this thing moves like I'm about to get thrown off love it love it love it. But bike is runing bad idle one cylinder is not working the whole time.
1. So I checked the front spark it was black cleaned it spaced it replaced the two with each other problem didn't go away.
2. Then I put a spark tester on notice rear cylinder light up bright and powerful so I tried the front one not so bright and pretty weak spark coming out of it through the tester. Switched the wires and nothing still weak on front cylinder before the spark plug.

My question is!!? Is this do to bad coil? Or bad position sensor? That doesn't send good signal? Bike off I get .68 or 6.8 on each end before the coil.

I change the wires from front to back and bike just back fires out the exhaust and never starts I'm guessing my bike doesn't have both fire at once!! And bike runs bad like crap while idling lot of spitting and back firing idle.


My real question is!! Is this do to coil? Or is this do to bad wire? Or is this do to bad position sensor? Or is this do do bad jets? I'm really confused what to fix first and no go broke all at once :)) so please any help I appericiate greatly.

I'd check compression.

does not look like a 2005 sportster to me. try to swap the two ignition cables...

Agreed, triple part rockers, oil tank, frame, rear brake placement. 2003 down.

Yeah, that looks like a solid-mount engine. Check the VIN, tenth digit will tell you the year. It doesn't sound like bad jets; sounds like your problem is with spark. Jet size won't affect that, though a carb clean can't hurt. My first tentative thought would be a bad CKP. If you can, get ahold of a manual for the bike (check the year first). That'll have electrical specs in it, and troubleshooting procedures.

spray the front intake gasket with some WD-40 while the bike is running just to rule it out..........

teaching opportunity:

why? what will happen? are you trying to isolate a bad gasket?

Sounds like it is definitely in the firing, start with the least expensive item and work your way through the system.

The gaskets on the intake are rubber and sort of triangle shape. The heads can get about 400º so they can tend to dry rot and crack. He should REV the bike to about 4000rpm's and spray water or WD-40 (etc.) where the intake meets the head. And if cylinder starts to misfire while spraying, more than likely it's sucking air and needs new gaskets. A free and easy test.....