My buddy has a 2002 Sportster. The top end needed to be put back together. We put it all back together and it fired right up. Problem is the rear pipe gets VERY hot, very quickly. The front seems normal. Someone told him it was the head. Sent it out and the head is fine but the problem is the same.

Any ideas?

 

Is there a heat sheild on the rear pipe?

 

No. They are no heat shields

 

I'm keeping an eye on this thread..I'm having a somewhat similar problem...

 

The rear cylinder may be running lean. Take the air cleaner off and see if the fuel tends to go more to the front while it's running. Also check the rear plug.

 

I checked the plugs and the rear plug looks to be running richer (its more wet and black) then the front.

I also check the cam timing. It looks right also.

I running out of hair to pull out.

Any ideas before I set it on fire.

 

Not enough information yet. Sportster...stock 883, stock 1200, 1200 conversion, stroker, modified, carb, jetting, heads, ignition module, stock pipes, aftermarket (what kind, and brand names are meaningless; need to know if they are baffled, open, modified, whatever, if aftermarket, what is the inner diameter?). It would also help to know what kind of gas mileage you got before the repair. I'm assuming nothing else was changed. These heads, what are they and what was done to them, and who did it?

Cams. Stock or aftermarket?

What is the condition of the oil? Is it clean and smell like oil or dark and smell of gas?

What kind of air filter?

When does this pipe get hot? Idling? After around town riding? After a steady 60 mph run on the highway?

The more information the better.

The rear plug is "darker and more oily" than the front? Is the front plug dark and oily too? (Type and number of the plugs?) How old are they, in miles?

There's a reason the rear pipe is getting hot. It is just a matter of discovering it.

 

well the rear is gonna be a bit hotter just from having most of the wind blocked from it. But to really know if it's hot or not, see if you can get a infrared thermometer, a number of auto stores carry them, and harbor freight sells one for $30. But then you can compare the actual temps to another comparable bike. And if you can get them for his exhaust, pick up some heatsheilds. And in terms of oil, have him run synthetic if he isn't already doing so, it'll help a bit also to cool things a little. Also in general, if he can ride the bike for a good 30minutes and have everything completely warmed up, and the bike will still idle normally, that's a sign that things are ok. Also on the heads, often times if they're running on the hot side it will ussually cause the powdercoating to start to glaze a little if your starting to get to the dangerzone, but you'll most likely experience engine stumble from overheating first. But yeah, definately get some heat sheilds, that rear header will fry your thigh out real quick without it. By the way, why did he have the head off to begin with, was it for the heat issue, or for something else?