HD Sportster muffleres or XS400 exhuast

[powershouse]

I've been out of here for a while, but it is time to get the 1977 XS finished because some @#$% stole my son's Nighthawk.

I have a set of exhaust pipes which were advertised on ebay as being for a XS650, but which don't fit quite right. When snugged up the flange that fastens the pipes to the exhaust port has about a quarter inch from the engine. I believe they may be for a 400 rather than a 650. They sure are pretty though.

My other choice is to run a pair or Sportster mufflers a friend gave me on the stock header if I can find a suitable bushing.

My thought is to go with the Sportster set up because I am worried that the other pipes not fitting right will lead to other problems.

[nj1639]

You should be fine with the 1/4 " gap.
Do you have an exhaust gasket set in the exhaust port before the pipes are put on?
I'm running mac headers that I replaced the flanges with stock. Also cut the inserts off a pair of stock junk pipes. Cut where the inner and outer pipes are welded on and then smoothed the face. Install is 1 exhaust gasket, the insert, the headers and snugged down with the stock flanges. I have about a quarter inch gap and no problems.....so far. 90 miles and counting.

[5twins]

I also run MAC headpipes and inserts made from the ends of old original headpipes. However, I made my inserts a bit differently. I left some pipe sticking out the front of them so they would insert into the headpipe as well as the head. This perfectly centers the pipe on the port and I think it helped with sealing as well .....



There is a rather deep step machined into the exhaust port to accept the end of the stock pipe, deeper than it needs to be .....



Even with no seal ring at all, the pipe will not stick in far enough to fill the step. This step disrupts and is detrimental to flow. A pipe filler ring can be made and inserted into the head to fill the space that the pipe does not .....



The filler ring is placed in the port and then the home-made insert is stuck in with some Yamabond on the flange. A factory seal ring and the new headpipe are installed over the insert. The assembled parts "stack" looks like this .....



The results were very good. The pipes seal tight as a drum and the bike is much freer revving than it was before when the headpipes leaked. The headpipe flange stands out from the motor probably even a little more than 1/4" but I've not had any problems with it. I've been running this installation going on 5 years now and probably close to 10K miles.