TOPIC:

The exhaust center pipe on my '79 was cracked open on the left and soon afterwards broken off on the right. Ideally a new exhaust would be great, but I'm determined to get the bike on the road with minimal replacement parts. I reviewed several suggestions here on the forum including the copper pipe macgyver which I attempted but will not pursue.

I took it all apart and will be sending it out to a performance muffler shop to have them weld on a new center pipe. I'm going to request a clamped connection in the middle, mostly likely 1" pipe going over top of the old nubs.

I decided to mock-up the system on the floor of my garage so they would have the correct geometry to work with or I could wait a another week and ride the bike over (nah). I made 3 wood spaces to set up the mock-up.

• A. spacer at the muffler brackets measuring 10 1/2", with a 1/4" dowel on each end to set with the bolt hole
• B. mid span spacer, between the pipes, towards the front using the exhaust screws (drains?) as a guide.
• C. manifold bracket, 4 x 1-3/4" holes spaced to match block spacing (1)3-3/16"(2)3-5/16"(3)3-3/16"(4).

This is what it looks like in case anyone out there is looking for a similar setup.

this is the B spacer, simply get a tight fit and add an alignment strap to the bottom

used a piece of cardboard to get the impressions of 4 of the manifold screws (they are equal to the center spacing of the pipes)

used my drill press to cut out the C spacer

muffler spacer A

A, B and C (I went back to C and added a stop board on the inside to prevent the pipes from sliding through, it also helps with the pivot angle and stabilizing the rig)

the mock-up using bungee cords to keep it all together

its hard to tell but is there a cross over pipe before mufflers?

P21 wrote: its hard to tell but is there a cross over pipe before mufflers?

Yes, it has rusted out and the reason I'm having a new one welded in.

Just picked up the exhaust last night from the shop. And had enough time to loose install the pipes back on the bike





The new muffer center pipe is a 1-1/2" exhaust with a sleeve/clamp connector at center. There is about 1/2" travel to both sides in the sleeve to allow for adjustment. The exhaust manifold is currently loose connected at # 2 and #3 and I used a come-along to hold up the tail pipes in position alongside the brackets.



I checked underneath and measured about 1/4" clear under the oil filter cap. Since the old muffler center pipe was never on this bike I don't know how far down from the pan/filter it actually sat originally. I'll pull the exhaust off tonight to get at the oil filter cap and install a missing spring in the oil filter assembly. I'm also considering shaving down 2 of the fins on the oil filter cap in order to increase the clearance to 1/2". I understand the fins are there to add rigidity to the cap but don't see a problem knocking off the corner to just above the surface of the cap.

Also since this center pipe is more rigid, I'll loose attach the muffler brackets to the pipes first and then mount the brackets to the frame to add more adjustment to the system.

Sometimes you just need a second pair of hands.