"S" type exhaust question (2013)

I am restoring a '72 Combat Comando that has and "S" type exhaust. The previous owner installed it in 1986 when he cafe'd the bike and turned it into a "show bike". at that time he purchsed the pipes and rear suppport bracket from Norton in England, and had stainless straight through mufflers made. in the last 27 years the chrome peeled on the pipies and the dog-leg bracket rusted so i ordered new pipes from Specialty Spares (which came from England) and a new dog leg bracket from CRA, which is a new Norton part. I am re-using the mufflers as they are like new.

My question is this; when i fit everything up the pipe from the right hand cylinder which wraps around the frame and comes through the left hand pipe hits the downtube on the frame Right side front), and if i try to rotate it up the clear the down tube it hits the cyl fins on the left front corner of the engine. I have the bike up on a lft supported by the frame, is this causing the engine to rotate back in the isolastics? will i have clearence when i set the bike back on it's wheels? can i add crush washers to space the pipe out from head to clear the down tube? (only one came out with the old pipe)

I took pictures of everything when i dissassembled the bike but i dont believe the old pipes hit. FYI i did not remove the engine from the frame or adjust the isolastice. i cant belive this is acceptable to leave unresolved, not sure if Specialty Spares will accept the pipes back now that they have been fitted up to the bike.

Any advice is appreciated, Thanks!

I have never had trouble with the S headers hitting the frame no matter in what state of suspension the frame/engine is in as long as it's all assembled. What I have trouble with is the upper exhaust pipe not going into the silencer enough, but I seem to have cured that. And the lower one hitting the chaincase, but I seem to have cured that too.

If the exhaust header is hitting the frame it shouldn't. Close, but I can just squeeze my pinkie at the nail under the frame and the pipe. Maybe 3/8" max?

I have taken a long bar and bent the exhaust pipes once to try to get them to line up with the silencers better, it didn't seem to bother the chrome, so far.

I find if you push the dog leg bracket as far forward as possible, it helps get the upper pipe in and the lower one away from the chaincase, but that's not going to help your exhaust pipe from hitting the frame.

Dave
69S

All very true but remember that Norton in the factory realizing the ex. pipes -headers fitting probs. would pick and choose pipes off the shelves that would(fit). Welding flanges would distort and necessitate choosing on the factory floor. New stuff has the same issues. Try this: Jam a iece of wood betwen pipe and frame to hold outwards then tighten up the Ex. nuts. as a final. Remove wood.

Thanks Dave, yeah, i loosly assembled the L pipe, muffler and bracket and had to move the bracket in (forward) to get all that to work, then tightened everything up, and i did apply a little "persuasion" to get the pipe bent to the correct angle. muffler slides over the pipe about 1 1/2".

The top pipe seems to have about 3" in the muffler but i;m wondering if the pipe isnt bent at the right angles. i thought about placing a block of wood between the pipe and the cylinder barrel then bending the pipe slightly but i dont want to kink the pipe, damage the chrome or "gasp" strip the threads in the head.

Torontonian; thanks, thats a solid idea, i worry about striping the threads, how much torque can i apply to the wrench? i applied about 80# on the end of the wrench alredy.

Im thinking this way , Soft wood like spruce chunk-wedges (used in factory times) to put pressure to where you want things to end up . The precious exhaust threads nut would be the final tightening . Smear the threads with Permatex (no product endorsements checques coming my way Permatex?) Ultra Copper high temp RTV gasket product (notice how everything is a "product" nowadays ?) with new crushrings (Honda CB 350 best). Then tighten down with proper tool with extreme force and prejudice. I stand on the tool. The other side gets the sledge upwards. So be it . No retainers. Pull the wood.

Yes, I put wood blocks in all the appropriate places so they try to maintain their positions when tightening. Here's how I ended up adjusting my S pipes.

Assemble everything loosely. Push dogleg as far forward as possible to get silencers onto headers. Use the CB350 round exhaust washers (which I didn't do but should) Put block of wood between chain case and lower exhaust to get as much clearance a possible. Same between lower and upper exhaust, but where they go into the silencers so the silencers don't bang together. Get good clamps, forget the originals, you need either the Moose clamps from Chrome Addiction or hobot had some that I saw and never got, forget the omega looking ones (Clubman and Old Britts I think), the aluminum spacer doesn't hold up, the S pipe clamps really need to be tight and strong, the Moose have an Allen head bolt and steel nut. Tighten everything from the front to rear. Run bike for 20 miles or more and do it again. Despite what others say, I've never had luck tightening the exhaust roses while the bike is running. I tighten them with all the wood blocks in place and a 4' extension on the exhaust nut tool, but don't go overboard. You can tell when it's tight enough, don't be a gorilla. 4' gives you plenty of torque, but it also gives you a feeling of how it's tightening up. You may need help especially if the exhaust is hot. Wear leather gloves. Use high temp (nickel) anti-seize, hobot recommends talcum power, not sure, never tried it, but it seems most of the anti-seize comes out.

I got my exhaust headers from Xanders years ago and I don't know where they came from, the silencers I got from Walridge, Wassal I think. But my upper header is a bit short, it barely goes into the silencer covering the slots. As I remember my originals were like that too.

But the pipes shouldn't be close enough to the frame down tubes to hit. It took me a year to get it adjusted and tight so it doesn't come loose or bang on itself.

Here's a pic of the clamps. I've cut off most of the protruding bolt.



Dave

I bought a new set for my "S'" and had the same problem. When I laid the new ones over the old ones the bends were way off, I sent them back and had the old ones rechromed for $120.00

Thanks guys, i hope to spend some time on it this weekend. i'll give your suggestions a try. I'm anxious to hear the sound it makes when done.

Success! thanks guys, i would have never guessed i would have had to use a crow bar, 2 spruce dowels, a floor jack extension handle, and a strap wrench to get everything tweeked into place. that upper pipe is like a piano wire now maybe a few heat cycles will stress relieve it LOL.

Thanks for your help!

Rich.

Mine went together without much stress. I did bend the upper header a bit though. Sometimes it helps to loosen the exhaust nuts and let things settle out and tighten them back up with the appropriate blocks to keep things apart. The first thing that will break will be the shields, I give it about 4K miles. Then the dog leg bracket will develop a crack in the top. Probably better to get the original bracket welded, I got one from RGM and wasn't as beefy as the original, but it was stainless.

Dave
69S

Hey if any of you have your old s pipes or parts you want to get rid of let me know! I'm a new member here and have a s type I am restoring to its original paint and want to keep the as is look. It's in such good shape I dont want to do a total restore and I want to keep the historic look! Let me know thanks! Or if you have any leads! Dont have to be in a plus condition!