PT: Exhaust Pipe Flange

[delboy]

Of course, we all have a TIG welder......

My experience over the years with different manufactured pipes, and "original"/ repaired exhaust ports/different height barrels/etc, is that the flanging needs to be more of a compound angle rather than 90 degrees to the pipe, so that the flange meets the head near enough square. I've sometimes had to skim out the inside of rear head nuts to clear the pipe to screw in okay.
It's just another area that the works weren't exactly Thou's precise about. Take a look at the original acceptance jigs for exhaust pipes; how did they ever fit properly?
The instruction sheets say the pipes were 20 gauge thickness steel originally. Much easier to flange [although weaker] and, the thinner pipe may have allowed them to "settle" into place after a few heating and re-tightening cycles?
Having said that, over the years the majority of pipes made on the factory tooling that I have fitted have gone on with little fettling.
Strangely enough, the worst being Three-piece ones fitted to my own bike 30-odd years ago!
Carry on fettling.
delboy.

 

[Bill Thomas]

Can I borrow your Tig Del , Oh and teach me how to use it !.

 

[clevtrev]

If you use a Norton exhaust washer, it`s a copper/composite one, it helps to take up the out of squareness that might be there.

 

[delboy]

Certainly; If i win the lottery Bill.

 

[vibrac]

Of course if you are really racing there is only one way to fix pipes -stubs!
Nobody has time to fiddle with exhaust pipe nuts when the race is called.....

 

[litnman]

Alpha crank pin spacers fit perfectly in the head and are easy to weld to the exhaust pipe.

 

[Robert Watson]

I'll chime in. here is how I fit pipe to flanges.
With no flanges on the pipes screw the nuts all the way home and push the pipes all together so that they fit properly, then take a black marker and draw a line on the pipes around the outer end of the nut. Take them apart again. Now you can see the 'angle" that the flange needs to be at to suit the pipe/head joint. I just turn up new steel flanges and tack them in place, and try the whole plot together again. If the don't fit correctly a tack will pop. When all is fitting nicely weld the flange fully and dress down the welds (if you weld like me) I like to use the tig for this although in earlier days I did them with an oxy/acetylene torch. The nuts certainly cover over any sign of welding.

fiddly job but worth it to get a good fit

Fitting finished pipes still in 2 parts I like to fit the rear pipe in nice and loose and then the front up from below the rear pipe and into the front head, then tighten up the anchor bolt, pipe clamp and nut a bit at a time until all is done.

Anybody from outside North America pop over and I'll do them for you! (He says boldly!)

 

[erik]

Fortunately I will fit the pipe on a single .So only one pipe has to fit and no correspondence with an other cylinder. Erik

 

[Vincent Brake]

aber einmahl musst du ja.

 

[Robert Watson]

I would still do it my way to ensure the flange is at the appropriate angle to the pipe and seals well. As you are not in North America Erik, just pop over with it on the weekend and we can sort it!