The Great Exhaust Pipe Hunt..

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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The Great Exhaust Pipe Hunt..

Postby crackon » Tue Mar 29, 2016 2:07 pm

..Goes on. '68 G15 CS. I've tried two suppliers for high level exhausts, no good, bends are wrong, outlet hangs down like they need Viagra. Not being the worlds best welder, I don't really want to go down the cut 'n shut route. So, I thought, OK, go low level, it's no big deal. I am now informed that P11A pipes won't fit. I was under the impression that the P11 and G15 CS were identical. Wassup?
Anyone out there got any ideas?

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Re: The Great Exhaust Pipe Hunt..

Postby bjork » Tue Mar 29, 2016 2:31 pm

crackon wrote:..Goes on. '68 G15 CS. I've tried two suppliers for high level exhausts, no good, bends are wrong, outlet hangs down like they need Viagra. Not being the worlds best welder, I don't really want to go down the cut 'n shut route. So, I thought, OK, go low level, it's no big deal. I am now informed that P11A pipes won't fit. I was under the impression that the P11 and G15 CS were identical. Wassup?
Anyone out there got any ideas?


P11 and G15 identical??? No, sorry they aren't. Frames, wheels and lots of other small bits too. I agree about pipe fitting though, almost every pipe I've bought has needed a lot of 'adjustment' (read that as severe persuasion) to line up where it should be. What really surprised me was how far you could bend them without any creasing or chrome damage. They make a lot of strange noises when doing this too! I only plucked up the courage to be this brutal after being advised by old hands that it was always like this in the old days and that's how it was dealt with back then.
Using yesterdays technology to create tomorrows problems today

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Re: The Great Exhaust Pipe Hunt..

Postby bitza » Tue Mar 29, 2016 6:25 pm

When I was in fabrication game if I did'nt have a bender or do a one off, I would pack the tube with dry sand ,the type you buy for kiddies sand pits, plug one end of pipe with wooden bung , fill with sand tapping the pipe on wooden block so as to pack it well, then bung the open end, then gently does it ,take your time and you should be able to work the bends to suit, try on a scrap pipe to get the feel, easy does it , is the way ,I see your in somerset if you crack the chrome plating I recommend ,
Doug Taylor at Banwell did a good job on my parts.

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Re: The Great Exhaust Pipe Hunt..

Postby Duncan » Tue Mar 29, 2016 7:22 pm

For the cost of some extra postage order the pipes unchromed, obtain the fit you desire and return them for plating.

Alternatively if it is common problem and your set up is standard you may be able to take the bike to the company to be used as a pattern

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Re: The Great Exhaust Pipe Hunt..

Postby crackon » Wed Mar 30, 2016 8:22 pm

Well, I've given the left hand pipe the treatment,using the above tips, thanks guys. I cut 1 1/2" piece out of the straight bit of pipe over the chaincase, slotted the piece left over and used it as an inside sleeve and tack welded it to the front bit of pipe. The pipe then cleared the toolbox, and I could twist it round to where I wanted it. I borrowed a mates 16 ton pipe bender and bought a bag of "Kiln dried sand". Filled the pipe and gave it loads of tapping, surprising how the sand settles and the level goes down. Crossed fingers and put the squeeze on, using the Mk 1 eyeball to judge it. Three goes, and the last bit of tail pipe was now pointed slightly upwards, and tucked in, as I wanted it. Three spot welds on the join and I've taken the whole thing off so I can get at it on the bench.There's a slight kink where I put the bend on, but I can live with that. If the right hand side goes as well tomorrow I'll be dead chuffed.
Onwards and upwards.

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Re: The Great Exhaust Pipe Hunt..

Postby bitza » Thu Mar 31, 2016 2:40 pm

Great to hear you've sorted the ex/pipe out, the problem we have in forming thin wall pipe is trying to stretch the outside of the bend
Whilst not squeezing the inner of the bend to much this is what creates the kink, the other option is ,pack it with the sand and use the
Oxy/acett torch to heat the pipe where you need to bend it, of course this is'nt doing the chrome plate any good, but ok if your making a pipe up out of plain tubing.

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Re: The Great Exhaust Pipe Hunt..

Postby crackon » Thu Mar 31, 2016 8:15 pm

It's not the bends that were my problem, they were all good, but not in the right places The two sets I came across just weren't correctly aligned. Neither pipe fitted under the oil tank/tool box and the end bits of the tail pipe stuck out and down. Not good looking to my eye.
In Bjorks reply he says that the P11 and G15 are different beasts, but I thought that as they both used the Matchless frame and Norton engine the exhaust would be the same. Ah well, live and learn. Cut, shut, and bends all done now, off to Doug Taylers for rechroming sometime.(Early afternoon so I can have a couple of pints in The Old Inn)

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Re: The Great Exhaust Pipe Hunt..

Postby mollymole » Sun Apr 03, 2016 1:45 pm

Be interested in your chrome plating results.They chromed my bare pipe and silencer ,it fell off after several months ,they said sorry about that bring it back we will do it again,now a year later its got rust spots.I got my money back in the end,but still need to chrome the pipe,don't know who to trust to do a decent job.

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Re: The Great Exhaust Pipe Hunt..

Postby crackon » Sun Apr 03, 2016 5:55 pm

I must admit I had a wheel re chromed there about 30 years ago. Got it back, masking tape around the rim, painted the centre black, took the tape off, and away came the chrome. I hope they've improved since.

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Re: The Great Exhaust Pipe Hunt..

Postby norman_john » Sat Jul 01, 2017 10:05 pm

Hi,
As far as low-level pipes go, where do we buy these from these days?
Thanks
John

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