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H1 Pattern Exhausts
Posted: Tue May 13, 2025 7:17 pm
by doodah
I bought some pattern H1 exhausts for my H1B years ago. I've come round to fitting them now, but I have found the L/H exhaust doesn't sit correctly. It's roughly 8mm above the mainstand damper rubber and is pressing hard up against the rear wheel nut. (when you're not sitting on the bike) I guess the only solution is to file out the mounting hole that the rear footrests use so it sits lower. Anyone else had a similar issue?
Re: H1 Pattern Exhausts
Posted: Tue May 13, 2025 9:45 pm
by Wolfie
This might sound silly but..
Are you sure that the other two are fitted to the correct Cylinder? Some Pipes are very close in shape so will fit to the wrong Cylinder leaving one with nowhere to go.
Re: H1 Pattern Exhausts
Posted: Thu May 15, 2025 3:39 pm
by doodah
Pretty sure, the centre one has the longest hanger at the fear footrest mounting and has a slight s shape the r/h one is plain, the l/h one has the plate welded underneath for the mainstand damper to butt up against. Plus the 3 hangers are different on the inner and outer sides so it would look odd if the l/h and r/h pipes were transposed and the bracket where they bolt onto the frame at the front would be backwards too and unusable. I guess what I will do is to take the shocks off the maximum preload setting, so shortening their length a bit thus effectively raising the swing arm in relation to the frame and exhaust. I have some muffler connector rubbers spare, so I will stretch them over the mainstand damper and increase it's OD
Re: H1 Pattern Exhausts
Posted: Thu May 15, 2025 8:15 pm
by robh1f
Are they Doremis????
Re: H1 Pattern Exhausts
Posted: Fri May 16, 2025 6:31 pm
by Smartbear
doodah wrote: ↑Thu May 15, 2025 3:39 pm
Pretty sure, the centre one has the longest hanger at the fear footrest mounting and has a slight s shape the r/h one is plain, the l/h one has the plate welded underneath for the mainstand damper to butt up against. Plus the 3 hangers are different on the inner and outer sides so it would look odd if the l/h and r/h pipes were transposed and the bracket where they bolt onto the frame at the front would be backwards too and unusable. I guess what I will do is to take the shocks off the maximum preload setting, so shortening their length a bit thus effectively raising the swing arm in relation to the frame and exhaust. I have some muffler connector rubbers spare, so I will stretch them over the mainstand damper and increase it's OD
The swing arm will stay in the same relative position to the exhausts, it’s got to maintain the same height above the ground due to the diameter of the wheel. It’s the sprung part of the machine that’s going to sit at a lower relative position.
Rob
Re: H1 Pattern Exhausts
Posted: Fri May 16, 2025 6:59 pm
by mcludd
Have you changed the rear shockers for ones that are bit shorter/longer (whichever may be appropriate)?
Re: H1 Pattern Exhausts
Posted: Thu May 22, 2025 4:05 pm
by doodah
I found what the problem was now. I got a new pair of shocks each for my h1 and h2. what I did was fit them onto the wrong bikes. The h2 ones are about 4mm longer than the h1 shock. Although you can fit h1 shocks onto an h2 with no problem, you can't fit h2 shocks onto an h1 without the exhaust being hard up against the wheel nut. Anyway I swapped the shocks over and now I've got about 2mm clearance between the exhaust and wheel nut. So problem solved apart from the gap between the centrestand rubber and the plate under the exhaust that it's supposed to butt up against. No, I don't think they were Doremi's I think the brand was something like PMC.
Re: H1 Pattern Exhausts
Posted: Fri May 30, 2025 3:20 am
by scouse
doodah wrote: ↑Thu May 22, 2025 4:05 pm
I found what the problem was now. I got a new pair of shocks each for my h1 and h2. what I did was fit them onto the wrong bikes. The h2 ones are about 4mm longer than the h1 shock. Although you can fit h1 shocks onto an h2 with no problem, you can't fit h2 shocks onto an h1 without the exhaust being hard up against the wheel nut. Anyway I swapped the shocks over and now I've got about 2mm clearance between the exhaust and wheel nut. So problem solved apart from the gap between the centrestand rubber and the plate under the exhaust that it's supposed to butt up against. No, I don't think they were Doremi's I think the brand was something like PMC.
It's very common for early center stands to be bent, did it sit fine with your old B pipes?
Re: H1 Pattern Exhausts
Posted: Fri May 30, 2025 5:53 pm
by doodah
It didn't seem to be bent, but I'll have another look and check it. It never used to have a damping rubber with the original pipes so it was always bashing into them when I took it off the centre stand. Most of the time though I ran it with expansion chambers coz of grounding issues when I would lean it round corners.