The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: ciderman on 06.11. 2020 12:51
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hi , just a quick question regarding my new super rocket exhaust bought from a well known UK supplier and are " guaranteed to fit " we have had these specially made etc etc ...well guess what ? they do not fit ! they will not fit in the cylinder head ports ( around 0.9mm too thick ) i have 3 sets of scabby A10 exhausts which fit perfectly . could it be possible I have an A7 head fitted ? are the ports smaller on the A7 ? I dont know ....on the brink of sending them back....thanks , Phil .
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I have a set of nice shiny headers hanging up in my garage. They too were too big on dia to fit in the ports. I was advised by the supplier to grind the ports out.
(roumArs)
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I'd compare the tube diameter of the new pipes that don't, and the scabby one's that do. So if they are the same, the fault lies within the ports, exhaust sealer and coke masquerading as cast iron.
The A7 and A10 castings are almost identical externally. It would make economic sense to use one size of tubing, and from experience an A10 pipe will fit into an A7 head and so I know the ports are the same size. Plunger head casting numbers are on the underside of the inlet manifold, wide fin heads have it stamped or cast on the underside of one of the bottom fins.
The claim for fit sounds the sort of advertising copy from a supplier local to me........
Swarfy.
Additional. Here in Suffolk it's a lovely day.
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A7 and A10 exhaust ports are the same diameter. DO NOT grind out the ports to make the pipes fit. This will just cause headaches when at some point in the future someone tries to fit correct diameter pipes.
I've never had any problems with Armours exhausts.
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thanks for the answers , i did consider shaving half a mill off the headers but that would leave them dangerously thin and taking a bit off the id of the ports is not an option .. ( and why should I indeed ) the thing is these are " not fit for purpose " so i am going to contact the supplier who is bound to say " weve had no complaints so far " ... let the fun begin ! cheers ,Phil .
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meant to add that new and old pipes are different diameters by around 0.8 of a mill so ports ok thankfully *smile*
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I thought it was just me...…...EVERY problem I address with a manufacturer is met with, "we have never heard of that problem before." Lying SOB's!
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G'day ciderman.
The local car exhaust shop should be able to shrink the last 1" or so of the pipe to fit the head.
Cheers
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This all rings a bell six months ago
https://www.a7a10.net/forum/index.php?topic=15307.msg129061#msg129061