The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Lindsay S on 24.08. 2024 19:57

Title: Exhaust port holes
Post by: Lindsay S on 24.08. 2024 19:57
My Golden Flash iron head has small holes in the top of each exhaust port where the pipes go; that could possibly be threaded. Has anybody come across this before, is it ‘factory’ or is it somebody’s modification to stop the headers from vibrating out? See attached picture.
Title: Re: Exhaust port holes
Post by: limeyrob on 24.08. 2024 20:16
Looks like a mod to me.  Probably to retain the pipes, wonder if it worked?
Title: Re: Exhaust port holes
Post by: berger on 24.08. 2024 21:02
i have seen them with springs attached to the exhausts
Title: Re: Exhaust port holes
Post by: Rex on 24.08. 2024 22:30
Looks like a mod to me.  Probably to retain the pipes, wonder if it worked?

Obviously not as the pipes aren't there, are they?.. ;)
Title: Re: Exhaust port holes
Post by: berger on 24.08. 2024 23:17
Rex  *lol* *lol* *lol* *whistle*
Title: Re: Exhaust port holes
Post by: Triton Thrasher on 25.08. 2024 10:17
Maybe had pins or screws through into the pipes, to hold them in.
Title: Re: Exhaust port holes
Post by: muskrat on 25.08. 2024 20:54
G'day Lindsay.
I did that to my A7SS head to use a spring onto the pipes.
Cheers
Title: Re: Exhaust port holes
Post by: Lindsay S on 25.08. 2024 21:20
That certainly seems a possibility, either that or a grub screw. I have read that Siamese pipes can be a problem with regard to falling out, so maybe the previous owner of this head had those fitted to their bike.
I bought this head off eBay to replace the head on my engine which has a rather unfortunate crack from a valve seat to the spark plug hole!
Title: Re: Exhaust port holes
Post by: berger on 26.08. 2024 12:55
i put a tie bar and allen grub screw on mine
Title: Re: Exhaust port holes
Post by: raindodger on 26.08. 2024 18:51
I have the same holes in my A10 head, I always thought they were oil drain holes.
The head gasket and the block have holes in a similar position.
Title: Re: Exhaust port holes
Post by: berger on 26.08. 2024 18:55
raindodger you are looking at the wrong holes mate.
Title: Re: Exhaust port holes
Post by: Joolstacho on 27.08. 2024 00:10
Is raindodger a father?
Title: Re: Exhaust port holes
Post by: raindodger on 27.08. 2024 08:55
Yes, he is!  But the eyesight is not what it was
Title: Re: Exhaust port holes
Post by: Joolstacho on 27.08. 2024 09:30
Lucky wifey then... "missed by that much!"
Title: Re: Exhaust port holes
Post by: raindodger on 27.08. 2024 18:44
Keep it clean, Lads.