The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Desburnett on 19.10. 2009 20:37

Title: Carb manifold heat resistant spacer
Post by: Desburnett on 19.10. 2009 20:37

A7 SS 1961

Is there a heat resistant carb spacer fitted to the manifold? I dont have one in my box of bits which I thought was complete and when mounting the carb I find the drip tray is fouling the manual advance / retard cable shroud by about 3/8".
The mag was rebuilt by SRM a few months ago, all the old replaced parts were returned to me and appear to be identical to their new parts.
The current assembly set up from the inlet manifold is,
Paper gasket
Drip tray
Paper Gasket
Carb with O ring
Spring washer
Nut

If there is a heat resistant spacer I would like to know the part number and if possible its thickness.

Thanks,

Des

Title: Re: Carb manifold heat resistant spacer
Post by: LJ. on 19.10. 2009 21:52

The set up is exactly as my A10s are... Incidental My M21 had a 1/4 inch tufnel spacer between the head and carb but still did not run properly when the engine was hot. Now I have a 3/4 inch tufnel gasket the problem has been solved. The A series engines don't get anywhere near as hot as an M series engine so you'll be okay to leave as is.

Title: Re: Carb manifold heat resistant spacer
Post by: old PJ on 19.10. 2009 21:58

I agree with LJ and my A10 has no heat spacer fitted.

Old PJ

Title: Re: Carb manifold heat resistant spacer
Post by: chaterlea25 on 19.10. 2009 22:01

HI,
I would recommed the use of a heat insulating washer,
Are the carb studs long enough?
I use the thickest I can fit,
I make my own ones from Tufnol so I dont know the part number
Regards
John

Title: Re: Carb manifold heat resistant spacer
Post by: rocket man on 20.10. 2009 21:00

your alloy head shouldn't get too hot but i have a super rocket and i have one fitted


dave

Title: Re: Carb manifold heat resistant spacer
Post by: RichardL on 20.10. 2009 23:18

I have one fitted and it is a listed part number (sorry, no part number while thumb typing). The problem I just discovered after running 950 mi. With it was that it was about 1/8-inch smaller in I.D. than the intake manifold I.D. Some not-so-quick work with the Dremel fixed the problem and it seems to have made a just-detectable performance difference.

Richard L.

Title: Re: Carb manifold heat resistant spacer
Post by: BSA_54A10 on 21.10. 2009 11:59

In any case you really need the Tuffnol gasket there as a smooth flat surface for the "O" ring to seal against.
Should be head , paper, drip tray, paper, tuffnol , o ring , carb