Cylinder Head.

[JohnAli]

Now that I have been informed that I actually have a 34A Scrambles barrel fitted on my Trials 24TCS, I though I'd better check the cylinder head.

Can't find numbers for 32A and 34A cylinder heads to check but the one that is fitted is stamped B1176 and the combustion chamber is a lot smaller than the piston top, is this correct?

Many thanks for all the help from Forum, much appreciated!

Cheers, John.

[trialrider17]

John, 32A, 37A is C11785 for release valve 32A ,37A is D11779 no release valve
33A, 34A,36A is B11910.
Simon

[johnrunnacles]

And B11765 is for 31/35A. John/Simon.

[JohnAli]

Thanks for replies, appreciated.
Would existing head be ok for trials?
Number stamped is B1176 but should it actually be B11765 ?
Bloody confusing trying to set up a Villiers engine which has been messed with, might have something to do with my age though

Cheers, John.

[John Wakefield]

Looks like the head maybe a 31A in which case it would be 7.4:1 compression which is low comp suitable for trials (cant find a 35A engine listed in Roy Bacons book Villiers Singles & Twins)
Best to take a pic of inside of head, then I am sure we can identify if its high or low comp. The combustion chamber in both heads was smaller dia than the bore.

[John Wakefield]

And B11765 is for 31/35A. John/Simon.

John I have found this pic of what looks like a B11765 cylinder head. Combustion chamber looks small so maybe 12:1

[JohnAli]

This is the head (B1176) fitted to the 34A Barrel on my 32A
Diameter of combustion chamber is 50mm compared to the 65mm piston top.



Also found a pic of a 31A engine which looks to have same head with same Decompressor that was fitted to mine when I got it.




Thanks for the assistance, I'll get there

Cheers, John.

[johnrunnacles]

34A head has combustion chamber diameter closer to 45mm, John A, and part number B11910. I know because I have three such in the shed which have been put to one side for various reasons (e.g. broken fins, peppered combustion chamber from blown big-end debris, etc!).
The one you have photographed, John W, looks to be one such too (i.e. B11910). 35A incidentally was the 31A modified for use in light cars, and that is perhaps what Jon A has if not a 31A (?).
John (R!)

[John Wakefield]

This is the head (B1176) fitted to the 34A Barrel on my 32A
Diameter of combustion chamber is 50mm compared to the 65mm piston top.



Also found a pic of a 31A engine which looks to have same head with same Decompressor that was fitted to mine when I got it.




Thanks for the assistance, I'll get there

Cheers, John.

Your head looks like a low compression 32A as chamber is much smaller on the 34A, so ok on your bike, heads look same from the outside.

[JohnAli]

Thanks for all the help, all good now I think


Cheers, John.