Motoscrubs.com

Hi,

What is the difference between wide-case and narrow-case heads? I think that I remember that the narrow-case has a different squish angle? I have tried a search here but nothing comes up.

Secondly, those using Amal carbs, where do you get your rubber spacers (between carb and inlet flange) from? Do you use those from a specific British bike?

Thank you,

Colin

Colin, I don't think there is any difference (could be wrong) I think the squish difference you suggest is between 250 and 350 heads but I have never actually measured it, pretty sure Nigel referred to this in some post on here somewhere. I never use those rubber inlet spacers....in my opinion they are just an air leak waiting to happen, Cheers George

I believe Jesus Guzman stocks rubber inlet spacers

Colin, sorry I misread in your post, what is the 'rubber spacer' between the Amal carb and the inlet flange? Assuming you mean flange type Amal's? I thought you meant the rubber spacer between the std Dellorto carb inlet spigot and the head (which I won't use) With Amal's I use either an alloy inlet spacer or my own preference is a tufnol spacer (thermal barrier). Amal 'flange' carbs...monobloc's concentric's GP's TT's are all subject to greater or lesser degrees of having easily distorted flange's and a rubber inlet spacer will just make the situation worse.
Not sure if that's the answer you are looking for?
Cheers, George

Hi Both Georges,

Thank you. The reason I ask about the rubber manifold spacer between Amal carbs and the inlet flange is that my 250 carb is 27mm and the only spacer that I could find of 27mm was the one that Jesus Guzman sells, but it is very thick and squishy and I can flex the carb back and forth, indicating that it could be leaking air. I would prefer a tufnol type but I could not find any in 27mm.

Cheers,

Colin

Aye Colin,

Same as George, if you are refering to the AMAL flange carbs and not the MKII Concentric?

Always used a Tufnol spacer between the carb and the cylinder head. Link to the Tufnol website below, if you want to know more? Followed by a link to the "Classic Bike Shop" who supply Tufnol spacers, with a 32mm bore. I am sure there are other alternative suppliers.

Tufnol_website or Direct Plastics Tufnol web pages Direct_Plastics_Tufnol_info

As with most engineering materials these days, you pay for the correct grade of material, in this case Tufnol "Whale", or "10G/40".

Classic_Bike_Shop_Tufnol_AMAL carb_spacer_32mm_bore

This link below, to the AMAL website, with regard to tightening the flanged carb to the cylinder head should be heeded!

Installing-AMAL-carburetters

Hope this helps answer yours and others questions.

Good health, Bill

Hi Colin, I bought a sheet of 8mm thick tufnol and made a heat shield spacer. I have more than I will ever use and can cut a piece off if you want to make one. Will post or if you want to put some miles on the Enfield pop over to Canvey.

Hi George,

That is really kind of you. PM sent.


Cheers,

Colin

Hi Colin

the 350 cc narrowcase Sebring has a diff angle squish band and i think some of the very late Mototrans 350 widecases to

40 versus 45 degree angle is my memory serves me correct

Eldert

Hi Eldert,

Thank you.


Cheers,

Colin