389 Carbs.

[Pilgrim]

Hi all,
Does anyone know the difference between
a 389/80 and a 389/42, or what bike the 389/42
originally was fitted to? Can't find the bike fitment
for the /42 on the Amal website. Cheers.

[bsa-bill]

Hi Pilgrim
AJS 350 according to this link

http://porklips.org/~mason/moto/amal_specs.html

useful site

[Pilgrim]

Hi Bill,
Thanks for the reply, and the link, very useful site.
I've got the 389/42 on the'63. All the jets, slide, and needle
are correct, it's the bore that's evidently 1/32" too small.
Perhaps that's why it pulls so well. It would be nice to have it correct,
but is it worth the outlay for a new carb? Having a think about that one. Cheers.

[Beezageezauk]

Hi Pilgrim, 

Could I suggest that you went to a couple of autojumbles looking for a suitable carb body.  Then swap all the bits over if you find one.  Take this next phrase in a motorcycle context but....bare bodies come quite cheap.

Beezageezauk.

[wilko]

I wouldn't even bother. You won't notice any difference unless you buy a new one to justify it to friends!!

[iansoady]

I agree. The extra 1/32" will only make a difference (and a small one at that) at absolutely wide open. Smaller bore tends to give better low speed running and mid range.

When I converted my Velo Viper to Venom spec I kept the smaller Viper carb which made it very flexible.

[Pilgrim]

Thanks for the replies guys,
I think I'll hang on to my £160 until the slide really starts rattling!
The bike goes well and the tickover's not bad. I'm going to the
South of England show tomorrow so I'll keep my eyes open for a 389/80,
might find a good body, if you know what I mean! ya never knows do ya!
Cheers.