81 carbs?

[madjap]

Hey, I was looking thru the 'carb ID thread' and I think I've narrowed my BS34 carbs year down to 1981... I have a single throttle cable, a single push / pull enrichener rod that controls both carbs AND composite floats. Sound right...?

 

[nj1639]

You got it!

 

[angus67]

80 had brass, all years forward was foam. You may eventually run across a 80 set that has been foamed. It was the cheapest alternative for my 80 carbs.

 

[5twins]

As Angus said, the brass floats in the 1980 set are often replaced with foam ones. Take a look at your float bowls. The 1980 bowls had a drain bolt just like the older BS38s .....

'81 and later bowls switched to a drain screw that enters on the lower left side .....

 

[TwoManyXS1Bs]

5Twins, those float bowl differences are significant.
I probably should have included that in the carb "quick ID" chart.
Something like 'bottom drain' vs 'side drain'?

I see a small bulge at the float hinge side, near the corner, in your '80 bowls pic.

Are those bowls interchangable for all '80-'83 carbs?

 

[5twins]

As far as I can tell, the bowls will swap, although I've not tried it. Here's a shot of some later BS34s and you can see there is still room for the early bowl "bulge" .....

Yes, I consider this bowl difference to be just about the biggest external "tell" on the '80 BS34 carb set. The push-pull choke narrows the year range down a little but they could still be '81 carbs with that.

 

[madjap]

By cracky, my float bowls DO have bottom drain plugs and NOT side screw drains, so maybe these are 80's with composite floats... JUST when I thought I had actually discovered something... DAMN! Oh, I did see a letter A stamped on mine and NOT a B, so that tells me even less... groan.

 

[TwoManyXS1Bs]

Yes, I consider this bowl difference to be just about the biggest external "tell" on the '80 BS34 carb set...

Great! I've put this on my todo list.

Looks like the gasket has provision for a passage.
Is there anything significant in that bulge area?

 

[5twins]

I don't have any '80 float bowls to look at. I grabbed that pic off eBay, lol. But, I don't think there's anything there. There isn't on the '81 and later carbs. Yes, the gasket has a hole in it for something, but all I can figure is that maybe there is some sort of passageway there on another version of this carb that's used on some other model. Here's a later carb, hole in the gasket, nothing in the carb body .....

 

[650Skull]

Again............. is this just a US thing. ..........Unless the carbs on my Oceania 80SG have been changed, the bowl is the same as your later 81-83 type with the drain screw to the side.

 

[TwoManyXS1Bs]

... Oceania 80SG ... bowl is the same as your later 81-83 type ...

Uh-oh. I'll put the chart update on hold then...