Intake pipe model ?

Vww18

XS650 Enthusiast
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Hi folks,

I think I ordered the wrong version of intake manifoilds...

The bike is a special from 1979 (european version I assume)

Looking at the identification post, I might have a bs38 ? Even though my fuel intake is located outside on each one with no center pipe, and that the choke is a little bit different to what I've seen on the 2fo's version

Anyway, my question is regarding the manifoilds, the one i've ordered seems wayyy too small for my carbs, do you know which one I should buy ? On google image, I can only find the small one that i've bought... Thanks !

(Side question, is this model of carb a good one ? Through the years, the carb kept improving to reach the state of the art at the end of its career ?)

IMG_20210410_191523.jpg
IMG_20210410_191611.jpg
IMG_20210410_191633.jpg
 
Those are BS-34's. The independent fuel barbs means it's the European model -34's.... learned that from @650Skull ... :whistle:
The boots look like the correct ones to me. are you saying the carbs wont fit inside them?
 
Stupid question and no disrespect...

your puttin the carbs on the right way??

Your emphasis on “wayyy too small” just made me think.

they should pop right on, sometimes a little assembly lube will help.
 
I hope i'm putting them the right way...

I bought them for a cheap price (ridiculous I agree, i renew everything, why saving 30$ on that ?)

I'll try to pop them but at this stage, I miss 1cm in diametre... I'll try the lube !

Thanks !
 
And for my side question so, the 34 means they are less performant than the 38 ? Was it a question of legislation and pollution norms ?
 
I'll try to pop them but at this stage, I miss 1cm in diametre... I'll try the lube !
That's a pretty big difference. Silly question... but you're trying the right end aren't you? The end you show in your pic is the back. The other end goes in the boot.

And for my side question so, the 34 means they are less performant than the 38 ? Was it a question of legislation and pollution norms ?
The 34's are more than enough for the engine. Others might disagree, but I call them an upgrade over the 38's
 
Thanks to all of you !

Yep I tried on the right side but it is very very tight, I have to push really hard... At least there in, maybe the rubber will get a little bit losse with time.

Thanks ! I found the post on the compare between those two ! And afterward I will work on the tuning (as I will have a nearly free intake) !

Thanks that's so good to have such an active community and precious advice !
 
Those intake boots are supposed to have a metal cage around them. The carbs will sag and eventually crack the rubber without 'em.


Intakes.jpg
 
Thanks Jim.

I thought that I bought a piece of crap, too small and without metal insert... Now i'm sure. Thanks.
 
I thought that I bought a piece of crap, too small and without metal insert... Now i'm sure. Thanks.
The quality of the rubber may be questionable, the boots sound correct. They should be a tight fit. I use a little high vacuum grease on mine. The metal guard is a separate part. Doesn't come with the boots.
 
Sorry to bother you again with my pipe but i would like a final advice before ordering new ones if needed.

With some grease, that finally went in but they are not centered meaning that when you look at the carb, there is a "step" on each of them, someting like 1mm of rubber that sounds to be in the stream.

The picture I attach are well centered.

Is it acceptable ? Am I fucking flies ?
(A litte bit of French slang...)
 

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Ideally, the transition from carb to rubber should be smooth, with no step either way. So an intake rubber that has slightly smaller insider diameter than the carb is preferable. Then you can use a sanding drum on a Dremel, to blend it to the carb.
 
I think you've got the correct manifolds. The BS38 manifolds have a larger inlet and would be very loose on the BS34 carb. Here's some dimensioned drawings for comparison .....

dH1sHYO.jpg


LYH1HHZ.jpg


The inlet O.D. on the BS34 carb is about 42mm. On the BS38, it's about 47mm.
 
What about fabricating some kind of rubber mount that takes part of the weight of the carbs? Maybe attached by slightly longer carb top screws?
Or just some kind of strap hooked under the clamp for the air filter connectors?
 
What about fabricating some kind of rubber mount that takes part of the weight of the carbs? Maybe attached by slightly longer carb top screws?
Or just some kind of strap hooked under the clamp for the air filter connectors?
Yeah... since he's building a bobber, something centered/rearward to support 'em would probably work just as well.
 
So... I mounted the carbs on the engine and from the other side, i keep thinking that it is not good, not good, not good.

Would you still mount them based on the fact that this engine is not a race one and that in any case I will drive it like an hard tail... ?

Or do we feel that this is a pitty to rebuild everything new and to ruin my intake flow with some 25$ chinese crap ?
 

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I would struggle to live with that much misalignment. On the other hand, I have absolutely no idea how much power it would make you lose. In any case, it would mostly be at pretty much full throttle that it would affect flow negatively.
But, I have a pair of unused JBM industries intake rubbers for BS34, that I could not use with my 34 mm flatslides, that I can let go for 40 Euro+postage from Norway to France.
New price from JBM is $74+shipping from US. See here: http://jbmindustries.com/HOLDERS.html
The bad news is that I am away working until early June, and it may be difficult to get someone else find them and ship them before that.
 
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