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Unknown Carbs - GS450L

  • Thread starter Thread starter berger
  • Start date Start date
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berger

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Good Morning!

My GS450L seems to have come with carbs that I cannot seem to find any info on. They don't appear to have any vacuum ports on them, and the fuel line connects to the left carb through a banjo fitting. I did have the bike running, without the tank, before I tore it down and I am currently cleaning the carbs. Anyone recognise these carbs?




 
I have a sneaking suspicion someone replaced the CV carbs that came on it with some earlier VM carbs...VM34s maybe?
 
CV means Constant velocity and these are CV carbs. They might be off a Yamaha xs650 1980-84...? but that's a wild guess. goto google or the like and look at Pictures. This sometimes helps...then maybe confirm on CMNSL by looking up the suspect bike and trying to compare...it looks like the fuel connection was possibly modified,judging by picture 2
 
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Rust_to_Redemption said:
I have a sneaking suspicion someone replaced the CV carbs that came on it with some earlier VM carbs...VM34s maybe?
Click to expand...

Thanks for the response!

Doesn't a VM carb have the throttle cable connected to the top? Very distinctive looking? I believe these are still CV carbs, as the throttle cable connects like the other CV carbs I am used to...Ural etc.
 
Can't help you much on ID'ing them but can say they don't look anything like the carbs on my 82 450t. On mine the throttle cable sits between the two carbs and the fuel line is plumbed in between them as well. The outlet (engine side) of them looks awfully small too.
 
One more thing I should add...the choke on the dual carbs is a manual pull on the carbs themselves, rather than cabled to the left hand control.
 
LAB3 said:
Can't help you much on ID'ing them but can say they don't look anything like the carbs on my 82 450t. On mine the throttle cable sits between the two carbs and the fuel line is plumbed in between them as well. The outlet (engine side) of them looks awfully small too.
Click to expand...

Ya, mine has the throttle cable between them as well, but not the fuel line T-connection. How large should the outlet be?
 
berger said:
Ya, mine has the throttle cable between them as well, but not the fuel line T-connection. How large should the outlet be?
Click to expand...

Just from eyeballing it, the same diameter as the inlet. As to the choke, mine looks different but is merely a lever on the side of the left hand carb, no cable with remote knob.

You can probably tell more about what yours are supposed to look like by checking out the parts fische.
 
The GS450 did use two different styles of carbs over the years. The earlier ones were rather unique in the jet arrangement, float bowl gasket, etc. Starting in '83 they carbs looked more like the 'regular' BS34 carbs that were on the 1000 and 1100 bikes, but not quite what you have pictured there. The overall look (but not the details) is pretty close, as is the black paint (which started in '83), but they're not quite right.

.
 
I don't know what they're off either. In fact, I'd pick that they're from a cut down set of four originally.
The fuel line setup is one I've done myself on modified sets in the past. If you don't have a T fitting of the correct length then end feeding the fuel rail is the simplest way out.
Looks to me like some of the original twin set parts are used - the rails mounting the carb bodies could be originals.

If they work when you've cleaned them, I'd use them.
 
GregT said:
I don't know what they're off either. In fact, I'd pick that they're from a cut down set of four originally.
The fuel line setup is one I've done myself on modified sets in the past. If you don't have a T fitting of the correct length then end feeding the fuel rail is the simplest way out.
Looks to me like some of the original twin set parts are used - the rails mounting the carb bodies could be originals.

If they work when you've cleaned them, I'd use them.
Click to expand...

Thanks! That was my suspicion as well.
 
As I hinted in my earlier post these are probably off a Yamaha. A simple search will show you what they are. BS34. Used commonly on early 80's XS 650s and I see, XS400s. The original ones were BS34SS on GS450s. The obvious difference is in the airbox-side air ports.

The fuel connection has been modded to fit the width as noted (again) by GregT.

If they don't run at peak, you might have to get into jet comparisons...

add. I see that BS34 were also used on Suzuki GS400s (and maybe GS425s)which are the earlier (1977) rendition of the 450.
 
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