Help me identify/troubleshoot these carbs

[louis]

Hey guys, running a 1973 with stock pipes and air filters and (I think) stock carbs. I didn't trust my RHS carb because it had a broken and repaired float post.

Asked a local guru if he had any carbs for a 1973 and he sent me one, issue is, it doesn't have the two tubes that feed fuel between the two carbs. What did he send me (it's on the right in the photo). My old RHS carb is on the left hand side in the photo.

Can I run this RHS with my original LHS carb and just block the fuel tubes off using some silicone or something? I'm running two petcocks so I'm not sure why it would matter? Or are they just not compatible and I need to source the right year carb?

Thanks

 

[650Skull]

One on the right is an XS1/1B right side carb. The cap on the throttle shaft was on the first 2 models, XS1/1B carbs. Choke mechanism is missing, should be a metal hoop as per the pics in the link.

Lerft carb looks to be the same right side as the other one. 2 right hand carbs, and it could be an XS2/TX carb. Some one else will pop in and confirm

Look HERE

Didn't read your post properly about one of the carbs being yours. link will still help

 

[louis]

Thanks mate. From that link I can confirm that my old carb (left hand side) is a TX and the one I was sent is a XS1. Difference is the dual and single choke I think.

I also realized the brass tube on my old carb is removable, so using some vice grips I pulled it out and fitted it to my new carb.

I don't see any reason these carbs cant work together but if you see a news article about a motorcycle tragedy then you know I was wrong.

 

[TwoManyXS1Bs]

Yes, 650Skull correctly points out your new carb as a 70-71, right side. There's numerous differences to the later 72-73 carbs, and you shouldn't mix the two. 70-71 carbs are fairly rare, 72-73 easier to find.

I suppose you could finagle a way to run it, but due to differences in jetting and, I believe, throttle lever length, they may be constantly out of sync.

We'll look for you in the funny papers...

 

[louis]

It was my understanding that the jetting was more or less the same except one size on the pilots? Yes throttle lever length will be a big issue if they are significantly different, I hadn't thought of that.

Has anyone out there tried to run mismatched carbs with any success? I'll have a go at syncing them today and report back.

 

[TwoManyXS1Bs]

One other thing you may want to check is if your later carb is the E1 or E3 variant. The E1 version has the idle outlet port similar to the '71 carb, with the E3 version having the outlet port moved, which could influence idle matching. Otherwise, you're trampling into experimental territory here...

 

[XSLeo]

Perhaps this will help.
www.xs650.fi/pohja_files/fi/XS650carbs.htm
I think it was in Dutch first, then translated to German then to English. Some of the words may be hard to understand but with the pics and a bit of study it can help.
Leo

 

[louis]

Thanks for the help guys, I checked most of that stuff yesterday like buttferfly size, jetting, throttle lever length, and there were no major concerns. Only thing is I won't be able to use the choke. But the paper fold under the throttle stop can solve that.

installed the XS1 right hand side carb and they were extremely easy to sync. Put about 50 kms on it yesterday and it didn't misfire once. Noticed a slight change at idle, a little inconsistent from 1200-1400. But if anything under load it has really improved. Pulled both the plugs after and they were nice and tanned.

For my standards this is a success so far. Obviously not ideal but in Australia parts are a lot harder to find.

 

[louis]

Rode it 200 kilometers (120 miles) in 30 degrees Celsius Australian sunshine on the weekend with the frankencarb set up. Didn't miss a beat once. Didnt want to kick back over when it was extremely hot but just gave it 5 minutes and fired first kick. I'm still running the original coils so that's an essential upgrade when I get around to it.