Mikuni carbs

[ChrisH]

I have 1977 xs650 D, the carbs on it do not have mikuni logo on them, they are definitely 38's ,problem is on starting it up it will walk across the floor, I have totally rebuilt it but am not sure of the provenance of the carbs.
My question simply put is can I just change the internals with a carb repair kit.
I have been a biker since 1967, current claim to fame I totally restored 1980 Honda 750-4 currently doing the same to a Triumph 900, work in progress if you like but the yamaha is proving to be thought provoker , also would it prove a prudent move to just ditch. I did read with interest 5Twins post if they don't have the logo on the body they are probably fake

 

[Kevin Werner]

Chris, many veteran XS people have identified difficulties with "carb kits". Genuine Mikuni jets and other bits are rather affordable from places like Niche Cycle, Google it. Use the "tech" section at the to0 of the Garage page and use search. The carb section has this https://www.xs650.com/threads/43 which is pretty well put together and has everything you might need. I have become pretty comfortable with my XS in the last year largely to lots of forum help and learning to use the search function. Welcome to the madness.

 

[WideAWAKE]

Post some pics of them

 

[gggGary]

Walking backward is a design feature not a problem! Start bike in garage, gear up, the bike will be waiting for you out in the driveway. :^)
Only half in jest. pics of the carbs?

 

[5twins]

I think the only place you'll find "Mikuni" marked on the carbs are the tops .....

 

[ChrisH]

Certainly got those right enough, have seen them with the logo cast into the body on that note what does "1E1" mean

 

[gggGary]

On the float bowl?

 

[ChrisH]

Not quite, I've managed to source proper mikunis 38's with 1E1 cast on the body, obviously I'll have to service them. 1E1 incidentally is date specific for my Yamaha

 

[5twins]

Yes, there are some letters and numbers cast into the bodies but honestly, I never paid much attention to them. Instead, I've learned to I.D. the various 650 carb sets by their external looks and physical attributes. So, as mentioned, give us some good pics of your carbs (top, bottom, both ends and sides) and we can most likely tell what year they are. It's important to know that, especially when jetting them. You jet them based on the year of the carb set, not the year of the 650 they're mounted on. There were no fewer than 4 different versions of the BS38s used on the 650 over the years. Each set was jetted differently and has minor external differences .....

 

[ChrisH]

Thanks for the info, appreciated, for my bike Yambits advertise 2 sets, the repair kit I will get mentions compatible with 1E1 carbs which I've just bought, did read a post on this forum about fake carbs, I did have a friend of mine look at them he was of the opinion they were not for a yamaha but probably a Suzuki. Once I get the 1E1's I will definitely post pics.