Floats

LineRider

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Good afternoon long time listener maybe second time caller.....My back story, owned and wrenched on my own motorcycles since i was 17 now 60. I have been a mechanic all my adult life 20 years out of a toolbox and now another 20 years off the tools in management and training so i know a thing or two and i still consider myself as a mechanic.

I bought a custom hard tailed stretched frame non running project (compete and licensed once runner but sat for years) with an XS650 engine, here is my dilemma, I do not know exactly what year model the power plant is nor the carbs. There are no points, no shaft thru the head and it has a black box (CDI unit) original charging and ignition system with a severely molested harness so this is what i know so far. I have since straightened out the wiring everything rewired and what it didn't need was eliminated. I removed and cleaned the carbs and the bike runs pretty well except i know i need at least one new float (they are brass) but it still runs ok till it sinks....... There are no numbers on these carbs themselves to identify what they are exactly. I bought 2 sets of new brass floats from different vendors online based on visual ID and once installed the bowls interfered with their movement and simply won't float (work) so..... to get the correct set of floats either brass or plastic do i simply just measure the inlet side of the carb to decide what MM they are?

This thing after sitting a couple days i can turn the gas on, set the choke, run the kick thru once or twice, turn on the power and one good kick and bam she's a runnin!!!
After a couple mins running on to a test ride she stumbles and sometimes cracks a little but get her past that and off to the races she goes! like i said my first experience with these engines so any good help and or worthy advice would greatly be appreciated.

I will get it ironed out sooner or later because i always do i would just like it to be sooner......

Regards
Scott C
currently own wrench and ride
2013 Harley road glide
2001 Road Star Midnight suicide clutch and jocky shifted
1978 SR500 Bobbed
NOW this XS650 Project.....................
 
Yes, pics of the carbs will allow us to I.D. them for you. But if they are original to the motor, I'd say they are BS34's, and having brass floats would make them a 1980 set. The brass floats used in them are smaller and narrower than the ones used in the earlier BS38 carbs. I'm guessing that's what you bought and they wouldn't fit. I recommend using only genuine Mikuni floats but unfortunately, I think the only place you can get this particular one is from a dealer. But on the bright side, it should be a one time thing, they should last longer than you will, lol. If they are indeed 1980 carbs with the brass floats, you also have the option of switching to plastic ones like the later models came with. Compare prices and you may find them a few dollars cheaper. There's also the fact that they are a solid foam plastic so can't ever develop a leak and should last forever.
 
5twins What I got.....?
 

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Thanks guys for the prompt responses. Yeah i have no idea if these carbs are even correct/original to this engine/year model

5twins you think the plastic or foam floats will work
 
Yes, that's a later linked set of BS38s. If there's drain nipples on the float bowls, which there may be as I see a hose coming off it, that would make them a '76-'77 set. Good news is that all the BS38's use the commonly available Mikuni VM24-171 float. It retails for around $15 but you can often find it cheaper .....

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And no, the plastic floats won't fit.
 
Yes, that's a later linked set of BS38s. If there's drain nipples on the float bowls, which there may be as I see a hose coming off it, that would make them a '76-'77 set. Good news is that all the BS38's use the commonly available Mikuni VM24-171 float. It retails for around $15 but you can often find it cheaper .....

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And no, the plastic floats won't fit.
Thank you Sir, These look just like the replacements i ordered that didn't work because of interference between the float bowls and the cross-bar piece between the two bulbs,
 
I know they fit and work as I have installed some. The pics above are also a comparison of an original bad float to this new replacement. They are identical. Compare the measurements in the 1st pic to those replacements you got, maybe that will show the problem.
 
I know they fit and work as I have installed some. The pics above are also a comparison of an original bad float to this new replacement. They are identical. Compare the measurements in the 1st pic to those replacements you got, maybe that will show the problem.
Good morning, I my referenced my new floats to your first pic and you can see in the first pic the area between the bulbs is too wide, this is the area that was making contact with the inside of my float bowls when I would install them holding the floats up causing the needle to be closed. I ordered a second set from a different vendor and without measuring them visually they looked identical, so I didn't bother installing them. Now with the pic and measurements you provided me I checked the second set, and they are correct!!! A little over 2mm difference in this specific area, that's substantial.

I will be installing these after work today and update.

Thanks 5twins

LineRider
 

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I know they fit and work as I have installed some. The pics above are also a comparison of an original bad float to this new replacement. They are identical. Compare the measurements in the 1st pic to those replacements you got, maybe that will show the problem.
UPDATE........ I installed the other new floats I had (see Pics) set the heights re installed the carbs, cranked it up let it get hot then readjusted my air mixture and it runs great, haven't taken it for a test ride yet as now I'm doing the clutch rod seal and bushing. I had the seals but no bushing so now I have to wait till weekend after next to receive my bushing. It was so sloppy and worn out I am wondering if the rod is the correct one? we will see in a week or so......
 
It's a good idea to "upgrade" to the long one piece pushrod as well. That short outer rod wiggles around a lot in the bushing and seal, causing both to wear out faster. I don't recommend the aftermarket replacement as the quality can be bad (not hardened on the ends). Instead, shop eBay for a N.O.S. original, they pop up all the time. Heck, even a used original is better than that shit aftermarket offering, lol .....

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It's a good idea to "upgrade" to the long one piece pushrod as well. That short outer rod wiggles around a lot in the bushing and seal, causing both to wear out faster. I don't recommend the aftermarket replacement as the quality can be bad (not hardened on the ends). Instead, shop eBay for a N.O.S. original, they pop up all the time. Heck, even a used original is better than that shit aftermarket offering, lol .....

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I have seen some use a one piecee but don't I have to now go thru the clutch side of the case to remove the other half?
 
I have seen that some models have a one-piece rod, but to go that route don't I need to now go into the clutch side of the case to retrieve the other existing half?
I have a book but it's a free bad copy, but I can read, and I can do the job.
 
With the seal out, it's easy enough to pull the ball bearing and inner rod out from the left side with a magnet. If the seal is installed, it may not come out that way. The long rod replaces 3 parts, two rods and the ball between them .....

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Save the ball in case you ever lose the one in the worm gear, it's the same size (5/16").
 
With the seal out, it's easy enough to pull the ball bearing and inner rod out from the left side with a magnet. If the seal is installed, it may not come out that way. The long rod replaces 3 parts, two rods and the ball between them .....

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Save the ball in case you ever lose the one in the worm gear, it's the same size (5/16").
Update: I replaced the two-piece clutch rods with new (OEM Never used from Ebay) single long rod new bushing and seal and so far, no leaks and the clutch adjustment is way different but seemingly easier to pull.

on a side note, there was no "ball" in there which would explain the long clutch adjustment I had? All is good now on to other things.
much appreciated 5twins!

LineRider
 
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