Float needle valves on Mikuni BDS carbs

[talkToTheHat]

I think I have a problem with the float valve on one of my carbs, bike had a few minutes of running like a wet fart, sorted itself out before I found somewhere to stop, so I pressed on home. Had a good look it, the overflow pipe for the front carb was moist with petrol, but the float heights seem ok. I will check accurately when I can find someone to hold the bike upright so I have enough hands free.

Fortunately the design of the XV535 and the BDS34 are such that I can get the side of the float chamber off with the carbs still in the bike. There was a little bit of debris in the bowl so I cleaned that out, and carefully cleaned the float valve and float valve. The float valve tip has a slightly discoloured ring around it where it seals.

I think I should replace the float valve, unless anyone has some tips on how to inspect and check such. I am not sure how the valve seat removes, the pictures of the part suggest it is not threaded. The BS carbs have a screw on part much like a figure 8 or truncated figure 8, but the BDS carbs don't. (The D in the part code denotes Downdraft). Any ideas? Should I even be replacing such a part?
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Bandit. does. everything.

[Snod Blatter]

It is not normal to replace the seat if you even can, far more normal to just replace the needle. How many miles has the bike done? Is it normal for the seat to wear? I was going to ask if you'd checked out the owners forum but you're there already!

When he says the new needles have a rubber tip, what are the old ones like?
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1994 CB250, 1984 CBX250RS-E, 1989 K100RS, 1995 TRX850, 2016 Z250SL

[talkToTheHat]

Oooh and I have replies there. Looks like my notification email went to spam. I digress.

About 44000 miles.

Tip on mine is hard black stuff that might be describable as rubber. I'm not sure if it has hardened over the years. I think the same needle and seat appear on BS series carbs that are fairly common on japanese IL4s.

I think the seat will stay put unless a new valve doesn't fix it.
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Bandit. does. everything.

[talkToTheHat]

Hmm, careful holding of the bike upright suggests that the fuel is indeed a bit high, like 10mm when it should be 14 (+/- 0.5) mm. (Measurement is distance of fuel below a line cast onto outside of carbs). Have reset and will see where we are at.

I am wondering whether the float heights were last set with the spring on the bottom of the needle (piston like device, not the little wire hook) seized with varnish and 2.5 years of heavy use has caused it to work properly again. Stealership spanner-monkey was known to be lazy, stupid and wrong.

Needle is as pictured
https://cdn.bikechatforums.com/files/needle.jpg
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Bandit. does. everything.