Miss November XS2 tribute

Not sure here but on BS 34 there is a float valve with a rubber tip
The operation Up and Down sometimes
binds / sticks Every spring ..but after a while it settles and start open close as it should
I tap on the outside of the carburetor with a screwdriver handle that can help
sometimes drain the float bowl or shut off the fuel feed getting a lower level in float bowl and then open so it rises .
It can take a while ..
On the side stand is not as good as central stand
 
Well, the l/h rear traffic signal finally lost its battle with gravity - the hollow bolt has sheared. First thought, that's gonna be a real pain getting the sheared-off bit out of the threaded stem. Second thought, I've got some stud extractors somewhere . . .

PICT1693.JPGPICT1695.JPG


Wow - that tool you use once a decade finally gets its chance and does the job its supposed to - broken bolt extracted.

On a roll here, took a look at why the signal has always sat skewy-whiff and turns out the cast alloy 'collar' piece is actually busted - hasn't come fully apart but the middle is coming away and sits the stem at an angle. Visited CMSNL to find the part number, did a search and to my surprise found the part, new old stock, in the Yamaha parts packet, for sale on UK ebay, £13 to you sir, so that will be here in the next few days. So will the float valves & needles.

Happy days.
 
Raymond said:
Thank you, IBALT, I've splurged for two, y'know how it is, 48 year old bike, things wear and tear. You get needle and brass valve insert so should be good.
Click to expand...
Always worth hunting down genuine spares for that. I find aftermarket parts unreliable for this, it's a very fine tolerance assembly. They're available from Yamaha but at a much higher price than the same Mikuni part.
 
Well, the postie has been busy, the float needles and seats turned up yesterday, also the alloy collar for the indicator/turn signal.



PICT1699.JPGPICT1700.JPGPICT1701.JPG


As you might be able to see, the new needles are smaller than the old ones? So I took the carbs indoors and used my very useful Captain Scott viewer to check the seats - old one is 2.8, new one is 2.0. I''ll take that to be mm. Hmm, but thinking about it, that not really a crucial dimension - it just means the fuel flow will be a wee bit slower, but as long as I'm not using Miss November for drag racing, I don't suppose that will be an issue?

Anyhoo, going to change both carbs. If one side is worn, the other must be too. Fitting new float bowl gaskets coz I have a pair and this is as good a time as any.

Spot the alloy collar too - at last Missy won't have the rear left turn signal sitting slopey-wise, which gave her a slightly dejected or neglected look.

Bit of carb cleaning, whack em back, should be good to go.
 
Setting float heights.


PICT1702.JPG


And with the new smaller needles, they were way off. Couldn't get hold of the bendy tab with pliers, so i gently used a narrow screwdriver to bend the tabs. A tiny bit at a time. Spec for float height is 24mm, 23mm with the gaskets in. Kept at it till happy it's near enough.
 
Raymond said:
No, but I don't fink they're leaking, gave them a shake when I dismantled the carbs and no sign of any petrol in em.
Click to expand...
FYI the "2" in the Mikuni part number is the needle valve orifice size. All my research suggested "2" is the right part for XS650 BS38 carbs. Which suggests to me that (either I'm wrong or) someone put needle valve seats in with a larger orifice size over the last 45+ years.

Good to see they came in Mikuni packaging too.

(The Yamaha part number 168-14190-20 also says 2mm orifice size and they're still available. That's the "20" in the part number. Same part as Mikuni but 2x the price and in a small Yamaha bag).
 
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Its been a long time said:
I just remembered. MikuniOz (good people) told me that I might have to "shim" the float bowl needle valve assembly with thicker/thinner copper/aluminium seal washer to get the correct float level without excessive bending of the float tang. Seems they were right.
Click to expand...
You've stirred the cobb webs, ISTR twomany delved into this long ago.
 
Well, I'm pleased with today's work, able to get an uninterrupted run at it and put her back together.


PICT1704.JPG


Took er out in the yard and kicked into life. Started easy enough, ran the engine about 6 or 7 minutes at a guess, a bit farty and missing, so maybe the float heights are not correct? But I need to take out on the road and warm up properly, which ain't going to happen till I fix the indicator (turn signal).

Worst case, got to pull the carbs off an have another go at the floats. But at least a job seems quicker second time round . . .
 
Today's plan, if I get the time, refit the indicator, I'll need to make up a button terminal for the bulb. Then take er out for a test ride.

My 3 am concern was, if the carburation is off, how will I know whether it's weak or rich? I had been assuming my buggering about with the float heights has produced a weak condition but now I'm not sure that's a safe assumption.

If it's weak, i need to lower the height? I set it to 24mm so I suppose maybe try 22m?

But if that makes it worse I'll need to go in there again . . .
 
Raymond said:
Today's plan, if I get the time, refit the indicator, I'll need to make up a button terminal for the bulb. Then take er out for a test ride.

My 3 am concern was, if the carburation is off, how will I know whether it's weak or rich? I had been assuming my buggering about with the float heights has produced a weak condition but now I'm not sure that's a safe assumption.

If it's weak, i need to lower the height? I set it to 24mm so I suppose maybe try 22m?

But if that makes it worse I'll need to go in there again . . .
Click to expand...
Float height should be set to the factory figure, Raymond. MikuniOz just warned me that sometimes the seats have a different installed height. But the fuel level in the float chamber should be as per the spec.

If you previously had 2.8mm orifice needle valves installed, I'd say they were actually not correct per Yamaha. A lot can happen in nearly 50 years.
 
Well the indicator is back on and re-wired but it's bucketing down so no road test today. I think the best thing will be to take the bike for a run and see how it goes once warmed up.

Been thinking about the float heights and as you say IBALT it's the fuel level that matters. Might be worth finding/making/bodging a drain plug with a clear pipe and checking the fuel level that way - takes the guesswork out of the equation.
 
Raymond said:
Well the indicator is back on and re-wired but it's bucketing down so no road test today. I think the best thing will be to take the bike for a run and see how it goes once warmed up.

Been thinking about the float heights and as you say IBALT it's the fuel level that matters. Might be worth finding/making/bodging a drain plug with a clear pipe and checking the fuel level that way - takes the guesswork out of the equation.
Click to expand...
I agree.
 
Take IBALT's advice to heart: changing washer thickness is the way forward. over-bending float tabs is the first step in a journey to tuning hell.
When you are in there again, dip your floats in your tea.
Troubleshooting is more often eliminating "could be's" than finding "AHA"s!
 
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