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Discussion Starter · #1 ·
Hi
Has anyone noticed that on the old K0 carbs the needle is held in place with a Aluminium clamping ring and its terminated with a plastic end to stop it moving. As shown on the pic with the arrow there are a series of numbers. On this one its 035000. Does anyone know what they mean, or refer to.
This was from a keyster replacement set as specified for the 13C carb that was used on my 450.
What I am finding is that the Right plug is correct nice biscuit colour and the left is running rich, with nice sooty deposit on the plug. The original needle had 052301. marked on it. Although it was 1978 the last time that that needle was used (the bike was off the road since then) I dont remember that there was any disparity between sides.
I have not tried it out yet when I do I will report back with my findings.
The manual suggests that ther would be a circlip that allos teh raising or lowering of the needle into the Jet, but as you can see, that is not the case.
To pre-empt other questions the main jets are new #125 (both replaced very recently) and the slow run jets are as standard spec also new from the keyster kits.
 

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I can't say anything about the needle numbers - I'm too old to actually see them, so.....
You see all sorts of stuff out there now, most of these carbs have been rebuilt more than once, and folks just put in what's in the carb kit.
I just try to get needles that pretty much look the same and go from there........

There is a circlip on the end of the needle, you just can't get to it.
And the needle is supposed to be kind of loose and floppy, not rigidly locked in place. This allows it to get centered in the jet properly - fluid dynamics take care of that. If it's rigid and the tiniest bit off center or tilted, wackiness ensues.
The set screw will keep it from moving up or down by itself.

Not that any of this helps...........
 

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Discussion Starter · #3 ·
Hi Bill
Im interested that you say that there is a circlip which you cant get to. Is it in the plastic nipple on the blunt end of the needle?
I was only the third owner of this bike, which I bought in 1971, so this would be the first rebuild of the carbs that I have done. I dont believe that they would have been done before but I cant say of course.
You are correct about the floppy fit which I believe allows needle centralisation in the jet itself.
I did try micing up the needle in a few positions and noted some differences in diameters but as its small and also no marks to make exact comparisons from needle to needle, I'm not sure if what I measured was relevant or not.
The old one that I have replaced in the carb seems to be slightly wider maybe this will have an effect of weakening up the mixture a tad. It was in the carb previously so I cant think that it would cause any severe problems.
Whats you thoughts?
 

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there is a circlip which you cant get to. Is it in the plastic nipple on the blunt end of the needle?

Yep, it's in there. I think it might be nylon, I've also seen them in brass.
It would be nice if you could tweak that circlip, but you can't, really.

My thoughts - put the original jets and needles back in - cleaned up of course.
That's what I'd try...........eliminate variables.
 

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Discussion Starter · #5 ·
I agree about tweeking them, that woud be an ideal solution, incedentaly that is exactly what is shown by the drawing in my workshop manual, which I am sure you have seen as well. Just cant understand why they did not make it actually happen, as per the manual, but hey ho.
I have put the original needle back in now, but I havent had an opportunity to even start the bike up since I came back from holiday, (and more about the Grecian bikers in another post, they are truly something else).
As you have seen the carb parts are still on my desk in my office.
I am off for a weeks surfing in the cool atlantic waters of North Devon and a winter wetsuit, so this will have to wait untill next weekend before I get to look at it.(google earth Croyde bay its really beautiful sceenery).
Now the rides there are awesome, but you can't get a board on a bike easilly...... and sadly my wife stoped riding pillion when she was seven months pregnant, I still can't really see her objection. Honestly........ I was doing the decent thing ........ sitting on the tank of, my then, CX500 :lol:
I will post again when I have seen the results of my fiddling.
P.S. I had to use a 6x magnifier to see the numbers too, and the varifocal glasses myself.
 
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