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Post by Deleted on May 13, 2018 19:33:46 GMT
Who's clever enough to know what this is all about?  |
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Post by BritPete on May 13, 2018 19:49:33 GMT
I accept I am a thicko
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Post by Deleted on May 13, 2018 19:52:58 GMT
You and me both..... I know what it is called (accommodates) but it stops there. |
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Post by buster on May 14, 2018 8:24:50 GMT
I could well be wrong but I 5hink its to do with california’s emmissions laws. I dont pretend to know how it works but I think it links up as part of the fuel tank system (all those funny pipes and gubbins coming from/to the tank) and what its supposed to do is stop fuel evaporating into the atmosphere. my nighthawk has the same set up, the tank pipes have long since been done away with and I have so far dealt with the little chamber by the simple technique of ignoring it, it shouldnt have any effect on running if you just put it back together and forget about it. as always I’ll happily bow to anyone who knows more about this than I do and any other information would be welcome, as I already said my bike has the same set up
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Post by Deleted on May 14, 2018 10:36:27 GMT
It's known as an accelerator pump I understand? The part that bolts on it that is. Can get a pic in a bit of the whole assembly.
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Post by buster on May 14, 2018 11:26:05 GMT
just had another look at mine, all it seems to be is a valve that operates as an on off switch as soon as you pull on the throttle. I’m guessing this opens and allows the natural suction of the carb to pull fuel vapour from the petrol tank (there should be a rubber pipe coming off the underside of the tank somewhere, probably near the front, this then connects I think to the manifold side of the carb) where it is then supposedly burnt off in the engine, as I said before califoria emmissions laws and most of what I’v ever read about these systems (which is admittedly not much) suggests that theyre a load of nonsense that dont really work. mines simply blanked off at the carb with a bit of rubber tube and a bolt in the end.
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Post by Deleted on May 15, 2018 9:14:49 GMT
just had another look at mine, all it seems to be is a valve that operates as an on off switch as soon as you pull on the throttle. I’m guessing this opens and allows the natural suction of the carb to pull fuel vapour from the petrol tank (there should be a rubber pipe coming off the underside of the tank somewhere, probably near the front, this then connects I think to the manifold side of the carb) where it is then supposedly burnt off in the engine, as I said before califoria emmissions laws and most of what I’v ever read about these systems (which is admittedly not much) suggests that theyre a load of nonsense that dont really work. mines simply blanked off at the carb with a bit of rubber tube and a bolt in the end. A lot seemed to happen on the US bikes from 1980 to comply with emissions laws.
Just out of curiosity, are your carbs VB22, Buster ?
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Post by buster on May 15, 2018 11:01:49 GMT
now your asking I wouldnt actually have a clue. if you know how to identify them Ill be happy to have a look for you
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Post by Deleted on May 15, 2018 12:16:50 GMT
There will be a serial number on the left hand side of them.
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Post by listey on May 16, 2018 6:34:20 GMT
Accelerator pump as you've already suggested.
There should be a diaphragm in there, either vacuum operated or mechanically operated with a plunger. It provides an extra squirt of fuel to briefly richen the mixture when the throttle is snapped open.
Likely standard fit on US bikes as they will be set-up very lean to comply with california emissions regs.
Cant be sure without looking but I think my 400 dream has them.
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Post by Deleted on May 16, 2018 9:07:24 GMT
If they are VB21 they probably won't have it, Listey. VB22 seems to have it (and others).
Let us know if you can.
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Post by buster on May 16, 2018 9:12:50 GMT
If they are VB21 they probably won't have them, Listey. VB22 seem to have them (and others). Let us know if you can. mine from what I can see are vb 2eb(cant read the numbers and letters after that). listey’s post sounds spot on as when I move the throttle on mine this triggers the plunger (quite close to the mechanism for the choke) and would make perfect sense ie lean for emmissions on tickover then proper running when you open the throttle. |
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Post by Deleted on May 16, 2018 9:55:33 GMT
I've been informed that VB31's (CB400N carbs) will work equally as well in place of the VB22 - from memory they are 32mm rather than the 30mm.
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Post by listey on May 16, 2018 11:17:45 GMT
If they are VB21 they probably won't have it, Listey. VB22 seems to have it (and others). Let us know if you can. VB22 seems to ring a bell, but it's a few years since i was inside them. Could be anything fitted on that bike as it's a bit of a mongrel. Bikes rotting away (I mean hibernating  ) at another garage away from home but due to go and rescue it shortly so will post findings. |
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Post by buster on May 16, 2018 11:25:50 GMT
I've been informed that VB31's (CB400N carbs) will work equally as well in place of the VB22 - from memory they are 32mm rather than the 30mm. that would all tie in with the emmissions stuff previously mentioned in this thread. smaller bodies with the accellerator pump vs normal carbs without. I’m going to leave mine as they are unless they turn out to be problematic, just because its the 450 model and I’m far to lazy to start messing around with jet sizes etc. |
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) at another garage away from home but due to go and rescue it shortly so will post findings.