B40 PUZZLED

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Glynn
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B40 PUZZLED

Post by Glynn »

Spent a lot of time on this bike now a Pre65 trials. Electronic ignition, new jets and stay up float. Starts, runs and ticks over on the side-stand but when you pull the bike upright it struggles to go at all. Scratching me head here any help much appreciated.
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Re: B40 PUZZLED

Post by HPbyStan »

Monobloc ?
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Re: B40 PUZZLED

Post by minetymenace »

<135 to the forum Glyn, please update your profile and let us know roughly where in the world you are please.

I guess it is going to be fuel or electrics, please give more details of both....give us something more to go on, I know that some of the guys here are very clever, but only one or two are clairvoyant.
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Re: B40 PUZZLED

Post by beat »

Glynn wrote:Starts, runs and ticks over on the side-stand
it is maybe adjusted for Flattracks only, - turning to the left always....
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Ian Hingley
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Re: B40 PUZZLED

Post by Ian Hingley »

Float level?

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66 BSA Victor Enduro, 72 BSA Lightning, 62 BSA B40 trials, 2015 Truimph Street Twin, 89 H*nda Bros 650, 2000 Aprilia Moto 6.5 Starck
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Glynn
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Re: B40 PUZZLED

Post by Glynn »

HPbyStan wrote:Monobloc ?
Yes Stan it is a monobloc. 376/41. New jets, thorough clean and new stay up float.
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Glynn
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Re: B40 PUZZLED

Post by Glynn »

Ian Hingley wrote:Float level?

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I fitted the new stay up float as it was with front to the front of course. I believe there to be no restriction to movement. Fitted the new brass collar to replace the plastic tube type.
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Glynn
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Re: B40 PUZZLED

Post by Glynn »

beat wrote:
Glynn wrote:Starts, runs and ticks over on the side-stand
it is maybe adjusted for Flattracks only, - turning to the left always....
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Beat
It is a WD B40 that has been geared down for trials. Monobloc carb, new jets and stay up float.
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Glynn
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Re: B40 PUZZLED

Post by Glynn »

minetymenace wrote:<135 to the forum Glyn, please update your profile and let us know roughly where in the world you are please.

I guess it is going to be fuel or electrics, please give more details of both....give us something more to go on, I know that some of the guys here are very clever, but only one or two are clairvoyant.
Thanks for that minetymenace.. It has Boyer Bransden electronic ignition and runs without a battery. If it runs on it's side would it not still run upright if it was the electrics?
Could this be slide or chamber wear in the carb and if so would I be best getting a new one or an alternative carb?
Is there any way of putting photo's on this site.
Sorry for all the questions.
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Re: B40 PUZZLED

Post by kommando »

Stick your old float back in and test, the new float may have dropped the petrol level in the float chamber. Are these new floats adjustable on the Monobloc as they are on the Concentric ? If so there is a pip on the float chamber cover to set the height too, take the cover off the bottom of the pilot jet and attach a short piece of clear plastic tube and loop it up past the pip on the cover, open the tap and see where the petrol comes in the pipe in relation to the pip and adjust the float to get the petrol level with the pip.
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Re: B40 PUZZLED

Post by HPbyStan »

Glynn, that's why I asked if it was a monobloc. It sounded like something with an offset float bowl that caused the level to be off when straightened up.
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Re: B40 PUZZLED

Post by minetymenace »

Glynn wrote:Is there any way of putting photo's on this site
Take a look at this beauty!

OK, might be carb (probably is) but I have seen loose connections only making contact in certain circumstances.....or pickup rotor hitting the electronics...etc
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Re: B40 PUZZLED

Post by hwan »

Does sound like fuel level to me - the beauty of the 'stay-up' float is that you can bend the 'tab' to adjust the level to where it should be.

If you are convinced it carb ................... then it will be electrics :grin:
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Re: B40 PUZZLED

Post by beat »

hi Glynn,

first I would go for carb.

is it too lean ore too rich ?
what says the spark plug ?

if it is too lean, press the tickler whilst getting it upright, - this should help shortly.

if it is too rich it will die evan on the sidestand.

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Glynn
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Re: B40 PUZZLED

Post by Glynn »

Wow! Such a wealth of information, plenty to work on here. Thanks to all for the time, will now set about it with a fresh head on and let you know how it goes.
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