Fuel Pump + float valve size with return loop?

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Adam_Winstone
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Fuel Pump + float valve size with return loop?

Postby Adam_Winstone » Thu Apr 27, 2017 10:31 pm

Hello all,

Rather than post the whole thread here again, filling the forum with my junk (not uncommon!), I'm running a thread in the Lambretta Tech section but wonder if I've got a chance of more informed feedback from the Vespa tuners on here as fuel pumps seem to be far more common in Vespa circles because of the low tank/high carb scenario. Any of you in a position to offer some decent advice please (other than buy a Vespa... I've got one!).

Ta

viewtopic.php?f=7&t=38636

Adam
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Ginch
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Re: Fuel Pump + float valve size with return loop?

Postby Ginch » Fri Apr 28, 2017 1:50 pm

Not sure about your float valve size question.

I've used a vacuum pump and found that it would flood fairly easily. I had a main jet in the return (link between pump out & pump in) and kept upping the size until it stopped flooding - ie reducing the pressure. I ended up using the threaded thingy from a spark plug... the little 'nut' from the top. Never had issues after that.
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Adam_Winstone
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Re: Fuel Pump + float valve size with return loop?

Postby Adam_Winstone » Fri Apr 28, 2017 7:01 pm

^... exactly what I ended up doing too! It seems as though a few of us have come up with this as an idea and, whilst I'm new to this issue, others seem to have used a plug top successfully for some time.

FYI - I've updated the other thread to say that today's ride / dyno / ride home went well and that the return loop seems to have resolved the issue.

Thanks for the reply and info.

Adam
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Ginch
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Re: Fuel Pump + float valve size with return loop?

Postby Ginch » Sat Apr 29, 2017 12:49 am

Great news.
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225worb
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Re: Fuel Pump + float valve size with return loop?

Postby 225worb » Thu May 18, 2017 9:34 pm

Adam ive been using a fuel pump set up on my Malossi 225 for years , its the dellorto type , feed in feed out and a vacume hope to the crankcase...
the float needle jet you need to reduce i think ive a 150 in mine rather than a 300 the standard 30mm phbh uses !!
no problems at all , im sure youll find there are smaller sized float needle valves for other makes ..
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