Author Topic: Vhb30 carbs gushing fuel after rebuild  (Read 1556 times)

Offline Joshtjeerdsma

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Vhb30 carbs gushing fuel after rebuild
« on: September 29, 2016, 11:02:19 PM »
I went to fire the bike up tonight after a lot of work and after 15-30 seconds with the fuel taps on,both of the carbs started gushing fuel out of every opening. I rebuilt them following Gregory Benders directions to the T. I also replaced the floats and needles. I checked the float heights and they were good. It seems like the floats and needles arent stopping the fuel flow and the carbs start gushing everywhere. Any ideas? Thanks
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1974 Moto Guzzi 850t

Offline Kiwi_Roy

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Re: Vhb30 carbs gushing fuel after rebuild
« Reply #1 on: September 29, 2016, 11:54:46 PM »
If you aren't careful when bolting the bowl on the "O" ring jumps out and holds the float down.
It just jumps off in one spot, I found if I held it down with a knife it goes on and stays put.
The other method is to stick it in the grove with some stiff grease or cement.
I'm talking about the large one that goes all the way around the outside of the bowl.
« Last Edit: September 30, 2016, 07:09:56 AM by Kiwi_Roy »
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Offline guzzisteve

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Re: Vhb30 carbs gushing fuel after rebuild
« Reply #2 on: September 30, 2016, 08:57:12 AM »
The floats can hang up on a dry carb, make sure they are spread wide enough to clear but not hang up on the outside and that the pivot pin is fully in. If you used the white floats all bets are off.
You could rap on them w/wrench also once gas enters the bowl to see if they free up.
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Offline Groover

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Re: Vhb30 carbs gushing fuel after rebuild
« Reply #3 on: September 30, 2016, 09:28:02 AM »
Are the needles the correct replacements (same length)? Was there a reason to change the floats or did you just change them as routine part of the rebuild? The black factory ones are good, I keep hearing about faulty white ones. Not just for Guzzi, but pretty much any Dellorto carb that I've worked on. I rebuild a lot of Vespa carbs, and the white replacements are "shitty" for a lack of a better term... the filter/screen too; I try not to replace those unless they are ripped.
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Offline Joshtjeerdsma

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Re: Vhb30 carbs gushing fuel after rebuild
« Reply #4 on: September 30, 2016, 09:49:25 AM »
I checked the needle in one of the carbs and it is the right length and identical to the old ones. I did use the new white floats as I have always thought it was good practice to replace floats and needles. The old floats where a yellowish color. I have the old floats and I can try them.
1972 norton commando production racer project
1974 Moto Guzzi 850t

Offline Joshtjeerdsma

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Re: Vhb30 carbs gushing fuel after rebuild
« Reply #5 on: September 30, 2016, 04:10:02 PM »
I put the one good old float in and I lighyly sanded down some excess plastic on one of the new floats. Now the floats dont stick and the carb doesnt leak! Now on to final carb tuning and breakng in the new cylinders. Thanks again.
1972 norton commando production racer project
1974 Moto Guzzi 850t


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