carb flooding

PASSAT50 · Post by **PASSAT50** » Thu Oct 25, 2012 3:22 pm

Hi Folks - I recently stripped the monobloc on my 1961 G12 and refitted today. The only unusual thing that occurred during the stripdown was that the metal rod on which the float pivots on dropped out of it's housing. During the rebuild I reinserted this, mounted the float, needle and spacer followed by the chamber cover and gasket. Fitted it to the bike today and it immediately flooded through the 'tickler' mechanism. I then tried a couple of different floats, needles, checked the tickler mechanism but with no improvement. If anyone can suggest what might be causing the flooding I would be most grateful. When the cover is off and I hold the float up against the needle the petrol flow stops, but as soon as I reassemble it starts to flood again. Cheers - Dave

Don Madden · Post by **Don Madden** » Thu Oct 25, 2012 5:43 pm

Could be that the loose pivot pin allows the float to rise too high or puts a side load on it that jams. Remove the pin, clean the hole with brake cleaner spray & use Lok-tite to bond it. Besure the pin is correctly located until the cement sets & leave overnight. Also, do you have a fibre washer under the float seat? New Amal carbs use one but the originals do not. Cheers, Don.

robcurrie · Post by **robcurrie** » Fri Oct 26, 2012 5:07 am

It could be the cover clamping the float if you changed the float, spacer or gasket and the spacing works out differently.

Mckorkins · Post by **Mckorkins** » Fri Oct 26, 2012 11:04 am

Don't suppose the float itself has been punctured by any chance? Worth checking - and make sure it's fitted the right way up!

PASSAT50 · Post by **PASSAT50** » Fri Oct 26, 2012 9:25 pm

Thanks again for all your helpful advice; I've given up with the carb after another day of frustration and ordered a concentric set up to the correct jetting from Surrey Cycles. Best Wishes - Dave

rayswadling · Post by **rayswadling** » Sat Oct 27, 2012 12:28 am

rayswadling · Post by **rayswadling** » Sat Oct 27, 2012 12:35 am

Oops..clicked wrong button.

Probably not much help now you have orderd a replacement, but did you use an Amal repair kit to refurbish the monobloc?
Just I did and had same problem.
If I recall, it was something to do with the washer under the float needle housing where the banjo fits.
I "think" the problem is that the new repair kits don't have a replacement fibre washer for under the housing. So when put back together without one, it constantly hold the float needle off its seat.
I was told new manufacture of these housings are longer and do not need the washer so one isn't in the kits.
I resued the old one and problem solved...

Ray.

dave16mct · Post by **dave16mct** » Sat Oct 27, 2012 10:38 am

You've got that the wrong way round. The new carbs have the washer under the banjo housing. The old carbs don't have a washer there. Dave

Don Madden · Post by **Don Madden** » Sat Oct 27, 2012 6:01 pm

The old float valve seat was a sharp angle step. The new type is chamfered so the needle seats deeper requiring the extra washer to adjust float height. Cheers, Don.

Mckorkins · Post by **Mckorkins** » Sat Oct 27, 2012 7:31 pm

Your right Don, I found that on mine and adjusted accordingly.