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Allan G, ricochetrider
Total Likes: 6
Original Post (Thread Starter)
#852254 06/23/2021 9:56 PM
by ricochetrider
Howdy folks

My new-to-me 1966 Thunderbolt seems to have a tremendous rattle in the tank. I wonder if there would have been a rubber membrane between the tank & frame from the factory- or if I should add one (seems to make sense)?

Thanks in advance.
Liked Replies
#852732 Jun 30th a 01:37 PM
by edunham
The original floats in Monoblocs can be effected by ethanol. Take off the float bowl cover carefully so that you can re-use the gasket. Do not lose the little spacer on the end of the spindle. Feel the action of the float with your finger moving it up and down. You will be able to tell if it is sticking. If so, replace the float with a new stay-up float from Amal.

Ed from NJ
2 members like this
#852311 Jun 24th a 01:06 PM
by Semper Gumby
Semper Gumby
Hi Tom.

In addition to what was previously said...

Is there a crossover piece under the front of the tank and the frame? There is a post that sticks down from the frame and intersects this cross piece. There should be a piece of rubber on the post or in the cup of of the tank cross piece. If not get some largish fuel hose and cut a short piece that will fit on the post and in the cup snugly. That could be the source of your rattle?

Parts book Reference

parts 23-26 on this page. 24 is called a bracket on page 70. These parts installed properly will help de-rattle your tank. Beware- not installed properly and your tank will crack around the bolt holes on the front bottom of the tank.

Do you have the large tank or the small tank? Picture?
1 member likes this
#852325 Jun 24th a 02:17 PM
by Tridentman
Very important to have the cross brace under the front of the tank fitted.
On the earlier A7/A10s it was a similar arrangement.
I forgot to replace the cross brace on an A7 once.
The noise was if World War III had started!
Think about it--if you take a vertical cross section through the tank it resembles a tuning fork----and that is what the tank is if the cross brace is not fitted.
Worse with the larger UK tanks BTW.
1 member likes this
#852619 Jun 28th a 09:28 PM
by ricochetrider
Originally Posted by Allan G
Sounds like the float is sinking/sticking or plain set wrong.

Are you using the original monoblock or concentric?

it's the original mono block carb.
1 member likes this
#852674 Jun 29th a 05:28 PM
by Allan G
Allan G
If it’s the original carb, make sure you haven’t fitted the fibre gasket under the tickler (this will raise the float level) if it’s a newer one, you can use the gasket as the machining was designed to accept it.

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