Author Topic: Carb Float  (Read 1338 times)

Offline bobandbec

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Carb Float
« on: 07.09. 2015 16:28 »
Hi
Sorry not directly A10 or A7 but only 987 into the run of the first A65's so very nearly! Hope ok asking this question. Could relate to a10/a7 as well maybe.

Anyway here goes.

I've just fitted a stay up float to my 62 A65 as the float that was in was sticking and flooding.
Is there an optimum petrol level for the float chamber and with fitting the new float (and float needle) is it necessary to adjust it in some way for optimum?
Reason I'm asking is that after fitting the float I've had the bike cut out a number of times on inclines (steepish ones). Didn't have this before putting the new float and needle on. Just coincidence or directly related?
Also when I fitted I noticed the tickler doesn't reach the float at it's top travel so can't flood the chamber on starting or when unexpectedly stops as described? This was the same with the float I took off though as well. Just the tickler too short?
Hope this makes sense.
Thanks

Online RichardL

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Re: Carb Float
« Reply #1 on: 07.09. 2015 16:55 »
Not that I am qualified to answer carb questions, but you might want to tell us what model carb so that those who could help can help.

Richard L.

Offline bobandbec

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Re: Carb Float
« Reply #2 on: 07.09. 2015 17:03 »
Yes sorry.

It's a 389/67 amal from the 1962 A65 Star.

Offline bikerbob

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Re: Carb Float
« Reply #3 on: 07.09. 2015 17:46 »
As well as my A7 I also have a 1963 A65 with the same carb as yours. If the tickler is not touching the float to hold it down look to see if you have any washers under the float needle seating these washers can be bought in a kit to govern the float bowl height they are not always needed. As to correct fuel level in the bowl if you look at the float bowl cover you should see a cast pimple just below and between the M and A in the word AMAL this is the correct fuel level. Now there are various ways you can do this you could try making a perspex cover and putting this on and putting a spot on the outside in the same place as the pimple then fit to carb turn on fuel and see  what level you get, or you could remove the pilot jet cover nut and using a suitable piece of clear tubing that fits tight over the pilot jet bring the other end under the carb and up in front of the float cover turn the fuel on and see to what level the fuel rises in the tube it should level out at the same level as the pimple.
56 A7 s/a
63 A65

Offline bobandbec

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Re: Carb Float
« Reply #4 on: 07.09. 2015 22:56 »
Thanks BikerBob

Can you advise how I would adjust the level if it proves to be incorrect. Is it the tickler/washer adjustment set up or can I adjust the float needle or float itself?

I'll try the perspex cover route to test.

Advice is very much appreciated.

Offline Butch (cb)

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Re: Carb Float
« Reply #5 on: 08.09. 2015 06:52 »
Just the tickler too short?

Ouch.
Warning - observations made by this member have a 93% unreliability rating.

Of Bikes; various, including ...
'58 S/Arm Iron Head Flash Bitza


Offline bikerbob

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Re: Carb Float
« Reply #6 on: 08.09. 2015 11:15 »
The level of the float is governed by the washers or shims under the float needle seating. These can be purchased in a kit from Burlen Fuel Systems who supply all Amal Carb parts. Type Bulen Fuel Systems into google on the Home page at the top click on Amal then scroll down click on monobloc series then your carb 389. In the list of parts they do not show the kit but if you type in the search box the following RKC/SHIM it will show you the kit.
56 A7 s/a
63 A65

Offline bobandbec

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Re: Carb Float
« Reply #7 on: 08.09. 2015 15:31 »
BB -Thank you for your advice.

Offline bobandbec

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Re: Carb Float
« Reply #8 on: 16.10. 2015 18:00 »
Shims bought and perspex test done.
The new stay up float was only allowing the chamber to fill a small amount before acting on the needle to stop the petrol.
Installed the shims required to get the required level as seen through the perspex.
So when used the tickler!! now works on the float as well.
The bike now starts and runs better than it ever has since I bought it a couple of years ago. (touch wood).
Thank you again to BB for his patience in explaining this to me.

I do learn but only very slowly now.
Thanks
Peter