Amal 89B-1AK Carby & SR1 Magneto problems

[Brian 54G80S]

I have an Amal 89B-1AK on my 1953 G80S.
I've cleaned the carby in an ultrasonic cleaner and installed a genuine Amal gasket and seal kit.
Seeking advice on two issues:
1) The washer (6-040, page 15 0f the parts manual) which sits inside the mixing body base leaks when the fuel taps are on. I've tried replacing it. Still leaks. I'm installing the washer dry with no sealant or goo of any description. I've crack tested the components and they are crack free.
2) The engine starts first or second kick and idles like a clock but under mid to heavy throttle it runs rough and doesn't sound right.
Just looking for advice on where to start my trouble shooting with both these issues.

My Magneto cover on the Lucas SR1 magneto is cracked. I bought one from Feked and while it will do the job it is a very ordinary plastic copy of the original item. Is there anyone in the UK who does NOS or high-quality reproduction caps for an SR1?

Getting very close to taking this baby for a shake down ride!

[Duncan]

I
1) The washer (6-040, page 15 0f the parts manual) which sits inside the mixing body base leaks when the fuel taps are on. I've tried replacing it. Still leaks. I'm installing the washer dry with no sealant or goo of any description. I've crack tested the components and they are crack free.

No sealant is correct, could it be that the fuel level in the float chamber is too high or the float is letting by with fuel coming from the holes around the carb body, they can tend to get wet in this location when tickling the carb, does it continue to leak while you are running the engine?

[Brian 54G80S]

Definitely drier after it has started. Ill lap the float needle and check the float height and see if that makes a difference.

[Brian 54G80S]

I have now lapped the float needle and I'm happy that I have minimised if not eliminated any leakage around the bottom of the float bowl.
I have installed the replacement magneto end cover with a new HT lead. I'm still not satisfied with the quality of the cover, but it will do until I find a better one.
Last remaining problem before my maiden ride....
The engine runs perfectly at idle but is rough/8 stroking at 3/4 throttle.
Guidance on where to start with troubleshooting this issue will be much appreciated!

[SPRIDDLER]

The engine runs perfectly at idle but is rough/8 stroking at 3/4 throttle.
Guidance on where to start with troubleshooting this issue will be much appreciated!

I've looked through your earlier topics and can't see whether the bike is new you but to start with the absolute basics........Are you operating the choke and ignition controls correctly?

From the '53 Owners Manual here: http://archives.jampot.dk/book/Owners_m ... ingles.pdf

Controls 1953 G80.JPG

[Brian 54G80S]

Hi Spriddler, thanks for your help, I've been looking forward to your response to my post.
I have only owned this bike for about 6 months. It's been in storage for at least 15 years and has not been started for about 25 years.
While I have not done a restoration as yet, I have systematically gone through each system, lube, fuel, ignition and electrical. It starts first or second kick every time.
Generally, the bike is better than I would have expected and is almost ready for a shake down ride but this rough running at greater than 3/4 throttle is an issue.
My bike only has choke and decompression, there is no control over ignition advance/retard.

[SPRIDDLER]

Hi Spriddler, thanks for your help, I've been looking forward to your response to my post.

Oh dear, no pressure then.

My bike only has choke and decompression, there is no control over ignition advance/retard.

Hmm, well a '53 would originally have an N1 mag with manual A/R control.
Does your SR1 mag have the automatic A/R mechanism? If so, is it working O.K? They have a propensity to be gummed up and stick, in which case it may not be advancing the spark as the revs increase.

At the moment it seems that the issue could be a carburation or an ignition fault but presumably you've checked that it has the correct main jet?
With these conundrums it's always a good idea to begin by fitting a new sparkling plug.

Still pondering.

[Brian 54G80S]

No advance at speed makes sense to me. My SR1 has the auto advance and I have not checked its operation so sounds like that will be a good starting point. My gut feel is the problem is in the ignition system....but....I'm wrong more often than I'm right!
I have:
Installed new plug, checked and cleaned points and set to 12 thou gap, new HT lead.
I have a nice blue spark and the engine starts first kick.

[clive]

The auto advance will not work if the chain is too tight.

[Brian 54G80S]

Can I access the auto advance mechanism to clean and lubricate without removing the magneto?