Comet with 10TT9 Amal

craig

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I ran the Comet for 7-8 miles yesterday. First road time since 1969. 50F sunny weather. Started with comp closed, i opened the comp and it smoothed out quickly. No idle , must blip as needed.
1-3/16" 10TT9
109 needle jet
#7 slide
320 main

My concern is gasoline leaks out the three air holes at the carb base when coming to an engine shut off stop. I think the float needle is leaking thru. I dont see spares for this fix, can i use some grinding compound to seat the soft aluminum needle in the soft seat? Or what is best?
The three air holes actually look like they are below fuel height of the float bowl.
Any 10TT9 experts out there?
Thanks
Craig
 

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A-BCD

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I have these on both of my twins, I use 340 main and No 5 slides. I put a small fibre washer underneath the float needle to lower the fuel level a little. Fuel shouldn't leak out, try a little twirl with metal polish to re-seat the float needle. I also cut some slots in the back of the slides to give a tickover. Great carbs !! Cheers, Brian
 

davidd

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Craig,

I use a remote float so I do not have much experience with the fixed float bowl. In my experience what you describe occurs when the float level is too high in a remote bowl. However, it seems to me it would also occur if the needle and seat are leaky, because the carb in both cases is receiving too much fuel. Grinding seems a reasonable option, but it would be nice if someone who has done it would chime in. It might be useful to check the seal with the float bowl off to verify the problem. You can also mark the height of the fuel and check it for a match to the carb.

I have used both Burlen and Surrey Cycles for spares. I tend to prefer Surrey because I can call them and chat about the problem.

http://www.surreycycles.com/index.htm

David
 

len.c

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I prefer to use a fine metal polish rather than grinding paste,Or better still jewellers rouge (if thats how you spell it} Len.c
 

craig

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First i used toothpaste - did not seal
second was white mild paint compound - did not seal
third was red paint rubbing compound - did not seal
i can inspect the needle with magnfying glasses, there appears to be a nice contact band.
i cannot see the seat very well, but will try different lenses tomorrow
i am moving up to fine valve grinding compound - tomorrow

bike runs okay simply drools everywhere, kinda like me!

Cheers
Craig
 

A-BCD

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Hi Craig,

presume you have checked that the float bowl is vertical - they are very sensitive to being a couple of degrees out, in my experience !! There's enough material at the banjo on the type 302 float chamber to allow some adjustment. Cheers Brian
 

craig

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302 float bowl angle

Hi Craig,presume you have checked that the float bowl is vertical - they are very sensitive to being a couple of degrees out, in my experience !! There's enough material at the banjo on the type 302 float chamber to allow some adjustment. Cheers Brian

Well, It is a 3°deg 302 float chamber and it should be 0°deg.......this aint easy for me to correct. Are there 0°deg 302 for sale anywhere? I see 302 listed at Amal, but no link. I will lift the tail today and see what happens. Thank you, but i hope not the issue.
Craig
Amal302FloatChamber.jpg
 

davidd

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Craig,

Zero should be the easiest to get. I do know someone who has one that may be available. Drop me a line.

David
 

A-BCD

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With judicious use of a fine file you should be able to correct it by at least 2 degrees at the banjo. Then add extra fibre washers as necessary.
 

craig

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VOC Member
i used Clover brand Fine lapping compound on needle and seat and it appears to have slowed the bowl leak thru to one drop every 15 minutes. When this float needle leaks thru it definately weeps out the 3 lower air holes. pull the bowl top and over fill the bowl and it leaks same.
I did have another leak at the taper fit of the bottom main jet cap , but have resolved that with short spin of both pieces and 600 grit paper.
Out for more testing today. Finding loose nuts and bolts........retorqued head...etc
Cheers
Craig
 
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