Author Topic: Nasty Cough...  (Read 134 times)

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Columbia13

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on: June 22, 2022, 02:33:38 pm
Hi
Can any of you kind people out there help me, my 2008 350 CI bullet frequently coughs through the carb when I shut the rev's off.
Amal 626 carb
Hitchcocks pancake filter
Standard exhaust
I have assumed the cause is a weak mixture, but there is no air getting in anywhere that I can see.
I have turned in the air screw on the carb.
Is there something else obvious I should try?
The bike runs fine on the throttle otherwise.
Thanks a lot
Michael
 
 


Carl Fenn

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Reply #1 on: June 22, 2022, 04:23:17 pm
Well you could try stripping the carb inspect it and check valves and carb connection.


Adrian II

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Reply #2 on: June 22, 2022, 10:04:10 pm
Maybe it needs a richer carb slide, e.g. a 3 instead of a 3½?

A.
Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


Carl Fenn

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Reply #3 on: June 23, 2022, 09:41:39 am
Could be a hard to trace air leak but in saying that l have run plenty of brits with bellmouth with no issue at all, l would strip the carb and clean inspect and readjust check jets look at valves l have had bikes spit back it was always normally a valve issue. Another thing you could look at is the throttle slide and bore leaking to much air l have had them wear out in as little as 8,000 miles on a triumph one of their symptoms.
« Last Edit: June 23, 2022, 09:49:36 am by Carl Fenn »


Adrian II

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Reply #4 on: June 23, 2022, 08:33:48 pm
You can get heavy brass slides, possibly some hard chromed, these will last a lot longer.

A.
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Carl Fenn

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Reply #5 on: June 23, 2022, 09:06:51 pm
Yes l know but back in those days l had money so l just bought brand new carbs, l know they were repairable but as l remember not that cheap.


Columbia13

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Reply #6 on: June 24, 2022, 11:34:59 am
Thanks for your replies lads.
I have checked and cleaned the carb so I don't think that is the cause. It was fitted (badly) by the previous owner and is virtually new. When I got the bike the carb had been over tightened and the flange was a bit bent, but I have had this straightened and I am pretty sure the seal on the inlet is good.
The bike has done less than 2K kilometers from new so I'm hoping the valves are ok.
I had thought myself that a richer slide might be the answer, does anyone else have to use a no 3 on theirs?
Cheers


Carl Fenn

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Reply #7 on: June 24, 2022, 12:32:06 pm
Might be worth checking the flangers again with a straight edge one of mine on head side was once warped on triumph.