Unable to get reliable tickover

[Bill Thomas]

Hello Howard, I cut the back out of the needle tube and it messed mine up, Just put a full tube back in and it feels much better, I am only 28mm carbs but mk2 cams and 9 to 1 pistons. I also found the stay up floats were touching the carb body above !! I had set the floats with petrol in to what Amals said but now lowered it a nat's. Cheers Bill.

 

[Chris Launders]

I had already done the float levels and needle jet tube Howard.Been out and done 30 miles, just had to make minor adjustments to the tickover speed and is much crisper on pickup and shut off,also pulling much smoother at really low revs.
The plugs are a dull black/brown suggesting it is too rich on the needle but I had better check them out on the open road as the last mile or so was very slow traffic.thanks for everyones input.

 

[Howard]

Hello Howard, I cut the back out of the needle tube and it messed mine up, Just put a full tube back in and it feels much better, I am only 28mm carbs but mk2 cams and 9 to 1 pistons. I also found the stay up floats were touching the carb body above !! I had set the floats with petrol in to what Amals said but now lowered it a nat's. Cheers Bill.

Like we all keep saying Bill, they're all different. I've got old style floats, and moved the seat to get the float height right. Wouldn't it be nice to make all Vin engines the same, so we could just look up all the setttings in a book??????.....NO!!!!!!!

Chrislaun, Sid Biberman has one more Mk1 mod - blending the square block in the opening into the taper (not explained well). It's not necessary with my bellmouths, so I haven't tried it, but if Sid says it's worth it, who am I to argue.

H

 

[Chris Launders]

Hi Howard,I understand what Sid means,any sharp edge disturbs air flow,I have seen the same sort of thing done on SU carbs.Went to East Midland meet today about a 90 mile round trip,stopped a couple of times to check plugs,still matt black.
The bigger pilot jets must be richening the entire range so I have changed from 106 jet-top needle notch to 105 jet-middle notch.Forgot to mention I'm using K&N style filters.