Andover Norton Petcocks--Heads up

When I went through my Mk III one of the "systems" I replaced was fuel delivery. I replaced the petcocks, the fuel line and the carburetors, I douched the tank; everything was sub-surgically clean and free of crap. For the first 250 miles all is well; as I begin to raise the throttle for slightly extended periods I find I'm swtiching to reserve. The first time it did this I headed to a gas station and found plenty of fuel in the tank, so I'm thinking that, maybe, I didn't do quite as good a job of cleaning the tank as I thought.

So, fine, I'll keep the tank full, keep both petcocks open and blow everything out at the 500 mile mark, but not wanting to be left without options I call Rabers and purchased a pair of Paioli petcocks, just in case...

Two days ago I start in on the 500 (early---I hate off spec performance), I drained the tank, looking for debris, but nothing. I removed the petcocks and did a visual, the main tap had a passage that was bearly .030 in diameter, bearly larger than the main jets! I stripped it and found that the hole drilled in the brass barrel was significanly offset to the main bore of the valve, causing the restriction. The reserve was properly bored, but had a great intrusion of the neoprene/butadiene sealing material, some of which I found in the screens just south of the carbs.

Needless to say I installed the Paioli's that have "guts" similar to the non-vacuum Japanese types.

Today, after a good warm up--beautiful day in New England-- I headed out to the interstate and found that crusing at 80 MPH (long enough to see a major difference--not long enough to hurt a new engine), on the main tap, produced no symptoms of fuel starvation.

Anover Norton petcock users beware of false fuel starvation issues

RS

RoadScholar said:

I removed the petcocks and did a visual, the main tap had a passage that was bearly .030 in diameter, bearly larger than the main jets! I stripped it and found that the hole drilled in the brass barrel was significanly offset to the main bore of the valve, causing the restriction.

Click to expand...

An all too familiar story unfortunately, the tubular seal type taps often have a poor flow rate due to the seal partially blocking the bore, and in certain cases the seal can rotate when the lever is turned and completely block off the fuel supply! I always run a 5mm drill bit through them first.

The UK made chrome plated brass cone taps which look more or less identical to the tubular seal taps and were the original equipment do seem to be available from certain suppliers once more.

Re: Andover Norton Petcocks-Alternative

RS/LAB thanks for sharing. I hope you sent them bck to merry ole England at the prices they charge.
I saw a set of Bap taps from Map supply out of St Pete, Florida, they looked built like a Mack truck.
When I'm due for taps I think I'm gonna give them a try.
Marshal

Hi L.A.B.
Have you tried the brass cone taps? I did and they either leaked or seized up. Sometimes they would leak and seize at the same time! :?
I will check my Andover taps but I have done 100 mph on one tap, so they cant be bad.
Stu.

I've replaced fuel taps three times in the last 5 years. No matter which brand of standard taps I've used, the rubber boot inside seems to get shredded and pieces of it find their way to the carb filters. I have the Italian made (BAP?) jobbers in there now, let's see how well they last.

MarshalNorton said:

RS/LAB thanks for sharing. I hope you sent them bck to merry ole England at the prices they charge.
I saw a set of Bap taps from Map supply out of St Pete, Florida, they looked built like a Mack truck.
When I'm due for taps I think I'm gonna give them a try.
Marshal

Click to expand...

I fitted the Bap taps and echo the comment from MarshalNorton. I am well pleased.

bigstu said:

Have you tried the brass cone taps?

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My Brit bikes all have a mixture of cone, tubular and BAP taps on them, the tubular & BAP taps cost practically nothing to buy (about £7 each, and you don't get much for 7 quid in the UK these days!) the cones are a liitle more expensive (£12) , so I tend to treat them all as disposable items, if one starts to get stiff or begins to leak, then I just replace it with another one from my "reserve" :wink: stock!

I've always used these, never had a problem with then sticking....and never had a problem with dirt in the carbs etc despite them not being filtered.....good flow too!!

http://uk.rs-online.com/web/search/sear ... &R=486-334

Another satisfied BAP user here. The taps that were on my 750 when I bought it leaked badly. I bought a set of the "tubular" style petcocks and they only lasted a week before the black rubber sleeve started disintegrating and clogging them. I sent them back.

I switched to BAP, no more problems. 8)

Debby