E: Engine What Else Can I Check On My 289's To Deliver Fuel

[CarlHungness]

There are 16-17 pages written by myself and helpful members in an attempt for me to re-start and keep my Shadow
running I've posted on the forum so far. I finally knackered the kick-start spring, an end broke and the new one should be
here tomorrow, so it's back to square one.
Near as my abilities allow, the bike is now timed at 35 degrees BTDC with a rebuilt mag with old ATD that seems to be
in good working order. The new one I ordered had a washer fall out of it, so I returned it and followed the Lucas installation
instructions on just how to tighten up the (old with new springs) ATD: one uses the center bolt and not necessary to 'set' it with a socket as I had previously done. Now, I'm pretty confident the mag/ATD unit is working as it should.
To recap, I got the bike running with the old B-TH, and it was 'missing'...sounded rough. Couldn't re-start. Got it
running with the Lucas, for 30 seconds, sounded great, died, had the Lucas rebuilt, started again, ran for 60 seconds,
sounded normal, died, couldn't re-start. Timed it at 6 degrees BTDC, couldn't start it. Re-Timed at 35 degrees, didn't
start, KS spring broke.
It just 'feels' like the plot is not getting fuel, and having it die after sounding normal seems to point to fuel
starvation. I did check float levels and they sure seem to be within operating range. Have replaced the jets, cleaned
the pilot holes in the jet blocks with a #76 drill, put the parts through an ultrasonic bath.
Thus the bike sits now at 35 degrees, have 'tested' the rear spark plug by holding it on my Britax bar, kicking it over
and see spark. Journeyman Doug Wood went through the mag so as noted, I think all's OK.
Anything else on the carbs I can check to see if I'm actually getting fuel? Shouldn't I see wet spark plugs when I remove
them after trying to unsuccessfully start it?
Compression is 90, and last I checked it years ago, after Bill Jean put spacers under my cylinders (because pistons were
just touching the valves) it was 90 then..and I've ridden it about 35,000 miles since. In between, Glen Bewley did a re-bore, a
top end job and I re-assembled the plot, and it ran per usual.
It's reached the unreasonable point of, 'it ought to start and run.'
Now that I know the machine ought to register in the 150 lb range on compression, I'm saddened Bill Jean had to resort
to installing the spacer plates, and would like to rectify the situation in the future. The point here is it has fired and sounded fine
a couple of times in the last month, and can't locate the gremlin that is making it run out of fuel. And or the one that is keeping it
from getting fuel in the first place. If it's starting on 90 as it had, compression doesn't seem to be the problem, and if it started and
sounded OK momentarily, compression wouldn't be keeping it from getting fuel.
So once again seeking suggestions.

 

[chankly bore]

Carl, I have followed your trials with a good deal of sympathy. The first thing I'd do is check the fuel tank vent or remove the cap itself. Then I'd follow through to the fuel taps, pipes and then to the cross drilling on the float bowl arms- either covered by a 2BA or 1/4" BSF setscrew. Then check the pilot drilling on the bottom of the jet block with a no. 76 drill bit or a single strand of control cable wire under .020" diameter. As mentioned before, this should not be obstructed by the jet block washer, this washer 7/32" wide maximum. Remove the pilot air screw and blow it through, you should use a bit of kerosene here to see if it blow up to the inlet tract and down to the jet block. Have you the right needle and needle jet? Needle should have "29" on it, 5 grooves and 3 3/16" overall (check this information, as it is from the Internet.) I seem to remember the standard needle jet is a 106.

 

[brian gains]

The tank doesn't have a liner that's delaminating and blocking petcocks ?.

 

[CarlHungness]

Carl, I have followed your trials with a good deal of sympathy. The first thing I'd do is check the fuel tank vent or remove the cap itself. Then I'd follow through to the fuel taps, pipes and then to the cross drilling on the float bowl arms- either covered by a 2BA or 1/4" BSF setscrew. Then check the pilot drilling on the bottom of the jet block with a no. 76 drill bit or a single strand of control cable wire under .020" diameter. As mentioned before, this should not be obstructed by the jet block washer, this washer 7/32" wide maximum. Remove the pilot air screw and blow it through, you should use a bit of kerosene here to see if it blow up to the inlet tract and down to the jet block. Have you the right needle and needle jet? Needle should have "29" on it, 5 grooves and 3 3/16" overall (check this information, as it is from the Internet.) I seem to remember the standard needle jet is a 106.

Thanks so much for sharing the dilemma. I've done all you note. The cross drilling bolt is 1BA, I just took it out to insert a fitting I made to check the float level, and didn't have a 1BA die so I used filed brass tube, and a bit of teflon tape to make a perfect seal. I've been through the jet block three times with the #76 drill and then ultrasonic cleaner. I have the same size jets, new now, as I've run for over 20 years, same needles in the second groove and installed new jet block washers too. Baffling scenario. Will check the new jet block washers, but it seems as though the original problem, whatever it was-is, still exists.

 

[CarlHungness]

The tank doesn't have a liner that's delaminating and blocking petcocks ?.

Hi: No liner and always run the carbs dry when I shut it off through the years as I recall Prof. Higgins told us today's fuel can lose its sparking qualities in a short period of time, so I've always made sure there is no fuel in the carbs.

 

[teunvandriel]

Hello Carl, I sympathise with you.... I'm sure it's nice where you live in the USA, but your living situation is a bit different from where we live, Holland, we live like herrings in a barrel (Dutch expression), a bit overcrowded here, but the advantage is that if I have a Vincent problem I can get on my bike and cycle to one of my Vincent friends a few minutes away to ask for advice, or borrow something, or ask him to come over.
My impression is that it's something simple going on with your Vin, but what?
I used Suzuki pistons for years, found them ramped (others love them) now I use CP pistons, with those Suzuki pistons I always had to work out the valve recesses with a hand router and Dremel until the valves were 1.5 mm clear of the piston, to check this I used modelling clay, but it's a lot of work.

 

[Bill Cannon]

You've checked the float levels with your plastic tube.
Do this again, then if OK, turn taps off, drop the tubes to drain the float chambers, raise the tubes then turn taps back on. Chambers should refill within 10-20 seconds. This will prove you have adequate flow. Good luck!

 

[CarlHungness]

Hello Carl, I sympathise with you.... I'm sure it's nice where you live in the USA, but your living situation is a bit different from where we live, Holland, we live like herrings in a barrel (Dutch expression), a bit overcrowded here, but the advantage is that if I have a Vincent problem I can get on my bike and cycle to one of my Vincent friends a few minutes away to ask for advice, or borrow something, or ask him to come over.
My impression is that it's something simple going on with your Vin, but what?
I used Suzuki pistons for years, found them ramped (others love them) now I use CP pistons, with those Suzuki pistons I always had to work out the valve recesses with a hand router and Dremel until the valves were 1.5 mm clear of the piston, to check this I used modelling clay, but it's a lot of work.

I inadvertently had to do the same thing after Bill Jean rebuilt my engine. It seemed to run OK, then broke a rear
rocker...and then another one. I called him and he said, "Oh I was afraid something like that might happen." Thus I tore it apart, put clay on the pistons, etc..and figured out the valve was kissing the piston. Took it back to him, he and Sid Biberman charged me to fix it, and on an on.

 

[chankly bore]

Have you checked the pilot orifice in the inlet tract?

 

[CarlHungness]

Have you checked the pilot orifice in the inlet tract?

Not certain I understand inlet tract, but if you are referring to the jet block in the carb, I've had them out five times, have cleaned the .021" hole with a #76 drill, put all parts through an ultrasonic cleaner, baptized them, re-assembled and did it all again another four times. Replaced the jets, slides are 3.5 and not wobbly. Checked float levels which sure seem OK, are at the bottom of the air screw. This is the single most baffling circumstance I've encountered in over 30 years of ownership. Ace Vincent rebuilder Glenn Bewley will have a look at it next weekend, and so far he's flummoxed. Maybe 'something' inside has slipped, but rudimentary checking of cams shows they are where they should be, but it seems like it's not getting fuel..can't really tell as the spark plugs are getting wind each time it is
kicked, so they haven't been wet and I thought they should be. Have cleaned tank, fuel lines, and on and on..over 50
hours thus far.