Engine cutting out at half to full throttle?

Hi,
I am new to this board and to Harleys in general, so I'll start with a little intro....

I have built numerous cars over the past 20 years and now own a '32 Ford sedan hot rod built i 1940's style, plus a '49 Cadillac Fastback (original but lowered)
I do most work in my garage and have a generally good understanding of most any kind of mechanics, making this a great hobby
My goal in life is to try not to die curious, leading me to get a bike license (at the age of 41..... go figure, haha!) and finding a freshly restored '42 WLC. I bought the bike from the widow of the man who built it.
I later found out that he was a renowned engine builder.


To the question at hand!

My bike was never started..... the builder died before getting to that so I had to do minor assembly work before I could start her up.
It started up pretty easy but seemed reluctant to take any kind of revs above 1/3 on the handle.
To make things clear, it has the original Linkert M88 carb, an Edbeyond2000 electronic module in the OEM distributor and I converted it to 12 volt with a new coil and G.E generator with an electronic regulator.

I have tried to ride the bike in 1st gear and opening the throttle..... it stalls and then I have tried to shut the choke a notch or two to force feed it, but no reaction.
I have taken the carb completely apart and found the venturi to have a loose fit, so in an effort to prevent a false air pass I put a layer of teflon tape around the venturi to make a tight seal in the carb bore, which it then had.

As mentioned above, I have no real knowlege in the how's and to's with these bikes as it is all new to me, so I would appreciate some oppinions in relation to my problems.

Thanks in advance, also for a good forum.

Thomas

Copenhagen - Denmark
http://www.traditional-hotrods.dk

Thomas!

My first suggestion is to bubbletest the manifold assembly for vacuum leaks:
http://virtualindian.org/11techleaktest.html

Good luck!

....Cotten

Thank you Cotten!

I will make a pressure tester (sheet of iron, rubber back and a tire valve i guess) and have a go at my intake manifold assembly.

I hope this shows a flaw

Thank you Cotten!

I will make a pressure tester (sheet of iron, rubber back and a tire valve i guess) and have a go at my intake manifold assembly.

I hope this shows a flaw

Let us hope not!

Leaks between the nipples and cylinderheads can be tragic.

....Cotten

That I see from what I read!
But if the leak is at the nuts/brass fittings it must be sealable?

THR!

Please note when bubble-testing that a constant, regulated air supply is required, not just a shot through a Schrader valve; Small fissures will take up to a half-minute to display themselves as blisters of fine foam.
A #8 rubber stopper works best for testing the nipples separately.

If the nipples are sealed, but the brass ferrules are un-friendly, the modern alternative to brass is a material called PEEK.

If the manifolds spigots are un-blemished, with no pits or wear marks, then a set of PEEK seals from http://www.endfieldracing.com/8html will save you time and money.

If the spigots are worn, however, they must be re-cut, and PEEK seals custom-machined to fit. Many shops around the planet now offer this service.

Good luck!

....Cotten

It seems I have solved the problem.

I got a loaner carb that was known to work, but befor installing that I attended the intake issues.
Did a pressure test and of course it was leaking heavily at the front cylinder and a bit at the rear cylinder.
Took the intake to bits and cleaned it thoroughly with brake cleaner (complete degrease) and reassembled, making sure to seal everywhere with heat resistant silicone sealant, especially between the brass and the intake itself.

I then left it to cure for four hours and put the carb back on....... fired it up and it ran good all the way up.
I still need to do minor adjustments and will probably buy a new intake and fittings in the future, but it is great to have her running finally!!

Thanks to cotten for good pointers and great advice!

Thomas

Thomas!

Have you tested the silicone sealer in your local fuel?
Let us hope the problem does not reappear far from home.

....Cotten

Thomas!

Have you tested the silicone sealer in your local fuel?
Let us hope the problem does not reappear far from home.

....Cotten

No Cotten, I have not.
I am though also affraid that the modern fuel will have a desolving effect on the silicone sealer

I rode it 60 miles yesterday and fine tuned it...... had a couple of stops and starts without any problems appearing.

In all, I am no fan at all of these silicone sealants as they were never meant for this application, so a set of new nuts and bushings are in the near future.