1935 VLD tuning problems

[snafalton]

Motorcycle gurus, please share your wisdom!

This is a 1935 VLD which is stock. The engine starts easily. Both cylinders fire. Good engine power while riding. After warmed up the engine will pop slightly at idle. During riding the engine will pop and cut at speed. Sometimes after warming up if left to idle the engine will stall out after a minute or so. Here are the specs.

Ignition system:
- fresh set of NGK A-6 spark plugs (heat range #3) with a .030 gap
- points set to .022 gap
- flywheel timing mark set to middle of rear half of timing hole
- points open right at ramp of small timing lobe as verified by the ammeter swing
- intake valve tappets adjusted to .005 (middle of Riders handbook spec of between .004 and .006 inches)
- exhaust valve tappets adjusted to .007 (middle of Riders handbook spec of between .006 and .008 inches)

Fuel system:
- Linkert M31
- 87 octane fresh gasoline
- clean tanks
- new fuel line, clean and clear
- fuel filter clean and clear
- float height set to ¼ from bowl top
- needle and seat show no wear and move properly
- low speed circuit clear
- high speed circuit clear
- main jet clear and fully seated in carb body
- no fuel weeps or drips anywhere in the fuel system
- Initial low speed setting is 2 full turns out (I have leaned it down once up to temp)
- Initial high speed setting it 1.5 turns out

[AdminGuy]

Float, float needle? teflon tape used for seal blocking gas line. Check coil resistance and wiring. Anyone else?

[B. Rodencal]

2 turns on the low speed seems real lean to me. Start at 3.5 and see if it keeps starving out. Check for intake leaks and an exhaust leak for the popping

[snafalton]

Float was set to 1/4" from bowl top as the Linkert book suggests as a rule of thumb. The fuel line, tanks, petcock, and filter are all clean and clear. No teflon tape and no leaks. The coil is good, wires are new and good as are the plugs.

I was already thinking about the carb to intake gasket. That might be a problem. I removed the old one thinking it was a homemade one but now that I've seen original NOS ones I know that it was stock. I have a replacement new manufacter one on there now and am not convinced its sealing tight so I might have some air ****ing in there.

As for the initial jet settings, 2 turns on the Idle screw is per the H-D Riders handbook. I've gone leaner but hadn't tried richer so between the intake gasket and a richer idle mixture that's a good start. I'll try it out later this week and see what happens! Keep the ideas coming.

I'd love to hear more tuning tips from VL riders that are out there riding their bikes. I'm trying to get this one running and operating right and realiable. It needs to be ridden!

[AdminGuy]

I agree with Bill. It's sounds like it's starved for gas. And would pop if you had an exhaust leak at the header to barrel.

Do not put locktight on the mano to carb screws. Found that out the hard way. But hey - my little scout is wierd and not sure if my problems apply to anything else.

If someone kicks the bike over- you can place your hand over the carb mouth and see if the gasket is sealing. It will blow/drip gas. As this creates
great suc ktion.

[T. Cotten]

snafalton!

I think Mr. Rodencal nailed it.

Please pressuretest your manifold as per http://virtualindian.org/11techleaktest.html

The carb to manifold interface is best addressed by grinding the manifold flange to flat, and lathe-cutting the carb's flange as well.

....Cotten

[rwrun]

I had a similar problem although with a RLD and after installing one of Cotten's floats it made a big difference. I have the low speed out about 4 turns. The book says 1 1/2 to 2 but 4 works best for my bike.

[T. Cotten]

And one more important thing!

If those NGK A-6 plugs are of modern manufacture, check them for resistance.

If they show any resistance at all, they will only service in modern Wisconsin motors;
With a conventional ignition system, they invariably foul out.

(And NGK will lie to you about it!)

....Cotten

[snafalton]

Originally posted by B. Rodencal
2 turns on the low speed seems real lean to me. Start at 3.5 and see if it keeps starving out.

Well, I finally got back to the VLD. I set the idle out to 4 turns and sure enough, its running properly again! I rode around for a while and then parked it on the side stand and it idles now without stalling out or racing like it used too. Thanks for all of the suggestions everyone. I'll be tweaking the high speed circuit and also testing for vacuum leaks next time I get a chance.