1931 Harley VL valve guide to valve stem clearance?

[Buster]

Need the VL valve guide to valve stem clearance spec. I've looked in Steve's book, Rider Handbook, and search this forum; but cannot find it. Guessing it would possibly be same as UL but not sure. Thanks!

[T. Cotten]

Need the VL valve guide to valve stem clearance spec. I've looked in Steve's book, Rider Handbook, and search this forum; but cannot find it. Guessing it would possibly be same as UL but not sure. Thanks!

I know what its like for a question to get crickets, Buster!

UL specs sound rational...

.....Cotten

[Kent Bennett]

Buster, I bought a reamer that should yield a clearance of approximately .0035" to .0040". Thanks for your help. You set a great example for up-and-coming antique motorcycle enthusiasts.

...Sparky

[Steve Slocombe]

Dear Buster, my recollection is that 3.5 thou is the minimum clearance. The repro valve guides seem to give 10 thou clearance and I'm OK with this. The more engines I build the looser they get. Harley built them tight with a 1000 mile break-in period, but nobody will do that today.

[Tommo]

I'm sure I've posted this before but here is the chart from Nicholson's " HD settings and clearances.jpg Modern Motorcycle Mechanics"

[Buster]

Thank for replies.!

[Steve Slocombe]

Thanks Tommo. Many owners have built the engine too tight by using the T-slot piston clearances when they need to be looser for the strutted pistons. The early magnesium pistons needed 18 thou clearance so no wonder they were noisy when cold.

[cHarley32]

Bought a 32V a while back and pistons to tight. Scored the cylinders and the connecting rods where installed reversed. Still has baffles not sure if just to tight or lack of oiling.

[Steve Slocombe]

Yes, the forked rod goes at the front on the VL. I'm guessing that your '32 was another VL engine built too tight. Those Nicholson clearances also look to be on the tight side. Note the repro VL pistons are not made to the original 3.422" bore but to the nominal 3 7/16" bore.

[cHarley32]

Yes thanks for reply Steve. The builder had experience with Evo and newer Harleys. It’s what he new. I got your book and still getting part’s together. Will have more posts and questions later.

[Tommo]

What a lot of people seem to lose track of is that these are 80 to 90 year old designs and they try and use 21st century technology in them and then ask why are they failing.
Old air cooled, side valve motors with virtually no oiling to the valve guides are accidents just waiting to happen if you use K liners, Stainless steel valves, etc, etc.
All the above are designed to be used in positive oil flow situations that you don't have in a J, VL and UL motor.
Piston siezures using modern clearences and oil control rings are quite understandable as the design of the motor is for oil to be left on the cylinder wall to prevent such troubles but if you scrap that oil away a siezure is almost certain to occur..
Harley said that after periods of overrun you should see "A light blue haze" from the exhaust as you accelerate and it is that oil that assists with the lubrication of among other things the valve guides.
This subject is miles too big to discuss single finger typing but my word of caution is that if you are going to introduce modern technology make sure their design parameters are in keeping with where you are going to use them.

[RichO]

Tommo your words ring true. I rode many hard and fairly fast miles for more than a few years astride a Super X and a 101 Scout over hill and dale. I never used oil rings and 4 to 5 k on piston clearance. Made a slight noise till they warmed up which was fairly quick and quieted right down. I know riders with stock Henny's and such would go to ten. If pump was adjusted right I never used the hand pump. on steep climbs if geared in the middle ratio you could run the throttle just short of the stop and feed in a little retard to take out the lug. With bushed early motors they get enough oil. I remember when in the sixties guys loved to put the new shovel pumps on their knucks and they over oiled. They didn't need 30-35 lbs. Harley books stated something like 1 and a half K on early overheads but breakin had to be slow and easy. If you built it for a young hot rod heavy handed kids you needed close to double that.

[Steve Slocombe]

I forgot to say that all the Harleys were built without oil rings until about 1940. I started building VLs with no oil rings on the poorly lubricated front cylinder, and the last two motors were built with the modern strutted pistons and no oil rings front or back. Piston clearance was about 6 thou front and 5 thou rear and so far so good. That's why the VLs over-oil at the factory oil pump settings, because a modern rebuild will use practically no oil compared with when they were originally built.

[cHarley32]

I have already bought replacement Pistons made by Eastern. They have oil rings should I look for something different. A friend had his skirts coated for his UL.

[gypsynw]

I have already bought replacement Pistons made by Eastern. They have oil rings should I look for something different. A friend had his skirts coated for his UL.

I'm running the same piston/ring set in my U model. Piston cylinder clearance is at about .005 clearance. The oil rings in the eastern kit are the old oil ring style as opposed to the newer 3 piece ones. Correct me if I'm wrong but I would rather use the old style in hopes of some oil left behind on the walls as opposed to the more efficient 3 piece rings.