What is going on with my Cam follower ends?

Hi:

Recently pulled the barrels of my 1962 650SS in order to fix excessive cam follower noise. Having a closer look at my current cam followers. Am a bit surprised regarding the profile of the pads. They appear to be equipped with radiused ends? I thought all Norton twins came with flat ends and no add on pads. I probably will not be using them again, but can't help wondering if my followers are original or have they been modified? If I buy new one's, what profile ends do I want? I am using a 2S camshaft, (not the combat one) same as early 750. Please see pictures below.

Thank you!

Not standard , fitted to earlier 88/99 engines with pre -daytona cam . Can be used but will change the action , Better or worse ?, no idea.

Won't make a bit of difference at all.

The cam in the early 750 is the same profile as the 650ss. Also the same as all later 750s and 850s except Combat and Production Racer.

Glen

The radius tappet against a flat tappet will open the valve later and close it sooner but not by a lot. It will ease the strain on the valve train.

and most had stellite tips. However, Andover’s latest version is using a modern metallic composition that is all one material.

kommando said:

The radius tappet against a flat tappet will open the valve later and close it sooner but not by a lot. It will ease the strain on the valve train.

Click to expand...

Agreed, but IMHO, the "radius" job was done poorly and introduces two sharp edges on open and two on close. If the cam actually touches those sharp edges, the I would think extra wear would happen. If it doesn't touch those areas the "radius" hurts nothing.

Radiused tappets I've seen are ground into a smooth radius across the entire surface. These seem to be releived, not radiused.

kommando said:

The radius tappet against a flat tappet will open the valve later and close it sooner but not by a lot. It will ease the strain on the valve train.

Click to expand...

That's the theory. Jim Schmidt's cams work well with radiused BSA or Triumph tappets and Jim's lifter blocks. The stock tappets can also be radiused to work with his cams. Those old tappets in good condition have enough meat on them to be radiused for the JSM cams or webcams or whatever floats one's boat.

Not an argument just a thought. The tappets in question are not radiused tappets. It is a straight crude cut. A cam with enough lift to touch that cut on those old tappets probably wouldn't spin in the cases without serious interference and would also hit the barrels. I have not tried it to verify, but have been around long enough to visualize it being a real problem.

I ran a 750 P11 engine with those same tappets in it with a 2S cam. Had to have the cases clearanced for the cam, but the cam never came close to that cut on the tappet when spinning around.

Feel free to shoot the messenger. I can't feel it.

Schwany said:

The tappets in question are not radiused tappets. It is a straight crude cut.

Click to expand...

Look again at the first pic, there is a definite radius but it is large, probably the 2nd pic makes it look like a crude cut but the surface has 2 shades caused by the difference in where the follower rides on the cam and where it does not.

kommando said:

Look again at the first pic, there is a definite radius but it is large, probably the 2nd pic makes it look like a crude cut but the surface has 2 shades caused by the difference in where the follower rides on the cam and where it does not.

Click to expand...

You are correct. I am sorry the photos are not better.

I do not think I will be using them again under any circumstances. I now understand that the cam I have installed is intended for flat end / stock profile Norton cam followers. The bike ran fine aside from the noise, but I see no reason to try to re-invent the wheel and I do not like the idea of one of those pads coming loose!

Thank you everyone for your advice / help.

I know it's too late and nobody is listening anyway, but...

Angle of the cuts is too steep to be a radius on the tappet for a cam. I'd get the surfaces refinished and reuse them myself in a mild or bone stock rebuild.

The stellite pads coming loose is probably extremely rare. I chased 916's and other modern bikes around in the Cailfornia foothills and beat the heck out of my 750 when I was a lot younger. Never lost a tappet pad and one of them was darn thin to begin with.

This is what mine look like after beating the poop out of the engine with the SS cam in it. Note how thin the stellite pad is on the left tappet. Witness marks from the SS cam are 1/8" from the cut. A stock cam would be nowhere near those cuts as shown by the witness marks in your images.

Schwany said:

I know it's too late and nobody is listening anyway, but...

Angle of the cuts is too steep to be a radius on the tappet for a cam. I'd get the surfaces refinished and reuse them myself in a mild or bone stock rebuild.

The stellite pads coming loose is probably extremely rare. I chased 916's and other modern bikes around in the Cailfornia foothills and beat the heck out of my 750 when I was a lot younger. Never lost a tappet pad and one of them was darn thin to begin with.

This is what mine look like after beating the poop out of the engine with the SS cam in it. Note how thin the stellite pad is on the left tappet. Witness marks from the SS cam are 1/8" from the cut. A stock cam would be nowhere near those cuts as shown by the witness marks in your images.

Click to expand...

Thank you very much for the information. Interesting to see one's that are similar to mine, but without the shallow angle cut into the ends. I suppose the witness marks could be from my bikes previously installed cam, as it was when I bought the bike, I never had them polished,. I must admit I never looked at the old cam too closely, the lobes were worn (as was everything else) so I binned it.

I have now given my barrels to Chris West at Fair Spares to play with. Cam follower tunnels are quite rough, so will need to be bored or sleeved. I know followers are stupid expensive, but these followers are the last vestige of the previous owners, shall we say, "love and attention". I will be glad to see the back of them!

Just to keep the water muddy

You could take the money you will spend in new AN tappets plus a little more and get a JS0 or JS1 smooth ramp cam from JSM and have those tappets radiused for real. The engine would be a little quieter that a stock setup if that is your goal.

I'll take those tappets off your hands for $20. Just saying

Yes, that would be the smart thing to do. I should have done so when rebuilding the bottom end. However, for various reasons I do not want to split the cases any time soon. So I am probably going to go with standard flat faced Norton followers, (assuming I can get the cam follower tunnels sorted out). My Commando has the same setup and is pretty quiet, (for a Norton). If I can reduce the noise on the 650 to the same level as the Commando I will be happy. I do run JS pistons and rods in this bike and very nice they are too! If I do another Norton, (or when either of mine blow up) I will definitely go with JS pistons, rods, cam and BSA follower mod.

Cheers,

James