yes you would think it would be readily available...but i can't find it

 

The reason you can't find the spec is because there is no such spec. Your question has been accurately answered already, but to reiterate what others have said: If the lobe shows any visible wear in the form of scratches, pitting, etc, the cams are bad. Cam lobes ARE NOT WEAR ITEMS, therefore, as a general rule, they do not wear out unless there is some other problem such as oil starvation or contamination, etc. Why are you asking this quiestion? Are your 255 cams looking like they are wearing? If they are, they need to be replaced. If they do not look llike they are wearing, they are not. It's that simple.

 

Harley engines have roller lifters. There is a roller on the bottom of the lifter where it contacts the cam. There should be no wear on the cam. Where the cam wear numbers are needed is when running flat tappet cams either hydraulic or solid. Then you have metal against metal. With a roller cam tappets you should get many thousands of miles with no wear unless the roller goes bad for some reason.

 

Again, you aren't making any sense.

 

if the cams are worn .00001" all the way around is this acceptable???and how do i know if they are worn if I don't know what the original measurement is??? can't cams be worn (polished) evenily all the way around the lobe and not be visible without measuring??? or am I to understand that any cam that is put into service is worn out because it will have "some" wear....I understand that some wear (gauges,pitting, spalling etc.) is obvious but an even normal all the way around the lobe polishing by the 2 parts mating together at some point has to exceed its wear limit....I just would like to know what that is....

 

I bet you'd be hard pressed to be able to even find anybody who can measure .00001".

 

if there is any marking on the lobe...replace them.

Roller lifters are different than flat tappets. Also, the lobes have a thin layer of hardening, if you see a "line" it is through the hardening and the cam is toast.

Not what you want to hear obviously, but I'm not going to lie to you to make your saturday that much better.

Drop the 3 bills and buy a new set from the dealer. Get some new lifters and some Torrington/Timken cam bearings while you're there.


~Joe

 

Exactly correct! And exactly what my cams looked like when I finally switched to gear drive cams at 81,000 miles.

How many miles on your bike?

 

Dude, there are million dollar coordinate measuring machines that cannot measure as accurately as .00001. That is one one hundred thousanth of an inch. So theoretically, yes, that amount of wear is perfectly acceptable simply because it is immeasurable.

Here's another down and dirty suggestion (I already gave a good method in post # 9)... Cam lobes should wear fairly evenly. If any lobe is worn to the point of being unusable it would more than likely be wearing at an accelerated rate and would measure different than others. You could determine that by simply measuring each lobe and comparing the results. Measurement accuracy within .001" is sufficient. If you measure each intake lobe and each exhaust lobe and the measurements are consistent, the cams are more than likely ok. To go a step further, you could compare your measurements to the same measurements of a known good cam.

 

Whenever you have contact between two moving surfaces, one of them is designed to wear and the other is not. The cams are hardened and will not wear under normal circumstances. If anything happens to make them wear it will be obvious simply by looking at the surface. No measurement is required. If the lobes are in a good polished condition then I think its safe to assume the cams are good. If you have any doubt, replaced them. The manufacturing tolerances are most likely proprietary information and you will not find out what that variance is. Even if you could you do not know of other geometric tolerances that may apply which could result in a tolerance stack up situation.