New 1976 R75/6 owner, LOTS of questions

[ME 109]

Those pictures are horrific Major! It is obvious that the owner was 110% clueless and 110% deaf. The engine was run for some time to do that damage.

I'll second Major's comment that 81-84 dropped valve heads, particularly when the valves are put in the wrong holes.
Again,
I'm not saying anything.

[Ken in Oklahoma]

Those pictures are horrific Major! It is obvious that the owner was 110% clueless and 110% deaf. The engine was run for some time to do that damage.

I guess when something like that happens there's often a certain disbelief, as in maybe it will clear itself up. Unfortunately, with that kind of clatter, there's not going to be a happy ending.

The R65 engines are apparently more prone to breaking a valve head off than the R60, R75, R80, R90, and R100 engines. I'm guessing that the R65 engines, because of their lesser displacement, and different crankshaft architecture, see a lot of throttle opening. A one time contributor here, Joan, was on an iron butt ride when she lunched a valve. From her report it was pretty ugly (as I think dropping a valve always is). There was shrapnel everywhere, including the carbs and naturally the exhaust. But worse, bits of metal had contaminated the oiling system. She did what is often done when facing such a disaster, she bought a replacement engine.

I've promised myself that should such a dramatic sound ever happen to one of my engines I will chop the throttle and pull the clutch to get that engine stopped turning ASAP. I wonder, if it ever should happen, whether I will have the presence of mind to keep my promise.


Ken

[Major Softie]

R65's are more prone because their valve stems are 1mm smaller. 7 vs. 8, if I remember correctly. The fact that most R65's were built during the 80 - 84 period doesn't help their rep any either.

It does seem like someone ought to be able to figure it out faster than that, but I think that's only for someone who recognizes what happened. For most people, if something like that happened on the highway they would immediately seek the side of the road, but would probably run the motor all the way over to the side. You'd still probably get 1000 impacts. If it happened at 5000 rpm, you'd get the first 100 impacts in about 2.5 seconds.

[ME 109]

I wonder, if it ever should happen, whether I will have the presence of mind to keep my promise.


Ken

I reckon you will Ken.

This was the result of my effort @ 180

[Jean]

Ain't it great how well they run on ONE cylinder?

[Deleted User 62]

Ain't it great how well they run on ONE cylinder?

Yeah, it's almost like they were MADE that way!