16H Lock Up

When you pulled the clutch did it coast to a standstill or was the wheel still locked? Are we talking motor or transmission.  If the motor nipped up as you were running at a specific speed it may be a breaking in issue or lube issue.  If the wheel remained locked  it’s transmission or brake issue.

Putting it on the stand allows it to start sounds odd.unless the time elapsed caused the motor to cool enough to free up.   What work did you do prior? Check colour of plug, oil discolouration, does it seize catastrophically or a degradation until the wheel drive train locks? Does the rear brake bind, is it hot? Some more background please.

J

Not on a 16H for me but same symptoms on an ES2.. 

The issue was carb set too weak on the air/  mixture screws and running far too hot.

As for 16H, it will depend on your gearing, mine (With Dolls head) runs most comfortable at around 40 mph in top. 55 is more like blowing up speed...Maybe I'm too sensitive? 

Incidentally, has it not covered too many miles since last re bore? I have learned a long time ago that a 4 thou interference tolerance works to start with. 

As Jonathon says:  More info please.

... I think you mean clearance. And in my opinion .004" is far too tight - I use at least .006" - .007". Modern rebore places are not familiar with the generous clearances required by our old engines. I'd rather have a bit of piston slap than constant worry about it tightening up.

As a point of interest Edgar Franks suggested reboring when the original bore was worn by .007" - ie a clearance of around .012".

It might also be a bit retarded. Bacon's Norton Singles lists 0.375" (3/16) but it should be at least 7/16", or it will run hot.

That is a 4 point seizure, piston overheating is the normal cause as these 4 points are where the alloy is thickness and hence expands the most on excess heating of the piston.

If that’s the worst it should clean up, but as John says that is more than rear oil feed issue. As Neil and Ian elude to, clearance could be low. Shiny oil is not synthetic I hope; it will never bed in with such high quality lube.  Check your clearance, maybe a light hone and your good to go, but gently for a while…

Good to see,  nice bike! Jon

Hi John / Jon,

Mineral oil the stuff to use in an old single. I use SAE50 in mine during warmer weather.

But I'm wondering if the lock up and damage would have happened @ 40 mph, I believe not.

Of course the blocked oil way didn't help and good that it has been identified.

A light hone so important at this stage.  Good luck, Kevin.