This always genuinely interests me, the "seize it or glaze it" debate. Having said this, I would rather glaze a liner than seize a piston.

I have always nursed new pistons and rings on bikes, but not tractors or chainsaws.

Out of interest, how does glaze buster oil work? I can't see it only busting glaze on liners and not causing premature wear on say, bearings.

email (option): sacombsashtrees@hotmail.com

When I used to help prepare Triumph engines for pre 65 scrambling they had to run flat out from the start of the first race...

However, they were built with a bore so slack that the engine smoked slightly when running...It worked very well (over 700 wins)but the engines weren't expected to do many miles/events without further attention...

BSA, on the other hand, recommended a 1000 mile running in period for road engines, starting gently and progressively increasing the loads and duration of loads through the running in period...

That method works well, as proven by countless thousands of BSA owners and I have always followed those principles..

I have had many reliable and crucially, non oil burning, high mileage engines to look back on that didn't suffer from glazed bores...

Frankly it puzzles me that a proven and recommended method should be totally ignored and replaced with the opposite when experience shows that is plainly not necessary...

I would say a further risk is being taken by running the engine hard on the road without even determining that the mixture settings are correct..Surely that could not be deemed to be a sensible strategy?...What if the mixture was weak?...Ian

email (option): ian@wright52.plus.com

Aaah, one of the two* everlasting debates!

Not being John Healy I have yet to build a bike that starts first kick, runs well and can be ridden off at full speed with mixture correct, engine running perfect on all cylinders (if more than one), clutch operating smoothly, breaks correctly adjusted and so on.

I respect the knowledge of John Healy in every possible way, but his recommendation on this issue has never been an option for me. I take it slow after startup, like Ian described.
Now, I do not have the extensive experience of Ian, but I've done just fine. So far...

Lots more to say on the subject but its all been said a thousand times by now. You now know the to schools, take your pick. This is said in no unfriendly tone what so ever, its just that the debate seem to be inconclusive how ever much you google. You just have to take your pick!
(or you could of course go with factory recommendation)

best regards,

Simon

*the other one of course being "What oils are best for a classic?"

Your right Simon..There's more than one way to get to the same place and people generally do it the way they have found works for them...

Some of these questions are eternal and will never be resolved in a way that everyone agrees with..It makes for an interesting discussion and when that ends I guess the 'undecided' have to make a choice.. ..Ian

email (option): ian@wright52.plus.com

There is a big difference between bedding in rings and running in a new engine.
I still run in new bearings & bushes.
The rings OTOH can be bedded in in 500 meters then I worry about the rest of the engine.
BSA recommended a lot of things that were more in the interest of BSA than the owner of the bike.
Generally the carb will be too rich, being adjusted that way to compensate for the worn bore leaking every where.

It is a thing that we will need to agree to disagree on.

And as this is a military forum, did the military nurse all their M20's for the run in 1000 miles ?

email (option): bsansw1@tpg.com.au

['being adjusted that way to compensate for the worn bore leaking every where...']

Not really..

I stripped my.. 'carefully run in but not thrashed to prevent bore glazing'... B33 engine after 78,000 miles for a cosmetic tart up and the bore, rings and piston were in used but sound condition...I did re ring it at that point as it was apart...

When the engine was at over 35,000 miles a 2400 mile trip to Scotland did result in a drop in the oil level but not sufficient for me to put any in..In fact I gave my oil to my friend who's Matchless sprang a leak..

I agree there are differing view points on this but I think it's best to retain a sensible perspective...Ian

email (option): ian@wright52.plus.com

Inevitably, I grew up doing things the old-fashioned way and I don't think that I could bring myself to assemble moving metal to metal parts with no lubricant.

My Commandos use no oil and I usually change the rings at 30,000 miles or so. Being gentle with them when new (and especially when the engine is cold) doesn't seem to have done any harm.

It also might be worth bearing piston speeds in mind. A 100mm stroke 16H or 120mm Big 4 is is going to be at over twice that of a short stroke modern multi.

Norton singles have a reputation for nipping up until they're well run-in and loose. I've never experienced it and will do my best not to.