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The Dutch 450

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K2-K6:
The case history posted about this bike and linked in forum by Ash is certainly interesting from looking at the number of people now owning these engines.

http://www.hondatwins.net/forums/55-engine-discussion/33075-full-synthetic-oil-fresh-build-cb450-k0-engine-mile-0-a.html

The abovementioned link came up in discussion about ZDDP in oil. I don't know how many have read it being an interesting and different view of running one of these engines, along with attempts to mitigate some of it's perceived shortcomings.

I've been going through it a second time and intend to post on this thread my view of that study.

Worth talking about initially is some of the interaction which appears to lead to some conflict / confusion as to how contributors interact. 
Initial posting by Jensen offers a question about if anyone is reading the thread and inviting comments as it travels along.
When one contributor "Mydlyfcrysys" contributes,  it ultimately leads to that conflict. I thought he had a very valid view of viscosity in particular and found his posts well informed and relevant.
It's a shame that this resulted in his inclination to cease giving input,  also that the originator ultimately appears to accept that there was some things to consider from Mydlyfcrysys.
I can see that the originator sets out to complete his test based on a series of modifications, and wishes to see that through to quantify what affects that has on the various engine components. But some of the initial comments from him seem to wrong foot the other forum members.

It does weave a broad set of test conditions as there are a few changes from specification, making it slightly complex to unpick in order to analyse.

I'll follow with posts in splitting it up as I interpret it.

K2-K6:
It's not often that someone constructs such a diligent,  insightful and candid overview of something like this. The time taken not only to carry out the live research but to record it so thoroughly on a public forum entails quite a dedication. I feel it's very interesting and worthwhile.

The view given particularly of using synthetic oil in this age of engine is valuable. As he points out,  many people offer opinion of this without direct experience or knowledge of attempting it. So very often the same old reason of clutch slip is rolled out to oppose even any thought about what is a very valid question. To test and record it is far more useful and productive, even if, as he points out, it ultimately does or doesn't work. Real evidence is created to prove in this case that it hasn't the detrimental effect that everyone predicts.

Thankyou to Jensen for such an illuminating record. Just from the photos and recorded experiences while riding the bike it's a great story.

As he also points out,  the whole point of starting this was for himself, with his bike, that he wants to run reliably and enjoy. We are looking in on it, but realistically he achieved most of what he set out to do.

It's not for me to judge how he views his own case,  but I think there are some important points I'd disagree with from an engineering point of view if you were to apply it to your own bike.

MrDavo:
It’s always hard to know, when writing long and carefully reasoned posts, whether you are talking to yourself or being carefully followed by readers with a real interest, it was touched on here in a long rebuild thread - I read every post, but the contributor despaired that no one seemed to care.

The question of modern synthetic oils has been discussed at length in air cooled Porsche forums which I frequent, where clutch slip is not an issue, the consensus is that your engine parts will last much longer, but the oil will be trying to make a bid for freedom through oil seals never designed to contain something so slippery.

K2-K6:
It's hard to judge how it balances I feel as the sentiment of Jensen's thread moved around a bit. I've read it about 3 times now by variously going back over  it to get some parts straight in my mind.
I've chosen to post about it on here rather than disturb the original thread for those that are running this type of engine.

There's not the intention to criticise the original, I hope it's not considered in that way. More that the original is so detailed with each effect reported it opens up a much further scope of discussion.
He seems a very interesting person with the confidence to form and carry out his own testing. I'd like to meet him.

K2-K6:
Starting with the camshaft and running this engine while preserving it's condition.

Two things for me stand out in this area,  there's a position of super diligence applied over both tappet clearances and oil condition. My feeling is these play an absolutely vital role in keeping any camshaft / valve train from undesirable wear. That's over and above any other criteria.

You can see from the long term data that the valve clearances generally diminish by very small amounts. That indicates that the original design and material integrity are able to support the intended use. Making the assumption clearances close up due to the valve face and seat wearing under normal duty cycle,  the changes he records entirely support that view. If you had any wear in the train components from friction, then the clearance would be increasing.
The above, in being as I see it,  normal, demonstrates the risk area in running one of these engines from assembly. If you let that clearance disappear, resulting in the follower running all the time in contact with the cam,  then it will have one of the greatest influences over cam life.

Valve train designs contain the springs already pre loaded and held in compression by their geometry. If you run the cam with even the slightest valve lift on the base circle of the cam,  it subjects the surfaces to the full force (virtually)  of the spring rate. Decent sized valves with rpm getting to 10,000rpm is always going to need fairly high rated springs. This would challenge even the most advanced oil you could ever use in there,  it's to be avoided at all costs.
It's absolutely correct to be so so diligent with these settings.

Oil condition is the real partner to the above. The shear loading of the oil is most challenged at this interface,  any degradation in film strength will be punished at this load site. Any dilution of the oil with contaminants will compromise it's ability in this field so all measures to preserve it's original condition should be considered.

This is another area that diligence is paramount,  jetting the engine to run correctly and burn it's fuel efficiently. He makes the observation about setting up and checking the carburation to get it correct. If you run with standard intake setup then you have a good start point with specified jetting etc. If you run any engine too rich it will pass unburnt fuel and combustion byproducts past the piston rings and into the oil. It's this that compromises the oil performance.
Ultimately,  I believe,  it's this point that the oil changes are relatively short interval on bikes of this era.

Again,  diligence in this area is vital to the oil performance.

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