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The Dutch 450
K2-K6:
Hi Jensen.
As I originally wrote at thread beginning, I found your experience and recording of it fascinating. My aim here was to expand some of the points based on my own thoughts about the impact of using synthetic oils in this way.
I believe, as you do, that there is a whole raft of disinformation about using synthetic oils in place of originally specified types. These seem to be perpetuated generally on threads around the world with no good or scientific basis. It often makes me wonder if you need to look after a camshaft, why then accept some casual reference to clutch slip that would prevent you following the most productive choice to preserve the valve train components.
It seems so many comments are made based on obscure sentiment rather than any sensible evaluation.
Any input you may have is certainly welcome, although you appear to contribute a fair amount of your time in making your own threads. I hope I don't compromise those.
Nigel.
jensen:
Yes Nigel,
I agree, how could I not. I have dismantled many 450 engines the past decade, and all have more or less the same issue's. Looking at the damage, anyone can tell, even with an untrained eye, that lubrication is (one of) the culprit(s). However, there are some designer issue's too, particular focussing on the valve train and crank set-up. On top of that, the engine is very sensitive how it's handled.
My goal was to build an engine to spec, use a modern oil to break in the engine, and see what happened while covering miles. The changes I made are not dramatic, but going from the centrifuge oil filter set-up to paper filter set-up was mandatory using a modern detergent oil (no matter if synthetic or not).
Until today my bike is working flawless, no major damage to the cams and other parts. Every year I try to ride as much miles as I can, to make as many test miles as possible (and because I like to ride it).
Every time I adjust the valve clearance (once a year) I measure the clearance with a precision of 0,01 mm to see changes in the valve play. I do see that the left exhaust valve clearance is changing faster then all three others, despite the used oil. But the speed of wearing out is much lower then all the examples I have seen.
I do ride a lot of highway and back roads, using the bike as they did in the past, as a rider, not as some show bike, low revs and short distances. I don't take the bike to classic rides, since the average speed is very low, and high way's are commonly avoided.
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jensen:
Hi Nigel,
Working through your comments, I stumbled upon this sentence : "It's not a surprise that it took 7000miles before he thought the rings were sealing".
What do you exactly mean by "thought" ? I measured the that the maximum compression was reached at this point (and a leak down test gave the lowest leakage at this point), and I suspected that this was due to the seating of the rings. The leak down tests also show that this is the case.
I have to say that your comments are precise and well build up arguments, I was hoping for this kind of quality of comments at the Hondatwins site, but unfortunately just a few comments were worth the effort. Writing a thread like that should give the writer energy, unfortunately, it started to cost energy, not giving it. Another reason I did quit, is that I got a few not so nice private messages regarding this and other threads I started.
btw, I did not quit the tests for the general comments, I found that not many people where really reading it, so I stopped writing in depth details about the process.
K2-K6:
Jensen, I think It's my poor grammar / literary skills so it looks an odd comment.
I'll expand, you've judged that it reached optimum condition based on your compression measurements at around 7000 miles. I'd expect to see that level of completion at around 750/1500 Miles with the hone more conventionally completing it's work by that much shorter interval.
Hope that explains, if not just say.
I guess it's part of writing on here essentially unedited, I go back over it to make corrections but some of it maybe slightly odd emphasis.
Nigel.
K2-K6:
Before I forget to include it, is a general running in point about why the recommendations are made by the manufacturers. This expands my thoughts rather than comment on the original thread.
The engine speed asked for by manufacture and layers put in, usually increasing speed steps, is something I believe is very misunderstood. As far as I can determine from engineering principle, it's predominantly the linear speed of lapping that calls for limits of rpm during this period.
More specifically, you've a fixed pressure exerted by the piston ring spring action, ideally you'll have an optimum piston speed ensuring that the linear lap speed doesn't exceed a predetermined maximum. This is of course usually given as max rpm. The first miles of using new bore and rings is going to be the most productive, purely because the maximum cut from hone is available.
Interestingly honing is not considered to be heat generating, seems only 1 to 2 degrees is typical. It's this characteristic that can make it such an accurate method of precise component finishing.
It's commonly given that engine rpm restrictions are to prevent too much heat, I'd disagree with that. Certainly you'd not want to overheat a new engine, but then the same applies to any engine throughout it's life.
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