Honda-SOHC

Why hide behind the sofa ?

I had not good results with 0W40 oil regarding cam issue's. The layer of oil seems not strong enough to resist the pressure of the tortion bar.

Jensen

Hi,

The difference between the pumped volume of an early steel pump and a later alloy pump is moderate. In theory 30% more oil, in practice lower due to different issue's. One of the advantages is that more volume reaches the cams faster when started cold, and to me, that's the only major advantage (without changing anything else to the engine).

I have build another CB450 K0 engine with the later pump, but I changed a few things to the engine. When looking closely to the differences between the K0 and the K3 engine cases, one will see the differences in diameter of the 2 orifices located at the engine case toward the cylinder studs, and that's exactly what I did to the CB450 K0 cases, enlarge the diameter of these orifices.

The most obvious consideration missed is that the cam lobe (which is the concern here) is absolutely not pressure fed. The cam on the rocker follower is completely at zero oil pressure. It follows that increased oil pressure cannot change this. Oil volume is different from pressure, interelated in a engine,  yes. But not the same thing

I couldn't agree more, and a later alloy pump does exactly that, adding more volume to the system, but without the proper changes to the engine, it's a waste of energy due to higher pressure in the system. This is why I wanted to do a test with another type of oil, a type of oil which has a very strong layer that won't break, even under extreme conditions (both, temperature and pressure).

As you've already stated, and it looks to me too, that the original issues arise from how it's maintained. That tappet clearance is probably the most vital of most engines we'll see on here given the spring loading it must use to get a valve of that size safely above 10,000rpm,  with some space above that for safety margin.

I partly disagree on that, however, in many cases you are absolutely right. I also think it's the nature of the torsion bar setup, the cold start issue's and some design errors Honda made during the development of these (early) engines.

this perceived exhaust cam problem has its roots in lack of oil changes and generally poor maintenance

No, I'm sure it's due to the poor design and magnified due to not warming the bike up properly. Honda was aware of this problem and solved it in the later engines. Honda has a history of poor design oil and lubrication issue's over the years (remember the first V4's engines).

After all, Honda spent millions back then developing this highly sophisticated engine

That doesn't mean that no mistakes where made. Today, car and motorcycle manufacturers spend even more money and effort on development, and despite all the experience and know-how, issue's arise from time to time.

If anybody could supply me with a complete list of the changes that were made by Honda at the time of the oil pump replacement I would love to upgrade the Bomber, but without that I see no point. Sorry.

I don't think anyone will do that, since not many people measure and test things, and publish the outcome. They just searching the internet and are asking to be convinced by others

I do ride my CB450 K0 on highways for longer periods, I do ride the bike as it should. I found issue's of the left exhaust cam, and yes, I replaced the oil every 1000 mls, and warmed up the bike before taking off. When I'm at classic events, most people unload there bikes from their vans or trailers. And when I ride with a CB450 club, highways are avoided and the average speed is lower then 40 mls an hour. Remember, the CB450 K0 is a supersport bike, not a tourer. Maybe a good read is this thread : http://www.hondatwins.net/forums/55-engine-discussion/4922-cb450-k0-dyno-run-why-doesn-t-need-five-speed-trans.html

Conclusion ?

No, it's not needed to add more oil pressure or volume in these engines when using them in a normal way. Warm it up carefully and maintain the bike and you're more or less ok. Some cam wear will be your share, but one will hardly notice since most people don't add enough miles to the odometer in their live.

I tried to solve it in an other way, using a better oil, an oil which has a stronger layer and doesn't give up at higher temperatures and pressures. Until today, this seems to be a good route, until someone proves otherwise, based on severe testing and  publishing results.

Jensen

CB450 K0 indeed, these arms are bend this way. Yes, you can mount them wrong, but the clutch won't turn 360 deg easily

I bought a nice aftermarket set, probably italian, it has the double skinned headers, nice exhaust damper and all the clamps. Coparing with a NOS original set, it's heavier, and has nicer chrome...

What is the overall quality of the CMS (NL) systems ? Any experience with them ?

Hi,

I won't correct you, you're right, that's what I meant 
btw, sorry for my English, sometimes I can't find the right words or way to say it,
so it might be unclear what I'm talking about to someone else.

Jensen

I pm’d Jensen, so he should see this

A late response since work, work and work consumes all the time I have at the moment.

If the lobes are ok, just can re-use this cam. Make sure you polish the edges a bit, so that no extra material brakes out.
I can't give you an advice about using the rubber rings in general or not. I only can say that I prefer them, makes the head noisy without them, just replace them when re-build an engine with fresh, original Honda rubber rings. Personally I only saw issue's with these rubbers on old engines with no history of rebuilding what so ever. I think it's wise to replace them within 20 years or so 

In this particular case I would't use them, there is a lot of material gone to keep the rubber in place, that could be a risk.

Jensen

Hi Nigel,

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

Yes, but I wasn't surprised, and knew upfront that it would gonna take a long time to reach the maximum compression. When looking for example to the BMW flat 3 and 4 cylinders (K-series), one of the complains was that these bikes used a lot of oil from new. It took a long time before the rings were set, something around 4 to 5 K km. These BMW's used synthetics from the factory as I remember, and there where a lot of discussions going on. Nowadays, all engine are machined to perfection, with very low tolerances, and using synthetics from new.

The CB450 is an old bike, made in a time that precision wasn't that high, and breaking in was a process to correct a these mis-matches between parts in general. The process of breaking in was much more important than it is now, a lot has changed. This was also the reason for me to experiment with breaking in on synthetics.

Using synthetics in my classic bikes is a no-brainer for me since I've seen the effect of using this kind of oil in an engine. Many years ago (1997) I bough a new XRV750 Africa Twin, and before starting the bike I changed the oil to synthetics. Since then I always used synthetics in this bike, thus including the breaking in process.

I travelled many kilometres on this bike, and in 2017 I sold her with 360.000 km on the odo. Every year the bike was on the dyno, every year I tested the compression, and between 8.000 and 10.000 km it reached the maximum compression. In the beginning the bike used oil, but stopped using oil around 8000 to 10.000 km. The last compression test at 345.000 km on the odo showed that the compression was still very good (way within the specifications). The bike didn't use oil in an amount that I had to fill up between oil changes (8.000 to 10.000 km).

The only engine parts I had to replace were the clutch plates at 220.000 km's. The other thing I changed on the bike were the spark plugs, I went from normal spark plugs to Iridium ones. Since the XRV has two plugs per cylinder, the costs were very high in the 90's, but I didn't have to change those either every time (however I checked them every year).

if you smell the oil after it has run in your engine then compare that smell to new oil,  is there a noticeable difference between the two,  if so how would you describe the change?

It smells good, but since that's an indirect measurement and depending on emotional and physical health, it doesn't say not much. I didn't smell gas / petrol, but it doesn't smell the same as new oil. The colour is much darker too.

is your view of filtering the oil so thoroughly influenced by that oil "debris" that collects in the crankshaft oil distribution channels?

Since the high detergent power of modern synthetics, debris is not collected in the crank or in a spinner filter (the oil just cleans the spinner filter), it collects the debris in the paper filter itself.

A substantial part of debris in the oil are clutch plate particles, the other is waste of burned oil and fuel leaking through the oil rings. The larger particles of the clutch plates and the other debris are caught by the paper filter, the smaller parts are pumped trough the engine.

I use an external filter setup because the filter setup from Cappellini Moto uses a paper filter which is too small according to me (there is just not enough room to place a bigger filter). The used filter (from a Suzuki motor scoot) is just a single layer of paper, and not like many larger oil filters for cars, multi layers.