Author Topic: Later Alloy Body Oil Pump in K0 Bomber  (Read 3900 times)

Offline MrDavo

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #15 on: April 02, 2018, 10:42:28 AM »
I think K0 ones are bent like that, though that one is advertised as later, luckily both of mine have a straight arm, or that would be another thing to worry about.
1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
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Offline jensen

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #16 on: April 02, 2018, 12:17:19 PM »
CB450 K0 indeed, these arms are bend this way. Yes, you can mount them wrong, but the clutch won't turn 360 deg easily
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

Offline AshimotoK0

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #17 on: April 02, 2018, 12:52:00 PM »
I have booked to go to see the man with the NOS oil pump etc tomorrow to buy it and I will trawl his old  literature to see if there are any Service Bulletins left from Honda UK's Service  dept. on the CB450,  if he will let me (pretty sure it won't be a problem...he's a nice bloke.

Meanwhile, I have PM'ed the member on HondaTwins.net to see if he will send me the SB's he originally posted but got deleted due to Photobucket.

Dave ..  if we find we both end up needing  a spacer making, I can bung the guy where I work  a few quid to make us a couple.....it won't cost much and I can probably get phosphor bronze from where I used to work across the road for free. That's if they need to be PB. Jensen?

Just noticed this in the States:

https://www.ebay.co.uk/itm/Vintage-1969-Honda-Motorcycle-Dealer-Service-Bulletins-CB350-CL350-CB450-L926/131686996680?hash=item1ea9281ac8:g:QiUAAOSw5IJWgXiX
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline MrDavo

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #18 on: April 02, 2018, 06:21:46 PM »
Whether we need that washer depends on whether that kit is to upgrade a K0 only or not. If I used the K1 rod, with the 500T piston attached, then surely there isn’t room for an extra washer.

If we do need one I’d be happy to go halves with you, Ashley.

We need more info about that kit, I think, or a clear scan of the instructions so we can check the number of the pump it replaces. Lots of our US cousins seem to have upgraded using a new piston on an old rod, what we don’t know, of course is what state it all was in 5,000 miles later. Some of these guys think it’s ok to delete head steadys and do tappets by ear, after all.

If I don’t know for sure what I’m doing before I’m ready for the road i’d Be tempted to go back to stock for a safe option.
1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
1985 Porsche 911 3.2 Carrera Sport
1978 VW Bay Window camper van

Offline royhall

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #19 on: April 03, 2018, 07:21:00 AM »
I have been watching these oil pump threads for quite some time now as I am about to start the restoration of my Bomber. I have read through most of the articles posted on here and on a few other sites, and have been generally impressed with the in depth analysis. I do hope my take on things does not upset anybody as that is not my intention, but I do also expect to be shot down in flames over this. :D   However!

A couple of things have jumped out at me that I found surprising. Firstly, I very much doubt that Honda thought one day that they would just stick a bigger pump on the 450 and leave it at that. The changeover from the steel to alloy bodied larger pump would have been together with a whole host of other changes to the lubrication system. Nowhere have I read on any of the sites a complete list of what these changes were as frankly, I don't think anybody really knows. My point is, just changing to a later pump without the other mods is not only pointless it probably introduces new negative issues. This has been covered in some of the threads ie. broken pump drives, opening up oil passages, now the offset of the plunger arm has become an issue, etc etc.

IMHO this perceived exhaust cam problem has its roots in lack of oil changes and generally poor maintenance. Remember we are restoring 1960's bikes here where back in the day riders were used to Triumphs where oiling was not a problem. A man using a Bomber as only transport would cover a 1000 miles in three weeks, and who had the disposable income back then to change the oil every three weeks. No, they were ridden like Triumphs that would do big miles without an oil change. Thus the problem arose.

Today we rarely ride these classics like that, so to my mind this larger pump issue is "a solution looking for a problem". My rebuild is therefore probably going to have a NOS standard pump and be reassembled as Honda intended. After all, Honda spent millions back then developing this highly sophisticated engine. Then oil changes every 1000 miles or so and careful attention to the valve clearances.

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 am however, very impressed with Jensen's work on the fully synthetic oil. I may follow that approach.
« Last Edit: April 03, 2018, 07:54:12 AM by royhall »
Current bikes:
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Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
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Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline K2-K6

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #20 on: April 03, 2018, 10:28:51 AM »
No criticism from me Roy. On the contrary,  I feel your assessment is near as identical to how I was thinking.

The general consensus in many things is that "more" is always better. This view very often fails to comprehensively consider subtle intricacies in the original design that have an impact that is completely missed in a very simple and basic decision to change something/anything,  in the vague hope that it may be better.

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.

Be interesting to see if a comprehensive mod list turns up,  but it may not make clear why it's done.

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. 

Nigel.



Offline hairygit

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #21 on: April 03, 2018, 11:50:42 AM »
Similar discussions take place on the C90 club forum, especially with the guys that race them (Yes, they really do have proper races for C90's!) It is recommended to fit a TRX90 oil pump, but it is ONLY advantageous IF the oilways in the crankcases, barrel and head are enlarged from 1.2mm (Stock) to 2mm, not a job for the average owner, but it certainly helps things stay cooler with a higher oil flow.
If it's got tits or wheels, it's hassle, if it's got both, RUN!!!

Offline jensen

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #22 on: April 03, 2018, 08:57:42 PM »
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.

Quote
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).

Quote
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.

Quote
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).

Quote
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.

Quote
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
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

Offline AshimotoK0

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #23 on: April 03, 2018, 09:06:00 PM »
Went to get the NOS oil pump today but no sign of any Service Bulletins from where it originated. My guess would be that it would have been an upgrade part as everything else I got from him has been upgrade parts for 60's Hondas. I need to get the oil pump which came out of my Bomber engine though to compare to it.
Meanwhile, here is £40's worth of NOS one.

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“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

Offline jensen

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #24 on: April 04, 2018, 05:07:43 AM »
Hi,

This the later version, there are 3 versions, the pictured one is the latest style early steel pump. The best also....

Jensen
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

Offline MrDavo

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #25 on: April 04, 2018, 10:11:20 AM »
It looks a lot like the one I took out, and am probably going back to.

Like when I get gout in my big toe, the exhaust cam suffers because it is the furthest thing from the pump, and the last thing to get oil on starting from cold. It is concern about this that makes me want to increase the oil flow.
1969 Honda CL450 'Scrambler'
1974 Kawasaki Z1A
2005 Harley XL1200R Sportster
1985 Porsche 911 3.2 Carrera Sport
1978 VW Bay Window camper van

Offline Johnwebley

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #26 on: April 04, 2018, 11:14:30 AM »


   on the question of cold start,and oil getting to the important bits ,could you use a modern 0w-40 oil ?

  this will give good flow when cold,and "body" when hot .


  runs away to hide behind the sofa !!!
lifelong motorcycle rider,and fan

Offline jensen

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #27 on: April 04, 2018, 01:35:42 PM »
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
assembly of Japanese motorcycles requires great peace of mind (Pirsig)

Offline royhall

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #28 on: April 04, 2018, 07:43:54 PM »
Am looking forwards to the outcome of Jensen's tests on the fully synthetic oil, that shows some real potential. I have looked closely at Ash's NOS oil pump and there looks to be subtle differences to my NOS item. How can you tell which version of pump you have, and what are the differences, and do the differences matter?  I have posted some photo's below. By the way Ash, mine was a little more than £40 but as you know you have to grab these things whilst they are there. ;)   Thanks all.

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« Last Edit: April 04, 2018, 07:48:36 PM by royhall »
Current bikes:
TriBsa CCM 350 Twin
Honda CB350F in Candy Bacchus Olive
Honda CB750F2 in Candy Apple Red
Triumph Trident 660 in Black/White
Triumph T100C
Suzuki GS1000HC
Honda CB450K0 Black Bomber
Honda CB750K5 in Planet Blue Metallic (Current Project)

Offline AshimotoK0

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Re: Later Alloy Body Oil Pump in K0 Bomber
« Reply #29 on: April 08, 2018, 11:19:56 AM »
Jensen kindly explained to me on the phone yesterday that the hole in the gauze filter on the original version of the steel pump was caused by fatigue of the wires due to the oil flow, which is pretty incredible. I plan to put the NOS later version in my engine and put  the alloy body one I bought  back on eBay.

Jensen has bought one of the early carb. upgrade kits from me and is going to evaluate on his bomber, in due course. Thanks for all of your sterling efforts Jensen !!!   
“Alright friends, you have seen the heavy groups, now you will see morning maniac music. Believe me, yeah. It’s a new dawn.” Grace Slick, Woodstock '69 .. In the year of the Sandcast.

 

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