Honda-SOHC
SOHC.co.uk Forums => The Black Bomber Board => Topic started by: AshimotoK0 on March 24, 2018, 02:36:04 PM
-
My understanding from the Bomber experts on Hondatwins.net has always been that fitting a later alloy body oil pump from a K2 onwards is the way to go to improve top-end lubrication.
However, I spoke with Jensen on the phone last night about various bike related subjects and it seems that in his extensive testing of synthetic oils in the Bomber, he originally fitted a NOS CB500T pump but experienced wear and reverted back to the steel body one. I will ask him to comment specifically on this but meanwhile I went through his posts and pulled out some pertinent points and copied them into the attached document. He certainly is a fountain of knowledge on the CB450 DOHC and CB72/77.
I bought a later alloy body oil pump, used but good condtion, for my K0 and passed on a NOS steel body one that I was offered fairly cheap .. I think I will contact the guy again and see if he still has it 'just in case'. Jensen told me that there were several modifications to the K0 pump. I suspect that the one I was offered was an upgraded part as it came from Honda's Service Centre that was in Nottingham in the 60's/early '70's.
https://www.dropbox.com/s/kb8pbuwl3a4jdxv/jensen.doc?dl=0
-
I’m not sure where this leaves me, Ashley rang me about it while I was on to of a French Alp, skiing, as Jensen had given him the impression that some modification may be necessary to fit the later pump. I am now in Chambery airport waiting for our delayed flight home.
My 450 is a K1, it did have the early steel bodied pump, and I have fitted a later 500T pump to get more pressure, I’ve read a few threads about it.
The pump I fitted was from a low mileage bike, and doesn’t (yet) have a worn alloy body. I don’t think I have a clearance issue though, as mine is a five speed engine, reading Jensen’s document the problem arises when you fit the late pump with the four speed clutch.
I’ve kept the original steel body pump, I can always switch back.
Perhaps Jensen can comment if he sees this, I don’t want to pull my engine apart again if I don’t have to.
-
Mr Davo, off topic but we, yesterday, drove back past Chambery airport from the alps leaving Les Arcs in the morning to return UK.
Brilliant snow this year, some of the best for a long time. Where did you stay?
Back on topic, some of the metallurgy in these areas can be the inverse of what would appear logical in wear patterns. A steel component may be worn by a softer material given the right circumstances. The cam lobes, also, are lubricated in a zero pressure environment, so increasing pump pressure will not improve local were rates. That specific point needs absolute flow to clear used / heated oil and replace with supply as fast as possible.
Pump pressure is similar to resistance in electronics, I believe. The system will need lowered viscosity to get more supply, only then would more pump capacity give a relevant increase in oil supply to the cam lobes.
Nigel.
-
I sent Jensen a Facebook message and sure he will respond in due course. he's been away on business so it may take him a couple of days to respond.
I read somewhere on HondaTwins that there was an official Honda Service Bulletin on the early pump. Someone had posted an image of it but it was Photobucket and no longer visible in the post. I will investigate further. The construction of the alloy body later pump is the same as the CB250/350K's so I will have about half a dozen of them that I can inspect. I think am going to grab the NOS steel body one if it's still available though.
-
Hi, took a while to respond, but better late than not at all......
The intresting part is the spacer, which is't a standard one, it's thinner. I will find the pump somewhere in my stash and measure the parts... I will also make a better picture of the install guide as soon as I have the time.
btw, happy easter everyone !
Pictures :
-
So unless someone can find me that thrust washer (Google can’t) I need to put the old oil pump back, which means dropping the oil, and taking the clutch and oil filter off again.
Feck.
-
I don't think it's difficult to make such a thrust washer...
-
Thanks Jensen... Mr Davo's bike is a '69 K1 CL... is the thrust washer change still applicable to 5-speed bikes?
When I pickup the NOS steel body oil pump this week, I will quiz the guy to see if he has any Service Bulletins pertaining to the CB450K0 ...if anyone has them it will be him ;)
-
http://www.hondarestoration.com/for_sale_motoqs.asp?m=Motorcycle%20Parts&p=Parts%20and%20Accessories&c=10063&k=CL450
I haven't time at the moment to look through here, but there's alsort of related parts.
May by worth a look through.
Nigel.
-
It looks like a matter of alignment, if the kit is for a K0 four speeder that would explain why Jensen got uneven wear without it.
However if it’s for any engine swapping a steel bodied pump for an alloy one, i may well need the thrust washer, even though mine is five speed, it depends on whether the washer compensates for the body being on a different alignment or something that changed between the four and five speed clutch.
It may be easy for you to make, Jensen, but not for me without a lathe. If I had the exact dimensions I’m sure I could pay someone to make it though, if I had to.
-
How many miles has your K1 done Dave? From the looks of your strip-down, the cams & rockers looked pretty damn good to me (apart from the PO careless damage to the damper ring flanges) .. So IMHO it may be better to put the old pump back and let the bike warm up on idle and it will be good for many more miles. If you can wait till the end of the week I am visiting the guy with the NOS oil pump and he may well have a Service Bulletin on the early oil pumps. He got most of the stuff from the long gone Honda Service dept. that was in Nottingham when the bikes were new. I can also compare the NOS oil pump to an early bomber one ..it may well be that they modified the design slightly.
-
This is the earliest one, fitted in my bomber, look to it closely and you'll understand why all the early bikes having camshafts and rockers damaged....
The modification was simple, but took a lot of work, the whole pump had to be disassembled. Some dealers however didn't, and just rotated the screen 90 degrees. A handy person can do that without disassemble the pomp.
-
If anyone wants a NOS filter screen sealed in bag I have a couple at £12 ea plus £1.50 UK post. DS charges £45 special order.
[attachimg=1]
-
I’d like to have the 30% extra flow from the later pump if I can, just for peace of mind.
Last night I read all the posts on the twins forum that Google could find about oil pump upgrades, the consensus from those that had done it with no problems was to use the conrod from the original pump, as there were small differences at the ‘big end’, but fitted with the steel piston from the new pump. That way the dimensions at the clutch end are perfect, but the action is exactly the same.
I’m going to pull it apart and have a good look and a measure, as I have been turning the engine over on the starter to get oil pressure I’ll look for any damage from misalignment.
The upside is that my kickstart return spring is pathetic, I’ll take the opportunity to fit a new one from CMS.
-
I wondered what this one is? As it seems to have a different alignment to others.
https://www.ebay.com/itm/71-Honda-CL450-Oil-Pump/270370216947?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20150313114020%26meid%3Dbc7d28487f4b40b3922a637ec8e6e992%26pid%3D100338%26rk%3D17%26rkt%3D30%26sd%3D142564278298%26itm%3D270370216947&_trksid=p2141725.c100338.m3726
[attachimg=1]
Appears to make an attempt to alter the sideways loading on the oil plunger.
-
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.
-
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 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
-
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.
-
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.
-
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.
-
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.
-
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
-
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.
[attachimg=1][attachimg=2][attachimg=3][attachimg=4][attachimg=5]
-
Hi,
This the later version, there are 3 versions, the pictured one is the latest style early steel pump. The best also....
Jensen
-
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.
-
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 !!!
-
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
-
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.
[attach=1]
[attach=2]
[attach=3]
[attach=4]
[attach=5]
-
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 !!!
-
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
The stated oil viscosity doesn't, and never has done, describe the oil film specification. They are two (it can't be said completely as they exist in the same fluid) separate properties that can, and are, brought into the oil specification to accomplish different aims.
I'd not agree about the torsion bar spring either. The valve dynamics require a certain spring rate to operate at the given rpm, that's delivered the same for coil or torsion arrangements to the same rating. The cam and follower "see" the same pressure. Torsion will have a different resonant frequency than coil and may make use of that to best use the cam profile and valve acceleration rate desired by the designer.
What they have done in original design is ask for a significant performance from the valve size and timing, coupled with a relatively high rpm ceiling. That dictates a high spring pressure, which is compounded by using a rocker on which the cam profile operates between the pivot point and the valve tip. This feature alone amplifies any spring loading experienced by the camshaft lobe as it's working at a leveraged disadvantage.
Essentially, they've produced a system that is very close to marginal. Any wrong steps in setup and looking after it are severely punished in breaching what an oil can achieve in keeping the parts frome breaking down their surface finish.
As the cam interface is open (at no pressure) the oil viscosity has virtually nill effect on protecting the components. At that point of interaction, the oil is subjected to a swingeing massacre of any film properties it may contain. It really is down to the base components existing in the oil to prevent metal to metal frictional pickup. This has usually been the principle task of ZDDP content in oil.
-
Well I got a copy of the relevant CB450K0 Service Bulletin pertaining to the oil filter screen problem, which Jensen told us about but it's a very poor photo of one, so here is my 'translation'. The original was posted by Chris Saxby on HondaTwins recently (Chris has restored a lot of bombers, all early 4-speeds I believe) So many thanks Chris if you read this ... Why no join us on here ...your input would be invaluable ?
Not sure if the mod is to machine the pillars or fit an updated part but I can't see anything wrong with carefully milling the posts.
Anyway here goes:
------------------------------------------------------------------------------------------------------------------
OIL PUMP INSPECTION/MODIFICATION
APPLICATION: Engine No. CB450E-000001 to CB450E-1021156
We have found that some top-end and oil pump failures in CB-450 units has been caused by
foreign matter entering the oil system through damaged oil pump filter screens.
The oil pump intake port is surrounded by four screen-supporting oil guide ribs. These
ribs must be separated as in Fig.1. If the ribs are jointed or partially joined, as in Fig.2, the oil flow to the oil intake port becomes highly localized. The localized flow will eventually
work-harden, embrittle and break the brass filter screen. Any break in the filter screen allows foreign matter, trapped in the oil, to enter the pump, possibly fouling the check valve and damaging the oil pump.
We recommend the following inspection and subsequent modification if, during routine
maintenance, any of the following conditions exist :
1. Cam chain dampers missing or broken.
2. Lubrication or camshaft failure.
3. The right hand crankshaft cover is removed to perform other maintenance.
[attachimg=1]
--------------------------------------------------------------------------------------------------------------------
-
I took the 500T pump back out of my CL450 engine at the weekend and put the original back, I decided any perceived flow gain wasn't worth the risk of cocking something else up, as Ashely said, the engine had done fine without it since 1969.
Here's the 500T pump (now for sale if anyone needs one) as it came out, the circular marks on the washer weren't there when it went in, as far as I remember, so I wonder if there may have been a tiny alignment issue, which would have only got worse in serice. Remember it never ran like this, but was turned over on the starter for a while to get oil pressure up. I note the 500T ribs are as per that service bulletin. I didnt take a picture of the gauze on the other pump (I hadn't seen this bulletin then), but it was 100% intact, despite the odd knock pin and piece of cam having been in the original oil. I'm unsure of the arrangement around the intake port on this pump.
(https://s5.postimg.cc/3og0mtdg7/IMG_2491.jpg)
This is the cast iron bodied CL450 K1 original that went back in, the F mark matched one cast on the clutch inner by the way.
(https://s5.postimg.cc/twr5c9puv/IMG_2492.jpg)
Back in place where Honda intended it:
(https://s5.postimg.cc/yin9ksyl3/IMG_2494.jpg)
All I can say is that the 500T pump did pump oil, but not worth the risk after considering all I've read.
The engine is now fastened up and in storage until the chassis is ready for it.
-
That modified oil entry point from the information posted by Ash would appear to be one of the most critical updates to the pump casting in terms of removing problems.
It looks like it would benefit from having the burr removed from the oil entry hole as the casting seems to be quite rough there. Something like a half millimeter radius would help in reducing any tendency to cavitation for the oil entering the pump chamber.
The overall layout of the pump and arm are interesting. It looks as though the cranked arm is to facilitate a straight pull during pump fill phase as tension line will line up more closely to bore axis. The piston has the clevis pin located right at the "back" end to promote alignment during suction, it's effectively much less lubricated during this phase as the oil is under vacuum around the piston so any clearing would not be penalised with bore or piston wear as the overall alignment seem arranged to mitigate this.
Conversely the pressure stroke is subjected to exactly that "pressure" as it pushes the oil into the engine and effectively makes its own load bearing film around the piston to prevent direct contact with the bore. It is in effect an oil bearing as having the clevis pin so far back it relies on this to prevent the leading edge of the piston being directly pushed against the bore when under sideways load from the crank arm being at more of an angle.
Why they changed to an alloy body is not clearly available. It looks like that increasing the capacity may have caused (more torque required to drive it) problems with the size of the clevis pin for durability anD bore in the aluminium piston. In this case, a switch to steel piston would resolve that. Which would bring a corresponding switch to the pump body the other way. It doesn't really matter which is which material for the components in terms of longevity of bore surface as the wear characteristics work either way.
The materials in the component's do tell you about oil performance if they wear though. If all is well then they will show very low wear marks. If the oil film breaks down, the soft components will be worn by the harder material, generally. If the oil contains anything abrasive though, the wear can switch because the hard particals become embedded in the softer material, resulting in a wear pattern experienced in the harder material. Basically you can see what was going on with the oil after inspecting the wear patterns.
It's this area that would first be affected by increasing oil viscosity and/or pump capacity without changing the following engine architecture to accept those differences. The load on the pump during pressure phase will rise but the oil film (unless you change its load properties) does not have a corresponding increase. This may cause the piston to breach it's oil film protecting it's normal operation and give clear wear marks on the components.