750 oil flow

[UK Pete]

with my rocker box off and engine and oil tank full of oil, i decided to check the oil flow was getting up to the top end
it was getting up there alright pumping through the cam bearings, and squirting out the four holes directed at the cam lobes, but to my horror i see that no oil passage to the rocker shafts, just a small hole on the top of each rocker in the hope that oil splashing around will work its way in there
anyway after having my engine running for about 5 mins on off, maximum of 3000 revs i took off the back tappet covers only to see them virtually dry, certainly not swmming in oil, and the inside of the tappet cap bone dry
does this mean that you have to rev the granny out the thing in the hope that a splash of oil gets to the shafts? if so what a shit design
or am i missing something
Pete

[Yoshi823]

Hi Peter. Have you checked that the small oil jets that are in the cam carriers are free to squirt oil onto the cam lobes & rockers? I seem to remember that once the oil came up through the oil restrictors just under the cam carriers, the oil is not in any way directed onto the rocker shafts...they rely purely on the oil that sits in the 'pool' of oil that is within the carrier once it's bolted down onto the cylinder head. Hence it's the splash from this that lubricates the lobes & rocker bearings. But this oil pool is supplied by the drillings within the cam carriers. Maybe a quick squirt with some contact cleaner will tell if the drillings are clear. Don't forget to make sure that the 'O' rings around the oil restrictors are new when you bolt the cam carriers back down.

[Spitfire]

Hi Pete, the fact that you are getting oil to both sides of your cam is good news, on each cam tower there are individual oil feeds to each cam bearing plus 4 spray feeds all pointing the same way. If you are not getting enought oil then it could be down to your pump, pump screen, or oil filter.
I have only looked into the front of the cam box through one of the tappet covers with the engine running and there was lots of oil spraying around. In fact I seem to recall that there were problems with the cam box running flooded (overheating ?)

Cheers

Den

[Yoshi823]

Hi Den. There were differant drillings in the cylinder heads between the F1 & the F2 heads. From what I remember there were fewer drain holes for the oil to flow away back down to the sump on the F2 head...presumably so as to keep the oil in the head for longer. The sump pans on the F2 are also slightly deeper between K/F1 & F2 sump pans, presumably to increase the total capacity.

[the-chauffeur]

Pete

There are no oiling holes in the cam towers that feed directly onto the shafts.  The feeds are the oilways you've seen spraying, and one each under the ends and centres cam journals.  The shafts rely on the holes on the top of the towers to collect spray - which isn't exactly an ideal method given the thrashing the oil pumps sometimes get.

It's probably a bit late now, but have you seen HondaMan's post on the shaft differences, top end oiling and modifying the towers?


 

[UK Pete]

I dont think i have a problem with oil, all the jets and oilways are clear and the oil pumps up through all the right places just on doing the kickstart by hand, what my point was that it is an awful design by honda just to rely on oil flicking up on to a 2mm hole in each rocker
The reason this all came to my notice was that i started my freshly built engine the other day , it fired up straight away, and sounded good for a few seconds, then a tapping noise started and became louder and louder, so i shut the engine off and checked all the tappets, they were all good so i checked the chain tensioner, again that was good, so feeling really depressed having spent  a year building this engine not to mention a small fortune on it i weighed up the options. I really was not going to take the bike apart again and remove the engine, so i thought i would try and get a gordon frame kit, unfortunatly he is not going to make the kits for a good few months, but still this sounded like the best option so i have cut the frame section out enabling me to take off the rocker cover
Anyway with the rocker cover off i looked it over and saw the problem,  it was a stupid mistake i had made which was to only do the cam sprocket bolts up by hand because i had lost my threadlock and so i was going to come back to that part the next day to lock them up, and yes i stupidly forgot about it, and reassembled the engine forgetting these two bolts, so i have now thread locked the buggers, and give them a whack on the back edge of thread with a center punch as a bit of insurance,
I put the engine back together and its up and running and sounding really sweet, just a few carb issues to deal with

Niel , the honda man posts on the rocker subjects are really good and sort of answer my original post questions which are yes a totally shit bit of design by honda, unfortunately i read these to late, so i dont think i will do the upgrade on this one just yet as i am just content with the engine running
I will update my f2 rebuild thread with my progress soon so you can see how its coming on
Pete

[kaceyk2]

Hya there Pete, I would not worry too much about the rockers on the shafts..as long as oil is spraying about through both cam carriers in a good misty way, you are good to go. I honestly have never heard of a rocker seizing on its shaft through lack of oil.. Except, repeat except, if an oil restrictor is blocked, and then you have total trouble anyways. The F2 does have more pressing foibles, as Yoshi said there are only four return oilways (one for each pair of valves) as opposed to the K series eight. (one per valve) But much worse , this desiegn has caused much confusion in folk especially tracing a persistent oil leak.... A "K" series head has all its stud holes enclosed..not so a F2 head, two stud holes at the back and two at the front are "open" hence the need for those four "special" copper washers and domed nuts in the head that are different from the rest of the head nuts. The f2's (slightly) higher lift cam was given stronger valve springs ( by todays science;caveman-like!) and yet no extra bolts to help hold the cam-towers down. All the forces are to try and wrench those towers up off the head...this is why APE do a valve cover that is threaded with extra bolts that go down onto the bolts that hold down the cam carriers, a very good buy indeed.
I am so glad you remembered that you had not tightened down the cam sprocket bolts!!!  I had a horrible mental picture of what the pieces of your motor would have looked like should just one of those bolts have unwound...and it was not good. With no disrespect, maybe a warning may be in order to stop the worse case scenario happening to anyone else??  DO NOT hand tighten bolts down thinking you will return later...either dont put the bolts back just yet, OR torque em down...this one is usually done by folk changing their oil, out comes the sump plug, and when the oil has come out they put the sump plug back in hand tight to stop drips...... 100 miles down the road later.. and OWW.., leave the sump plug out where you can see it or put it back in and tighten it up!!! Please...
I am so chuffed that you DID remember Pete, it's not just the expense of another rebuild., but you avoided being gutted and getting a severe case of "restorers depression!" As an aside but slightly conected....D. daegans (I think thats how you spell the guys name) from Dresda...using 5mm valves and single springs that can be compressed with the fingers so easily you would think they are knackered, but they are not, getting 14,000 revs from motors fitted out like this....  Imagine removing all that spring pressure from an f2 head!!! .....

[UK Pete]

Hi Kaceyk2, i wondered where you went , you were a different user name last time we spoke,
Yes you are right it could have been a horrible expensive mess if the engine had run for longer , if that had happened i would have probably sold all my sohc stuff and given up, anyway all is good i was quite lucky
Pete

[SteveD CB500K0]

Pete: he was Kaceyf2 (changed bikes I presume...)

Kacey: it's Dave Degens. Here he is a couple of years back on Eamon's Dresda 900

[kaceyk2]

Hya again Steve..Yees, I changed Bikes!!! BUT, (please for the last time, please...like really) I changed my user name for this reason; I had my kaceyf2 account on quite a few sites, and like a good boy (which my misses tells me I have to be) I had different passwords for different sites. ...(which you are meant to do) BUT, being me, I could neve remember which one was which..( my misses can remember ALL of hers, because she has a "girl brain" and also as you probably know; Missess's NEVER forget anything.) Soooo, knowing how crap I am, I wrote all my passwords down in a folder thinking that would take care of that...
What i didnt count on was (a.) changing the service provider, changing the computor, and LOSING the folder.
Then , when I tried to tell .net site I could not find me old email address AND I had a new IP address, they couldn't help me keep Kaceyf2. This upset me some, cos I liked it. Sooo, I have had to re-register with most sites, and thought Kaceyk2 would noe be more appropriate seeing as I am restoring my k2.
Anyways, I think I am still me. 
The pics of Dave are brilliant, truly, thanks so much, this is one man I could never tire of listening too, I read and re-read everything he has had to say in the magazine articles I have. His wealth of experience and vast knowledge should be wrung out of him and set in stone as far as i am concerned!!! magic.
According to Dave, after years and years of racing and bench testing, he catergorised breakdowns in racing into two main groups....gearbox failures and valve train failures, and for cb'ers I believe the latter and his knowledge of the latter is well worth learning?
Again, lovely pics Steve.

[the-chauffeur]

I don't need to use my imagination to know what you end up with if a cam sprocket bolt lets loose . . .

 . . . I found one of mine in the oil pan when I disassembled my K2 engine, together with a handful of metal shavings from where the cam sprocket had been flapping about and cut a chunk out of the rocker cover.  Dunno how it happened; I thought I'd done everything up right when I last put the engine back together, but I guess I'd missed something.  And no, the damage didn't stop there - something sharp had gotten into the oilway, gone up into the head and scored one of the camshaft end journals and the corresponding rocker tower.  Added to that, the oil pump suffered scored internal surfaces.  It's not a sight you want to see more than, well, never.

Work since then: completely stripped engine, replaced all bearings (SKF ball bearings), rebuilt the oil pump with additional parts, new pistons, new camshaft and sprocket, new chains and rollers/tensioners together with better cam towers (modified like Hondaman suggests), rebore, new valves, recut valve seats, replaced valve guides and a handful of professional thread repairs in the head - and swapped the final drive for a later K model version (which benefits from a more substantial bearing than the early models). It's been a long few months waiting for bits and engineering work but I'm just about at the point where I'm ready to bolt the cases together again. I'm still not quite there yet (the frame has had a Gordon kit fitted and needs re-powdercoating), but with the help of Hondaman's book I'm hoping I'll have a nearly new engine by the time I've finished.  The only thing the engine will lack is paint.  After any number of disasters with fuel I've given up with that and for the sake of my sanity am going the ACF50 route.

Back on topic - Pete, you're right; the rocker shaft oiling system that was put into production was pretty crappy.  Such a shame Honda didn't drill out all the extra holes in the cam towers at the factory, but I guess that's production economies for you.

[UK Pete]

WOW Neil thats bad news when things like that happen, i suppose my near miss was almost the same, but yours went a bit further, and done destruction to your engine, i was not prepared to take the engine back out of mine so i cut my frame ready to fit a frame kit, unfortunately he is not making them for a few months, so i might make  a temporary one like the APE kit which was a tight fitting sleeve which slides over the cut ends and is bolted or clamped in place
Again the frame on these is another bad design, it would have been so easy for them to make the top end accessible, but they didn't
Once you have altered the frame it becomes a real joy to work on , like i said you can have the rocker cover off turn the engine over and make sure the oil is coming up where it should, and be able to ovehaul the top end in situ,

The por15 engine paint is petrol resistant , i know this as in getting my engine running correctly involved taking carbs off a few times spilling petrol all over the engine, silly little mistakes like taking the tank off but not turning off the fuel tap ect.
The engine paint withstood quite a few spills , but i am really peed off about my brake stuff, i sprayed all of this stuff up with por15 and have found out that it does not like brake fluid and has ruined my calipers , i have had quite a few downers while building this bike , and have learned some valuble lessons, just like the sequence of how you reassemble, you can spend half a day putting all sorts of bits on only to find you have to take them all off again, to fit a piece that slipped your attention, still you live and learn i get really frustrated at some points but if you stick at it it all becomes worth it
Pete

[the-chauffeur]

Yeah - it's been a steep learning curve for me, too. Two steps forward, three/four/five back.

As far as the frame goes, I did a bunch of research and found that removing the section above the engine was a common mod among racers in the '70s.  Since I'm not putting the bike under anywhere near that kinda stress, I spent a few months riding round on the bike with that section removed waiting for my kit to arrive and didn't notice anything untoward.  Don't rush with the refit - the kit is well worth the wait.

As for callipers, I tried hot paint (may well have been POR15 black spray) which I then cooked in an oven I got at a car boot sale for

[Yoshi823]

I was asked several times by people to replicate my frame mod back in the early '80s. The only problem was that the standard tank would need to be cut & modified to fit the new frame.

[kaceyk2]

Pete, ditch your old corosive brake fluid, nothing likes brake fluid, paint, chrome, its just nasty. I use and would recomend silicone brake fluid, I know folk who have used it in k0's for years so its fine. Its purple, and is none corrosive, if you spill it on paint it will just make the paint shine, same on chrome..... hARLY'S (notice the small "h" ha ha) use it as stock in all there bikes....way to go.