SOHC.co.uk Forums > CB750

750 oil flow

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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.

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