SOHC.co.uk Forums > CB750

750 oil flow

<< < (3/4) > >>

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.

Navigation

[0] Message Index

[#] Next page

[*] Previous page