Honda-SOHC

Starting a thread on my bike. Im in no rush and need to delay spending until its needed for that stage of the rebuild. Bike has been repainted and has lots of new cables, refurbished clocks, new spokes etc. It had just been 'sympathetically' restored but I wanted the engine to look brighter as I feel that is the centrepiece. Decision to strip engine taken out of my hands when it dropped a shifter fork due to incorrect replacement of the fork shaft retainer. Was thinking originally to fit an aftermarket 4/4 exhaust but seeing how low the prices are for fully restored bikes am certainly reigning back my spending plans. Im not looking to make a profit but having paid 3K for the bike and being personally happy to enjoy using a non mint restoration for a few years I am weighing up the restoration spend carefully to not to spend money that actually wont actually  be appreciated by the eventual owner.

 I'm chewing over what to do with the cases but present thinking is paint strip and repaint with perhaps a vapour blast of the barrels and head only.

 have managed to buy a later gen rocker cover with secured rocker shafts. The oil restrictors were blocked with sealant from the rebuild and there was barely any oil making it up to the top end. Also managed to get some headlamp ears from USA that will be suitable for rechroming unlike my dented ones.

I have stripped the frame completely which was a lovely easy job due to the recent rebuild. Going to send off the frame/ swingarm  for powder coating gloss black and need advice re the centrestand, side stand, footpeg mounts and steering yokes. Should these be satin black powder coated to look original or the same gloss black as the frame ?

Thanks in advance for all helpful advice that is typical on this site. I will try to use search and link in previous advice for others viewing this thread when useful.

all the best

David

Many thanks Sesman. I didn’t like the look of the galleries to and from the oil filter in terms of visibility. What is the problem with the cylinder head gallery isn’t it just a straight  drilling from top to bottom? Or do you mean the gallery that feeds the bottom end bearings ? Is soda blasting quite a new thing then ?

Glad to hear that Ken. I have really learned a lot from your historic posts. BTW everything seems to be working out OK with my original bottom end.

New ones were from a K3 David. The engines are identical, put 2 side by side and cover the numbers up and you wouldn't be able to spot the difference. It's not like putting a 550 in a 500 frame or vice versa. As I said IF it was so important, keep the original cases and sell them with the bike, let someone else have the expense of fixing them. £120 for a set of cases with marching shells, really good shells as well and a matching crankshaft is beyond a bargain, check ebay and see. Now you've got to pay for alloy welding and that's IF you can get the pins out, new shells, which if going by the state of the mains the rods will be buggered as well, that's 18 shells each around £20, another crank, ask Ted how much he paid for one, another £100-150, that's the fat part of £500-600. That's money you will NEVER get back, the 550 is not that collectable, it's not an investment bike like a 500K0 or even a 500K1 or a 750K0.

But it's your bike and your money and your choice.

Oh and it's a 550K1 not a 550K0 Julie. Not worth even half as much, not that the K0 is worth anything anyway.

Really sorry for the thread hijack Simon, I really wanted you to avoid the mistake I made with the clips, you have a lovely bike and it's important to me that you keep it that way, the 500 has always been MY bike, it's my first love so if I can keep one on the road that's worth going that little extra mile for. In an effort to stress how important it was to made I made that statement on your thread instead of starting a separate one which was always my intention. Sorry mate.

Ken if you would like to keep in touch about this ( I haven’t yet got any idea on the sizes, cost or availability of shells for my  engine which is pretty crucial)  pls pm me your email since I  can’t message you. Sorry for the Thread hijack Simon

Hi not really a new member since I joined in 2013 and ran a lovely 750 for a couple of years before I caught the two stroke bug and traded it in for a Yamaha RD500. Been away from forum since then. Now I've bought a 74 550k1  with intention of restoring it as a tribute to to the 500/4 which was my first big bike in 1979. Rode that bike to Adriatic coast of Italy and back which was quite an adventure but then gave up bikes until 2008 when i was the typical 50 year old born again biker. I love working on bikes and service my small collection including a Suzuki RG500, Yamaha RD350LC ypvs and my daily rider a Y2000 BMW R1100GS which unusually has been converted to run on carbs.

The 550/4 was supposed to have been fully restored mechanically but my first ride  was eventful. I got to within pushing distance of home and it conked out. Turns out by resetting the tappets before I rode it I had disturbed the fuel pipe connections under the tank which were just pushed on with no clip and the pipe had become disconnected. There was no obvious stream of fuel because the restored tank had no internal or external filters and the fuel tap was almost completely blocked.
On my second outing I rolled the bike out of the garage in neutral only for it to stop dead, The only way it could  be moved was with the clutch in. Turned out that the plate which secures the selector fork shaft in the clutch housing had been put on the wrong way round allowing the shaft to slide out and drop a selector fork into the sump. operating the gear lever in this condition just locked the transmission shafts. So the complete engine strip had been brought forward !

Ive enjoyed stripping the engine ( my tip is to take the head,  block, clutch, starter motor and as much else as possible  off when engine is in the frame making it a doddle for two people to lift and manoeuvre out.) Ive found worn out rocker shaft housing , blocked oil restrictors and best of all that the transmission bearing race pins have been driven into the crankcase by incorrect assembly. In one case the pin has cracked the housing under it and in the other actually fractured a chunk out which fell into clutch housing during the strip. Its not pretty but hopefully recoverable with some epoxy eg JB weld. photo below. Any other thoughts or previous experience with this all too common problem ?

Also not sure about the condition of the crank main bearings - look a bit like oil starved or contaminated to to me - what do people think of the photo ?

I have learned so much reading and searching for posts on here since i got the bike a couple of weeks ago and look forward  to joining in the discussion which makes this such a useful place
cheers
David

Hi David were abouts in Cumbria are you ? thanks for the offer of help  we will have to try and meet up for  a ride some time  cheers Mick

Hi Mick, I'm in Grange. Definitely up for meeting for a ride at say Devils bridge.Would be interested to see what you make of my bike. I haven't ridden these before but despite the low mileage though smooth  it seems a little wheezy and unwilling to rev freely to the red line. Might just be that I am more used to modern engines.  Previous owner thought the carbs may need synching - may be we could have a look at that sometime?
cheers
David

Hi David and welcome.
I am in the same shoes had a couple of modern bikes loved the XJR1300 but still prefer my 750 anyday.Its nostalgia maybe but for me it reminds me of the old days which I have to say for me were far better than they are today except the parts are friggin dear now.
Enjoy her
Cheers
Bitsa

Cheers Bitsa - I really like riding different bikes and enjoying the contrasts. The 750 is an easy  pleasure to ride whereas the seating position and crude controls on the commando are definitely from another 'acquired taste' era.

Hi David and welcome, the 750's are great bikes and i recon if they are survivors in standard condition then they should stay that way as much as possible, dont worry yourself with frame flex i very much doubt you will experience this unless your really racing it hard, you are more than likely experiencing the worn swingarm bearings and bad suspension, and perhaps knackered steering head bearings,
i would change the swingarm bearings and fit new taper roller head stock bearings, then possibly progresive fork springs and new oil, and last of all new rear shocks,
i just get on and ride mine as a classic nice and easy does it , i am not at all bothered by the negatives i here other people say about these bikes, they are in the top ten of all time best bikes for a reason http://dsc.discovery.com/video-topics/cars-bikes/motorcycle-guide-videos/space-age-bike.htm
pete

cheers Pete - I enjoyed the clip. My bike only has 8k on it so I wonder if the swingarm / head bearings would be worn ? I agree about nice and easy classic riding. Got rid of my Blade this summer when I realised I didn't really have the talent or appetite to exploit it nearly enough. For nme pride of ownership and burbling along in the sunshine is something to savour in the same way as carving out bends on a sportsbike.

Hi David. Sounds like that was the bike on eBay that a chap called Tim was selling? If so I think you've bagged a great bike...welcome to the world of cb750's. I'm biased as a self confessed Honda addict, but for me they're the greatest of the 70's superbikes as an all round package. Enjoy.

cheers James - Yes it is that one - just around the corner from me. It is truly staggering to think that this bike is  40 years old when it looks like it could be two. I will be looking after it and keeping those perfect original exhausts good and condensation free.