Well, this is going to be a long thread with lots of pictures, I would think the thread will be active for over a year as this project is going to take quite a while. I picked up 1981, CB750 K a few weeks ago. I have done loads of work to it already, but this mainly boils down to getting it to charge, and am still trying to get it to run properly, but its all slowly getting there. The pictures below are one when I got it, and the other with dropped bars and a seat literally thrown on. Excuse the different camera lights and therefore different colours, but its the same bike There is so much work to be done I really can't list it all, but it will virtually be a new bike when its finished, lol I will update the thread as I do the work, so sometimes it might go very quite if we are busy. I will also retrospectively update the thread with what I have done to date.
The work done so far involves the following: Note 1: Read the internet thoroughly before doing any work, it will take less time and cost less 1) Charging system When the bike arrived I knew it was not charging, so with my knowledge of modern bikes I went ahead and bought a rectifier, mistake number 1, it wasn't the rectifier! Knowing now it can only be the stator as that's all that's left, I went out and bought one of these, promptly fitted it with a smile, and,.... nothing, mistake number 2. At this point I took heed of note one above, READ THOROUGHLY! From another forum on CB750's, I found out the part often at fault is the rotor, so with multi-meter in hand I checked the resistance in mine, which was lower than it should be, I also checked the rotor and rectifier to find even the old ones were fine So, bought a rotor, fitted that, I now have a charging bike. Running The bike never ran well from the moment I got it, but I was aware the tank was dirty and needed a clean. Back to note 1, take heed of others, but no, I decided in my haste to start it and it ran like a bag, getting worse with each second, also noticed it was dripping fuel. So, carbs off, quick strip down, check float heights and not much better. Did I mention note 1? As it was leaking fuel and it wasn't the float heights, I ordered new bottom gaskets to "try to" stop the leak. Note 1 again! Turns out this thing has hidden jets, so I ordered a carb repair kit, which included the bottom gaskets and new jets! So, with shop manual and someone's notes on how to do the job properly, I set about cleaning and rebuilding the carbs from scratch. To my amazement, it started up and ran really well, but, still with a fuel leak! The one point I skipped in the instructions was to replace all the "o" rings with new ones, I tried using similar ones which I had in the shed So, order new "o" rings from USA, fitted those, way hey, no fuel leaks, however its now missing on cylinder 2, so carbs off again soon to try to fix that, lol. Other work so far: New plugs New plug leads New rectifier New stator New rotor New seat hump New café racer type handle bars New fuel filter New 65mm rev counter Most of the rear end of the bike stripped off Indicators removed New battery New 20mm stick on racing seat foam Work to be done at some point Strip carbs again to fix cylinder no. 2 Attempt to fit seat properly Re wire from virtually nothing as it all needs moving Cut and weld fuel tank to a better shape along the bottom seam New 4 into 1 pipe New levers New shorter clutch cable New shorter throttle cables New shorter braided front brake hose New front light Find way to mount new front light in lower position Do "something" with the front mudguard, open to ideas on that one! New 60mm Speedo Fit new speedo and rev counter, somehow Cut back end of bike and re-weld if need be, depends on where the battery is going Replace front springs with progressive springs and new shock oil New rear shocks New tyres Take engine out Strip bike and spray / powder coat the frame Re - shim valves Maybe re spray engine Put it all back together And finally, no doubt a load of other stuff which I have not even thought about, lol I will of course post up stuff and pictures to show what's been going on, but there will be weeks between them as I have a life too, lol
Nice one Steves, looking forward to this, just coming to the end of a deep service/modernisation of my NC30 I know where you are at brother
It's not comprehensive, and it's not a rebuild like yours, on here under NC30 Shakedown. I think I will get it finished tomorrow, just got to refit the front wheel, calipers and bleed, mod the reg/rec wiring and fit the bodywork, set the front suspension up and have a beer, and post some pics up and ignore my bank balance The one thing I have learnt, is that the biggest destroyer of old bikes is fire from fuel leaks, hence I have replaced every seal and gasket and hose
