What have you done with your bike/s today?

[muskrat]

G'day Bergs.
I bought one of them new in Feb 81. Prior to 81 the Yanks had the 750 and we had the 900. I got the first black CB750FZ in the country. Did about 250,000Km's on her and she grew up to be 985cc.
The first dohc was a CB750KZ RC01 in 78/79 (had one of them too), older styling like the K's but with dohc motor and comstar wheels.
That front m/cyl can't be original. Mine had twin piston brakes.
RC04 is 81 dohc, yours must be an import. The F2 was the later faired version.
Cheers

[berger]

musky thanks for the info, but mine is single pot twin discs and I think 1981 were twin pot  . it is an import all the stuff is in Japanese and then at the top corner I found cb750f. I think it's a 1980 and over the years some one has put f2 stickers on it. the front master cylinder seems like it has never been off the bike and matches pics of late 70's early 80's 750's although it is a four screw lid and most I have seen are two screw I have searched the internet and looked at the manual and books but there are so many variants it's hard to tell. the only frame numbers I find start RC04-2 and mine is RC04-10003**, any way I have no luck with a used or new rear master cylinder so will be bodging one on that's nearly the same

[RDfella]

At last the new timing chain adjuster cover arrived and so fitted it and put the project on the starter rollers. Blew a fuse (it takes a bit of turning over) replaced that and started it. Ran fine until I eased the choke off. Stumbled then stopped. Tried again - the same. I've just spent a couple of weeks sorting the electrics - a real hassle requiring relays and diodes - and fitting the rear chainguard and primary cover. Apparently this work has now affected the jetting of the mikunis (because nothng else has been changed). Maybe you have to fit bigger jets for the winter?
Well, I've had a gutful of these carbs and I'm not going to play with jets anymore. The Amals I have won't fit without cutting a chunk out of the side of the fuel and oil tanks, so that's not going to happen either. Oh, and the gearbox leaks oil, but frankly I don't care. It's a BSA box so probably incurable anyway.
So I have a bike that's a pig to start (1,000cc @ 9:1 need spot-on carburetion to kickstart and that's an oxymoron with mikunis) and so roller-starter is the only real option. And it won't now run without choke. Was looking forward to showing you guys a video of it running, but now looks like the end of the road for this project. Very disappointed.

[BigJim]

Take a big step back RD. You've put so much work in and really pushed hard to get this beast this far! I can fully relate to that frustrated/angry/defeated feeling. Tho not having put anywhere near the skill and time into any of my bike projects. It's a bit too special to keep as an ornament! You'll get there fella, if not i'll assist with the sledgehammer.
 

[Worty]

Jim's right RD, take a big step back and give yourself some time.   This looks like a brilliant project and will be well worth it in the end.   There were times with a simple A10 rebuild that the lump hammer came out, occasionally I used it and paid the price  (trying to get the swinging arm spindle in through the bushes - the swinging arm didn't want to fit in the frame and the spindle didn't want to go all the way through ).  Oh, and by the way, this was the FIRST job I attempted.

[chaterlea25]

Hi RD
Have you tried some fresh petrol?
I have had had similar problems when a bike has sat for a while
Other times the petrol seems fine several month later

John

[metalflake11]

Pre winter service. 

Every fluid changed, all adjusted, greased, oiled, cleaned, prodded, poked, and inspected. Carb cleaned out, jets blown through, float height checked, mag and dynamo bits cleaned of dust

Hate doing it as much as I look forward to doing the pre summer service for obvious reasons!

Next is my winter wear.... I need to find my combinations which might need a quick rinse after being worn all last winter. After that it's soddin' waterproofing everything.

What a faff!

[RDfella]

John - been caught by modern petrol going off in short order before. Learnt my lesson a few years ago when I spent half a day with my son trying to start the B31. Kicked it to death, pushed it for ages - nothing. Started 1st time with fresh petrol.
Petrol in this bike is under a month since bought from filling station so shoukd be OK. Normally the result of stale petrol is starting, but this will start and run - but only whilst the chokes are on. Runs all throttle openings but with choke off it chucks it at any opening. And apart from cleaning one float needle valve (again) nothing has been changed since it last ran - without the choke. Haven't touched the rear carb at all - if the front carb was at fault, at least it'd run on one cyl.
I've been pushing hard to get this finished and registered but, as others say, I need now to take a break. When you've run out of ideas, there's no point in continuing. Normally in a situation like this I'd call in a mate as a second pair of eyes / opinion often does the trick. Unfortunately, at my age virtually all of the candidates have either passed away, retired to another country or are physically not up to it. Added to that, when I was in business I was the 'go to' guy when others had run out of ideas. I even used to get main dealers sending me customers' cars they couldn't fix themselves. But who does the 'go to' guy go to when he's stuck? This forum, I guess.

[Greybeard]

I haven't done much with my bike this year. Today I had the idea to just go for a pootle. The weather was not too bad so put my bike riding gear on and got the old girl out of the shed. After a generous tickle of the wossname and a heavy right foot she fired up first kick. I checked the oil flow and this time remembered to put the cap back on. I rode around Warwickshire and the Cotteswolds for a couple of hours. I didn't go over 60mph. The countryside is lovely at this time of year. The leaves are turning golden. The back roads were quiet. The villages were beautiful.
A great ride out before winter comes.

[metalflake11]

I haven't done much with my bike this year. Today I had the idea to just go for a pootle. The weather was not too bad so put my bike riding gear on and got the old girl out of the shed. After a generous tickle of the wossname and a heavy right foot she fired up first kick. I checked the oil flow and this time remembered to put the cap back on. I rode around Warwickshire and the Cotteswolds for a couple of hours. I didn't go over 60mph. The countryside is lovely at this time of year. The leaves are turning golden. The back roads were quiet. The villages were beautiful.
A great ride out before winter comes.

And secure your shoes firmly?

[Greybeard]

I haven't done much with my bike this year. Today I had the idea to just go for a pootle. The weather was not too bad so put my bike riding gear on and got the old girl out of the shed. After a generous tickle of the wossname and a heavy right foot she fired up first kick. I checked the oil flow and this time remembered to put the cap back on. I rode around Warwickshire and the Cotteswolds for a couple of hours. I didn't go over 60mph. The countryside is lovely at this time of year. The leaves are turning golden. The back roads were quiet. The villages were beautiful.
A great ride out before winter comes.

And secure your shoes firmly?

No shoes were lost during the making of this pootle!

[metalflake11]

Last job for me for the winter service was clean the sump filter.......

Squashed little pieces of alloy/aluminium! 

Couldn't find any anywhere else in the oil system, and the only thing I could think of was the fancy alloy pushrods being the same material.

Sure enough, one of them at the follower end (exhaust) was an odd shape, and the hole that goes through it had sharp edges.

These are only about 15,000 miles old, so I'm guessing something has dropped down the tunnel and sat in the follower cup and started chomping away.

I am also guessing the bits got squashed by going around the cam.

It all keeps S.R.M. (my go to people) going I suppose!

[KiwiGF]

Last job for me for the winter service was clean the sump filter.......

Squashed little pieces of alloy/aluminium! 

Couldn't find any anywhere else in the oil system, and the only thing I could think of was the fancy alloy pushrods being the same material.

Sure enough, one of them at the follower end (exhaust) was an odd shape, and the hole that goes through it had sharp edges.

These are only about 15,000 miles old, so I'm guessing something has dropped down the tunnel and sat in the follower cup and started chomping away.

I am also guessing the bits got squashed by going around the cam.

It all keeps S.R.M. (my go to people) going I suppose!

There was a batch of alloy push rods around that had the wrong radius tips, so they could get jammed in the rocker and cause large clearances and even pop out and generally cause mayhem, maybe you had some of that batch?

[Joolstacho]

OOooo Eeek! I've got those sexy 'racer' alloy pushrods... I'd better check me tappets! 

[Greybeard]

... fancy alloy pushrod...
... one of them at the follower end (exhaust) was an odd shape, and the hole that goes through it had sharp edges.
.......
It all keeps S.R.M. (my go to people) going I suppose!

Soon after the rebuild I had one of my replacement alloy pushrods break. I bought a steel set from SRM.