Author Topic: CB750F2 .... silk purse from a sows ear.  (Read 5735 times)

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #15 on: July 30, 2018, 10:59:32 PM »
It's a multi stage task....

1) strip and carry through the house to the shed to work on main assemblies.

2) dry build in back garden where it's safe

3) when it's all snag free...break it down for final assembly out front.

I want to be able to work in a safe place e where I can stop for a break and not need to pack everything away. Nasty right turn off the hall prevents a clear run with a complete bike...and not getting a divorce prevents me building it in the hallway 🤔
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline MCTID

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #16 on: July 31, 2018, 08:27:03 AM »
My Brother in Law built a 26 foot long steel boat in his back garden, then when it was finished he lifted it up and over his Bungalow with a Crane.................just saying.
Now: CB750K4. 1970 Bonneville. Various other 1960's 650 Triumph T120's/ TR6's/ TR6C's. Previous: CB1300 (2). ZXR1200S. VFR800. CB750 Nighthawk. CX500. XS500 Yam. Suzuki GT500. BSA A10. Various Lambrettas. Zunddap Bella (honest).

Offline SumpMagnet

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CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline paul G

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Honda CB400 4
Honda CB550 K3
Honda CB750 UK K1 restoration
Kawasaki Z650 C2
Kawasaki Z650 cafe racer (bitsa) ongoing

Offline moorey

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #19 on: July 31, 2018, 08:52:20 AM »
Leave the complete front end off, remove the rear wheel and stand it up on the swing arm ends on a sack cart or dolly and a couple of you should be able to get it through the house. I've done it many moons ago. But you have plenty off time to think about that one yet.

Offline royhall

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #20 on: July 31, 2018, 09:17:48 AM »
Hi. Are you selling off the bits you don't want to help fund it. If you are can I have first dibs on the exhaust headers. I fully restored one of these a few years ago and at 14000  miles the head will be ready for a rebuild, specifically the exhaust valve guides. Sorry to sound mercenary about the exhaust but you have to get in quick on here. Good luck with the build.

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Current bikes:
TriBsa CCM 350 Twin
CB350F in Candy Bacchus Olive (still smoking on pot 4 Ggrrrrrr)
CB750F2 in Candy Apple Red
CB1300SA in Black
Triumph T100C
Suzuki GS1000HC (DHL morons ruined my tank)
CB450K0 Black Bomber (current project)

Offline Oddjob

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #21 on: July 31, 2018, 11:24:06 AM »
I have a pair of NOS headlight brackets for the F2 if your interested.
Don't play stupid with me, I'm better at it

Offline Spitfire

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #22 on: July 31, 2018, 12:46:01 PM »
Looks like that will keep you off the streets for quite some time, it's good that you are taking lots of photos, I found it handy when reassembling, especially for cable and wiring runs.

Cheers

Dennis
1976 CB750F

1977 CB750F2

1964 BSA A65R

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #23 on: July 31, 2018, 01:02:02 PM »
With front and back ends off, we just about managed. Made a harness for the front to take the weight, with second person steering from the frame rails at the back. Damned heavy.. my back is aching...but we did it. These things are VERY heavy. Will get a sack truck for next time.

Next job is to get the engine out. I have made a cradle out of scrap wood so I can roll the frame over...and lift it off. Then I have a stretcher frame to move the engine so I can get it in the shed and on the bench. Once I have recovered..

As far as mileage goes...I am pretty sure the Speedo is not original, so I am assuming high mileage...and expecting at least a tip end overhaul. Plus..can gain tensioner, guides etc.

Better that way I think. Pessimists only get nice surprises. Optimists set themselves up for disappointment......

Nice surprise 1...
The forks dropped out if the yokes nice and clean, with no suspicious tight spots. A sign of straightness. Chrome is amazingly good. I have got bikes through MOTs with worse. 

Nice surprise 2..
The headstock was nice and tidy with no I ovalling, and the bearings had been greased. And the castle but had never seen a hammer and screwdriver.   

Today's odd find.   
Something looked to have been welded on the frame behind the tank mounts at some point, either side of the centre top tube. Then removed and painted over. Thought it was damage until I realised it was on both sides and symmetrical. Wonder what was there... 

Now...my surplus parts...
I probably will be selling on the bits I don't need to help buy the bits I do. Not immediately, just in case plans change...but as soon as I have a replacement part paid for. But drop me a message on the headers and I will give you first refusal when  I sell. Going to cut off the remnant of tail pipe as the clamp is messed up and give the chrome a clean so I can check condition.

Not sure yet on the headlamp brackets. The clamps on the ones I have are good...and I have some scrap 4mm ally plate (6061 I think) so might make my own. Depends if I can find an original headlamp assembly.

This afternoon's job is to make a bearing retainer tool ....
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: CB750F2 .... silk purse from a sows ear.
« Reply #24 on: July 31, 2018, 01:09:50 PM »
Going great guns, well done. False economy and bad practice just hoping to do a top end rebuild. There are rubber seals and O rings that will be perished in the bottom end and it is a bit fool hardy not changing the primary chains whilst the engine is out. You could start it up after a top end overhaul and the bottom end could most probably be clanking away (more than they do at the best of times) and you would need to take engine out again.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #25 on: July 31, 2018, 02:55:46 PM »
Good point and noted about the primary chain and tensioner. I'm more used to Hy-Vo types that last forever, and this is a roller one. Added to the list of things.

So it's strip down the top and both sides, flip it over and split the cases. Check gearbox bearings, shafts, gears, selectors. Check the state of the crank, replace the primary chain and tensioner, sort the camchain and tensioner/guides. Gearbox output bearing and seal will probably get swapped as well. Exhaust valve guides, find at least 3 more exhaust collets, add in a full gasket set....and replace anything worn out or broken. Which will probably include me by then :)

meanwhile....the shelving set aside for bits in the shed is filling up nicely...


All the smaller bits are labelled, fasteners replaced in situ, and boxed or bagged up


The frame and engine are in the back garden safely wrapped up while I tidy up and get ready for the next stage. I even had time to relax and experience the joys of the laid back easy rider bars this thing arrived with.....


you didn't think I was going to put  them on a bike!!!

While I try to figure out what might have been attached here....

Weld scar on the first layer of bracing....at the corner of the second. There is an identical one on the other side.

I also need to work out how to strip and paint the frame without losing the rivetted on ID plate. Sure, there is a seperate stamped number, but I would really like to retain it.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1978 CB400/4.
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Re: CB750F2 .... silk purse from a sows ear.
« Reply #26 on: July 31, 2018, 03:06:47 PM »
The frame looks standard to me, no extra bits and no bits missing either.
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline K2-K6

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #27 on: July 31, 2018, 03:08:51 PM »
The weld scar is just a weld through point to the underlying tube of main frame. 

It's to raise the torsional rigidity of that top tube going into the headstock or else the pressing could to rotate around the tube. Also distributes the weld loading further along the tube from that seam weld to assist in avoiding a stress fracture at the seam point.

They'd have had two holes there in production so that they can build weld up on the base tube within the hole and then fix it to the perimeter of the outer pressing.

I think.

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #28 on: July 31, 2018, 03:48:40 PM »
Thanks ...you lot know EVERYTHING!

Nice to know this sort of thing, as I want to learn all I can about the beast as I go, good and bad, and ugly. I would be tempted to break out hte grinding pad and remove it...but now I won't. It's supposed to be there....so there it will stay :)
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Bryanj

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #29 on: July 31, 2018, 04:04:47 PM »
Gearbox bearings rarely need replacing unless allowed to go rusty and several are Honda only (expensive) due to grooves on the outer, rest is just time, care and super cleanliness