Author Topic: CB750F2 .... silk purse from a sows ear.  (Read 5029 times)

Offline petermigreen

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #30 on: July 31, 2018, 06:53:50 PM »

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.
There are two ways to retain the vin plate. You could mask it off or ask your powder coater/painter to mask it off but mine won't do it.

or you can carefully remove the rivets and replace the plate after painting. I used these

https://www.oneillvintageford.co.uk/cgi-bin/sh000001.cgi?REFPAGE=https%3a%2f%2fwww%2eoneillvintageford%2eco%2euk%2f&WD=rivet&PN=Ford_Model_A_Dash_Plates%2ehtml%23a_23100#a_23100

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Probably available elsewhere also but haven't been able to find them.

Select suitable size rivets from the pack and measure diameter then find a drill bit a shade smaller and they tap in quite easily.

BUT.
If you need to get registered in the UK make sure you take a photo of the vin plate BEFORE you remove it for evidence. I nearly came unstuck with my CB400F restoration because the dating officer said it showed evidence of tampering which technically it had as I'd removed it and replaced it but on the same bike so no shenanigans  ;D
« Last Edit: July 31, 2018, 06:56:28 PM by petermigreen »
1944 42WLA
1972 CB750K2 USA Candy Gold
1972 CB500K2 USA Candy Jet Green
1975 CB400F0 USA Ruby Red
1976 DT175C
1982 RD200F

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #31 on: July 31, 2018, 07:36:54 PM »
I'm my own painter....so I will try masking it off.

If that fails...I will follow your advice, remove it and re-rivet...but photgraph it first. I have the US title paperwork with the details on confirming year of reg etc. plus VIN/Engine numbers...so I will hold that up in the photo too. That's a handy thing to know. Easy pitfall to avoid.....but only when you know!
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline moorey

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #32 on: July 31, 2018, 08:21:21 PM »
If your HT leads look a bit grim do not bin them. Click on Alladins Cave and read Ash's coil fix.

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #33 on: August 01, 2018, 11:26:21 AM »
The leads are rock hard...and I am on the 'how to swap your leads' article like a tramp on chips.

No point troubleshooting ignition faults with corroded caps and crusty leads....and I don't want to buy pattern coils if my originals are still good.

First job on the electrical side is to stick a 12v DC supply on the battery end....and see what comes through. If anything!
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Rob62

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #34 on: August 01, 2018, 12:53:57 PM »
I also had problems with my 44 year old leads, they looked ok and weren't hard, but once the motor fired up and warmed up, the centre insulation started to melt and the suppressor caps fell off!. I think the coil repair idea is cool and definitely one for the concourse restoration. But if you want a trouble free cheap solution the wemoto coils are ok.. £25 each and even though they are cheap they have to be better performance than the 1960's / 1970's ones they are replacing. You cant see them on the bike (although they look ok anyway) and the motor runs beautifully. The other option is to go electronic and ditch the whole system, coils, points, condensers etc... I may go down that route eventually. but for now the wemoto coils are a cheap easy solution. As always, its a matter of personal choice.

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #35 on: August 01, 2018, 08:50:22 PM »
Now at crunch point.....it's time to take the engine out of the frame. My strained muscles ahve recovered enough after I dragged it through the house with the aid of my eldest lad. Damn...it weighs a TON!!!!

Now...I have knocked up a little wooden frame which will fit around the points cover. It's not a wonderful points cover....and a bit crinkled....but that's not the point. I don't want to grind it into the floor. My plan is to roll the bike over onto this little frame. Then I can lift the frame and bits off the engine....Then the engine can be carried to the shed and rolled back the right way up on the workmate. Then I can start the top end strip in slow time.

For some reason...I am not 100% sold on just lifting the engine out sideways. Clearance is not good...and the lump is ...er...a lump!

If this goes well...I shall use the same method to put a hiny rebuilt engine into a shiny freshly painted frame. Should result in a whole lot less scraped things. If there is a better way...well...please tell me know! This shall be done by the weekend.

Meanwhile...I will be trying to sort the wiring and electrics, which I have left on the frame for now. Makes it easier to work with as I do not plan on using engine power here. Points will be 'simulated' with a push to break switch so I can energise the coils and break the circuit to cehck for sparks. Should all go well :)

Then..well...then I need to start drawing up a list of what parts just need a refurb, what just needs a cleanup...list what I know I need to buy and start pricing up the things.I need to spend a few days thinking....doodling...planning...and deciding. I have an outline vision of what I want to do....and now is the time to turn the outline into a much more concrete plan.

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 #36 on: August 01, 2018, 09:16:20 PM »
If you need a proper engine stand, we make them and sell them to forum members. They give enough clearance that you can build the complete engine, including sump. PM me if you ever need one, no complaints from forum members so far who are or have used them. Check the max weight if the work mate, you need about 100kg. I help Graham lift these engines and I'm no wimp but they are bloody, bloody heavy, especially lifting from floor to strip down bench so just be careful.
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 #37 on: August 02, 2018, 07:41:45 AM »
The workmate is ok for the weight, but I hear you on just how heavy these things are. We barely managed to shift the lump in the frame, so was guessing around the 100kg mark for the engine. Hence my desire to avoid trying to dead lift it out if the frame.

Engine stand interests me. Any chance you could message me some details/pics/prices? May have to save up the pennies, but these sorts of things often repay in ease of working, lack of scraped knuckles and avoided aggravation further down the line.
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 #38 on: August 02, 2018, 08:09:20 AM »
PM me your email address and I will send you some pics etc later. Off out for a ride now, it's such a glorious morning.
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 #39 on: August 02, 2018, 09:32:18 AM »
For just generally laying them on their side to remove engine or just sitting around and to avoid find/casing damage, you can use an old car tire.
They'll usually let you have one for nowt at a friendly tire depot,  14 Inch diameter is not a bad size for it.

Offline UK Pete

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #40 on: August 02, 2018, 09:57:38 AM »
What a good idea nigel
For just generally laying them on their side to remove engine or just sitting around and to avoid find/casing damage, you can use an old car tire.
They'll usually let you have one for nowt at a friendly tire depot,  14 Inch diameter is not a bad size for it.

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Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #41 on: August 02, 2018, 11:44:26 AM »
Car tyre.....DOH.

Bloody obvious really. Annoyingly...the wife just had 2 new tyres on the car, and I could have had one of those while it was being done...but I have a tyre place just round the corner. Guess whereI am off to next :)

But we got some more stripdown work done today. Found things....learnt things....discovered my knees have more  wear then an old set of exhaust valve guides. Sadly...I cannot find replacements on E-Bay so will have to just spray with WD40 and give them a wire brush. Worked for most other parts.

Got a pile of odds and ends off, and discoverd my brake pedal is bent and was fouling the footrest. Will ease this into shape. Otherwise...it's perfectly usable for now. Onto my second box of 'bits' all labelled, itemised, and itinerised. Is that a word? I will not be rummaging for lost bits when I put it back together....... ( OK ... I know I will....and will be reminded of my rash statement... )


Carbs are off....levered from the iron hard grip of the carb 'rubbers' ..... Might need new ones here....or a sledge hammer to repalce the carbs. Slides look pristine...but any wear will be in the body not the slide, as chrome is harder than alloy, but I dreaded rust spots on the slides. Found some fuel residue in the bowls. Was liquid.....but fuel is probably giving it more credit than it deserves. But rather that than bone dry and dusty.


Now...as with all strip down sessions...there were things found I didn't like.

1) The rear upper engine bolt is the wrong size. Too narrow by a few mm. Don;t like that. I thought the bolt was bent...but no. It was just skewed in the frame. All the other bolts are OK and all the mounts line up nicely, so I reckon someone wrecked the thread 'removing' it with a hammer at some point. This was not a recent bodge, as the thing was quite corroded along the groove it sits in. Have noted that for replacement.


2) One of the points cover screws has been helicoiled. The bottom screw was missing...but thankfully the thread isn't! Also the cases underneath are not damaged. The end cover is battered, but the alloy under is unmarked. I suspect a swapover.....

I also learnt some lessons.....

1) The rear oil pipe is the feed pipe. This is the one that will still be full of oil when you drain the tank, and whilst it does not hold much oil, it is enough when you are trying to block it off and keep oil off the patio at the same time. This brings me onto lesson 2...

2) I found out the use for the plastic trasy under the seat. The one next to the battery holder. It's purpose is to ensure you cannot get the oil tank out of the frame while trying to move the gunk coated oil pipes out without dropping more oil on the floor. Yes. Who says the Japanese have no sense of humour. It is the perfect depth to prevent the tank coming out.

And I have one of those 'what is this thing' issues to resolve.

Whilst prepping for engine out, I have removed the breather pipe from the back of the gearbox that goes to the oil tank. I also have another pipe going from the cam cover down to a small round catch tank under the battery tray. This had another pipe running to...well..I don't know because it was not attached when I got the bike, but I suspect the airbox...and a drain pipe that weaves it's way down to behind the right hand footrest hanger. Presumably it's a catch tank for a cambox breather, recycling into the airbox to burn off residue in the engine, and an overflow pipe for emergency and to prevent airlocking. Is this a standard fitment for all ...or is this a US emissions thing? I would expect the crankcase breather....but not sure about the other.

I also....thankfully...found the most useful of tools. It was also the first EVER special tool I bought. 32 years ago. From a Honda dealer in Yeovil, Somerset. I had a CB125T2, and was struggling to undo the cross head screws on the sprocket cover to fit a new chain. Asked for advice...and was told to buy a particular t-bar screwdriver....which they happened to have. 32 years later...I am still using it, and it is still a perfect size and fit for 70's Honda screws in engine casings. Fits snug, gives good purchase, and lets you put enough weight on while you turn it.


Thank you Paul Branson's of Yeovil. ( I think they are still going as well )

But with all the engine mounting bolts loosened off, and lightly nipped back up ( so I know they will all budge with minimal effort ) , the wiring off, the oil pipes off, and everything likely to get in the way removed....I was beaten by the heat. Tomorrow.....the engine leaves the frame :)

edit: Forgot to say...I found the cover from between the horns jammed into the toolbox under the seat... and...one lug from the left hand sidepanel. It was missing when I got the bike..but guess what...I have one mounting lug! It was wedged in the rubber.
« Last Edit: August 02, 2018, 11:54:19 AM by SumpMagnet »
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Trigger

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #42 on: August 02, 2018, 12:30:51 PM »
Breather cover and oil filter housing off makes it easier  ;)

Offline paul G

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #43 on: August 02, 2018, 12:38:00 PM »
Interesting writeup sumpmagnet :) keep up the good work.
Honda CB400 4
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Offline UK Pete

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #44 on: August 02, 2018, 12:38:41 PM »
And exhaust studs
Breather cover and oil filter housing off makes it easier  ;)

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