Author Topic: CB750F2 .... silk purse from a sows ear.  (Read 31629 times)

Offline Spitfire

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #255 on: September 17, 2020, 07:09:33 PM »
Good luck with the house move, a very stressful time, I recently narrowly avoided it by building an extension to give me more garage space and spent some more on the garden for the "Boss".

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #256 on: June 14, 2021, 10:21:29 AM »
Yes!

this project isn't dead, and can now ..after 9 long gruelling months of trying to move house, finally get back under way.

Next week I get the keys to the new place, and it has a garage! the space I need to start assembling the beast. Before, all I had was a shed in the back garden with no access to the road..meaning aything I put together woud have to be carried through the house and assembled in the front garden. Not an ideal thing, and after that, it would have to live under a cover in the garden like my working bike does. Not the best setup either. Now I will have both the space and the storage.

Moving is going to be a bit of an upheaval, but once I am settled in, it will allow me to take stock of my stuff, lay stuff out, and start putting together the bits I have. There will be some bits that have suffered in storage ( I know I chipped hte frame paint....aaargh!) but I am so looking forward to getting established and getting this project back n the road now I have the space I need to enjoy it :)
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
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Re: CB750F2 .... silk purse from a sows ear.
« Reply #257 on: June 14, 2021, 10:45:56 AM »
Good luck with the move.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

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 #258 on: July 31, 2021, 05:08:20 PM »
Well....I love my new garage! All the hassle of moving, boxing stuff up, unboxing stuff, and not knowing what is where is fading, and I have got some quality time in the bike space!

Ordered some parts from DS to get me going. Got a full engine gasket set ( which isn't... as it has no head gasket) and an oil seal set as I work my way towards getting the motor back together. Just need a load of gearbox bearings and a new primary chain and tensioner before I put hte bottom half together.

I also got myself a set of head bearings. I wanted the genuine Honda ones...but no stock, so I bought taper roller. I had bought a set before ...but they simply were a rubbish fit. The adjuster castle nut would barely get on the first thread, let alone do up. So....it was with a small degree of trepidation that I bought another set...and set to this morning.

The bearing sets went into the headstock with no dramas, the old bearing seats providing a handy drift to settle them in snug. Before I started though, I knocked out the set I had tried to fit....and put the stacks in order next to each other.....hmmm...



Can anyone see an issue here..... the newer set from DS is on the right..

They came with a spacer, and no instructions....but when I offered up the stem it was clear that the spacer was needed on the lower bearing, to let the lower yoke clear the headstock, and as it also placed the lockstops dead centre....it was obvious I needed it. The spacer needed a bit of dressing to slide on smoothly, and then I could pack the bearings....drift the lower race into place, and it all screwed up together just perfect.

It's at this point, that were I an engineer of Alan Millyard's calibre...I would have had time and opportunity for a cupcake. But...the Mrs doesn't bake anything humans can eat so I just got on with some more stuff.... Lucky bugger gets to be a genius and gets cupcakes.

Anyway...with the steering parts in place, and the hideous bars it came with bolted up for convenience....I thought I would drop the forks in. I know the top yoke has to come off again for the headlamp, and a few other jobs....but I wanted to get it all together for an initial build to make sure I had everything, and to make sure I found any snags. All went swimmingly!



I dusted off the wheels, front and rear, and got them into place, mainly so I could get the thing up on it's wheels to make it easier to move about. Things like the rear wheel spindle, spacers and the adjsuter end blocks are all a bit tatty....so I might invest in a plating kit to re-do these parts. Not sure how cost effective it is...but...it just might be a fun thing to try and do.

As a last vanity act....I just dropped the tank onto the mounts.....



Reminded me why I wanted to own one of these in the first place. Lovely clean lines.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline philward

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #259 on: July 31, 2021, 05:58:36 PM »
Good work and looking good!

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Current Bikes:-
Honda CB750K2 (1975)
Honda CB500K2 (12/1972)
Honda CR750 Replica (1972)
Honda CB350K0 (1969)
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Kawasaki ZZR250 (1990) Project (Going on eBay ASAP)

Offline Spitfire

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #260 on: July 31, 2021, 07:22:29 PM »
It's nice when you can actually see something to justify the hard work that you have put in.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline K2-K6

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #261 on: July 31, 2021, 09:22:45 PM »
Good progress and always gives encouragement when you can see a rolling chassis too.

Garage looks good too, is that a work pit in centre covered by planks? 

The taper head set you can tighten them to about 30 lbs torque to fully set everything while swivelling them to help the rollers seat the assembly.  Then undo and finally tighten to  5 lbs for good running loading.

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #262 on: July 31, 2021, 09:36:18 PM »
It is indeed a work pit :)

I've gone from a tiny shed in the back garden......to a palace of a garage, with a separate workshop area.
I can finally have my tools like this:

and I can find stuff!

Top yoke will have to come off again for headlamp/clock assembly.... I'll set it properly then. Process noted for when I do :)

Brakes are next. Need a new piston and seal for the rear...but have new parts for the fronts. Need some high temp paint for the calipers first. I also noticed the frame has a few marks from storage/moving that I need to fix on the lower rails. Annoying...but I should be able to blend it in
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Johnny4428

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #263 on: July 31, 2021, 09:39:44 PM »
Looks good! I must admit I am forgotten what a tidy workshop looks like! Maybe Monday.😂
1952 Cymoto on Triumph bicycle.
1961 Matchless G3
1974 Honda CB550K1. Running resto,
1978 Honda CB550K3.
1999 ST1100 Pan European 50th Anniversary.
1975,1980,1984,1986 Honda C90’s
1973 Honda CB750K3

Offline Spitfire

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #264 on: August 01, 2021, 10:54:57 AM »
That garage/workshop looks great, I will have to sort mine out, it started off neat but is a mess now.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #265 on: September 02, 2021, 10:01:21 PM »
Only been able to do a few small things, but some major decisions await that could affect teh whole direction the project takes......so I got some serious deciding to do...

Today, though, I decided to try and sort out my poor old exhaust headers. They are not in bad shape...but where the join to the silencer sits....corrosion had set in. The back end of the pipe was a wreck. BIG hole blown out and the thing was rotten as an old pear. But the headers were nopt so bad. When I took off the clamp and chiselled off the crusty gasket...I found a chunk of the surface under the gasket was ......not metal anymore.

It was quite localised, with an area the size of a postage stamp gone.... so I figured I would have a go at fixing it.

I cut out the bit that looked bad....only to find I needed to cut out about 4 times that to find metal that wasn't too thin. It's bad enough trying not to blow holes in sheet metal without it being so thin you can poke holes in it with your finger....

Found a bit of scrap steel the right thickness....and spent a while shaping it. Got it perfect roundness...then realised it's only round at the end...and had to 'unround' it to fit right.

Fired up the old MIG welder....and then spent a while grinding it back and making it nice. Found the pinholes I had missed....filled them...ground back again... Quite pleased with the end result. Well..on the outside. It's not so nice on the inside, but there isn't a whole lot I can do about that. Its solid though, which was the thing I needed.



My problem now, though, is how to proceed. It was always my intention to go mildly cafe-racer on this, but the question now is how far to go down that route. The only rule here is I will not cut,slice or ruin anything Mr Honda made....but the seat is in the bin ( it was too far gone to save and not a genuine part anyway ). The exhaust is toast at the back. I also have some issues with the brakes.

The rear brake has issues with the master cylinder and reservoir...and the actuating rod. It also has a shot piston and needs new seals, dust caps and hose. I have cleaned a LOT of corrosion out of the master cylinder...and don;t know if it will actually hold pressure. Trying to find a decent replacement has not turned up anything that looks any better than mine...and some that look much worse. The fronts need hoses and new pistons....but at least the rest is OK. Need to read up on the seals...as they don;t look directional...but I want to be sure before I put them in!

I had a glimmer of hope when I was told that the brakes off a later CB750F/900F could be used with the brackets and give me twin piston calipers....yeah. They are rarer than the hens teeth I am already looking for. So that was a no

plan a) rebuild rear master cylinder and hope!

plan b) use a non standard replacement master cylinder. This will involve making a new bracket, which is no big issue, but I have no idea how to select a suitable replacement. Ideally I would want one that shared the same hose connections...so I can buy a proper hose...and be able to fit it.

Plan b) is where things get complex though.....as if I am making brackets....I could get some ally and make footrest brackets to fit rearsets....which leads into exhausts.....

I simply cannot find a set of exhausts I like. The Delkevic straight pipe system looks OK...but I do not like the lines under the engine not being horizontal. I could get my headers rechromed....if I can ever get the damn things apart ( one header out....one not shifting!) and fit a replacement silencer....but it's not convincing me. The only setup I went YES! at was a custom setrup on a KZ....which would mean having it made. But..if I am making custom footrest hangers.....

Just got no idea how to find a compatable master cylinder.

Oh well....time to drink beer and ponder. Usually works
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline McCabe-Thiele (Ted)

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #266 on: September 02, 2021, 10:54:30 PM »
Thinking of your exhuast system particularly the manifold pipes -  how about having them all made in stainless steel?

About 20 years ago the front pipe on our Merc a W124 260E was very badly corroded due to the PO visiting building sites so cement slurry rotted a lot of underbody parts.
A new MB front pipe was daft money - over £500.
A firm in Huthwait, Notts http://www.stainless-exhaust.com/ basically made a replica manifold a 6 into 1 system. I've just looked it up my manifold cost me £200 in 1999 - including fittting.

There is a similar firm called PD Gough who build similar systems they are in Watnall & have a website https://www.google.com/search?q=pd+gough&rlz=1C1CHBF_en-GBGB934GB935&sxsrf=AOaemvKCWX7C9DfnQgrAv3U9CK71BbeZLQ:1630619189766&tbm=isch&source=iu&ictx=1&fir=hyf40v1P6rRpDM%252C8yiKlWGz0XjIdM%252C_&vet=1&usg=K_Nbz7H1lSAlaJEX6q0gauX7u1-Ao%3D&sa=X&sqi=2&ved=2ahUKEwiBjsfsoeHyAhVpQfEDHThdBm4QuqIBegQIbBAD&biw=1920&bih=937#imgrc=hyf40v1P6rRpDM

Maybe there is someone similar near you offering a similar service - might be expensive - we had a full system made & fitted for our SL back in 2003/4 by PD Gough's they even asked me how loud I wanted it to be - they baffled it accordingly so you can't tell it from a standard system it was way cheaper than a genuine MB system.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline SumpMagnet

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #267 on: September 05, 2021, 03:20:37 PM »
Thats an interesting thought. If I can find a reasonably local supplier.

There are plenty of places selling exhaust pipe and pre-bent mandrel bends. Now....my little home MIG kit isn't up to a neat job ( not my welding skills at fault...surely...I mean....blobs and spatters add character..) but I could tack weld bits together and get them professionally welded up. Most custom pipe makers seem to need the vehicle to build the system on, which is a bit of an issue for me.

To ride the bike..I need an exhaust...which means I either paying for a trailer job, or finding another way. It's either that or finding someone who has the right patterns for making up a suitable system. I've contacted a couple of possibles, and will see how I get on.

Could be interesting!
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline K2-K6

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #268 on: September 05, 2021, 04:11:08 PM »
I've made accurate forms in tube before for rally car roll cage on which the tubalist (made up name for man wot bends pipes) got me to bend sections in aluminium welding wire to work from as they involve compound bend section. He was very competent in that craft though, but it is relatively easy to interpret if given an accurate form.

You can also do things like thread foam pipe forms (like those swimming float things) onto the wire to get clearance etc.

Spattering on fluxed welding wire, keep anything with flux component in airing cupboard or similar ensuring it's bone dry as it's the moisture content that makes it spatter and stick. It's much more consistent when dry and you'll usually be able to use a more accurate amperage to weld with if you're not coping with it being awkward.

Offline K2-K6

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Re: CB750F2 .... silk purse from a sows ear.
« Reply #269 on: September 05, 2021, 04:21:36 PM »
Also may be of interest
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Loose copy of Yoshimura pipe made by "Carpy" expat brit bike builder in USA,  he has ordinarily been helpful of shipping protocols from what I've read and so may be an option you'd like.

 

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