Author Topic: CB750F2 .... silk purse from a sows ear.  (Read 31592 times)

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #195 on: March 31, 2019, 06:11:42 PM »
Heat did the trick....along with a light 'tap' from the other end. Took a fair bit of work to clean the crud and rust residue out of the circlip groove, but it's all intact and the alloy itself has virtually no corrosion. None at all along the important section where the seals move.

Much cleaning up to remove the crystallised brake fluid that filled the space between the seal and the spring.

One rebuild kit to be ordered from DS .... and I am much happier doing that than fitting a replacement part. It will get a coat of satin black, along with the handlebar clamp piece which was black...but had been painted silver.... There is some flaky paint to clean back, but it should look nice when done. Circlip and washer were rusty as hell and went in the bin.

It's no wonder I couldn't push the pistons out easily....the seals were well gone
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #196 on: April 07, 2019, 07:09:58 PM »
Crowbarred open the wallet...and bought my first round of bits from DS.

Genuine master cylinder rebuild kit, front brake seals and dust boots, plus fork seals, dust covers and clips.

Went for a genuine rebuild kit, which actually costs more than the pattern setup....and twice what the cheap E-bay kits go for. But when it comes to stopping....I don't like to go economy.
Going to get the forks rechromed when I can afford it. Head bearings and a repaint of the yokes comes next. Plus I need to shell out for a set of brake hoses. Refitting 40 year old brake hoses is ....not a good idea.

edited...because I think I miss-typed just about every other word...
« Last Edit: April 07, 2019, 07:53:15 PM by SumpMagnet »
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Green1

  • SOHC Jedi
  • Posts: 2656
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #197 on: April 07, 2019, 07:18:39 PM »
I have used a few cheap rebuild kits on a few different bikes and the pattern kits almost always have the wrong size washers.
Other then that there OK.
All the little bits are what drain your wallet.
Current bikes
Honda CB750k1 Valley Green Metallic
Honda CB750k1 Candy Gold
Honda CB550k Candy Jade Green
Honda CG125
Aprilia Pegaso 650
Moto guzzi 1200 sport
Kawasaki EX650R (Mine until dave pays for it)
Kawasaki ZXR400 J

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #198 on: April 09, 2019, 04:19:07 PM »
Here is the first wallet drain....



But I have a problem.

I put the old and new piston assemblies together, and now I can't work out which is which. Can anyone help me spot which piston assembly is the new and which the old. They look identical...

CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline haynes66

  • SOHC Pro
  • Posts: 662
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #199 on: April 09, 2019, 04:28:19 PM »
always go with the one with patina...
honda firestorm
silverwing 600 scooter
honda britain project
phil read rep project
YGS1 80cc yamaha
LE Velocette

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #200 on: May 05, 2019, 09:22:29 PM »
Now the weather is less grim again, and I got a free weekend, some work has been done. Well,, once I had refreshed the coolant on the working machine that was...

Well...the less than wonderful satin black paint issues wer eresolved, and hte fork lowers treated to a fresh coat of satin black. This time they look much more how I wanted. Better coverage and better finish.


Then I broke out the paint stripper and started on teh frame and other bits. POR15 stripper is the business. Just like paint stripper used to be back in the good old days. Removes paint, varnish..skin...yup. Burns like the devil if you get some on your skin, or..as I did...get some splashed into the gloves you put on to stop getting splashed... oh well.
Really did the job.

Still got to do the headstock, but want to make sure I don;t ruin the info plate though. Will get it taped and protected before I go near it. Some surface rust in a few places, but the wire brush and wet and dry took care of the worst of it. I have put a cover coat on the areas I cleaned up to keep corrosion from starting again.The sections I have done look really nice.

While I had the paint stripper out, I thought I would see what state the petrol tank was in under the matt black paint job it had been treated to at some point...

I knew I was going to find filler, as the badge recesses had been filled both sides, so wasn;t surprised to find a blob of filler on both sides. Will grind that out and check what's under before re-doing it. Was pleasanlty surprised to see how little actuial rust there was. A few scabby patches on the flat areas where rust had propagated under the paint, but very little rust on the seams. Underneath is very solid. There is an oily probably once petrol substance in the tank, but no coatings or linings. Still got it's cap security chain too. The only worry is I can't see what has been done with the badge mounts. Whether they were taken off due to damge, or just covered over as a 'de-badge'. Will ind out when I dremel out the old filler.



Interestingly...I found traces of paint under the filler. Shiny black paint that had been lacquered black. I also found evidence of orange at the back corners and roughly where the badges would have been. So....originally...she was black. Or at least the tank was :) Black with the orange stripes looks pretty good...so she may well end up looking that way eventually.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Online K2-K6

  • Grogu
  • *
  • Posts: 5234
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #201 on: May 05, 2019, 09:41:11 PM »
Decent progress,  frame looks good too.  Encouraging when things come up well after cleaning.

Did you sort out which mastercylinder part was which  ;D

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #202 on: May 12, 2019, 03:56:42 PM »
Did some more work on the last bits of the frame...and while I was out in the shed...as it was such a nice day today...I thought I would have a dig to see what lurked under the filler.

Now...the filler itself looked to have been put on over the original black/orange paint, but I always worry what lurks beneath. You paint the thing..only to find there was rust under the filler that pops it free, or else the tank had been holed, and a dollop of Araldite used to petrol proof it before hiding it under more epoxy. So I will always rip it of and re-do it after proper preparation.

Both sides of the tank had a big area of filler, so I was expecting dents. Did this once on a Kawasaki tank only to find huge dents on both sides that had reduced the tank volume by nearly a gallon.

Sods law operates well in these events, and predictably the filler was really well attached and showed no signs of budging...so my cheap low power dremel type tool was pressed into service with a burr to grind away the filler. After an afternoon of hard graft, one side is fairly well excavated....and this is what I found:



Looks like the bulk of the filler was just slapped on to de-badge the tank. Not sure if the tank badge fixtures were machine screws or self tappers, but it really does look like it ought to be possible to reinstate proper tank badges. Something I would really like to be able to do. Obviously, I haven't done the other side yet...but having cleaned the filler away from the whole badge recess on one side, I can see there is no damage to the metal around the badge.  Overall...I am really impressed with the state of this petrol tank.

Relief really...as when I saw the bike advertised, it had a red tank on it which lacked a tap and looked scabby...but had badges. The seller told me it wasn't the original tank, and that he had that one as well. I was basically offered the choice. He brought both along and I went with the original tank as it had a tap, the original cap with security chain and looked a lot better inside. It was just painted horridly and lacked badges. Now I have stripped it....I can see it is in really good order, really not rusty, and if I can get the badges back in situ....I will be a happy bunny indeed.

Of course....the other side could be a horror story...but I will get to that in due course!
« Last Edit: May 13, 2019, 12:15:46 AM by SumpMagnet »
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #203 on: May 26, 2019, 04:35:46 PM »
Damn.....I am pleased with how this turned out.

After much paint stripping, wire brushing, sanding and wet and dry fettling, the frame was ready for paint. I am not a fan of powder coat, though I do see it's advantages. I also wanted to do this myself, and do as much as I physically could. Now...I do not have pots of cash, so am trying to swap spending for time, effort, and elbow grease when I can. I also am really not on a time schedule and find this project to be as much therapy as anything else. Today was one of those 'happy' days.

The frame was suspended in the middle of the shed with acombination of contrived contraptions and bits of wire and chains. It was solid, and the thing wouldn;t swing. Musn't swing...the shed isn't big enough! There is room to swing a small cat in there...in certain directions....but a full sized moggy won't twirl. Everything else in the shed had to be covered up, and was. The weather was nicer and warm...but not too hot. It was time.

2 cans of smooth black hammerite and a couple of face masks later, the deed was done. The floor was also painted and sticky. Bit like an old pub carpet...everything not covered up was sticky with overspray. The masks clogged...and I had to take regular trips outside to breath.... but I am dead chuffed with the end result.



It is soooo...shiny!

Of course, it's also only touch dry, so I don't dare try and lift it down, and I also want to rig up a stand through the swingarm pivot and engine mounts so it won't rest on soft paint It is OK where it is for now...but I can barely get around it, and it's kind of...in the way...hanging in the mifddle of the little space I have.

Next job, really, should be to get the forks done. While that is happening, I can clean...strip and paint the swingarm. Seems to make sense to build up a basic rolling chassis so the frame doens't sit on it's paintwork and it will make it easier to move about in the shed if I can move the bike too. Happy days.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Nurse Julie

  • 1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1. Honda CD250u.
  • Grogu
  • *
  • Posts: 8206
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #204 on: May 26, 2019, 05:42:59 PM »
Great job you have done there......ooops, watch your head , don't ruin the paint  :)
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 paul G

  • SOHC Master
  • Posts: 1748
  • No room left in the garage what now !
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #205 on: May 26, 2019, 07:22:03 PM »
Looking good keep up the great work and the posts  :)
Honda CB400 4
Honda CB550 K3 (sold)
Honda CB750 UK K1
Kawasaki Z650 C2
Kawasaki Z650 cafe racer (Sold)
Honda CD175 sloper

Offline Spitfire

  • SOHC Master
  • Posts: 1769
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #206 on: May 26, 2019, 08:21:18 PM »
Great job, I too like doing things myself and the last time I did a frame I had it hanging on a washing line in the garden, had to wait for a sunny dry day with not a lot of wind. When I painted the smaller parts with rattle cans like you have found out everything in the garage was coated, years later I'm still finding the stuff.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Laverda Dave

  • SOHC Jedi
  • Posts: 2531
  • Health is wealth
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #207 on: May 26, 2019, 09:35:05 PM »
That's a good day's work there. Be careful when you handle the frame as my past experience of using Hammerite is that it stays quite soft for a period of about a week. I painted a workbench and moved it a couple of days later when it was dry only to leave finger marks in the still soft paint! Keep it hanging up for as long as you can before you touch it.
Keep the updates coming, great to read 👍.
1976 Honda 400/4
1977 Rickman Honda CR750
1999 Honda VFR 800FX
1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
1982 Laverda 120 Jota

Offline SumpMagnet

  • SOHC Pro
  • Posts: 683
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #208 on: June 01, 2019, 03:49:15 PM »
More stuff done, and some progress.....and issues.

Started stripping and cleaning the swingarm and rear brake assmebly. The caliper came apart fairly easily...which was good. The sliding pins were free sliding, which is amazing considering virtually every bike I have ever owned seemed to have siezed them.

But...I think the rear master cylinder is going to give me trouble...
When I took the rubber boot off...



hmmm....it's an interesting combination of sand, dirt and rust powder. It's not really useful...and not really helpful in any way. But I have a load of it if anyone wants it....
The rest of the assembly is soaking in WD40, as I can see the ciclip ends...but not budge them. I am expecting there to be some trouble here, and possibly a rebuild kit.....

The swingarm is in pretty good order, with just rust around the ends where the wheel spindle was. I will also really want to replace the rubber bushes for the shock mounts. They are cracked and perished, and I really don;t see them being usable. The other end showed a grease nipple installed. Looked like an original fitting. That's good...

Or would be if it wasn't sheared off.



Gonna be a bitch to drill that sucker out, but I will give it a shot.

The POR15 paint stripper made short work of the original paint, and it just needs a second going over to remove the few patches the first coating didn;t strip.
CB750F2 - in pieces
CB900F Hornet - the daily transport

Offline Spitfire

  • SOHC Master
  • Posts: 1769
    • View Profile
Re: CB750F2 .... silk purse from a sows ear.
« Reply #209 on: June 01, 2019, 07:43:44 PM »
That master cylinder looks pretty much like mine did, lots of fun but they do clean up nicely, I must try and get on with my F2, I feel guilty every time I go out to the garage.

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

 

SimplePortal 2.3.5 © 2008-2012, SimplePortal