CB750F2 .... silk purse from a sows ear.

[SumpMagnet]

K2-K6 ...thanks for the info I did wonder what the hell that goo could be....and how it got there.

hairygit....good to know I don;t need to take that apart. That's only coming out after it gets drilled....and I hate drilling  screws out as you never know the first time whether you will have any meat left on the shank to get the stump out. So far only one screw has needed the DeWalt treatment and that was one I knew fropm the screws around it was plenty long enough.

Presumably that whole assembly can come out in one piece...or do I just leave it in situ when I split the cases?

If I damage one of those 4 big screws I will make sure I fit new ones before I rebuild. Never know when you need to go back in.....

[hairygit]

Take it out once the cases are apart, can't clean the casings properly with it left in place, comes out easily

[SumpMagnet]

Progress has been a bit slower over the last week or so, due to family stuff....and those inconvenient bits of life that stop you doing what you want to do ...but we still push on.

Made myself a tool to undo the clutch centre nut, which I reckon will do the job. Second attempt...first attempt scuffed the nut...so I might well fit a new one on rebuild. The final tool was basically a 6" section cut from an old Trriumph fork tube. Dad has a good supply of these....all rotten...after many a front end rebuild on bikes he has renovated. They score up and the screw on bushes corrode in place. Replacement is the only cure. He keeps the old ones to make spacers, drifts etc. and to stick yokes on when painting, so I was able to get a piece to bring away. Chopped it into a 4 peg array...which was about 1mm off on the internal diameter and slipped scraping the nut. Mk2 was fitted iwth an internal sleeve epoxied into place to line up right....then drilled through for a tommy-bar to turn it.

That's when I hit problem No2.

The damn thing won't stay put! I made sure it was in gear before I took the shifter mechanism apart, and sure...it is in gear. I just haven't figured out a way to stop the sprocket turning!

I tried a wooden block wedged in, I tried wrapping the chain around..... damn thing doesn't stay put when I put proper pressure on the nut. GAhhhhh.....

I know the time to step back from the problem was at ahnd, as clear thinking was the order of the day, not aided by building frustration, so I found something else to occupy my mind!

The frame is in need of a good clean, and a light respray. The more I stripped it, the more I realised it actually has a lot of good original paint, which I can flat back and recover. Other areas need more work...but I like the idea of keeping as much as I can, and just perking it up a bit. The centre stand had to come off, and that was nice and easy. Just slacken the pinch bolts and drift out the pin. Stopping only to extract the drift I had wedged in ..... and found a better one that didn't get stuck it was soon free along with it's spring and half moon spring bracket. Side stand off next, followed by the seat catch. Now she is ready for proper cleaning and sanding back.

Next stop the seat.

Now....this thing is a horror.....humped semi K&Q thing with crunchy vinyl and buttons down the centre. Yes....buttons. The seat pan looks to be usable, but the cover has been rivetted on, and the buttons have also been rivetted through the foam to the base. There was some rot to the sidestand low side of the base, but it looked pretty solid, so I had ideas of using it for a new seat. I planned on a cafe style seat, long enough to look good with the frame rails uncut ( I don't want to ruin ANY parts originality, to make it easy to revert to stock if I wanted.  ) so I thought I could use the front half of the pan, reshape the foam, then get it covered. That way the hinge and locking points from the stock frame can be used with a GRP rear section glassed in and fixed to the rear.  That....as they say...was the plan.

The cover needed cutting off, which was done, but I could feel a lot of 'crunchiness' around the edges....

Oh dear.



Half the seat base metal is still glued to the foam buy it's own corrosion. The side sections at hte front are largely gone at both sides, wioth metal so thin the screwdriver 'poke' test failed all along. I emptied out hte contents of the vinyl and foam.....and got this.


Going to stick it on E-Bay as genuine 1970 Honda iron oxide, rare and original. Can be fitted to all 70's honda motorcycles. Came as standard with many models......... £7.50 per bag. Bargain. Woin't be here long at that price. Of course...I will give a discount to SOHC Forum members

[Moorey]

Somebody will buy it and restore it. 

[hairygit]

If you advertised it as Honda iron oxide, you'd get negative feedback coz that seat is obviously NOT Honda, some vile aftermarket thing the yanks seem to love! And the way they have been with DS and others, Honda themselves would probably sue you!

Sent from my X6pro using Tapatalk

[SumpMagnet]

The seat base may yet serve a purpose.....as a mould to make a fibreglass version.

I'll amend my E-Bay ad to read 'Rust taken from a Genuine 1978 Honda's seat' ..... and reduce the price to 50p per bag ( £7.00 postage )

And yes...that seat was vile. Combined with a lovely pair of high rise bars with stupidly swept back ends. There is no excuse for either.

[Rob62]

Engine doesn’t look too bad inside, bit of sludge in a 40 yo motor...... you can buy a new seat pan off ebay for 40 quid, why mess about with fibreglass.

[SumpMagnet]

Clutch is still an issue...and I need to take a step back and work out a proper solution to lock up the rear sprocket before I damage something in frustration. In the meantime...I have turned my attention to other bits and pieces and am working my way through the shelf of shoddy and appraising what I have/need/should dicard.

Which brings me to the point of todays post....

I have a lot of small odds and ends that are a bit rusty...but which were originally plated. things like the metal cover plates under the footrest rubbers, the insdie of the pillion pegs, the pins that go through the pegs. All things that while they were not really rusty....had worn the plating off...or have a bit of surface corrosion.

Now...I could bundle up a whole load of things and send them off to a plater...but I don't have anywhere local and I am not sure who I could trust to actually send me back things. I could try and replace....or...I could try home plating. I would rather refurbish original parts rather than replace unless I can get genuine parts. With footrests...I will use pattern rubbers...but not the other parts. I have bought cheap e-bay footrests before....never again. I only did that one time as I was selling the bike and tore the end off the rubber on an overly tall traffic island....

I have no problem cleaning up and polishing the parts...but wondered how easy/successful home plating actually is...or if it's best left to the pros.

If the latter....is there anyone in the southeast I can use who knows their stuff...and knows what a MOTORCYCLE is?

[Nurse Julie]

Always re zinc or powder coat if you can. There is no guarantee that if you source new parts, they will actually be the same as what was originally fitted, especially with parts classed as 'Genuine', which is not the same as 'Original' and then the superseded parts numbers, which have been superseded again...it's a minefield.

[kent400]

There's www.colmorfinishing.co.uk based in Borough Green Kent. Small operation, little more than one man and a dog. Always seems to be a fairly quick turn-around

Picked up these a few days ago charged £40. Think there were 14 of them.

[UK Pete]

There's www.colmorfinishing.co.uk based in Borough Green Kent. Small operation, little more than one man and a dog. Always seems to be a fairly quick turn-around

Picked up these a few days ago charged £40. Think there were 14 of them.

I might try these people out it's quite near for me
Did you have to do any prep, I might see what there coming prices are like as well

Sent from my SM-G930F using Tapatalk

[SumpMagnet]

It's funny....but some days go from triumph to disasdter in very short order.

The triumph first.....
Having given up on the home made attempts at making a clutch tool, I had oprdered a cheap one from China as a whole lot of Hondas seem to use a 24mm peg spanner for clutch centres, and I got one for the princely sum of £4....posted....so I figured what the hell and bought oner to give it a go. Took a couple of weeks to turn up, but worked brilliantly. Was a tight fit in the pegs, and a few judicious taps on the ratchet, and the nut came loose. Hooray. Notoced some odd scratches on the back of the clutch centre...but nothing too bad looking.

Ot came the clutch centre and all the plates. Some wear and tear...but usable. Will need a good clean as they are gummy and fairly well stuck together but there is enough left on the friction plates not to have me running off to buy new. I might.....but that depends.

Dug out the puller, and gave it a quick mod to thin it down to use the hole near the gickstart gear and stay nice and central. Found a plug to fit into the end of the shaft to ensure no damage from the puller. Figured all was good to go.

Dug out the circlip pliers to remove the large circlip on the shaft at the centre....and found the clip came off really easily. TOO easily.......
Popped the basket off and had a good look at the end of the shaft.....and the swearing started. Lots of it. Loudly. Some things got kicked as well.

The ends of the shaft where the clip should locate were rough and jagged. A quick delve in the oil pools under the clutch found a few fragments that clearly used to live there.

Now I don't think the engine was run like this....as the shards were clean and sharp but I now need to find out what I have to replace...as I cannot rebuild it like this.

Looks to me like someone removed the basket with a crowbar and never took the clip off. I counted 7 'broken' places on the shaft....and have 3 shards. When I split the cases I am going to have to look REALLY carefully as the other bits have got to have gone somewhere. If I am lucky...they fired out when it happened. At least they were not in the top end, the sump or the oil strainer. The bits I found were in the dimpled recesses in the bottom of the clutch area.

Gave me that sick feeling when I found them....and a sudden pain in the wallet area.

[K2-K6]

Oooooh, that doesn't look good 

What is that marking on the bearing housing at about 11 o'clock?  Is it a shadow of casting mark or damage?

[SumpMagnet]

Casting mark as far as I can tell.

I have been studying all the pictures I have of the gearbox shafts etc. trying to work out exactly what it is I have to replace here. I assumed it was the end of the layshaft...but none of the manual diagrams I have seem to look like what I am seeing.

The damaged splines are the ones for the clutch basket....and the smaller ones for the clutch centre. So presumably...the inner part is not attached to the outer part.

What part is it I need to source?

[K2-K6]

The drive comes in to the outer clutch basket from primary drive assembly through that damaged hollow shaft. It's this component that will have to be replaced.

It gets transmitted through clutch plates and clutch centre to the central shaft to gear assembly,  passing back through that first hollow shaft. Which appears undamaged.

Hope that makes sense