Honda CB250K something - very very long term project...

[pdg]

Part 1.

Will it run?

https://i.imgur.com/1GA2FHp.jpeg

Might need a bit of redex.

That beautiful hunk of scrap formerly identified as a 1970-'72 CB250 engine.

It was actually worse than that, I'd already 'cleaned' some of it before I thought to take a pic.

Unfortunately for it, I'm sometimes a twat and I left it out in the rain for approximately one decade, give or take 0.2 decades or so. In my defence (not that I deserve it) it really wasn't that much better beforehand.

I did however have the foresight to put the head, rocker box and other associated gubbins in a box in the shed, so they've got nothing more than patchy surface rust in a few places. Pretty sure I even have a camshaft somewhere too.

I got the block off after draining a few litres of water out of the cases and that's as far as I've got...

I also have the bottom end and gearbox of a slightly later one, it was sat outside next to this one. It's even less complete, but some internals may or may not be interchangeable.


So yeah, I have no idea when or even if any progress will be made, but I thought I'd bung it in here anyway - it might be fun to see what happens.
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Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[stinkwheel]

I suppose it'll mainly come down to if you have a viable crank and cam. I'd imagine most of the other bits are available out there because they are raced a lot in classic racing on account of them being flying machines.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

Boat anchor
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[pdg]

[pdg]

[pdg]

Update the first. This post contains good news and less good news (it's not bad until I say it is).

I popped off the side covers and discovered very little in the way of rust. I proceeded to remove the clutch plates to separate diagnostics of the engine and gearbox.

Less good news, so we can end on a high:

The crank is stuck in the mains , the conrods are stuck on the big ends, the gudgeon pins are however free with little to no play. To be determined is how stuck and why.


Gooder news:

The starter motor turns and the starter clutch appears to operate. I didn't apply power so I don't know if the starter actually works, but it turns by hand.

The kick starter works (on these engines the kick operates on the gearbox side of the clutch).

All gears can be selected and the gearbox turns freely and smoothly in all of them - it was superficially stuck initially but it's likely that was dry greasy oil in the bearings and/or gunk around the clutch basket.



I think splitting the cases is next on the agenda - it'll be way easier and more mechanically sympathetic to assess and hopefully make good the crank that way.



Interim thoughts - I'm not unhappy.
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Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[blurredman]

Looking forward to it. I like rags to riches stories on bikes!
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CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k, 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k.

[jeremyr62]

By the time that ever runs again, petrol stations will be long distant memories.
But best of luck with it, and rather you than me.

[pdg]

[A100man]

I'm an optimist and love a phoenix story but that is scrap..

..it has been screwed by water induced corrosion... any rescues will involve £100s (£1000s?) on new parts - pistons shells,balls, rebore crank grind etc.etc..

by all means try and rescue a forlorn motor but give yourself a fighting chance.

PS its not a Vincent after all.
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[WD Forte]

On reflection, calling it a boat anchor was outrageous flattery
it is now a worthless peice of shite
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bikers smell of wee

[jeremyr62]

It wasn't my intention to goad you into action
I agree with the naysayers. It will cost serious money to get that going again. There are much better better ways of spending your hard earned.
Sometimes, you just have to let go.

[pdg]

Ok, so let's discuss...

If someone brought that to me and asked me to fix it I'd offer them a fiver for weighbridge value. If they were insistent, I would quote based on replacing and/or machining all of the internals and consider it a bonus if I could reuse the clutch pushrod.

However, that's not the case.

There are levels of survival I am prepared to accept

When I had my 2 stroke 50 the oil injection pump failed and the engine heat seized - I took off the head, made sure the piston was on the down stroke and dumped the clutch in 2nd while rolling downhill, then ran it on premix for the last 4 months of it's life (with me).

Would I build a daily use commuter out of it? No. I could, but that would not be financially viable.

Would I build a show bike out of it? Yes. Show bikes don't have to run...

How about something in between - say a bike that is built to maybe look reasonable to me and maybe do a couple of hundred miles a year pottering around for entertainment, where if it stops working (with variable levels of enthusiasm if/when said stop occurs) it's really not the end of the world because I'm not relying on it?


So yeah. It might be scrap. It might be an exercise in futility. It may not happen quickly but even if it never runs it won't be as expensive as an evening in the pub and it'll be more fun than watching tv.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[jeremyr62]

Yeah but realistically there is no way back for that engine. It doesn't make any sense in any universe to try to resurrect what is essentially a lump of iron and aluminium oxide. Far better to find something else to mess with that has a fighting chance. IMO.

[pdg]

[pdg]

Undeterred by his own stupidity and fuelled with belligerence, our hero bravely battles on and undoes some screws.

Firstly, the left side generator cover comes off to reveal:

https://i.imgur.com/iw5MfCa.jpeg

Then the clutch cover succumbed to his will, as did these 4 bolts

https://i.imgur.com/EVd6TA1.jpeg

This liberated the clutch pack from it's bonds and allowed further inspection confirming that they are indeed clutch plates and that they kept their living quarters remarkably tidy

https://i.imgur.com/mQ4EPyQ.jpeg

https://i.imgur.com/uK2IOop.jpeg



Oh, and then he sprayed some penetrating oil in some places.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[jeremyr62]

It's not the initial cost I would be considering, It's how much it will cost to get it running. To me, it looks like very little of it is useable. By the time you have it in a running condition it will resemble Triggers broom.
Anyway, it's your money.

[Easy-X]

The Motorcycle of Theseus
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[WD Forte]

I always wondered what sort of person would actually try and polish a turd.
A turd they created themselves too by the way

Contrast this to Ariel badgers revival of two 1940's era Ariels
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bikers smell of wee

[Howling Terror]

Allen Millyard can be heard sucking through his teeth.

I did hear him say that anything can be repaired...maybe that's a thought you can cling to.

I want you to succeed yet from the few photos it looks like a big ask..then again I've never spilt the cases on anything and certainly haven't the equipment to fit new liners or machine replacement parts.


Keep us posted. During my time here I've learned that there are still some key members that are willing to help, if required.
Just give them the right information.
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The Harry Turner Project

[UncleFester]

That looks like way more effort than reasonable return.

Wife rebuilt an NC50 which was in way better nick than that and it ran into 4 figures, not including the time involved. She's also got a 94 CB400SF that's headed the same way). It's the stupid little stuff like replacement bolts / washers / gaskets / bearings or things like rechroming etc etc. Then there's what you break along the way or just can't find at all then you're too far down the rabbit hole and you end up spending daft money on some unobtnamium (looking at you CB400SF carbs and parts) part because you're already daft money in and can't leave it unfinished.

Scabs should be left well alone, not picked at
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Module 1 and 2 passed - October 2014. Happy owner of a 2017 Z1000SX, ex owner of a YBR125 / CB500 / VFR800.

[A100man]

[pdg]

Ok, maybe I've got the wrong end of the stick but the vibe I'm getting from the replies are:

Everyone is taking it far too seriously.

Everyone is utterly misunderstanding the intent.

It seems to have been assumed that I'll need to outsource work.


Clarifications:

This is not a restoration. It's not even really a rebuild as I consider them. I have another CB250 of the same model that is pretty much complete and a runner which is a far better candidate for that. If I buy parts for this one, then 'worst case ontario' is I have some more spares for the better one.

I actually enjoy this sort of thing - I would rather spend an evening in the shed fiddling with rusty junk instead of going to the pub and pissing seventy quid of beer against the wall then having nothing more than a headache to show for it.

Rebore? It's not like it's plated - if it really needs a rebore I can do that in the shed. Likewise pressing the crank apart and back together if it really needs new mains. It's an early 70s twin, it's hardly rocket surgery.



I only made the thread to shoot the shit - seems I may have misread the room.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[to v or not to v]

[UncleFester]

If it's just playtime tinkering then carry on as you were

It read like you had desires of making it a 'runner'
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Module 1 and 2 passed - October 2014. Happy owner of a 2017 Z1000SX, ex owner of a YBR125 / CB500 / VFR800.