Had my cam chain done but...

[davidkent]

Not solved cracked crank case. Waterpump sits off centre slightly because of the crack so it taps, a good lever will hold it over but once released it goes back and taps again

[riedrider]

cracked crank case.

How can this happen?

Regards
Guenter

[davidkent]

My chain snapped many moons ago .
Ruined the original water pump and sprocket cover.

This, it seems is the aftermath

[riedrider]

Thanks for the exlanation.
Very annoying....

Regards
Guenter

[davidkent]

Yes, gutted but someone has replied to my thread re crank case welding so perhaps there's hope yet

[davidkent]

See pics for the damage:

[red98]

Hi david....been following your thread with interest.........not taken a pump out myself but I've got my haynes manual out and theres some very good piccies in there.....I cant see how the crack in the casing is causing the tap.....or have I missed something  :o........the pump or impeller is in its own casing and dosn't come in contact with the cracked housing, have you split the pump and looked for signs of the impeller fouling on the pump casing ?........or is the pump housing tapping against the crankcase housing ?.......great pictures, what about something like "chemical metal" to fill the crack......loads on thr market ....

[davidkent]

The crack is causing the pump to move slightly at an angle
when I undo bolts and lever the pump back square it doesn't tap.

I'd imagine this is a lot of stress on the bearings on the oil pump and water pump.

Seems odd but it's true. After replacing a lot of parts.

The impeller isn't touching in either of my water pumps

[red98]

Ah, I see........think I would be tempted to use a very thin washer beneath one of the two mounting bolts and parhaps fit a new O ring to the body of the pump.or is it going to need a wedged shaped washer to correct the misalignment ? Looking at the position of the front sprocket in relation to the pump body iam guessing the chain has hit the top of the pump so parhaps a spacer/washer underneath the bottom bolt might correct it ........welding the casing aint going to be cheap, a lot of these metal fillers on the market might be a cheap fix 

[davidkent]

it may be a chemical metal job.Washers under the bolts don't work. I've tried
it hit the pump at around 1-2 o'clock and virtually smashed it.  As you can see it's knocked the pump straight a log at 180 degrees.

May have to look into something in there to hold the pump over. Some kind of shim or similar

[red98]

Ah.....ok.getting a bit tricky now.do you know how much room you have between the pump and housing ?  Wont be much or O ring wont do its job, using a shim will shift the pump over but how are you going to hold it in place, if it falls out it could do more harm than good.......how about boring the pump mounting holes out so you've got a bit of sideways adjustment, looking at haynes it looks like you've got a bit to play with...

[davidkent]

Could be an option.
was worried about a shim for the reason you mentioned
I have contacted an engineering company. Perhaps they'll come Up with something perhaps.

Chemical metal is never that good and could also end up in my sump

[red98]

Yeh.....your probably right about the filler.something else to worry about  :rolleyes........boring the pump holes out might work, your eexperiment with the washers tells me its not that far out so boring the holes 1 mm oversize is going to give 0.5 mm of sideways movement, might be enough........thinking about the crack, if its not getting any worse might be best just to leave it, probs wont stop you checking it after a few miles though  :lol

[davidkent]

Just don't wanna keep cooking oil and water pumps it'll get expensive though I don't use it heavily

[His Dudeness]

The casing is aluminium so it'd have to be tig welded which would mean getting the tip of the tig torch and a filler rod into that hole which could be a problem if there isnt enough access due to the size of the hole or if there was other stuff getting in his way. That'd depend a lot on whether the welder was willing to have a go at it. Also you'd probably have to machine the hole back to round or if its still all still bolted together maybe try and file it back.

[davidkent]

My engine is ruined isn't it?
In reality?

[His Dudeness]

My engine is ruined isn't it?
In reality?

The engine's not ruined but the casing is probably beyond economical repair. If the rest of the engine is in good working order then it's probably worth rebuilding it with a good casing. You could buy another engine to keep you going for now and rebuild the original then swap the rebuilt one back in and sell the spare one. If it was me I'd rebuild it but that'd be as much to learn how it all goes together as it would be for fixing it so I suppose it depends on whether you want to put the time and hassle into it and buy the few specialist tools needed to do it or not.

[davidkent]

That post makes good sense.

My worry is a small mistake can ruin it all.

I could in theory use the bike as is for the summer then rebuild over the winter which wouldn't be a bad shout.

Depends how in depth a job it is really I guess.

Massive is my guess. only ever really done work on 49cc mopeds back in the day so totally different game.

Doubtful that there'll be a whole idiots guide available either

[His Dudeness]

That's true if you make a mistake it could blow itself to bits so as a bare minimum you'd need enough experience and patience to be able to read and follow a manual accurately step by step. You'd also need enough experience to know when things don't feel right and you're about to break or cross thread things which you only really get from breaking a few things :lol You'd need a decent size shed or garage to lay the stuff out in. You'd need a few specific tools beyond the basic tool set like low range torque wrench, pullers, holders, you'd want a compression tester and probably some more tools that I can't think of. You'd need a full gasket set. You might want to look at replacing bearings and seals while you in there too. It'd add up pretty quickly. You're not going to get an idiots guide to doing it because an idiot wouldn't have a hope of getting it right. Plenty of very intelligent people wouldn't be able to do it either. I think it comes down to whether you've got a bit of a mechanical head or not.

[davidkent]

I can do most of that and do have most of that kit

Done a few cam beltsee and had some heads off cars and definitely broken plenty.

My engine is perfectly up together bar this I'm tempted to pay deefer to rebuild it rather than to have the other engine.

A touch more and I'd still lose my engine  number I guess too but I'd have a justifiable reason for having  done it. I'd sooner an enine rebuild of a known engine by a reputable  person than what could be a totally random engine (if I were buying the bike) if that makes any sense.