Busted Crank

[ClunkintheUK]

So following from the crank bolt thread. I've taken my engine apart to discover that one of the big end bearing shells has disintegrated . There are two main lumps, half a dozen smaller lumps and a load of grit. Most of this was in fact contained by the connecting rod and crank shaft and damage to the rest of the engine looks to be minimal, but the crank pin is pretty deeply scratched on one half, the other half looks to be pretty much intact.

I am just wandering really what my options are from this point. I figured I can either swap the engine, replace the crankshaft or scrap the bike for parts. I am just trying to figure out my best route.

[Alexander94]

I think that whether it's worth it or not comes down to how much you can get a replacement engine for. I've seen crankshafts that cost more than complete engines.

Is it not possible to just replace the bearings? (possibly a stupid question)

[ClunkintheUK]

I think because the crank pin is so scratched that just replacing the bearing shell will leave to great a tolerance.

[AlexAdams]

Around £500 for an engine, it just comes down to money and time. Can you have the bike off the road for a while replacing the engine or buy a replacement bike and sell off the spares?

[squirrel_hunter]

I am just wandering really what my options are from this point. I figured I can either swap the engine, replace the crankshaft or scrap the bike for parts. I am just trying to figure out my best route.

Well that's pretty much your options. The easiest is to swap the engine. Parting the bike out can be a chore and what are you going to do for a bike after? Replacing the crank is not a quick job and can be as much to do as the engine replacement route. But if its something that interests you why not...

Is it not possible to just replace the bearings? (possibly a stupid question)

It's not a stupid question. However no its not as simple as replacing the bearings. There are no oversize bearings from Suzuki so you have to source them from something else. Then there is the problem of the crank, there will likely be damage to the pin as Clunk has found, and fixing this is difficult if not impossible. From experience this refinishing can weaken the crank and cause failure. That's not to say its impossible, but its why most people replace the engine or the crank should the worse happen.

[Alexander94]

There was a guy in London that had a 15k miles engine for £100. I donct know of he's sold it or not.

I've got an SV that I've been selling off for months and it's proving to be a very arduous task...

Thanks for clearing that up squirrel.

[andrewsmith]

Shells are available for suzukis but it's a chew on. I know someone that's been rebuilding a gsxr 1000 k5 for a turbo bike and he had to do some blagging to get them

sent with all the fury of a clogged drain!!

[ClunkintheUK]

The main bearings I think are fine. It's just the bearing shell on the big end of the rear con rod. I guess my main question is the difficulty of putting it all back together again and getting it to work. The rest of the bit I need (various gaskets and replacing crap bolts that nearly sheared in the dismantling) are about 150.

[squirrel_hunter]

I guess my main question is the difficulty of putting it all back together again and getting it to work.

Well if I've managed to do it before...

[DJ123]

Well if I've managed to do it before...

twice . . . .

[ClunkintheUK]

Well if I've managed to do it before...

Yeah, but you have quite a bit more experience with mechanicals than I do. I've only had a garage in which to do things like this for two months.

[squirrel_hunter]

What do you think I started with...

Do you want to do it?

[Stinka]

If it was me I'd build it up with all the nice things like busa pistons, Carrillo rods and get it all lightened and balanced, swap the cams, thinner head gasket and then get it set up/jetted on a dyno

[ClunkintheUK]

I had thought of doing that, but I don't think the rest of the bike is worth it. I commuted on it for two and a half years through London. I am also about to be commuting 30 miles up the M5 each way, so my plan prior to the bearing shell disintegrating had been to sell it soon, and get something a little more fuel efficient.

[ClunkintheUK]

Also to confirm I have read the Haynes correctly, if I replace the crank shaft, I also need to replace the main bearings, I.e. the ones between the crank case halves and the crankshaft, as these are selected fit.

[Stinka]

Yes if you get your crank out get new shells

[Craig380]

My 2p worth is this: if you want to keep the bike, I'd look for a decent used engine you can drop in.

I know some people would say "you've already got one used engine, you don't need another" :) but a complete rebuild with new crank and mains, seals & gaskets etc all adds up.

The alternative is not to break it, but eBay it as a complete project. Someone out there might want the complete rolling chassis etc

[ClunkintheUK]

Hadn't thought of the last option there. Looks like all the part I need for the rebuild, including crank, are about 370-400 all in.

Breaker round the corner offered 200 as is.

[ClunkintheUK]

Can you use a crank from a pointy on a curvy?

[squirrel_hunter]

Also to confirm I have read the Haynes correctly, if I replace the crank shaft, I also need to replace the main bearings, I.e. the ones between the crank case halves and the crankshaft, as these are selected fit.

Correct. Piston Broke will be able to do this for you if you are in Bristol.

Breaker round the corner offered 200 as is.

I'll give you £250 for it.

Can you use a crank from a pointy on a curvy?

I believe so. From memory they are different part numbers as there has been some slight differences over the years but as far as I am aware there shouldn't be a problem with the older and later cranks. But as I've not done that (knowingly at least), I'd recommend doing a little more checking. Remember to set the end float though.

[ClunkintheUK]

Correct. Piston Broke will be able to do this for you if you are in Bristol.



I'll give you £250 for it.



I believe so. From memory they are different part numbers as there has been some slight differences over the years but as far as I am aware there shouldn't be a problem with the older and later cranks. But as I've not done that (knowingly at least), I'd recommend doing a little more checking. Remember to set the end float though.

Yeah, they are a 5 minute drive away. Found a curvy crank for 220 delivered. Seems about the going rate.

If you offered 500, it might work.

[squirrel_hunter]

£220 sounds a little more then I would expect. Admittedly its been a few years since I bought one. Does that come with the rod? And any sort of guarantee with it?

And if you do go for crank replacement, you going to be doing the build yourself?

[ClunkintheUK]

No I believe that's just the crank. Only found a few yards up north, so there is postage too. Phoned a few down south, but none seem to have one.

Yeah, going to be doing the build myself.

[squirrel_hunter]

You've got to ask why its been sold without the rods. So you also need the bearing shells to go on the rods.

Have a look on eBay there might be something. Try internationally as well, depends on how long you have before you need the bike back running.

If all else fails I'll give you £350 for it as it is now.