This old 550 crankcase...

[pjac]

Don't know much here, this is my first post on Sundial!! Hoping someone can help...

If I start with this... could I clean the surface rust off the crank and make sure the bearings are good and leave it together? Take a chance and not split the case? Is there a way to tell if the inner crank seal is good? Etc... Or am I talking crazy?

Don't mind splitting and refurbing if necessary. Will the case areas around the crank need attention?

[Clifford]

Split the cases and start from the beginning!

[rngdng]

I doubt that the crank is good with that much water and crud in there.


Lane

[pjac]

I suppose if the journals have any marring on them at all then it might run a resurface job up past a reasonable cost point. Back to the drawing board...

[rngdng]

I suppose if the journals have any marring on them at all then it might run a resurface job up past a reasonable cost point. Back to the drawing board...

In a crank rebuild you can replace any bad bearings, and the seals. Where the crank contacts the cases (the journals) is not a big issue like it would be with a car or many four-stroke bikes.



Lane

[pjac]

So, that old nasty crank and cases are not too far gone to be used again if the crank was rebuilt with new bearings and seals and trued up?

[Alan H]

So, that old nasty crank and cases are not too far gone to be used again if the crank was rebuilt with new bearings and seals and trued up?

No. Cases media blast and cranks can be refurbed. Clean it as much as possible before the crank builder gets it.

[rngdng]

So, that old nasty crank and cases are not too far gone to be used again if the crank was rebuilt with new bearings and seals and trued up?

Good news!! They can be fixed.



Lane

[pjac]

Thanks Gents! That is good news

[Vintageman]

If you have rust on the connecting rod surfaces (Big End - Little End), The rods are no good, roller bearing and crank pin as well could be rust compromised. Sure it would run for while but it won't be long before it gets noisy and goes bad or throws roller needle about as you rev it up

Rust is the worst thing for cranks even a little if on precision surfaces is a problem sooner than later. The bike can look nice on the outside, but for example if the crank wan't turned for many moons, those mating surfaces grab moisture a little at time causing tooth decay... I mean rusting decay weakening the enamel ... i mean metal surface. The one downside of two stroke is they required roller bearing for lubrication. Those have large air gaps where air brings along moisture and the few contract surface rust first even if no liquid pored in. Your case looks like liquid did get in to crankcase, not just humid air.

[Suzukidave]

You may be better off finding a good crank on Ebay , with new rods , bearings and seals your going to be in for over $500 i bet