RZ or Banshee cranks into LC cases

[BRG1200]

Out of interest has anyone got pics they can put up of the mods required to get a Banshee/RZ/YPVS crank into the LC cases?
From what I've seen there may be two approaches, and as said in other threads, off the shelf Banshee cranks are the easiest option (at the moment). I'd be very interested to see what the mods actually look like.

[jools58]

machining of the outer flywheels, the ignition side bearing outer race and either an offset circlip or machining of the drive side bearing inner & outer races.

Alternatively the cases can be shaved for clearance but this is more involved and requires more set up and work.

Some cranks will fit in ok but just require the bearing work

[BRG1200]

"But father, all I want to do is sing!"
I take it you're a Python fan.

Those sound like the approaches I've heard of before, but a picture is worth s thousnad words, and probably saves a few f$ck ups along the way ;-)

[jools58]

No pics sorry.........

The secret is to machining the webs down (and its only the outside raised ring ouch !) gaffa tape the rods to stop them flailing around on the lathe, running it with a live centre on the slowest speed.
Fill the bearings up with grease to catch the swarf. A mandrel is required to do the inner race and make sure you press the ignition side bearing back on the crankshaft the correct way around..............

[hybrid]

IMO the cases are the better option to be machined.
Once done, your next crank drops straight in too.

[JonW]

I agree, why would you machine cranks and not the case? Ive also read that some cases are wide enough anyway and you should test fit a crank and see if it fits as some just do...

[BRG1200]

Someone I know, not terribly closely, I think went the machined cases route once upon a time, will see if I can get in touch.
This is a theoretical question for now, but keen to have a solution to future crank changes up my sleeve.
Was technically very curious as to how its done. Seems odd that what I presume is a die cast crankcase would have any variation in such a dimension.

Speculation, Did they make more than one mould, and a case from mould A would be narrower than mould B? Did they have the next gen YPVS in mind and fitting early YPVS cranks in late LC cases to make some kind of production transition easier. Just speculating. Is it later cases that take YPVS cranks or is it random?

If anyone has a pic of the machining at some stage I'd be very interested.

[JonW]

I asked about this on another forum and there was a bunch of info put up, but i cant find the link now... :/

[jools58]

I agree, for commercial reasons the cost of the tooling to do cases might be repaid over a period of time. But the circlip on the drive side bearing will still be a problem as its position is dictated by crank width. That means a special offset circlip, or re cutting the groove in the cases.The bearing clearance on the ignition side could probably be tackle by machining the cases but may need another tool and set up. All costly and time consuming and knowing the tight nature of folk, they won't want to pay for it LOL!

But practically, for how often I expect to change a crankshaft, I will go down the crank/bearing machining route.

[JonW]

No one mentioned the circlip before in any of the info ive seen online, which made me think it wasnt an issue... interesting...

[jools58]

Steve at the TSS used to sell offset circlips for this purpose. The other option is to machine the difference off the bearing inner and outer race to bring it back in line, as mentioned above.

[JonW]

Never heard of an offset circlip, I dont know how that works as there is no clearance between the bearing face and the crankcase for the offset to sit in unless the offset was very small, ie could be contained by the width of the clip itself, ie circa 1mm. Not doubting you, just saying...

Anyway, TSS is still going and you can email Steve and ask him if he has any or has a supplier and he may help you perhaps?

[L.B.]

Apparently it helps greatly if you run straight cut primary/secondary gears as well.
Saves the crank from getting pulled under uber load....
Im getting all this out now to have alook at this....pics soon...

[jools58]

Apparently it helps greatly if you run straight cut primary/secondary gears as well.
Saves the crank from getting pulled under uber load....
Im getting all this out now to have alook at this....pics soon...

Then you don't need the circlip