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I'm wondering how they remove material from FZ-YZF cranks when lightening. They seem very hard.

Is material machined ie: turned as in a lathe with tool steel, or does it have to be ground? Is it possible to drill and tap this metal (hardened cast). Do they anneal and then machine and heat treat afterwards? I know they drill into them to balance after lightening.

Any insight into the actual process would be welcomed.

Take crank to machinest, leave for two weeks, return to machinest
and leave a kidney behind, take crank home, thats the way i did it..........

stan

Not really the way I want to go about lightening Stan (ie: kidney). I've seen some photo's of cranks being machined on what look like lathes, they would have to be special.

I'm interested in drilling out the end of the crank and re-tapping.

Also lightening

Duke22 is the expert on this one.
He set the crank up on a millling machine in a rotary head and machined the sides and inner faces of the crank webs down.
From memory he ended up removing something like 1.5kgs.

I remember that some extensive rebalancing was needed, but boy does that thing like to rev!!!!!!!!!

I used Falicon for mine Spook. Although it wasn't a kidney they charged me, just 'bout $500 or so, something like that, didn't think that was too bad for the job they did. Especially as the speciallized machinery necessary to do the job now that stuff would cost a Kidney and then some, that's for sure.

I used Falicon for mine Spook. Although it wasn't a kidney they charged me, just 'bout $500 or so, something like that, didn't think that was too bad for the job they did. Especially as the speciallized machinery necessary to do the job now that stuff would cost a Kidney and then some, that's for sure.

Ahh, Falicon - the holy grail of crankshaft work, but from this end of the globe you could probably add a thousand or so dollars of courier charges to get the crank there and back - but when I win lotto...

The distance between NZ / Australia and the rest of the world is what has made our countries great inovators in the past as having work done overseas is just so expensive that it makes good sense to have a go and find out what works and what doesn't. It could also have something to do with my Scotish heritage.

kiwi60 wrote:The distance between NZ / Australia and the rest of the world is what has made our countries great inovators in the past as having work done overseas is just so expensive that it makes good sense to have a go and find out what works and what doesn't. It could also have something to do with my Scotish heritage.

Indeed Kiwi. Plus we love the institution of the shed and our beloved toys!

I remembered those photo's from a while ago, but I'm glad to see them again. I didn't realise at the time Duke himself did the machine work... NICE work Duke! That must have taken some time to do!

I think the problem is that my machines-lathe specifically are not heavy enough. I have a mill, it is old but might do it. the problem with a lathe is the impact of the tool on the journal each time it comes around. Milling would negate this. I found this photo on the APE website. Looks like a lathe?





Duke, what sort of tooling did you use to get through the crank material? how did they wear? Did you do it dry or with coolant?

I'm keen to do it myself as I have quite a few to do as the bike-engine list grows. If I had to pay people to do the work associated with building bikes I could never afford the hobby

The reason I was wondering about drilling and tapping is I'm thinking about adapting a GP type starter attachment to the end off the crank shaft.
An larger bolt and an oil seal over the end of the crank is all that would be required? There is also already provision for a locating pin oem

He used the 2 insert cutter you can see in the photo's and took it reasonably gently on the speed & feed.

It took a few Saturday's to get done, but the results were worth it - that was one seriously fast 750.

Spook - I love that starter!!!!

Now, if I can just talk the wife into letting me buy a mill, a lathe, maybe a TIG welder, and perhaps a shed to put it all in.....................

kiwi60 wrote:Now, if I can just talk the wife into letting me buy a mill, a lathe, maybe a TIG welder, and perhaps a shed to put it all in.....................

Problem is that perusing what one desire as bloke generally negates the possibility of the other.

I couldn't really imagine asking anyone whether it was okay to do what I wanted to do. How does that work?

Down side is that creature comforts, romance, and endearment are absent in the world I live in.

Though, from what I have observed, of the majority of people I know in relationships... not many actually experience the above mentioned.

What!!!

Creature comforts - check
Romance - not since I was 20; ok maybe 30
Endearment - is that the onset of calling each other dear? - check

If you want someone who you don't need to ask if its ok to buy stuff marry someone from the middle ages like I did.

Cranks - talk to Alan Curran at Cranktech in Ferntree Gully 9758 2013 he did John Rickards crank 87 FZR1000 and has a highly modded VFR750 just like mine...I am in awe