General Good Tip Required

[Guest yellow peril]

Hi all - bit random - but...........

 

on my kart the key that sits in the crank end that holds the drive cog from spinning bust, and has now become two - of course it's filed itself level into the shaft and the other half sits in the cog - an hour of pickling away with a small screwdriver hasn't lifted the shaft bit out - and the other bits as solid as a rock - any tips -

 

thought I'd ask a group of hoodies used to akward engineering tasks

 

cheers

[Guest chris brown]

Hi all - bit random - but...........

 

on my kart the key that sits in the crank end that holds the drive cog from spinning bust, and has now become two - of course it's filed itself level into the shaft and the other half sits in the cog - an hour of pickling away with a small screwdriver hasn't lifted the shaft bit out - and the other bits as solid as a rock - any tips -

 

thought I'd ask a group of hoodies used to akward engineering tasks

 

cheers

If it is the curved (half moon) type then use a punch and tap down at one end and the other end will (should) pop up. If it is the square type then the shaft should be cut out right to the end and it’s a case of tapping a pointed drift in the grove. the third type has a slot in the shaft with rounded ends if it is this type then it may be a case of carefully drilling into the broken key and screwing in a self tapper and pulling it out this way

[Guest yellow peril]

cheers chris -

 

like the ideal of drilling a v small hole and using self tapper - not sure what u mean about cutting out right to the end of the shaft though i've had a longish week and am feeling a bit dense - of course its a ruddy small key being on the end of a 100cc crank which makes it awkward

 

rather annoying - as the 95p key messed up my last race when i went out - still could have been an expensive bit that broke

[Guest salty_monk]

He means the keyway or slot the key sits in should be cut all the way to the end of the shaft... I suspect that you mean it's on the engine sprocket not the axle sprocket though in which case ignore that bit as you'd never get access to the back without pulling the engine apart!!

 

Drill & tap/self tapper sounds like the best bet to me. Worst case you'll have to cut the sprocket off & replace.

 

Dan

[Guest yellow peril]

yep it's engine starter sprocket - sprockets off as the key has broken well and good so it's just trying to get the bit thats left out - and a drill and self tapper sound genius to me - knew i could rely on you lot for a handy and sensible tip - I just loose patience usually and end up damaging something more than it was in the first place, but i

didn't want to get too brutal or take chunks out of a shaft that revs to 18,000 - things need to be fairly straight at that speed.

[Guest salty_monk]

It might be hardened so beware when you come to drill /tap.......

 

Worse case you may be able to mig weld something to it & pull it that way.

 

Lets have some pics... I used to run a kart with a friend a while back. If it's 100cc I presume it's a Zip Kart two stroke?

 

Dan

[Guest yellow peril]

hi dan - it's a formula blue (100cc watercooled 2 stroke) on a tonykart chassis - ruddy marvellous entertainment -

[Guest yokel]

Don't know how useful this is but welding (mig or arc) causes the parent metal to shrink when cooled, not going to be easy on a 100cc puddle jumper! but if all else fails...

 

Good luck!

[Guest salty_monk]

One of these boys.... http://www.kmsracing.co.uk/FormulaBlue.html bit more high tech than what we had Ours was direct drive, lift the rear & push to start!

 

I've driven a Rotax max or two (125cc) those are fun too.

 

Good luck with the key!

 

Cheers,

 

Dan

[Guest yellow peril]

had a tkm 100 before which was good ole push start and jump in before it flies off stuff - feel as though i'm cheating a bit with a starter button

[Guest salty_monk]

Reckon I'm well past that now.. the cheat sounds good

[Guest yellow peril]

drill - self tapper - 2 minutes later and ready to go - thanks for that - save me plenty of head scratching