Screwdriver
Member
- Messages
- 10,157
I've had an old GSXR750K4 engine kicking about in the shed for years. I bought the Gixxer after the owner blew it up at Cadwell, did a swap repair on the engine and just tucked the old one out of sight. This was it a few years back.
And here it is again after ripping it apart yesterday.
It's eaten the big end bush on the last two cylinders. The rest of the engine looks MINT!
So I am taking it apart and selling the bits. I need to get this off:
33mm x 1.5 thread. Easy just find a lump of steel, drill it out...
Bore to size and give it a relief at the dead end of the hole.
Then just cut an internal thread.
Your eyes do not deceive. Close but no cigar!
After a ton of faffing about and cups of tea, the culprit is found.
Someone has swapped the 35T changewheel for the 42T. Gives you a very close but very wrong pitch.
It's not the first time I have tried thread cutting on my old Colchester but it's the first time I have to get it done. Previously I gave up and just used a tap/die. Not an option this time and finally (I think) I have discovered why it has always gone wrong before.
And here it is again after ripping it apart yesterday.
It's eaten the big end bush on the last two cylinders. The rest of the engine looks MINT!
So I am taking it apart and selling the bits. I need to get this off:
33mm x 1.5 thread. Easy just find a lump of steel, drill it out...
Bore to size and give it a relief at the dead end of the hole.
Then just cut an internal thread.
Your eyes do not deceive. Close but no cigar!
After a ton of faffing about and cups of tea, the culprit is found.
Someone has swapped the 35T changewheel for the 42T. Gives you a very close but very wrong pitch.
It's not the first time I have tried thread cutting on my old Colchester but it's the first time I have to get it done. Previously I gave up and just used a tap/die. Not an option this time and finally (I think) I have discovered why it has always gone wrong before.