DIY cylinder bore gauge - comparator

[crazypj]

Hi All,
I was looking through Instructables site and came across this DIY cylinder bore gauge

http://www.instructables.com/id/Measure-Cylinder-Wear-without-a-Micrometer/

It's a great idea for anyone who want's to know if cylinder is tapered or out of round.
The actual diameter could be measured with a vernier or similar, but, if all you want or need is a comparison from top to bottom and side to side this is fine.
Pretty sure if you made it out of steel it will be accurate to at least 0.001"

 

[NortonGuy]

Wow, is this a waste of time.

All you have to do is put A piston ring square in the bore in areas of interest and use the feeler gauges to see the difference in the ring gap, done.

Of course I have a starrett dial bore gauge that I got so cheaply used that any other option is not even worth consideration for me.

 

[crazypj]

It's been proven by experimentation that ring gap is pretty immaterial, the only thing it really tells you is the fitted pressure will be OK to seal, but, if you fit 0.25mm oversize rings and adjust for correct end gap you can get higher ring pressure.
The DIY gauge will give a much better idea of actual bore wear which you can't get by measuring ring gap

 

[Sonreir]

Wow, is this a waste of time.

All you have to do is put A piston ring square in the bore in areas of interest and use the feeler gauges to see the difference in the ring gap, done.

Of course I have a starrett dial bore gauge that I got so cheaply used that any other option is not even worth consideration for me.

Yeah... well when you ride Brit bikes you probably have enough money to buy whatever tools you want on a whim.

And checking ring gaps doesn't tell you if the bore is out of round.