Yep, a dial caliper. If you don't have one of these in your tool box, you should. Once you have one, you'll wonder how you got along without it for so long...
These used to be expensive, but low-cost import models have brought the price down to where anyone can afford one. This is a cheap Harbor Freight inch version (getting old now, originally bought for $8) but you can spend anywhere from $10 for a plastic version up to $150 for a 'name-brand', top-quality one. The stainless-steel one pictured above can still be gotten new from HF for under $20, less if they're on sale and is plenty accurate for our purposes (in fact, my HF caliper reads indentically to my name-brand unit). You can also check eBay or other online sources, this type is sold by a lot of sellers and they're pretty much all the same. Inch versions are cheaper/easier to find compared to metric models, but there's some that do both. Choose your features and price range and pick one up! You won't be sorry!
One place these are invaluable is for setting carb float heights, well worth the price even if that's the only thing you ever use it for.
Fast, Cheap, Reliable... Pick any two
'78E original owner - resto project
'78E ???? owner - Modder project FJ forks, 4-piston calipers F/R, 160/80-16 rear tire
'82 XJ rebuild project
'80SG restified, red SOLD
'81H more parts...
Other current bikes:
'93 XL1200 Anniversary Sportster 85RWHP
'86 XL883/1200 Chopper
'82 XL1000 w/1450cc Buell, Baker 6-speed, in-progress project
Cage: '13 Mustang GT/CS with a few 'custom' touches
Yep, can't leave nuthin' alone...
Last edited by crazy steve; 04-19-2012 at 10:03 PM.