Compression Test Adapter

[jrgamble_89]

Does anyone know what size adapter (10mm, 12mm, ...?) for a compression tester will work on a 2001 YZ 250? I am looking to buy a compression testing kit and would like to get the right adapter for my bike.
Thanks

 

[mo2stroke]

i may be wrong but i think maybe its 14mm

 

[1BAD250]

i bought mine from sears & it came with all the adaptors. it was only 20.00