When is it time to change rings, preventatively?

chee_dee

Member
Feb 26, 2019
76
19
44
South Africa
I know one should do a Compression Test and once it gets below around 100PSi, start planning to replace the rings.

The compression Tester I have is not the proper one for the Bikes. It has the none return valve at the gauge side and not on the plug fitting thread side which means the readings will always be lower.

My 3 Blasters measured 100, 104 and 116 Psi respectively, with the lowest reading bike performs the best lol.

Is it a good thing to pull the head off to inspect the piston and rings? I would suspect that one will look for movement sidewise. What else?

Until I manage to get the right Compression Tester I am contemplating this on the bikes. I like being preventative but no use I do the job and it is in vane.

Any advice, pointers?
 
I would suggest checking the piston to cylinder wall clearance when you pull the cylinder off to replace the rings. If the clearance is too large and you just repalce thr rings, you run HIGH risk of breaking a piston and filling your crank case with aluminum. It is possible you piston is just as worn as your rings are.
 
  • Like
Reactions: chee_dee
I would say when comp gets below 115psi. As mentioned cylinder/bore clearance is critical with stock/cast piston. Not quite with forged.

May sound crazy, but the owners manual for my 73 Elsinore recommended changing rings after EVERY race. Theory being that you'd lose 1-2% per race (weekend).