How to install rings to a piston?

[skiri251]

Sorry for another non-GL topic but how do you install piston rings to a piston?
This is for my CT90 again. I was removing rings from the old piston and managed to break oil ring and ended up buying a new set. This time I don't want to break them of course.

As usual, I don't own piston ring insertion tool as mentioned in Honda service manual.

 

[dan filipi]

Being the oil ring I would slide it up the piston skirt to it's groove.

 

[slabghost]

If you are very careful you can use snap ring pliers to expand the rings. Be sure the groves are clean first.

 

[scdmarx]

The oil control ring is normally much more flexible, and the scraper and compression rings are the brittle ones that will bust on ya. And generally, the larger the piston is, the easier they are to work with.

 

[skiri251]

Hmmm...
It looks so easy in the video.
I was okay when I did BSA. Maybe CT90's piston is so small..
I shouldn't twist the ring, correct?
That means I should just expand the gap in the horizontal plain?

 

[scdmarx]

Hmmm...
It looks so easy in the video.
I was okay when I did BSA. Maybe CT90's piston is so small..
I shouldn't twist the ring, correct?
That means I should just expand the gap in the horizontal plain?

Ya, obviously he's done that before.

Do as little as you can get away with. Either way, be very careful. The technique he uses to put the ring in the groove, then kinda roll it on is the best way to do it in my opinion. Use your own sense of "feel".

 

[skiri251]

Everything went okay. Thanks every one!

Measured old ring gaps and they are completely out of spec so good thing to use new rings.
Assembled everything and measured compression but it is lousy 130 PSI (spec is 170 PSI) which is the same as before.
Can I expect the compression to go up once the rings bed in?
How should I break in the rings and the cams?

 

[slabghost]

Yes compression should go up after break in. Break it in as recommended for new. Staying below a certain rpm manufacturer recommendations provided for the recommended period.