Fitting pistons

[andeks]

Hi everyone,

Just got to the stage of fitting pistons into the bores of my 400/4.
Been rebuilding it for a few years so thought I ought to get a move on !
New rings fitted so a bit worried about possibility of breaking them.

Any tips on fitting, should I use clamps that fit round piston and compress rings or just try and use hands to compress them?

Advice much appreciated.

[Nurse Julie]

No clamps needed, just use your fingers. How exciting, you're getting close now.

[Laverda Dave]

I found if using clamps they are too big and foul on the upper crankcase. I've always fitted them without clamps, the taper is normally enough although I compress the rings using two coffee stirrers as the piston ring enters the taper of the individual bores. Use plenty of oil on the bore at the taper end and plenty on the piston and rings. Go very gently and have patience, just tap the cylinder block down over the pistons with a gentle tap using the palm of your hand.
I've never broken a ring using the above method.

[paul G]

As Julie says no clamps needed Hondas have very generous taper lead in on the bores just be gentle 

[Tomb]

I always polish the taper lead in with a bit of smooth emery, and oil, this allows the rings to glide in. And start with the inner two pistons up, once they are in its easy with the outer two.

[andeks]

Thanks everyone, all good advice just not looking forward to doing the deed
My barrels look a bit of a mess, any ideas on the best way to clean them up or should they be sprayed with the paint i've done the crankcases in. Also one of the fins is missing a bit, is that aluminium filler ok to build it up.

Thanks
Dek