Topic: Installing tight pistons: cylinders first? (cb400f/466cc)

[jessezm]

I'm hoping to avoid the trouble I've run into in the past trying to install my pistons in my bored cb400f (466cc), and I think I remember someone saying they installed their pistons into the cylinders first, then lowered the barrels down over the con rods with the pistons already half-way installed and pushed the wrist pins into place (inner two first, rotate the crank, then outer two).  Can anyone confirm that this is possible?  Or smart?

Trouble is that it's really hard to get the bottom oil rings on the outer two pistons in at the same time and I snagged a ring last time and don't want to risk that again.   I figured with a well-designed ring compressor I can take my time and install one piston at a time into the barrel without breaking anything.  I know it might be a little tricky getting the outer circlips in but the ones that came with my latest pistons have the wire bent in and look really easy to grab and install with the right set of pliers. 

Thoughts?

[mattcoff1]

I just did this the other day
But from the bottom took two hose clamps and and old ring compressor that i cut the bands to fit.worked really well also use lots of oilhttp://i290.photobucket.com/albums/ll272/mattyc1_photos/rebuild047.jpg

[Triffecpa]

the big bore cylinders (if they did not recut a taper into the bottom of the cylinder) can be tricky.  I've done it both ways.  It's certainly do-able.

shove the 1-4 pistons all the way into the cylinder to get them out of the way.  Install the circlip on the inside of all the pistons before you put them in the cylinders.  then roate the crank so that the 2-3 rods are at the top of their stroke and install those pistons.  Then you can push the 1-4 pistons down thru the cylinder and rotate the crank and install those wrist pins. 

Best to have some sort of clamp or visegrips to install on the cylinder studs to hold the cylinder from dropping down while you are fiddling with the wrist pins.  If you use visegrips, you don't need to make them super tight and risk marking the cylinder studs. You are just trying to keep the cylinder from falling lower.

Tracy

[jessezm]

Awesome, that's exactly what I was looking for.

[MRieck]

the big bore cylinders (if they did not recut a taper into the bottom of the cylinder) can be tricky.  I've done it both ways.  It's certainly do-able.

shove the 1-4 pistons all the way into the cylinder to get them out of the way.  Install the circlip on the inside of all the pistons before you put them in the cylinders.  then roate the crank so that the 2-3 rods are at the top of their stroke and install those pistons.  Then you can push the 1-4 pistons down thru the cylinder and rotate the crank and install those wrist pins. 

Best to have some sort of clamp or visegrips to install on the cylinder studs to hold the cylinder from dropping down while you are fiddling with the wrist pins.  If you use visegrips, you don't need to make them super tight and risk marking the cylinder studs. You are just trying to keep the cylinder from falling lower.

Tracy

How about slipping some fuel line over the stud and grip it? Put a slit in the line so you can get it off.

[jessezm]

Great idea, will do it