Fitting Pistons to M900

[MonsterMadMarty]

Is it best to fit piston to rod and then lower the cylinder pushing the ring in by hand or fit the piston with rings into the cylinder and then lower the entire assembly with the lower half of the piston protruding below the cylinder and then attaching to the rods.  I've tried both ways neither seem to be working for me! I've now resorted to drinking beer instead 

Please help

[koko64]

I prefer the latter, but do both. Working solo the latter method is good, but having a mate hold the cylinder makes the former method easier. I broke rings doing it the former way once. I changed my ring compressor after that to a Nichols type. No problem since. What ring compressor do you use?

[MonsterMadMarty]

I prefer the latter, but do both. Working solo the latter method is good, but having a mate hold the cylinder makes the former method easier. I broke rings doing it the former way once. I changed my ring compressor after that to a Nichols type. No problem since. What ring compressor do you use?

I'll have another go at the latter as I have no friends! I have an adjustable type ring compressor which works well on car not so sure about bike!

[ducpainter]

If those are stock pistons and rings be really careful with those oil rings.

Ducati rings cost more than aftermarket pistons and rings together.

[MonsterMadMarty]

If those are stock pistons and rings be really careful with those oil rings.

Ducati rings cost more than aftermarket pistons and rings together.

I was trying with a set of NOS genuine pistons and rings but now had success with a new set of JE Pistons 

[koko64]

The adjustable car type ring compressor is what led to me snapping rings. The point where the adjustment is, is the point where rings can pop out and catch, as that's where the ring compressor gets out of round. They are not so good for confined spaces or smaller pistons. Mine probably got out of round which is always a danger with those. A quality tool probably helps. Lesson learned. The Nichols type are so good, getting them or a similar type really makes a difference.

Put one circlip in the piston and pop the cylinder on it's head on the bench, nice and comfortable. Just get the orientation correct for when you flip it back with the inlet facing the correct side! You need good lighting putting the other circlip in...

With the pistons on the rods, a small ring holder works. Many ring holders will not clear the engine studs. If you are replacing them (and you should), just fit two to start with so the ring holder can come out. If the studs are in already then you are fitting the pistons on the bench. At least the cylinders are light and not cast iron, so you can slide/wiggle it with one hand while holding the Nichols type with the other. If you pay express freight, you can get the ring holder in 3-4 days from CCW.

[koko64]

Speeddog, Brad, Howie, etc  may have some handy tips for us all.

[Speeddog]

I've always done it by fitting the pistons to the rods, then applying a ring compressor and installing the piston.
Brad likely does it the other way, as he's in Australia. 

Installing the retaining ring for the piston pin is a difficult operation, I prefer to do it with the best possible access, without a gooped-up base gasket in the vicinity.

I use a Blue-Point ring compressor:
http://buy1.snapon.com/catalog/item.asp?search=true&item_ID=635923&PartNo=RC980&group_id=675642&supersede=&store=snapon-store&tool=all

It's directional, so you've got to use it opposite orientation to how it's labeled, as it's intended for car motors where the pistons go down into the block from the top.

It's not particularly fond of short, slipper skirt pistons, but with the band gap aligned on the skirt, it does the job.

The ears of the band sometimes need to be folded over a bit to maneuver it out from amongst the studs.

[Howie]

I've put rings in many an engine, but never a Ducati.  Never had the opportunity to use that Nichols tool either, but it looks like it would be my tool of choice.

[brad black]

i use this compressor: http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=635922&group_ID=675642&store=snapon-store&dir=catalog

and put the piston into the cylinder first.  gooped up base gaskets don't worry me so much.

[monsta]

ha.. good thread! 
I put the piston in the cylinder then lower down to connect to the rod.
I ALWAYS struggle and have mild panic attacks!
Lining up the pin is one thing then getting the clip in!!
last time I did it, (couple of months ago) the clip when flying and I never did see where it went!   

If you do it that way make sure you stuff rags around the rod so that if things fly they dont go down inside...

[SpikeC]

 The last time I did this I used a beer can and a hose clamp!

[MonsterMadMarty]

I put the piston in the cylinder then lower down to connect to the rod.

That's the way I went in the end after changing my mind and fitting the JE pistons, I had been trying with genuine Ducati pistons but I may have the incorrect rings! I have two sets of rings I know are for the later model 900 but then I have three sets same part numbers but one set has a different type of oil ring! I suspect the single set is the correct set but no good when I need to do two pistons!

I ALWAYS struggle and have mild panic attacks!
Lining up the pin is one thing then getting the clip in!!
last time I did it, (couple of months ago) the clip when flying and I never did see where it went!   

The clips are the easy part, I place them in flat end first at 90 degrees leaning the clip over to one side I then use a mid-side flat head screwdriver and push the turned up end in towards the semicircular indent. I place my thumb over the top to help keep it all in line.  Easy 

If you do it that way make sure you stuff rags around the rod so that if things fly they dont go down inside...

Great advise, after dropping a few things in there I learnt that one! (Everything recovered (I hope) care of a magnet)