Nikasil

[Zombie Master]

So with a Nikasil bore, if you want to re-gasket your top end, can you just put the piston back into the cylinders with the original rings?

[George Ryals]

Yes, assuming everything looks good.

[SteveD]

Measure first, decide second?
Compression ok?

[Wobbly]

You can do that with any cylinder, but I would definitely measure the ring end gaps and look for signs of wear at the top (cyl head end) of the bore.

[Seth]

why not replace the all the sealing pieces without removing the pistons?
assuming before you take it apart and check compression.

http://www.pbase.com/dqmohan/prtseals

[Zombie Master]

Can I change the push rod seals without disturbing the base gasket?

[Seth]

No. You still pull the cylinder off the case, but you don't have to remove the piston from the cylinder.

[Zombie Master]

No. You still pull the cylinder off the case, but you don't have to remove the piston from the cylinder.

How can you put a base gasket (or o-ring) under the cylinder without removing the cylinder?

[Kurt in S.A.]

How can you put a base gasket (or o-ring) under the cylinder without removing the cylinder?

First, you place the pistons at top dead center. Then you pull off the cylinders just far enough so you can get access to the clips that hold the wrist pins in place. Once the clips are removed, you can push out the wrist pins and continue pulling the cylinder with the piston inside. Be careful that the connecting rod doesn't drop and slam against the engine opening edge.

I'm not sure how easy all this is to do. In my limited experience, access to the clips can be difficult and you will need special pliers to extract them. On the /2 models, the clips are actually stiff split rings which fit into a groove which are very difficult to get out. The clips on my /7 were external to the wrist pins so were somewhat easier to get to. On the Siebenrock kit I installed to replace the entire top end on my /7, the clips are now like the /2 models. IIRC the wrist pins are slight interference fit. In order to get them out, you need to use a hair dryer or something to heat up the bosses that hold them.

You're doing all this while holding the cylinder in the air with your 3rd hand. I'm not sure the hassle is worth it. Not to mention you have to repeat the process on installation.

Kurt

[Zombie Master]

That sounds like a good time....NOT!