TOPIC:

Bucko wrote: Keep in mind tire sizes are not %100 uniform across MFRs: i.e. one MFR's '140' my be wider (once installed) or narrower than another MFR's '140'.

Very true, the rear wheel on my 1300 has been converted to run a 180 section tyre, with about 5mm clearance to the swingarm on the drive shaft side with a Dunlop D207. I then tried to fit a Metzeler ME888 & that closed up the clearance completely to the point that the tyre made hard conatct with the swingarm. So I had to revert back to using a Dunlop D207

Could you post more in short detail how you converted the swing arm and whatever else for this 180 tire? If too much for here, maybe a quick new thread with a couple photos?

Right, got the pistons back, with extra oil holes drilled into them. As they broke off two drill bits in the process, they did a few with five holes and the rest with three each side. As they did not do what I had asked them, they did not charge me at all... so no complaints!

Here they are with the rings on, ready to go into the engine.



Next steps are to read up on how to get the cylinder tub on and get on with that.

Question: do I need to apply liquid gasket seal on both sides of the paper gasket for in between the block and the cylinder tub or will the paper gasket by itself be enough?

Paul

Wow !! They drilled them by hand. This was a perfect job for an indexing head, a 1/8" center drill bit and either a drill press or a milling machine. The pistons will be fine but I would question using their services in the future. What were they thinking??
Not meaning to rattle anyone's cage but here's another fine example of what kind of service people are providing and I've had 2 issues in the past 1-1/2 years where I thought I was about to get professional work done and got taken to the cleaners by people who talk a good talk but haven't got a clue.

Good you had it done Paul! I'm a bit confused with the sand paper marks. I imagined all will be done on a lathe and a milling machine, no need for such an extensive clean up. Not that it want work. You have a good set of upgraded pistons.

One thing I'd check before installing the pistons is their weight. Just like connecting rods, which are stamped according to their weight and the engine should have all of the identical, pistons should have a very close weight as well for balance. If one has 10 holes and the other 6, that's a difference of 4 holes missing material. I wonder what difference would this make in weight. I'd shave off some weight of the heavier ones to be closer to have all of them equal.

McBoney wrote: Question: do I need to apply liquid gasket seal on both sides of the paper gasket for in between the block and the cylinder tub or will the paper gasket by itself be enough?

One side.

I haven’t followed the discussion on these holes....

But those holes will have no real effect. Oil holes belong in the groove. On the down stroke, both oil rings force oil into the ring groove. The holes in the ring groove relieve the build up. In doing do they 1) lubricate/cool the top of the rod/underside of the piston and 2) continually pump fresh oil through the ring pack (reducing carbonization of oil in the rings - keeping them free.

Those holes below the ring pack will only evacuate oil more or less from the space directly above the hole. Keep in mind the piston has very little wall clearance so oil won’t significantly travel sideways as the clearances are so tight.

Holes in the ring groove have room for the oil to flow in the ring groove to make it to the nearest hole.

You can google images for “piston oil holes” and see that these go in the groove.