Ariel Owners Motorcycle Club

I was fitting the square four barrel - which incidentally I found easier to fit with both the bottom end and the barrel lying on their sides and aligned - when I noticed a damaged scraper ring. Other than a test fit for this ring in the barrel it hadn't been fitted so the damage must have occurred before it got to me. Probably happened in the post as it wasn't that well wrapped.
Oh well, contact the seller and get a replacement. Plenty of other jobs to do while I wait for the replacement to arrive.
I don't like to think what would have happened if I had not spotted it.

That was lucky

Annoying but its good you spotted it.

Hi Paul I have got to fit the barrels to my bottom end very shortly and was wondering the easy way of compressing the rings to insert into the barrel and remembering that we have four pistons to cope with Keith

Hi Keith,
I've found it much easier to fit the pistons into the barrel before fitting the connecting rods to the pistons.
Regards, Chris

I have used 4 strips of plate and 4 jubilee clips.
I once did it with the cylinderhead still mounted on the cylinderblock to save an expensive Otto gasket. I placed the crankcase in a box with sand covered with cloth so I could adjust the position. Then I lowered the block very slowly with an engine crane.
It worked.

My late father bought a set of ring compressors and they work quite well. They are effectively 1 1/2 inch wide jubilee clips of a suitable diameter.

Roger

Hi Keith, here is a pic of how i did it.
With the crankcases and barrel lying side by side, and positioned to be exactly in line with each other it was straight forward to move the pistons up in to the barrel one at a time by rotating the crank. I used a ring compressor, which helped. It wasn't quick, it took a lot of care and and time to move each piston in slowly making sure it wasn't pinching and that the ring gaps were not aligned. Also it was hard to see what was happening on the side that was out of view.
Plan B was to put the pistons in the barrels before putting them on the con rods - as suggested above. Plan C was to get two helpers, one to hold the barrel and one to hold a crank.
Whichever way you end up doing it, take it slow and easy, have all the tools to hand, keep the work bench clean and clear, and set aside an hour or two free without interruptions. Good luck!

Very basic, I know, but I have always (previously) been stupid enough to fit the barrel having first fitted the coupling gears. I like the idea that the flexibility of no coupling gears gives.

That said, my ring breakage rate on Squares is no different to that on singles or twins and I still swear by the bungees over the frame tube trick to support the (any) barrel.

The singles were always fitted with a taper at the bottom of the cylinder to feed the rings in. I am not sure about the 4s as my 4 was in a sorry state when I bought it, having thrown a rod and smashed off the bottom of all the liners
I purchased new liners for fitting and realised that fitting the pistons later would be a problem with the square ended liners. I turned a bevel on the bottom edge of the liner before fitting the liner. The bevel that I turned was the same as used to be on the singles. ( I notice that the liner for the singles that are supplied now do not have a taper at the bottom).
After boring, when it came time to fit the pistons into the cylinder I used the Ariel method of some timber between 2 of the pistons and the crankcase to support the pistons in place, lower the cylinder over the pistons and jiggle or a gentle push of the ring with a finger to feed the rings in then support the lower 2 pistons and do the same. With the taper at the bottom of the liner to feed the rings in it is very easy. For anyone that has to fit new liners, turn a taper on the bottom first.
David