New Baileys BB kit not a very pretty sight

[stihlboy]

Take the smallest diameter solder you can get to start with. Pull your spark plug and fish the solder in towards the flywheel side until it hits the cylinder wall. Then crank the flywheel by hand until the piston hits TDC and rolls over toward BDC. Measure, then repeat on the clutch side with a fresh piece. Use the smallest number.

here's a pic I found on the net. this is a 4 stroke, but it shows well.........

that look good?

 

[bayshorecs]

Leave off the ring and install the jug without the base gasket. Measure the squish and see where you are at. Ideally, you want to be around .021ish on the squish. Any less, you need a gasket. Any more you want to drop the jug down.

For me, there was no gasket and .042 squish. My only other option is to mill some off the base of the jug to lower it down.

.042 (my squish) - .021 (target squish) = .021 (to mill off). I would take off .015 and call it a day just in case... Either way, if you take too much off, just add a gasket.

 

[Billy Jack]

This has been very informative. The only thing that remains is a recommendation for sealant in lieu of a gasket.

 

[bayshorecs]

Don't have it nearby right now to tell you the brand I used for sure. It needs to be fuel rated. I think the kind I got at an autoparts store was the only one they had. Most are water pump and intake/exhaust gasket stuff.

Super Tacky or something rings a bell.

 

[constantine]

Great information. Thanks. Rep all around. I will report what I get when I measure by your methods.

 

[redunshee]

This has been very informative. The only thing that remains is a recommendation for sealant in lieu of a gasket.

I use Dirko HT. Never had a problem. Also bought some gasket sealer at my Yamaha dealer as well. Also good.

 

[redunshee]

Leave off the ring and install the jug without the base gasket. Measure the squish and see where you are at. Ideally, you want to be around .021ish on the squish. Any less, you need a gasket. Any more you want to drop the jug down.

For me, there was no gasket and .042 squish. My only other option is to mill some off the base of the jug to lower it down.

.042 (my squish) - .021 (target squish) = .021 (to mill off). I would take off .015 and call it a day just in case... Either way, if you take too much off, just add a gasket.

Any way to mill if you don't have an actual milling machine? Though about gluing sand paper to a piece of glass but wonder if that's an option.

Bob

 

[bayshorecs]

Maybe someone else has a better idea, but I would think getting a flat surface .015-.020 would be very tough free hand.

 

[constantine]

Maybe someone else has a better idea, but I would think getting a flat surface .015-.020 would be very tough free hand.

The old timers could do it. They spent a long apprenticeship learning how to handle a file. One test that an apprentice in the London gunmaker's shops of the Victorian era had to pass was to file a steel cube so that it would pass between a fixed space between two flats in all three directions, without showing light at the edges. Not easy, but it can be done. Alas, today we have CNC mills. I think I'll stay in the present.

BTW, the sandpaper on glass thing can be tricky. I wouldn't recommend it. Believe me, I've tried.

 

[redunshee]

The old timers could do it. They spent a long apprenticeship learning how to handle a file. One test that an apprentice in the London gunmaker's shops of the Victorian era had to pass was to file a steel cube so that it would pass between a fixed space between two flats in all three directions, without showing light at the edges. Not easy, but it can be done. Alas, today we have CNC mills. I think I'll stay in the present.

BTW, the sandpaper on glass thing can be tricky. I wouldn't recommend it. Believe me, I've tried.

I've used this method for sanding crankcase halves smooth and was wondering if it work on a cylinder. Not same material granted.

Thanks

 

[bayshorecs]

Just not worth messing with IMO. If you want it milled, find a machine shop and pay $50 if you don't have a CNC. Too easy to mess up and then you are SOL for sure.

I can't cut 4 table legs to be even. That jug would be fubar if I tried to hand file it.