Chainsaw Repair

copper sample pack:  http://www.onlinemetals.com/merchant.cfm?id=155&step=2&top_cat=87

if you need thinner, on that site they call it foil. 

sometimes you can find it if there is a tv/stereo repair shop near you.  that is getting rare in this throw-away day and age.

hope it helps.

-joe

DARK 52mm "Big Bore" cylinders. Look familiar?

http://farmertec.en.alibaba.com/product/671185709-217004262/BIG_BORE_52MM_Cylinder_piston_kit_with_rings_for_HUSQVAR_372_365_chain_saw_Aftermarket_replacement_parts.html


Other interesting stuff
http://www.alibaba.com/product-detail/HUS365-chainsaw-for-husqvarna-365-372_1534782349.html?s=p

http://www.alibaba.com/product-detail/Chain-Saw-Cylinder-kit-for-HUSQVARNA_1518686123.html

http://www.chinaseniorsupplier.com/Tools/Tool_Parts/20140112/chainsaw_parts_chainsaw_spareparts_chain_sawpartspa_004_flywheel.html

For 345-350 series....looks REAL familiar. Even the pictures. maybe a source?
http://www.alibaba.com/product-detail/BIG-BORE-45MM-Cylinder-piston-kit_671161696.html

I have two "dark" BB cylinders coming from two separate sources.. HAVE a meteor 064 piston and ordering more. Cheap fun isn't it? Saw puzzles

WD, I remember reading about some Kiwi or Aussie that was trying to put a 272 52mm piston in a 372 52mm BB kit saw without cutting the squish. Had a little problem with the slug meeting the top of the jug. However I have been wondering about doing it for quite some time. The 272 piston is quite a bit taller than the standard 372 piston 1.5mm in compression height but shorter overall by 2.5mm. Not sure about the skirt width and the possibility of a short circuit because of the reduced overall height.

If I come across a decent parts saw I may mess around with it just to see if I could get it to work. This would be one of those situations where variances in manufacturing tolerances may work in your favor. Alsled and I have built identical saws with jugs from same AM manufacturer and meteor 064 pistons, he got away with no base gasket and I had to use one.  So there you go!

I read that again.... the shorter overall height will effectively increase intake duration won't it?.. So with a GASKET (Not a bad thing) and that piston concept theoretically you could both increase compression and increase intake duration without touching a die grinder. Interesting concept. Seems to me that at that point in rotation where the piston skirt is opening the intake port, it takes between .018 and .020 to get a degree. So you can ball park what kind of timing changes that shorter piston can do. I think I have a decent 272 piston from one of the kits around. When those "Dark" "Jinhua Farmtec"cylinders arrive I'll see. My first "Huztl/Jinhua" cylinder/piston had the intake timing at around 76 degrees BTDC if it could be built w/o gasket, 75 with a gasket (up .020). Would take almost .080 to get it where I wanted w/0 gasket & .1 with a gasket.  1mm =  approx. .039in so that would advance the intake timing 2 degree's each 1mm change in skirt . For compression, one of my Jinhua's had a squish of .052without a gasket so 1.5 mm would be a approx. .059. A .020 stock gasket would yield .052+.020=.072-.059 ... .013 in squish. That's pushing it a bit. Maybe a thicker gasket? Raising the cylinder also changes the timing numbers.... wonder if just no gasket makes more sense, Worth a chits & grin build though.

If your numbers above are accurate 0.018-0.020 then the decrease in piston height of 2.0mm ((2.0*0.03937)/0.019) should yield 4.14° change in intake timing.

Quote

ewithout touching a die grinder

that is what I want to do! I want to publish a set recipes using 'off the shelf' parts that the average Joe can follow, without a bunch of grinding or expensive machining and get results close to a custom ported saw, while maintaining reliability.

Don't know if that is where you are at but I think there is a definite audience for these kinds of information. Look how the membership here is growing, so there are at least 2000 folks that would jump all over it IMO.

I spoke to Spike60 briefly by telephone and he seemed to agree that it would be a valuable endeavour.

That is exactly what my video's are all about, simple change for changing power characteristics.... "Farmer Jones" mods!