Chainsaw Repair

Well I've been yapping about it for long enough so it's been started that's the basic putting together that is I have mocked up the cylinder and crankcase assy and have new parts here to get her done plus a pensioner machinist mate to help build the new crankcase assy to unite the Mac crankcase to the 090 cylinder the basic dimensions sound good 66mm bore and 46.5 mm stroke about 157cc give or take a tad



This engine will be a build using all brand now components and some parts I will be using I wont be disclosing .... but it will be interesting I can assure you

Here's part of the new cylinder assy's along with pistons I have here to set up and test with.



The Mac crankshaft and rod are new as are the needle rollers for the rod and new main bearing are all here just waiting on the machinist and the phone call to say the crankcase is done and dusted.

The aim is to get a standard look to the big bore SP125c

McBob

P.S Neil you always said to stop yapping about it and get it done well it's on its way

And proudly supported by

Cool. Thinking outside the box.

Be neat to actually see it in the cut in the  future. 

Not my idea originally the basic concept was created by a farmer in the sticks in the late 70's who built a Mac 15 and using a 090 cylinder quite a few years back great idea but it didn't work but I have the needed bits to get her to 157cc something he didn't have.



Plus he went to all the hassle of getting it running but only achieved 120cc dam.

Should be interesting Bob!

So then by "standard " looking does that mean a horizontal cylinder or standing up like an 090? If it's horizontal you're going to need the deal with a bottom discharge exhaust .

You're going to have to fab something up to take it down under and out the side without having a dead end square transition to get the full benefit of that larger cylinder .

Whatever it is it looks like an interesting idea .

So what then about the rod and piston pin .125 rod,kart rod like a Horstman?