91 square nose motor replacement

[bored&stroked]

2 stroke oil

 

[DylanS]

Thanks for all the replies. I found what seems like a good deal locally.

My plan is to order a gasket kit and tear it down so I can check bearings, cylinders, etc... do you guys recommend lubing the needle bearings with anything specific prior to putting it back together.

Replace the needle bearings they should never be reused. And yes put 2 stroke oil on needle bearings/pins/cyl walls/crank bearings before assembly. Anything that’s a rotating/contact part lube it up before assembly.

 

[Husqy510]

Thanks. Pulled the head on the new motor and everything looks pretty good. Everything turns over nice with no slop and no scoring on the cylinders. I'm going to do a fresh bore and hone, and install a new top end kit.

Now for a dumb question. It looks like the rebuild kits come in .25mm increments. Is that the actual size of the piston, or the size of the required bore?

 

[kevbo]

Get the pistons first and send them with the cylinder to be bored.

 

[Husqy510]

Get the pistons first and send them with the cylinder to be bored.

Makes sense. Thanks

 

[Husqy510]

Seems like there are a lot of rebuild kits on the we for roughly $200. Are any better than the rest for a stock rebuild?

 

[Roseand]

Seems like there are a lot of rebuild kits on the we for roughly $200. Are any better than the rest for a stock rebuild?

If the compression is good why do you want to bore it out? If you're going through all that effort it'd be worth it to at least tear down the cases and check crank and replace crank seals at a minimum.

 

[Husqy510]

I wanted to remove the cylinder to inspect the crank and bearings, and I figured if I have the motor a part I might as well freshen it up.