78' Moby Engine bearings

For those of you following the saga, I got the variator clips out (destroying the second one). I headed the crank case and gave the post a good tap and it fell out. However, it left the bearings in the case.

Advise on how to get those pups out?

It was a good idea breaking down the motor though, there was a big rust spot on the base of the crank where it had been sitting for 40 years. I sanded these down and got them super smooth again.



Re: 78' Moby Engine bearings

Getting the bearing out of the carter half is easy, heat in a 200°f oven and slap the hot casing open face down on a plank of pine. Usually they will pop out the first slap - sometimes two.

Re: 78' Moby Engine bearings

Great! Thanks!

I thought I had really messed up.

Re: 78' Moby Engine bearings

Bearings and seals out

Re: 78' Moby Engine bearings

I use a couple of sockets and a pair of shaft collars for a seal driver to install the seals without folding the seal casings. Best seals to use are the ones which are rubber outside diameter not steel, they are more forgiving to drive in and there is less chance of leaks with rubber on aluminium rather than steel on aluminium. Seal spec is SC 15x21x4.

Only install a spi seal on a cleaned and inspected casing, this is a one shot deal for the seal so if you have more machining to do or have not fully cleaned the carter then do not install the seal.

Check there is slight lead in for seal on the carter half

Place 10mm socket into vise

Place two 1/2 collars or wood block to level and support carter

Place carter onto 10mm socket

Put little 2 stroke on socket

Place spi seal with garters facing out onto socket

Slide to seal seat

Place 14mm socket onto 10mm socket

Drive seal into seat with light taps of hammer


This works with my 10mm socket as a pilot but check first if socket is a good fit into the crankshaft orifice on the carter half. You may need to use a 11mm or a 3/8 socket depending on the socket. Also check first if your 14mm socket driver is a good fit to the pilot socket you selected, it should be a good fit not overly tight but not rattly loose.

Make sure there are no nicks or burrs on the side of the pilot socket - any imperfections will rip the spi seal and render it useless.

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