Engine Teardown

[Ricks]

Rick ,

About the transfer ports , have they been altered ?

Pete .

I think they have been enlarged. I don't have another cylinder to compare it to.   When I get the engine case finished, I will put the rod/piston back on the crank and check why they cut the piston skirt so much.  I removed the bearings so I can't check that yet.

[pd]

It wouldn't surprise me if they were hogged out , considering the over the top 'mods' already apparent .

[Ricks]

After bead blasting the case clean, I found out why the cylinder cracked!  The case was not originally a 150cc motor case. The builder bored the opening for the cylinder spigot, but not deep enough. The cylinder bottoms out on the sleeve before it meets the sealing surface. As soon as the bolts were tightened, I am sure it cracked.

I measured the base OD of a 150cc cylinder at 2.36", and a 125cc at 2.17".


First 2 pictures are 150cc cylinder, notice how it will not seat.
2nd 2 picture is 125cc cylinder, seats as should.

[Ricks]

Here is the sleeve around the rotary intake port.

[cotton]

I picked up parts at the Wollard estate about a year before the auction and got a fly wheel cover for my 1941. It was brass also, and I assumed it was factory but I'm not sure.  I'm going to polish the brass and use it like that.

[Ricks]

I thought Gary might have made these.  He liked to cast things is brass.  I am going to bead blast it to remove the powder coat and then sand and polish it.  If I don't like it, I will use the aluminum one I just bought from Bill E on eBay.

[Ricks]

I have not done much lately, but as I was cleaning up some of the parts, I noticed that the motor seal didn't look quite right.   I like to use a 6mm wide double lip seal, but I have used a 5mm single lip seal when I couldn't find the other.  I guess all the builder had was an 8mm seal.  These are way too wide and bind up the motor against the motor pulley and case.  His solution?  Get out the belt sander!!!.  Now, this might work, but I don't think for long, as the lip holding the spring in is almost non-existant.

I have sent the cylinder to Wayne, as he thinks he can have it Tig welded and then resleeved.  The wall thickness on a 150cc cylinder is very thin, and I am going to have it resleeved back to a 125cc overbore size.

[Ricks]

I spoke with Wayne yesterday, and he said we could not save the cylinder.  He said the base had been cut too thin, and that was one of the causes of the breakage.

I am on the lookout for a single spark plug cylinder, so if anyone has one for sale, let me know!

[mike montgomery]

Rick, I have a cast iron cylinder with one spark plug hole.  It has the decompression lever attached. Is this what you are looking for?  Mike

[Ricks]

Rick, I have a cast iron cylinder with one spark plug hole.  It has the decompression lever attached. Is this what you are looking for?  Mike

No Mike, but thanks anyway.  I am looking for a late model, aluminum, single plug cylinder.  125 or 150 cc, doesn't matter as I will have it resleeved.

[Mike Sal]

How is the single plug head different than the double?  Did they just pull a core pin cast the second hole solid, or did they have a different design all together with a plug in the middle?
Mike Sal

[admin]

They moved the plug to the center of the head. Other than that, I believe they are the same.  If I can't find a single plug cylinder, I wil use a double plug cylinder.