Engine Teardown

[Ricks]

I just disassembled an engine I have to see what kind of shape it was in.  I don't think this motor had any chance of running!  Check it out.

Solid aluminum compression plate was too deep, so the rod bearing retaining screws were ground down to make clearance!  Who would do such a thing?

[Ricks]

Billet rod was balanced/lightened horribly. This rod has so many stress risers, it would probably let go in short order!

[Ricks]

The piston was also clearanced,balanced/lightened with who knows what!

[Ricks]

An attempt was made to add weight to crank.  Don't know how this worked out, but Simplex did this through the years.  Also, a repair was made to the key way.

[Ricks]

Not enough clearance for the crank nut?  No problem, lets break out the grinder!  WTF?

[Ricks]

In an attempt to increase performance, the carb inlet was hacked out.  The engine was also sleeved to tighten the intake clearance.

[Ricks]

And last but not least, one of the cylinder mounting bosses was broken off and held on by RTV.  Part of the cylinder sleeve is missing, as I only found the one piece inside when I opened it up. 

I think this cylinder can be saved by Tiging the broken piece back on and resleeving the cylinder.  Guys, what do you think?  Is it worth the effort to try to save an otherwise good single sparkplug head?

Oh, the motor pulley is also cracked and has been welded!

[mike montgomery]

Rick, A call to Bob Kerr should probably be your next move (regarding saving the engine).  I never seen so many problems with the same engine.  Best of luck to you.  Mike

[pd]

WOW !!! What a mess .

Do all single plug cylinders have large exhaust ports like that has , Rick ?

[Ricks]

Rick, A call to Bob Kerr should probably be your next move (regarding saving the engine).  I never seen so many problems with the same engine.  Best of luck to you.  Mike

Mike, I think Wayne can provide most, if not all that I need to get it fixed.

[Ricks]

WOW !!! What a mess .

Do all single plug cylinders have large exhaust ports like that has , Rick ?

I don't think so.  I think the builder was trying to increase performance.

[pd]

I'm no pro engine builder , but it seems to me that the PO went way too far in his attempt at higher performance . But , maybe he was simply experimenting .

Still , there are a couple things that I don't understand : the shaved piston head would decrease already low compression and the added weight to the crank counter weight would slow the RPM gain , robbing power .
Are the transfer ports raised ( opened to the top side ) to make the skirt over cut at least somewhat effective ?

[Mike Sal]

PD, this is an undersquare engine (longer stroke vs bore), meaning adding weight to the crank is a good thing, as long as the weight of the piston & rod are considered. 

This motor can be saved, but the question becomes is it worth it compared to finding another simplex motor. 
Mike sal

[Ricks]

The motor will be saved.  I will put in a new piston and rod.  I will see about saving the cylinder.  I think it can be welded, machined and a new sleeve installed. If not, I am on the look out for a single plug cylinder. If anyone has one for sale, please let me know.

The good part is the mag looks great, no problems there. 

Did these bikes come with a Brass flywheel cover rom the factory, or did someone make this one?

[pd]

"PD, this is an undersquare engine (longer stroke vs bore), meaning adding weight to the crank is a good thing, as long as the weight of the piston & rod are considered. "

Proof that I wasn't lying about not being a pro engine builder . 

Thanks for that , Mike . I like learning new things .

Rick ,

About the transfer ports , have they been altered ?

Pete .