A rider ...

[pd]

The only new rings were what came with the new piston from Wayne .
I have to tear the top end off and take measurements . I plan on another set of rings , at least .
Hopefully that will improve the compression enough to make the motor serviceable .

I think I recall you saying that ring end gap should be .006" -  .008 or .010" .
IIRC , the last end gap was at .014" .

Like I said , I have to take some measurements .

Pete .

[Ricks]

The 1953 Book of instructions lists gap at .008-.010.

[pd]

Rick ,

 I don't see that book of instructions . Maybe I missed it ?
Where can I find it ?

Pete .

[Ricks]

Rick ,

 I don't see that book of instructions . Maybe I missed it ?
Where can I find it ?

Pete .

On the shelf in my den.  Come on over, you can borrow it.  LOL

 If that is too far to travel, it is posted here:  http://www.simplexservi-cycle.com/index.php?topic=100.0

[pd]

Ha . Thanks for the invite , but I already have that book downloaded . I just didn't know it was a 1953 publication .
And , It sure does state the ring end gap , right there in the middle of page 5 .
I guess I'll have to reread ALL the manuals and whatnot .

Thanks ,
Pete .

[pd]

I think I found the cause of my low compression .

Something got in between the piston and cylinder wall and created a few scores . Just enough to have locked the rings in the landings . The scores are not deep on the piston and virtually nothing on the cylinder wall . I have the rings off the piston and have cleaned and refurbished the landings .
I'll put everything back together and see what happens .

Hopefully , the bad gremlins have had their fun and this will be the end of the shenanigans . It's been one seizure after another ... I've just about had it . For some reason , my patience is starting to wear a bit thin .

Pete .

[carryall]

Been there on more than one occasion.  Like they say, anything with tits, tires, or transistors is bound to give you troubles eventually!   

[pd]

 I've had my trials with all of those . Some were good and some not so .

I'd really like this one to turn good .

Pete .

[carryall]

What could have gotten into the chamber you think?  When I get frustrated with a motorcycle/moped project, I find taking a ride on one of my other bikes that's running well, sometimes helps with my mood and outlook on the problem. Or you can just beat the hell out of the bike with a hammer...LOL

[pd]

I really don't know , but I'd guess maybe a grain or two of sand while doing a plug check .

The motor was cleaned with brake cleaner each time it was apart . I suppose something might have slipped by , even then .

I ride almost daily and true , it is good for the soul . Like I've read , you never see a bike in front of a psychiatrists office .

Pete .

[Ricks]

Pete, what is your piston clearance?  Did you ever do an oven check?  I have found that I need .005-.006 or I have seizure issues.  I heat the piston and cylinder in an over and check clearance every 50 degrees.  I have gone as high as 400 and still have .003 clearance, this is starting with .006.

[pd]

Rick ,

I can fairly easily slide a .006" feeler between the piston and cylinder wall . An .008" feeler is very tight and will not allow the piston to travel . So , being as I don't have a .007" feeler , I'm guessing that the clearance is ABOUT .007" or maybe a half a hair less .

I have not done an oven check .  According  to your findings , I would think that I'd be OK .
But , I'll fire the grill up anyway .

I'm thinking that these air cooled motors only reach about 250° . Could be a bit higher .
You took temperature readings of a running motor a while back . Do you recall what those temps were ?

Pete .

[Ricks]

I think you are way underestimating upper cylinder temperature.  I can't remember exactly, but I seem to remember my bikes at around 275-295.  I seem to remember Jim Lokai told me he has seen 400 degrees!

[pd]

Wow . That just seems way too high at 400° .

Anyway , I just pulled the cylinder and piston out of the grill after a 20+ minute heating on high .
I could slide a .005" feeler between with some force .

Hopefully , that will be good enough and not too much clearance .

Pete .

[pd]

I put the motor back together and it ran for a second .

But , now , the carb is clogged with what , I don't know as I have a fuel strainer in the tank along side the strainer in the petcock .

I'll tackle that after dinner . Maybe .

Pete .