Ducati Monster Forum

Moto Board => Tech => Topic started by: TAftonomos on July 17, 2011, 01:06:13 PM

Title: Question about my squish measurements
Post by: TAftonomos on July 17, 2011, 01:06:13 PM
Putting a testa motor back together, I used solder to check the squish. Stock base gaskets, stock headgasket.

OE pistons, OE base gaskets, OE HG.

My front and back clearance was 1.02-1.05mm, but the side piston crown to head clearance was 1.5mm (or more?)  These are flat-top pistons btw...

1.00 mm is what I'm shooting for, but I was told by several people that nearly all of the testas need a .02mm thinner base gasket....wondering why mine seems spot on.

Also, if I did this correctly, why is the side clearance on the piston to head is more than the front/back. (piston rock? Or is the piston not really flat?)

Title: Re: My squish measurements
Post by: ducpainter on July 17, 2011, 04:51:34 PM
Your piston pins would have to be very loose to account for that much side rock I'd think.

I'm thinking something isn't machined just right
Title: Re: Question about my squish measurements
Post by: TAftonomos on July 17, 2011, 05:49:45 PM
I was figuring the piston rock fore/aft would close up the squish there, where as the side to side play is non-existant.  I guess it's OK, I didn't change/machine anything.  Just weird that it's spot on and not all over the place like the dozen or so 900SS's I've checked.

Here is where I placed the solder.  Front/back or top/bottom is where the measurement was recorded.  The "side" measurement didn't come up with anything (at least 1.5mm)

(http://i3.photobucket.com/albums/y54/TheoAftonomos/Smoke/95ff6cf9.jpg)

Maybe it just wasn't close enough to the outside edge.  I'd assume the only rocking motion would be fore/aft, so as long as those are OK, and I didn't change/machine anything, I'm good to go.
Title: Re: Question about my squish measurements
Post by: ducpainter on July 18, 2011, 03:10:00 AM
I think you're good to go.