81 GS1100 squish measurment

[gsryder]

Does anyone know what the factory squish measurement is for a stock 81 1100?

I have looked everywhere and cannot find what it is.

Thanks.

[Steve]

Rapid Ray should know that one.

.

[gsryder]

Bump.....anyone?????

[Graham]

Squish measurement? Is that a new term?

[gsryder]

Distance from the piston at TDC to the head closest to the cylinder wall.

I have had some machining done different pistons different gaskets....just want to make sure I dont have any clearance issues when I fire her up.

I have looked but have not found anything.

Figured one of the builders on here would know off the top of their head....maybe not.

[Graham]

Distance from the piston at TDC to the head closest to the cylinder wall.

I have had some machining done different pistons different gaskets....just want to make sure I dont have any clearance issues when I fire her up.

I have looked but have not found anything.

Figured one of the builders on here would know off the top of their head....maybe not.

Squish is a term I’ve only herd used for 2-stroke head design. I always use little clay buttons to measure piston to head clearance and piston to valve clearance. I use 0.040 in minimum for both.
If you need something more model specific I can’t help.

[Steve]

Squish is a term I’ve only herd used for 2-stroke head design. ...

Four-stroke engine designers use it all the time. By have a "squish band" around the edge, any mixture that is along the cylinder wall (the coldest part of the combustion chamber) is forced rapidly into the center, which promotes turbulence. Properly-engineered turbulence in the combustion chamber promotes better, quicker combustion for more power and lower emissions. Depending on how tight the squish band is, it can also effectively raise the compression ratio for the last few degrees of crankshaft rotation toward Top Dead Center.

.

[Graham]

Four-stroke engine designers use it all the time. By have a "squish band" around the edge, any mixture that is along the cylinder wall (the coldest part of the combustion chamber) is forced rapidly into the center, which promotes turbulence. Properly-engineered turbulence in the combustion chamber promotes better, quicker combustion for more power and lower emissions. Depending on how tight the squish band is, it can also effectively raise the compression ratio for the last few degrees of crankshaft rotation toward Top Dead Center.

.

I don’t think it is really would be as cridical for a 4-stroke as it is a 2-stroke.
Case in point my GS1100gl hase a little taper at the edge of the cubustion camber (sguish band) but an 81 GS1000 doesn’t. It would be easy to conclued that Suzuki put the taper there to get the GS1000 castings to work with the 72mm bores of the GS1100.
I haven’t noticed many squish bands on 4-strokes and it doesn’t seem very commin. I have had to take some metal off the edges of a cubustion chamber to get a good piston clearance after milling. Just never thought of it as a squish band.

[gsryder]

Its not so much for a performance issue but more I want to know what the distance is from the factory so I can check against what I have now.
Last thing I want to do is smash a set of $600+ dollar pistons into the head or valves because I didnt take 5 minutes to verify I had the proper clearance.

[gsryder]

So does anyone know what the proper clearance (squish) whatever you want to call it??

[Steve]

Well, a couple of days ago I mentioned that RapidRay should know that.

Evidently he hasn't seen this thread.

Evidently you have not yet taken the incentive to send him a message.

I guess this is the time where I need to stop hinting and come right out and say it: contact RapidRay.

Send him a PM. Or look up some of his posts, he frequently posts his phone number with the invite to call him.
It's not an inconvenience, that's his business. He builds those engines.

.

[mlinder]

Dunno what stock is. .035 is a minimum, a spec I use for race bikes. .040 is a good number all around. I wouldn't want any more than .050.

Squish is as important on 4 strokes as it is on 2 strokes.

[rapidray]

The MINIMUM head gasket thickness I use is .043. This gasket, if you have the piston @ .000 deck height, will give you plenty of room for piston to head clearance on a street engine. If the pistons are .005 down in the hole, even better. When I blueprint one of these, I seek .000-.005 in the hole for piston deck height. Pro Stock GSs turn over 13,500 rpm & use .043 thick head gaskets. The reason for this is that at max rpm, as the piston reaches TDC & takes all the play out of the main bearing, rod bearing, oil squeeze & rod stretch, all of that play is VERY close to .040. That leaves you with a safety margin of .003 before the piston hits the head. On a sreet engine you will never see that rpm (HOPEFULLY!!!) so a .043 head gasket with zero deck height will be plenty safe. I believe this is what you are asking for because "squish" is a totally different issue. Make SURE you still check piston to valve clearance as that can kill you just turning the motor over by hand if you don't have the cams degreed correctly. Ray.

[gsryder]

That is exactly what I was looking for. Thank you.

[blowerbike]

deck height?
valve to piston?
i think your asking for info that doesn't pertain(factory squish) to what your doing...not factory pistons anymore.
especially sense your using after market pistons.
set the pistons at zero or down in the hole up to 010.
you should have plenty of room depending on your valve size and cams.
if these are both stock...
you will have plenty of room.