Identifying 1066 piston for GS1100E, and more.

[Guest]

I need some help identifying a 75mm 1066 piston for GS1100E. I bought a used top end and it looks like it is in good shape. There is no name on the piston. It is forged, and there is a a single C on top of the piston. If you look at the bottom there is a single O in the boss for the wrist pin, near one of the oiling holes for the wrist pin.

I looked in my factory manual and it recommends .002" to .0025" clearence for a stock piston. Since forged pistons expand a little more than cast I am assuming that I need to add about .001" to the factory clearance ?? This is for a street engine that wont get pounded relentlessly, but on occasion it will get run hard.

If someone can help with the piston ID, and clearence it would sure help.

[Nessism]

Photos would help. Upload to photobucket or similar and then link the "img" code here and the photo will show up in high resolution.

[rapidray]

I would almost bet money it is a Wiseco. Pictures will help & piston to wall clearance is based on NEW pistons. If the skirts are used & collapsed ANY you will probably be fine with .002-.0025. You need to measure the pistons right at the pin area & then 1/2 inch up from the bottom of the skirts. Get back to us when you know. Also, 75mm bore is 1166. Ray.

[Texasgs]

re

I cant post pics right now, my Nikon went south. Check out this ebay URL it has some pics of the auction where I bought it.

Piston Pics

I finger fumbled the keyboard and wrote 1066, I know it is 1166, must have been late. The clearance and ring gap is what I am most concerned with I suppose. I have built hundreds of performance engines, mostly automotive and marine, so I am not up to speed on forged piston clearance in a GS1100. If anyone has any hard data I could use it. I was looking for a min/max type specs for the ring gap, and piston to cylinder clearance.

Also does anyone have and airflow data for the GS110 head, or what it is capible of. I have a flow bench that I am bringing out of storage, and I was going to use it to help me improve the flow on the 82 GS1100 head I am using. If anyone has any info on specific areas to clean up that would help. I have ported more heads than I can remember, always using the flow bench, so I know the general do's and donts. I have heard a lot about using GSXR oil cooled heads on the air cooled GS1100, but I am assuming that this wouldn't work for the street because of cooling?

[posplayr]

Here is a pic of a very well done head with about 22% increase in flow rate after porting with 1mm over 1150 intake valves.

http://www.thegsresources.com/_forum/showpost.php?p=999223&postcount=29

[Texasgs]

re

Good stuff, that is right along the lines I was thinking on the ports. Having some type of baseline always helps. Thanks

[rapidray]

The GSXR heads work fine on the street, I build a lot of them. A stock GS 1100 head is in the neighborhood of 80 cfm stock & can go over 150 cfm with the right work & enough money thrown at it. Ray.

[chef1366]

I can show you what NOT to do with an 1166 kit.

[posplayr]

The GSXR heads work fine on the street, I build a lot of them. A stock GS 1100 head is in the neighborhood of 80 cfm stock & can go over 150 cfm with the right work & enough money thrown at it. Ray.

Ray is this a 150 cfm head?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=380173220492&viewitem=&_trkparms=tab%3DWatching

[rapidray]

Nope! MAYBE 120. Ray.

[Texasgs]

re

OK, I am going to proceed on the premise that there are no stupid questions (with limitations), and only stupid mistakes from not asking the right questions.

Ray so you are saying that the oil cooled GSXR heads do fine on the air cooled GS1100 street engines? is the combustion chamber on the air and oil cooled head the same size. Are there variations in the combustion sizes in the oil cooled heads from year to year, other than the expected small variations that production engines have.

[rapidray]

The 88/89 750 heads or the 86-90 1100 GSXR heads are the ones to use. The 1100 heads have 26cc chambers & the 88/89 750 heads have 22cc chambers which up the compression .7 of a point. I like to use the 88/89 750 head & cams on motors I am using flat top pistons in. I use the 1100 heads for high compression motors. Some of the Katana 750, 1100 & Bandit 1200 heads are good too. A stock 1100 or 1150 that you put the 88/89 750 head & cams on will see a 20 HP gain just by bolting those parts on, degreeing the cams, & jetting optimumly! I have seen it many times & it is an honest gain! This is on motors with 4 into 1 pipes & jet kits, NOT stockers! Those GSXR cams from the 750 are .350 lift intake & .330 on the exhausts! They WORK! Ray.

[Texasgs]

re

Ray thanks, for the info.

[posplayr]

The 88/89 750 heads or the 86-90 1100 GSXR heads are the ones to use. The 1100 heads have 26cc chambers & the 88/89 750 heads have 22cc chambers which up the compression .7 of a point. I like to use the 88/89 750 head & cams on motors I am using flat top pistons in. I use the 1100 heads for high compression motors. Some of the Katana 750, 1100 & Bandit 1200 heads are good too. A stock 1100 or 1150 that you put the 88/89 750 head & cams on will see a 20 HP gain just by bolting those parts on, degreeing the cams, & jetting optimumly! I have seen it many times & it is an honest gain! This is on motors with 4 into 1 pipes & jet kits, NOT stockers! Those GSXR cams from the 750 are .350 lift intake & .330 on the exhausts! They WORK! Ray.

Not that I'm looking to change anything mu my ED, but what specific changes do you have to do to get the GSXR head to fit?

What head gasket do you use (GS or GSXR?)

What do you do with the oil line ports on the GSXR head?

We know the issues with the exhaust flange spacing.

Anything else (Stud replacement ?)

GS Timing gears on the GSXR cams.

You loose the Tach drive also.

[rapidray]

GS head gasket, 1150 cylinder studs, GS cam chain & sprockets, NO gsxr idler gear, plug the oil returns in the bottom front of the head, block the oil supply holes in the rear of the valve cover, GSXR front cam chain guide with the bottom ground to fit the GS cases, & 4 plugs in the top of the GS block that are left uncovered by the GSXR head. Probably something else I forgot but that's most, if not all, of it. Ray.