GS1000G/gs1100G motor

[Joe'sGS850]

I have a gs1000g engine that I want to build up for more power. This will replace the gs850g engine that is currently in the bike. My bike is a Burgundy colored 1980 GS850g. It is just as clean and nice as the bike on Basscliff's site. I've owned this bike for over 20 years. I may be going about this all wrong, but this is what I would like to do, replace the original gs1000g head, pistons and cylinders with a gs1100g D ported head, pistons and cylinder. Replace the gs1100g cams with Andrews S-2 cams, the original gs1000g carbs with 1989 Katana 1100 carbs. Right now I have a 4 in 1 Supertrap exhaust on the bike, no problems with it. Original exhaust system rotted off. This bike is for the street only. I need input from you guys as to where to purchase piston rings, valve springs, valve guide seals, and what type of gaskets are best for the street in terms of maintenance. I do not want to tear this engine back down because of a leaking gasket. Which gasket set would you use, Cometic or oem Suzuki? If I use the oem base gasket, I'll have to have the cylinder head gasket surface milled to compensate for the thicker gasket than if I used a Cometic .005 thick copper base gasket. I'm open to any helpful critism. Thanks Joe.

[Nessism]

OE gaskets and rings are best. If you use the entire top end off a later 1100G then you don't need to shim anything. The crankcase may have to be shaved a little to get the liners to fit down into the engine from what I've read here but it's pretty minor.

Sometimes you can find good deals on OE gasket kits on ebay. As for the cams/springs, if you can't find some good used parts you can always talk to Ape.

My opinion is to keep your stock head. The combustion chamber is slightly smaller which will increase compression if you use some stock 1100 pistons/cylinder parts.

To put an 1000G engine in your chassis you will need the larger drive shaft (I think). Never did a project like that but there is info in the archives since other have done it with good results.

Good luck

[7981GS]

Ed is correct. Use the 1000 head with the stock 1100 pistons/cylinder as it will slightly increase comp. ratio.
The S2 cams are great! I have been using a set in three different engines (850, 1000 and currently 1100) for almost 30 years.
The 1100 cylinder sleeve on #3 will need a slight grind (crescent shape) where the sleeve hits the crank gear.
You also want to check the deck height vs. the 1000 cylinder.
IIRC, you need to mill .010-.020 off the top (I took .020 off). I also am using the .005 Cometic base gasket to lower the deck height and a .020 Cometic head gasket.
BTW, the 1100 cylinder just falls in (except for the crank-gear interference). No grinding of the case is necessary.

Daniel

[Graham]

I’ve been looking at the Dynoman pistons for the GS1000 for my GS1100GL. I just haven’t found the cash. I love the 12:1 and can always shim the deck height to lower it if need be. The 73.5mm is an easy bore in for the 1100 block and all is the stock gaskets. They also offer 78 and 79mm bores.
http://www.dynoman.net/engine/piston...om.html#gs1000

[Joe'sGS850]

GS1999g/gs1100g

Guys, thanks for the info. I'm leaning towards using the Cometic head and base gaskets at .020 and .005 respectively with the gs1100g head and cylinders. I've tried to source the parts locally but to no avail. Does GS Resource have any sponsors that they recommend. I don't mind contributing to sponsors if it helps keep this web sight open. Also is the Cometic head gasket made from copper? thanks, joe

[7981GS]

Cometic makes them both ways and any thickness that you desire.
If you are going to go with stock thickness, just stick with the OEM gasket and save some money.

Daniel

[trippivot]

guys help me understand why you are choosing to use the 1100 cylinders, 1000 bottome end? because it seems as if you are doing the hard way to get some more power. not to mention making the engine fit tighter up in the frame - maybe the shaft is different too?

the GS 1000G has a crank stroke of 64.8mm
the GS1100G has a crank stroke of 66.0mm
both are 72 mm bore

1000 and the 1100 cylinders are different heights, why use a spacer when the .997cc set fit and have the same amount of over bores?

cant the 1000 cylinders and head go right on the 850 bottom end?


spend money for a manual APE camchain tensioner
APE studs, APE head nuts are important because stock stuff cannot torque high enough to seal the copper gaskets. It can be done and run but it will drool oil forever from the base and edges.

stock gaskets and stock head nuts are fine for 8 or 9 to 1 compression

I don't like supertrap because I had one and probably 20 plates, The silencer blew off one day on the highway and the bike jumped forward! never put one on again.

[gs1428]

if he allready has a 1000 engine i would use it before trying to find a 1100 engine. the 1000g has a bore of 70mm same as 1000 chain drive. the 2mm over bore makes a very decent performance gain of the 1100 shaft drive engine.IMO. have built several. the 1000 parts will fit on top of the 850. but the 850 has 16mm wrist pins like the 750 2 valve. so pistons are unavaiable. then you have 2 options. (first) take one millimeter out of the top of the wrist pin hole and use kawasaki pistons. 1000 kaw pistons. same bore as 1000 suzuki. 70mm.and take roughley 195 thousands off the top of the cylinder block depending how you want to set up your engine..which i have done or (second) which i love building. take two millimeter out of the wrist pin hole and use suzuki pistons. you can then use 1000 pistons. 1100g pistons, and if you have 105 thousands cut that puts the suzuki pistons at 0 deck height. or if you want a mean little sleeper, put a set of 79.5mm dynoman pistons in that 850. like i have

[trippivot]

very cool this is stuff is not listed in a book and handed out.

having specific mix-match specs is a vrey cool thing. sorry to mess the groove I' m into 115o stuff nowadays.

[gs1428]

alot of it is trail and error. many many broken parts till you get it figured out. i race the 4 valves as well. but still love the torque the old 2 valves make. into the big 4 valves now. 1640's. putting togather 1790 now.

[Joe'sGS850]

gs1000g/gs1100g motor

Well guys, these are my reasons why I wanted to go this route. A good friend of mine bought a gs1000g bike new and after one year, he totaled it. Mike saved the engine (perfect shape) for all those years. He gave me the engine and rearend. I kept bugging him about not needing it so I got it for free. Knowing that the original gs850g engine's base gasket leaks in hot weather, leaking oil all over my left boot, I wanted to do something about it. Having a free engine, wanting more power than stock gs850g, I read all articles on GS Resources I could. Reading that the gs1100gk head breathed better, I thought why not just use the cylinder and gs1100g head and add a hotter cam, and carbs . Sounded like the way to go. My Supertrapp exhaust has been on my bike for years with no problems. Mine must be the older style, no canister, only removable disks. I played around with removing some disc , you end up with more noise and not much more power. I suppose I could have just used the stock gs1000g and been happy, plus save some money, but the old retired diesel mechanic in me said, modify and try for more power. Thanks for understanding, Joe.