GS1100G Largest Bore On Stock Cylinders

[Gixer1460]

1 hour ago, wraith said:

Not quite sure what's up with you theses days, seems like most of your posts are just telling people how bad they are, how wrong  they are etc, If you don't like people trying to build a bike these days and can only put them down whether you know them and there skills or not just don't reply if you don't want to help. 

The forum was/is here to help people with there OSS bikes not keep telling them to go and Google it. We all don't know everything and there are some out there who are just starting out on building there first bike. So help out or keep out.

Well excuse me for breathing! I was agreeing with a post above and the OP by his own admission higher up said that his main experience was with singles / dirt bikes not bigger bike engines, only later to confirm auto / diesel experience! Maybe because the 'internet of instant answers' / Google, wasn't around 35+ years ago when I started building stuff, I researched parts, comparing spec sheets to make informed decisions then went and did it, and no one taught me, I had to learn everything from books and/or trial & error. All the points and queries above are valid - neither you or I are standing in front of the bike or engine to know what state it is in, whether parts provided or sourced will work together or what machine shop facilities the OP has to rely upon! 'You/we' cannot build an engine over the internet - all the advice in the world can't help if the person turning the spanners is a klutz or an Engineer! And, as regard your last statement - I've more often than not advised a poster to get a workshop manual - OEM, Haynes, Clymer etc and read it and read it again as all the basics are there in black & white!

And while we are talking advice - where are your pearls of wisdom in this thread? How are you helping the guy out? Have the site to yourself - it matters not to me!

[wraith]

Yes we all need to learn BUT just because you x decades ago had to do it like everyone else and do the research on the net or going through different spec sheets to find your answer, does this from what you're saying because this is how you did it they have to even if you have the answer. 

I've been in contact with him via pm because I now won't put messages up on the forum because trolls like you just throw your toys out the pram and just have a go and say everything wrong but your right even thow you don't give any help. 

If you're going I for one won't miss your anti help nay saying, maybe you should just stick to FB  you'd probably be at home there, instead of a forum that's there to help anyone at any level, not just the people with there own bike shop or putting lots of money into a build. If OSS is now just for the pro builder's or shop owner and not here for the individual bike builder trying to make there first bike OSS is not what it use to be. 

So from my point of view we don't need you. 

[BretIPC]

I'm not looking to get into a pissing match here.  I wasn't asking for anyone to tell me what parts to buy or how to build the engine.  I started with a simple question of what the limit was for the stock cylinders to be bored out to.  Then it morphed into where to find parts for this not-so-popular engine.  I wasn't looking for advice on how to build it, or what combination of parts to use to get the most power.

Sure, I could guess and spend thousands of dollars in parts and hours and hours of time test fitting, modifying, and trying different things.  But why not use the resources we have at hand in this modern day and age to make the process faster, easier and cheaper by inquiring with people who already know the answers?  Isn't that basically what the service manual is?  Someone with more information and more knowledge wrote that so we didn't have to put all the time and trial and error into figuring it all out.  Just because forums and the internet weren't an option 35+ years ago, doesn't make it an invalid source of help and information to streamline a process.

 

[clivegto]

Some people on hear have fitted gsxr 1100 and Bandit 1200 liners to air cooled blocks to fit bigger pistons. 

[BretIPC]

Just now, clivegto said:

Some people on hear have fitted gsxr 1100 and Bandit 1200 liners to air cooled blocks to fit bigger pistons. 

I talked to LA Sleeve directly.  They used to make sleeves for this engine to go bigger than 75mm.  They stopped producing them due lack of need in the market.  They can still produce them for me if I want to go 76-80mm.   I am not going to go that far with it.  I am going to stick with boring out the stock cylinders a bit and doing some top end work.

[Poldark]

Take a look at this

78-81 Suzuki GS1000 1100cc Bigbore Piston Kits with Head Gasket | CRUZINIMAGE.NET

They are in Japan but ship to the US; very fast shipping.

I have not yet used their pistons, but a local friend has built a few hopped up CB750 street engines with their pistons and has not had any issues.

[gs7_11]

The OPs bike is already an 1100.

[wraith]

1 hour ago, Poldark said:

Take a look at this

78-81 Suzuki GS1000 1100cc Bigbore Piston Kits with Head Gasket | CRUZINIMAGE.NET

They are in Japan but ship to the US; very fast shipping.

I have not yet used their pistons, but a local friend has built a few hopped up CB750 street engines with their pistons and has not had any issues.

Had a set of the 1100cc one in my old gs1000g and for a standard comp pistons I can't folt them.

[Joesmotos]

First post on this forum so...dont hurt me. Concerning the 2 valve GS1100 engine stuff..you might want to look at the later model GPZ Kawasaki pistons with *i think* the 18mm wristpins(1983 and 1984 models had a 18mm wristpin.The stroke is the same on the Kawasaki as the Suzuki. Not sure about the valve angles and deck heights but i bet its close. Most of the older 2 valves would take cams up to around .420 lift..with the shim on top standard setup. Beyond that youre now talking about shorter valve guides,a shim under bucket set up with better springs. Also,you have to be mindful of the clearance between the cam lobe and the cylinder head,we used to have to not only clearance the valve cover so the lobe didnt hit it,but also  modify where the lobe begins to contact the shim. I cant remember exactly but i think the 1100 2 valve had the bigger intake manifolds? You might could use the larger Kawasaki ones and slap some bigger carbs on..(like 34 flatslides)..on your cylinder head,theres a fair amount of gain just by doing some bowl work around the seats,and cleaning up around the valve guide. Not talkin full out port job..just gains. As far as valves go...you can get stainless valves in all the sizes,blank keeper grooves,and have the grooves cut into them if you decided to go the bigger valve route. Again..i would try to get my hands on a GPZ Kawasaki valve and compare the stem lengths and keeper groove location,and the stem height. Most of these old bikes wake up a good bit with more compression,but its hard on the starter set up,the starter rotor has the starter clutch built onto the back of it,and after you raise compression and all the other stuff,if the battery is weak and you go to start it and it doesnt spin fast enough,and kicks back,it can spin the rotor loose and or tear up the starter clutch..neither is good,the rotor is a tapered fit theres no keyway or key and it will tear the crap out of the end of the crankshaft that it rides on. If your guy really wants to go fast i can tell ya he is going to have to stay on top of the maintenance end..sometimes we end up opening the ole can of worms. They do make a heavy duty clutch  backing plate set up(with heavier damping springs and a thicker plate that holds them in place) for the 4 valve stuff,i think that the clutch hubs are similar if not the same. The crankshaft is all pressed together and welding the pins to keep it from twisting was the norm. Not sure on the availability of heavier cylinder studs,,you could always mix and match from 4 valve stuff,if you measured the stud lengths and called APE they might could hook you up They may even have some 2 valve piston kits,,maybe. Worth a call anyway those dudes are some pretty clever cookies and Jay Eshback knows his stuff on these old engines. Ok hope this helps...

[BretIPC]

37 minutes ago, Joesmotos said:

First post on this forum so...dont hurt me. Concerning the 2 valve GS1100 engine stuff..you might want to look at the later model GPZ Kawasaki pistons with *i think* the 18mm wristpins(1983 and 1984 models had a 18mm wristpin.The stroke is the same on the Kawasaki as the Suzuki. Not sure about the valve angles and deck heights but i bet its close. Most of the older 2 valves would take cams up to around .420 lift..with the shim on top standard setup. Beyond that youre now talking about shorter valve guides,a shim under bucket set up with better springs. Also,you have to be mindful of the clearance between the cam lobe and the cylinder head,we used to have to not only clearance the valve cover so the lobe didnt hit it,but also  modify where the lobe begins to contact the shim. I cant remember exactly but i think the 1100 2 valve had the bigger intake manifolds? You might could use the larger Kawasaki ones and slap some bigger carbs on..(like 34 flatslides)..on your cylinder head,theres a fair amount of gain just by doing some bowl work around the seats,and cleaning up around the valve guide. Not talkin full out port job..just gains. As far as valves go...you can get stainless valves in all the sizes,blank keeper grooves,and have the grooves cut into them if you decided to go the bigger valve route. Again..i would try to get my hands on a GPZ Kawasaki valve and compare the stem lengths and keeper groove location,and the stem height. Most of these old bikes wake up a good bit with more compression,but its hard on the starter set up,the starter rotor has the starter clutch built onto the back of it,and after you raise compression and all the other stuff,if the battery is weak and you go to start it and it doesnt spin fast enough,and kicks back,it can spin the rotor loose and or tear up the starter clutch..neither is good,the rotor is a tapered fit theres no keyway or key and it will tear the crap out of the end of the crankshaft that it rides on. If your guy really wants to go fast i can tell ya he is going to have to stay on top of the maintenance end..sometimes we end up opening the ole can of worms. They do make a heavy duty clutch  backing plate set up(with heavier damping springs and a thicker plate that holds them in place) for the 4 valve stuff,i think that the clutch hubs are similar if not the same. The crankshaft is all pressed together and welding the pins to keep it from twisting was the norm. Not sure on the availability of heavier cylinder studs,,you could always mix and match from 4 valve stuff,if you measured the stud lengths and called APE they might could hook you up They may even have some 2 valve piston kits,,maybe. Worth a call anyway those dudes are some pretty clever cookies and Jay Eshback knows his stuff on these old engines. Ok hope this helps...

Thank you for all this information.  I have basically all my stuff ordered, and confident that most of it will work.

I went with Wiseco 73.5mm pistons for the GS1000.  Only 1.5mm oversized, but was all I could really find for a 2 valve piston.  I did look briefly at some of the Kawasaki stuff, and I don't remember at this moment if there was more options there.  I know this was a safe bet.  The compression will be higher so that will help and the customer was happy with it.

I went with Kibblewhite valve train parts.  All were for the GS1000 as the OEM part numbers were all the same to the 1100.  Kibblewhite had all the lifter conversion parts, springs and guides.  Not 100% sure if their guides are shorter than stock, but from my experience their stuff usually is.  I can modify if needed.  They didn't have a listing for the valves though.  I went with Kawasaki Model J valves as they seem to be pretty much identical and their tech was pretty confident they would work. I believe the intake 0.5mm bigger than the GS.  I would have liked to go +1mm on both valves, but the customer didn't really want to get into custom stuff.  I will be doing some minor porting work along with that.

Once I figured out the 1000 and 1100 have the same exact cams, that was a pretty easy pick.  I sent them out to Web Camshafts to be hard welded and ground.

I was able to get APE stuff kits and some other upgrade parts from them including clutch pack.  I didn't upgrade the basket.l though.

I don't have the carbs.  The customer just dropped me off the long block.  He is sending me the new intake boots he got so I can see how they line up with the intake ports and make changes if needed when porting.

[Joesmotos]

Sounds like a good plan..just fyi those clutch baskets take a beating,the stock springs will either collapse or break and wallow out the backing plate,and make a not so soothing sound. He will probably be in the 90-100 hp range with the combo youre doing(at the rear wheel)..might be a bit more but should be alot torquier(is that a word?)...im considering using an 1100 2 valve cylinder on my GS1000 with similar mods..its a streetbike ,im not a racer,just want a decent ride. Hope it all comes together for you..

[Safra]

On 1/22/2024 at 5:50 PM, Gixer1460 said:

Which is doubly confusing as the Euro / UK GSX1100G was oil cooled 16v! but the GS1000G - 8v wasn't LOL!

The year model is where the main differences start with most of these weird different short lived models