GS1000 Cylinder Head Performance Upgrade Options

[srsupertrap]

I would like to get some more street performance out my 79 GS1000 which currently has 43K miles on the clock w/o sacrificing bottom end grunt & reliability. I already have the Wiseco 1085, 29's, mild cams, supertrapp, coils etc so some cylinder head work seems like the next logical step. Currently I am considering two options with my tax return and I am certainly open to exploring all others.

So Option 1 would be send my original small head out for Stage 1 modification which includes 3 or 5 angle valve job? and have some mild porting work peformed. I am not sure of the costs but I am sure Ray or someone else does. The problem, in my opinion with this option is my 1000 head has the cam end float mod, might need guides and has several helicoils repairs. I am not sure whether it's smart to invest more money in it. On the positive side it still looks clean & it's original

Option 2: GS1100G head swap: I don't much about this one but I skimmed through some threads which mentioned the GS1100G head bolts right onto the GS1000. I would like to hear about the issues if any and the performance gains. I think renobruce & sharpey mentioned this but I lost track of the threads. Not sure how this would work with a 1085 Kit? The only problem I know of right now is I would not be able to use the VM29's on a big port head, right? I would hate to shelve them for pair of finickey VM33's. I would appreicate your experiences with these or any other cylinder head mods.

[rapidray]

You could do it either way. If you like the 29s, do the small head. If you want more power EVERYWHERE send me the G head & about 700 bucks. That will get you hot tanking, new guides, guides installed, seals, a RADIUSED valve job, porting, & re-assembly. That price would be for either head but the G head will make more power. You could then sell off your 29s, get some RS 36s with ACCELLERATOR PUMPS! & still have some money left from the 29s! Either way it will still be fun but if it were mine, I would build with the G head. If you have questions about it you can call me at 714-356-7845. Let me know if I can help, Ray.

[Guest]

$700 for what Ray is suggesting is dirt cheap. Pull down the shop service price list at Star Racing for a comparison.

[Nessism]

My first 1000S (large port head) had VM29's with Kawasaki intake boots (the bolt holes were elongated slightly). I didn't look inside the boots to see how well they matched the intake ports. Russr33 is setting up his S this way so you might want to drop him a PM.

[srsupertrap]

I want more arm straightening power, I have never been interested in peaky high rpm engines. My GS1085 was pretty good at sealevel but it's lacking at 5200 feet and up. I guess I will start snooping around for a good low mileage GS1100G head.

Different subject: Ray when you hot tank the head or jug does that remove the factory paint? Ed has stated these parts are all painted by Suzuki. I ask because I had the head off a couple of years ago had it hottanked and from a appearance standpoint it came back lookin like new. I thought the hot tank process would remove the cylinder head paint with all the crud. Not sure

[rapidray]

Hot tanking will only remove the paint that's already loose. I've seen what Transmission shop dip tanks will do & that's another story entirely! Ray.

[gs road racer]

Hot tanking will only remove the paint that's already loose. I've seen what Transmission shop dip tanks will do & that's another story entirely! Ray.

Ray when you speak of "hot tanks" this is caustic soda bath heated? Nasty stuff I thought it would take the paint off....I know if you leave carb parts in to long they dissapear.........poof der dun gone away!

[srsupertrap]

My first 1000S (large port head) had VM29's with Kawasaki intake boots (the bolt holes were elongated slightly). I didn't look inside the boots to see how well they matched the intake ports. Russr33 is setting up his S this way so you might want to drop him a PM.

Ed,
Thanks for the input & advice, I will follow up with a PM to Russ33 and learn from his project.

[Nessism]

I recently bought a low mileage 1100G head off ebay so they are out there if you keep your eyes open. Not sure it's worth the effort to change if your head is still in good shape though.

[srsupertrap]

I recently bought a low mileage 1100G head off ebay so they are out there if you keep your eyes open. Not sure it's worth the effort to change if your head is still in good shape though.

Does the 1100G head have a different combustion chamber shape, like D shaped chamber? BTW do you mind sharing what you paid for the head?

[49er]

The late 1100G heads have "D "shaped exhaust ports. They flow better than round ports, due to a reduction in turbulence on the short side of the elbow.

Chamber shape is still hemispherical.

How superior to your small port head, that's debatable? Mid and top end will be stronger.

With 36 flatslide pumpers, the drop in bottom end performance will be minimised.

[Nessism]

Does the 1100G head have a different combustion chamber shape, like D shaped chamber? BTW do you mind sharing what you paid for the head?

The head cost me $100 + shipping and I can't comment about the chamber shape and so forth since it hasn't arrived yet. My main wonderment is the combustion chamber size.

[srsupertrap]

The late 1100G heads have "D "shaped exhaust ports. They flow better than round ports, due to a reduction in turbulence on the short side of the elbow.

Chamber shape is still hemispherical.

How superior to your small port head, that's debatable? Mid and top end will be stronger.

With 36 flatslide pumpers, the drop in bottom end performance will be minimised.

What year 1100G's have the D shaped exhaust ports?

Second I don't know anything about the 36 flatside pumpers are those the CV carbs that came equipped on the 86-91 air cooled GSXr's or are those aftermarket mikuni replacement carbs that cost as much as VM29's on EBay?

[49er]

What year 1100G's have the D shaped exhaust ports?

Second I don't know anything about the 36 flatside pumpers are those the CV carbs that came equipped on the 86-91 air cooled GSXr's or are those aftermarket mikuni replacement carbs that cost as much as VM29's on EBay?

I believe '83 onwards. My '83 head certainly has them.

RS36 Flatslides are manual slide, Mikuni racing carbs. You could pay around $800 for new ones. Good second hand, probably $400-500.

[Nessism]

The 1100 head I bought off ebay was damaged so it's going back. It's an '82 so no D-port exhaust. Combustion chamber looks same as the 1000 head but I need to measure to confirm.