GS1000 Cylinder Head Performance Upgrade Options

[Nessism]

Ray & all, what do you think of the small port head converted to the "D' profile with the port cleaned-up and matched. Proper valve job included, natch. Going for maximum port velocity & low to mid-range punch with good reliability. Fresh, matched springs with titanium keepers & collars. With 29mm Smoothbores & a set of mild cams, this might make for a nice street performance set-up. Thoughts, suggestions?

Stock retainers are fine for what you describe. Regarding the D profile, I think you would have to build up the ports short side radius with epoxy or maybe welding (not sure this is possible) which seems like way too much work and expense for an 8V engine.

 

[49er]

Welding is probably out because you would cause too much distortion. Most folk who have attempted this use an epoxy resin. It will eventually burn away though. How long will it last, a very good question?

My suggestion is keep an eye out for a later model head (83 onwards).

 

[BadBillyB]

Ray & all, what do you think of the small port head converted to the "D' profile with the port cleaned-up and matched. Proper valve job included, natch. Going for maximum port velocity & low to mid-range punch with good reliability. Fresh, matched springs with titanium keepers & collars. With 29mm Smoothbores & a set of mild cams, this might make for a nice street performance set-up. Thoughts, suggestions?

Titanium retainers are not suitable for street bikes IMO. The cams you are using will determine what kind of valve train parts you should use. You said you already have mild cams. What are they???....I wouldn't be so concerned with the "D" shaped exhaust ports as you can make the short side turn flat with a sanding roll. There is more to be lost/gained by how the valve seat area and ports are done. If you want max port velocity and low end grunt I would stick with the small port head and have it done by a pro, even if you have to pay a little more. Choose wisely here as I have seen very pretty port work done that had great flow bench numbers but didn't make any power...I have personally ported both the large and small port heads and agree, the large port head is easier to work with because of its size....And is perfect for drag race motors....Billy

 

[rapidray]

D porting the small port head requires NO epoxy or welding & will help the exhaust side flow a LOT! You also won't lose any bottom end or drivability. Titanium retainers aren't needed for a street engine unless it is a REALLY high performance or race engine. Put that money to use elsewhere. Ray.

 

[srsupertrap]

D porting the small port head requires NO epoxy or welding & will help the exhaust side flow a LOT! You also won't lose any bottom end or drivability. Ray.

Ray,
I am curious how do you convert the 82 GS1100G head with the round ports into a D port? I see a couple of those floating around the Forum.

 

[rapidray]

Yes, it is not a problem. Ray.

 

[49er]

Ray,
I am curious how do you convert the 82 GS1100G head with the round ports into a D port? I see a couple of those floating around the Forum.

If you want good low to mid range torque, find a factory D port. Why do you think Suzuki added metal to that area, instead of blending that shape into the existing port configuration?

 

[srsupertrap]

Here is my 1100G Head D port which is currently soaking in cleaner at Tkent02 house. I was wondering does anyone know can I reuse the original GS1000 Head Cam chain guides for the tunnels and for the one that goes between the cams?

Or should I find GS1100G cam chain guides?

 

[Nessism]

Tensioner guides all seem to be within the same supercession chain so you should be able to use your old ones assuming they aren't worn.

 

[Guest]

Gs1085s

Gs1085s

had my Gs bored to wiseco 1085cc,had crank welded ,new camchain head cleaned up.
Gs1100g cams as i wanted torque not topend,bronze ape valve guides seals,cams, degreed
in on slotted sproxs, high volume V&H oil pump gears, stock carbs (28mm) K&Ns oval type.
Had it Dynoed setup a treat 90Bhp backwheel 68ftlbs,of torque.
ride it two up alot, now it doesnt notice wife on the back,and dont use a litre of oil every 200miles,in fact oil consumption is zero now.
exhaust is a V&H mega.
power wheelies first and comes up in second gear if hits a bump in the rd, so job is done.

 

[srsupertrap]

A couple of technical questions about this head conversion: with Weisco 1085's in a 78 GS 1000 (8v), the piston crowns are relieved for just a single intake & exhaust valve. With the 83/84 GS 1100 head, are the valve reliefs in the Weisco pistons appropriate for the larger valves in the 1100 head?

The GS1100G Intake & Exhaust valves are the same P/N's Suzuki used in the 79 GS1000N/EN/SN according to Alpha Sports

1984 SUZUKI GS1100GKE Touring - CAM SHAFT - VALVE
Intake Valve: P/N 12911-49020
Exhaust Valve: P/N 12912-49020

1979 SUZUKI GS1000N & EN - CAM SHAFT - VALVE
Intake Valve: 12911-49020
Exhaust Valve 12912-49020

Yes, the Wiseco valve reliefs are adequate because the 1100 valves are not larger.

 

[srsupertrap]

Question: If I bolt on the 1100G Head onto the bored GS1085 Jugs I will have less compression if the 1100G combustion chamber has a larger volume. Correct?

If I want to maintain the same compression or bump it from 10.25 to 10.50:1 (sea level) how many thousandths needs to be removed from the GS1100G cylinder head to accomplish this or what formula should I use to calculate this? I am at 5280 Feet

 

[Nessism]

Steve,

How about...

1) measure the combustion chamber volume of the 1000 head

2) measure the combustion chamber volume of the 1100 head

3) calculate difference between the two

4) calculate how much must be shaved off the 1100 head to match the chamber size of the 1000 head (assume a cylindrical section will be removed by decking).

To measure the chamber size people use a piece of clear plexiglass with a hole though it. Stick the glass down on the chamber with a little sealer around so it won't leak, then use a graduated cylinder of some sort to measure the volume of fluid required to fill up the chamber.

 

[srsupertrap]

Steve,

How about...

1) measure the combustion chamber volume of the 1000 head

2) measure the combustion chamber volume of the 1100 head

3) calculate difference between the two

4) calculate how much must be shaved off the 1100 head to match the chamber size of the 1000 head (assume a cylindrical section will be removed by decking).

To measure the chamber size people use a piece of clear plexiglass with a hole though it. Stick the glass down on the chamber with a little sealer around so it won't leak, then use a graduated cylinder of some sort to measure the volume of fluid required to fill up the chamber.

Ed,
Good idea & method. I will have to scrounge up a GS1000 head from TKent02 garage. I think we collectively bought a extra GS1000 head for $10 when I bought that 81 GS1100E rolling chassis in the summer. Forgot all about that one. If not Tom probably has a couple more GS1000 heads lying around .

 

[larrycavan]

I just ported a GS1000 head for a 1085 street motor. This was as small runner head. I hadn't done one of these in a long while.

Street Port - Stock Suzuki Valves

For 1085cc motor, VM33, Yosh Stage 1 Cams

lift - cfm@10"
.100 - 33.2
.200 - 58.4
.300 - 80.1
.400 - 92.0
.500 - 97.3

 

[Road_Clam]

LC, I was curious if you were a member here on GSR.... you and your drag cronies always amuse the poop out of me with witty ball breaking conversation over at the "other" enemy forum ! LOL

Rich

PS I have NOT forgotten about you, as soon as I dig the GPz head out of my attic, i'll get it to you...

 

[Nessism]

I just ported a GS1000 head for a 1085 street motor. This was as small runner head. I hadn't done one of these in a long while.

Street Port - Stock Suzuki Valves

Larry,

How about tossing us a bone and explain where gains are to be had porting these heads? I know the short side radius is terrible so smoothing that part is obvious but would love to learn more.

BTW, I "ported" my GS1000 head using a rat tail file! No joke! Only thing I did though was to smooth over the sharp squared off edges on the short side radius. Beyond that I was afraid to touch the port because it looked pretty darn good from the (untrained) eyeball perspective.

 

[larrycavan]

Larry,

How about tossing us a bone and explain where gains are to be had porting these heads? I know the short side radius is terrible so smoothing that part is obvious but would love to learn more.

BTW, I "ported" my GS1000 head using a rat tail file! No joke! Only thing I did though was to smooth over the sharp squared off edges on the short side radius. Beyond that I was afraid to touch the port because it looked pretty darn good from the (untrained) eyeball perspective.

This was an early model head with the small runners. These heads respond quickly to all the usual porting techniques. Suzuki cast them with a fairly generous bowl. They could have easily made this a killer head for it's day.

The place you have to watch is you go in there with a porting tool is the roof of the port isn't overly thick under the tappet bore. Careless grinding there will get you a nice hole :lol:

You can see in the photos that it's not cut too deep on either side of the guide but the flow killing guide boss has been reshaped.

Throats are 88% bone stock. A generous amount from an OEM casting.

I could have gone back and fiddled with the valve job to pick up the low lift numbers but on the overall, the numbers are good so I left it be. This was cut, a 3 angle, very light valve job was done, resurfaced and on the flow bench. Once and done.

It's flowing 90 at his cam lift. He'll notice a difference...that's for certain.

Runners are sized for the larger carbs.

The owner seems to me to have his act together. He wanted a mild cammed, mid size motor that will pull hard on the street with 33mm carbs. I found him some great cams for that. He already had the carbs.

They came out of an 1170 with pretty much the same porting. You could not give that bike a hand full of throttle in first gear without it standing straight up on the rear tire. That dam thing was a handful to hang on to with that slippery seat :lol:

Pretty much everyone knows I'm a dyed green Kawasaki guy but that doesn't mean I dont' appreciate the potential of these old GS1000's. They really respond to the correct parts and some head work. I've ridden a couple of unbelievably quick GS1000s over the years....Awesome motorcycles


PS... if you attempt your own, don't over do the exhausts. The suck side is where it's going to make the biggest difference

 

[larrycavan]

LC, I was curious if you were a member here on GSR.... you and your drag cronies always amuse the poop out of me with witty ball breaking conversation over at the "other" enemy forum ! LOL

Rich

PS I have NOT forgotten about you, as soon as I dig the GPz head out of my attic, i'll get it to you...

Hi Rich

Oh yea......it get's real interesting sometimes. If I hear BS34 Mikuni one more time I'm going to find a tall building and bail

 

[srsupertrap]

I just ported a GS1000 head for a 1085 street motor. This was as small runner head. I hadn't done one of these in a long while.

Street Port - Stock Suzuki Valves

For 1085cc motor, VM33, Yosh Stage 1 Cams

lift - cfm@10"
.100 - 33.2
.200 - 58.4
.300 - 80.1
.400 - 92.0
.500 - 97.3

Larry, Nice Looking work . . . I am starting my GS1000/GS1100G Head, Cylinder Project and would like to discuss my project with you.

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