GSXR "DOT" head on my GS1100

[slayer61]

So, I have read here & on other sites that a GSXR DOT head CAN be installed onto a GS(X) 1100 block & I decided, "why not?" Special thanks to Bob Bertaut who did this Frankenstein graft years ago, RapidRay and all the others who have gone before me & done the leg work... the "pre-running" if you will.

Onwards. Step one, start with your average tarted up Suzuki GS1100

Collect 1 fresh DOT head from Red at Motogpwerks

Remove head & do what ever it takes to remove factory head studs

Install a set of APE GS1150 head studs & torque as directed

Trim exhaust connections to fit DOT head. My exhaust has spigots with spring connectors on it, so it was an "easy enough" task to hand 'em over to a pal with a lathe & turn them down to fit!

The head cooler ports were blocked because I (we gs guys) don't have a low pressure/hi volume part to our oil pumps

But I did add a

My old girl already has the 750 oil pump gears installed (no pics. sorry )

But I did test fit the cooler a while back before I pulled her all down...

There will be more... slowly... as I contend with other projects and Mrs slayer's new bathroom

 

[Nessism]

Nice project!

What pistons are you running? Big bore?

And that head, is it from a 750? How much more flow compared to the stock 1100E head?

 

[slayer61]

Nice project!

What pistons are you running? Big bore?

And that head, is it from a 750? How much more flow compared to the stock 1100E head?

Thank you Sir.
As I'm trying to do this on a "budget" I'm trying to use stock pistons. Actually I'm hoping not to have to break the base gasket seal & fight pistons & rings back into the bottom of the jugs. My mentor has suggested that I "at least" put fresh rings in it... but it doesn't smoke, I replied. Cuz I know that as soon as I put fresh rings I'' just as well put fresh pistons, and FFS they might as well be BIG new pistons... see where this goes?

The head was originally used on the 88-89 GSXr 750 "slingshots" and the oil cooled Katana 750s from the same era to 96 or something.
Off the shelf, the slingshot head has bigger valves and a "semi-down draft" intake and a smaller combustion chamber than the 1100 piece. The use of "stock" GSXr cams will show an increase of lift AND duration over the GS pieces. Using "factory" parts I hope to see 20-25 HP.

Be safe guys.

 

[Buffalo Bill]

Hey great story!
I did get a couple suggestions to put a DOT head on my 92 GSXR-N engine, because the smaller chamber will raise compression.
However I did see the 750 valves are a bit smaller, balked at that plus I'd rather keep my 750 on hand in case the 1100 goes bad.

 

[Rijko]

My mentor has suggested that I "at least" put fresh rings in it...

​

Rings can be inspected for wear, instructions are in the factory manual.

Actually I'm hoping not to have to break the base gasket seal & fight pistons & rings back into the bottom of the jugs.

​

If i were to say 'at least' .. i'd say at least replace the base gasket, they often spring a leak
when disturbed by removing the head.

You replaced studs, so even more likely the base gasket will not be ok.

 

[dorkburger]

Cool. I was wondering what bike you were doing this mod on. I think RacingJake did the same on his gs1100 drag bike.

 

[slayer61]

​

Rings can be inspected for wear, instructions are in the factory manual.

​

If i were to say 'at least' .. i'd say at least replace the base gasket, they often spring a leak
when disturbed by removing the head.

You replaced studs, so even more likely the base gasket will not be ok.

What you say is true & understood. It would be kinda stupid to go this far then have it run great, but piss oil out the bottom of the block... :upset: dammit... grumble grumble back to the shop & a harder hit on the Mastercard!

 

[slayer61]

Sorry GS overseers... i didn't realive piss was a cuss can word

 

[Guest]

Are those Honda Comstar wheels?

 

[Nessism]

Are those Honda Comstar wheels?

No! They look like Astralite wheels, or something similar. BIG $$$ (unless I've got it wrong, which is possible!)

 

[zed1015]

Are those Honda Comstar wheels?

Astralites.....

 

[slayer61]

Are those Honda Comstar wheels?

Sacrilege! Put Honda wheels on a Suzuki!

No Sir. They are, in fact, Astralites

 

[slayer61]

It's my busy time of year at work, so progress is minimal, but last night I added new OEM Suzuki inlet rubbers to the head. new hardware etc.

 

[slayer61]

So, I dropped the head onto the bike, with the newly installed studs.... before I realized which location was to use the acorn/closed top nuts and which locations were to use the open nuts.

Looks like I'll be rearranging the studs. The only location for the open nuts is the very outside 4... the incoming oil paths :distracted: Looks like I'll be moving the 2 rear middle studs to the outside where the long stud without a sealing copper washer is needed. mock up number 3.. or 6 or something ffs.

 

[Nessism]

Live and learn. Good on you for climbing the learning curve!

 

[Cipher]

Sacrilege! Put Honda wheels on a Suzuki!

No Sir. They are, in fact, Astralites

Yes the poor Honda wheels must be mortified.

 

[slayer61]

Mock up time while other bits get finalized...

Carbs stuffed in...

Fuel tank "on"...

that's gonna take some fettling.

After removing petcock, signs of improvement!

Head mods in general

With that small piece of aluminum welded in place, the mating surfaces will actually meet up all the way around the head gasket!!

 

[GregT]

For what it's worth, those heads like the cams on 104/104 lobe centers. If you weld in that piece of alloy, bolt the head down to a flat surface while it's done. Last thing you need at this point is distortion. .
I'd also probably have looked for alternative carb rubbers - angled. I've personally never run CR's on that much angle.

Very interesting though, carry on.

 

[slayer61]

Thanks Greg, that's good info about cam timing. I will certainly put it into the data base. Yes Sir, I'm familiar with metal distortion. If we get that much heat that the distortion rears it's ugly head, we have access to a milling machine & a lathe. Never seen angled carb rubbers either, but if the CRs don't like running down hill, I could swap them out with the TMs on the GPz.

be safe!

 

[slayer61]

As some parts come in, onto the es they go. Clutch pack was within spec and reinstalled with OEM clutch cover gasket.

Pictures back from the welder (Thanks Steve!) setting up the head.