Martin GSX1100

[Rijko]

Hi folks,

i recently bought a Martin GSX1100 in parts.
With it, a GS110X engine which i believe is 1981.

I am looking for more power and from what i can find, the 1135 is much better.
Welded crank, cheaper power and torque than tuning the existing GSX1100.
Most power and better gearbox from the 1985 and up EFF engine ?

Can you tell me if this is a good option ?
Are engine dimensions and mount points the same ?
Do i need more than just the engine ... igniter, wiring loom,  other parts ... or can i just hook up the engine to the GSX1100 wiring loom ?

I am new to  the GSX so feel free to dump the knowledge on me

 

Edited January 10, 2023 by Rijko

[Joseph]

Much better, not sure ? It does have more hp and torque from the get go but they are basically the same engine. Both are the same big, heavy, capable blocks.

Using what you have already should make a very good bike to start with, but you can swap the engines over in any GSX 1100 frame, the mounts are the same.

[Swiss Toni]

Or go oilcooled. More power, slightly younger and lighter. 

[Rijko]

20 hours ago, Swiss Toni said:

Or go oilcooled. More power, slightly younger and lighter. 

oilcooled as in GSXR ?
Your sig leads me to think you have experience with that

Edited January 11, 2023 by Rijko

[rodneya]

It will probably be easier to find a 1127 oilcooled replacement motor than an 1150 one. But that is a really cool old bike and I would keep the engine you have in it

[wraith]

In the old days, when you could get them, people just put the efe head on the et bottom end. As the efe heads flow better, I'm told 

[Rijko]

2 hours ago, rodneya said:

But that is a really cool old bike and I would keep the engine you have in it

thanks, and agreed. 25HP extra is very nice to have but the standard GSX1100 still is an impressive engine i like a lot.

And it only has 13K on the clock so will get it running anyway.

i already bought new inner legs for the ET fork that came with it, working on polishing the lower legs now.

Plan is to first just assemble the bike, and ride it for a bit and see what is what before throwing (too much) money at it.

 

[Jonny]

Defo stay air cooled, IMHO they look so much cooler in a bike like that!

[Safra]

1 hour ago, Rijko said:

i already bought new inner legs for the ET fork that came with it, working on polishing the lower legs now.

Strange that it would have ET forks with leading axles maybe someone kept the original forks 

[Rijko]

18 hours ago, Safra said:

Strange that it would have ET forks with leading axles maybe someone kept the original forks 

Martin sold "kits" in the day.

Cheapest kit contained mainly frame, rear "De Carbon" shock, bodywork and rearset.

Optional kit contained Martin wheels, Brembo brakes and 42 mm Betor front fork with clipons and triple tree.

So to see an ET fork and standard brakes with an ET engine indicates only Kit 1 was bought,
and confirms originality / "as built" ..

The ET triple tree wears the bearings that fit the Martin frame. (larger than the ET ones)
So another indication it was built with ET stuff.

Seller confirmed his father bought it from second owner and knew the first owner and told me
the bike was not changed since new.

Edited January 12, 2023 by Rijko

[Rijko]

For the eagle-eyed amongst us : those are not ET wheels in the picture.

The seller's father (deceased years ago) owned the bike for decades but seller never knew it running.
I may have found the reason for that in the wiring loom btw

After decades the frame was rusted and a teacher of the Da Vinci College Leiden offered to restore the bike in his technical classes with his pupils. That project never flew - they powdercoated the frame and the project died.

After some years he collected the bike in bits as in the pictures but the original wheels were not there : the wheels in the picture do not belong with this Martin. Guess another project died there in school ...
I found some very nice original GSX1100ET wheels (Thanks Jeroen !) so that's good.

Edited January 12, 2023 by Rijko

[Rijko]

Carb time !

The Da Vinci guys tried to remove the jets .... buggered up 2 and gave up.
Fortunately

I got the other 2 out and measured up what i had to work with.

Enlarged the jet opening to approx halfway in the jet : this leaves some meat to tap a screwdriver in.

Put some WD40 in there, applied some heat, more WD40 and let it soak for a day.

Next, heated up the tower holding the jet until the WD40 started boiling and gently tapped the screwdriver in there.

Edited January 19, 2023 by Rijko

[Rijko]

A little motivating and both jets came out without any damage (to the carbs   ).

Succes !

 

Edited January 19, 2023 by Rijko

[Rijko]

Ordered rebuild parts, should be there shortly.

Love the carb stand by the way ...

 

[Rijko]

Next up, ultrasonic cleaning.

All 4 came out great like this one.

 

[FJD]

That carb stand looks really nice, can you post some more pictures ?

[Rijko]

2 hours ago, FJD said:

That carb stand looks really nice, can you post some more pictures ?

It is great, would not want to do without it !
It is for sale here : https://eshop.econ-werkzeuge.de/Vergaserhalter-6676293

You can set the carb fuel level using the exact angle as on the bike, turn the carbs while working on them, it also has a leak container below.

 

Edited January 19, 2023 by Rijko

[Rijko]

Also it allows a nice way to check for dirty or sticky float valves without a big mess !

Check out this short movie :

https://photos.app.goo.gl/CvRrkfWCNt2L8Yfy5

 

Edited January 19, 2023 by Rijko

[Rijko]

About the kit options : here's a brochure describing them.
Ofcourse money talks so customers could buy any single option.

 

 

Edited January 19, 2023 by Rijko

[Safra]

On 1/19/2023 at 5:15 PM, Rijko said:

About the kit options : here's a brochure describing them.
Ofcourse money talks so customers could buy any single option.

 

 

Cool bit of bike brochure history there 

[cnap504]

You’ve got a nice project there, congrats on the find.  To me the GSX1100 engines look better than the 1150’s especially in custom frames.  The 1100’s make good power but if you’re thinking you’d like more they respond well to a cam upgrade, displacement increase, and a bit more compression.  A high velocity free flowing exhaust with a set of performance carbs will certainly complement the engine mods

[Wagola]

It is for sale here : https://eshop.econ-werkzeuge.de/Vergaserhalter-6676293

That link doen't seem to work but I would like to know how much they are charging for the carb stands.

[Rijko]

They seem to have removed the stand. This is another site selling them :

https://probike.co.uk/workshop-equipment/diagnostics/carburation/carburettor-stand

 

 

[Rijko]

16 hours ago, cnap504 said:

You’ve got a nice project there, congrats on the find.  To me the GSX1100 engines look better than the 1150’s especially in custom frames.  The 1100’s make good power but if you’re thinking you’d like more they respond well to a cam upgrade, displacement increase, and a bit more compression.  A high velocity free flowing exhaust with a set of performance carbs will certainly complement the engine mods

thanks. I would like to have more power, but it looks like that drags one into expensive territory ....
Starting with the non-welded crank that does not seem to be able to handle much more than standard.
Straight gears on the crank and clutch basket, bigger valves, flowed head, expensive carbs, etc.
Too bad, if crank revision/welding was not so expensive i would probably be able to get a fresh flowed head with new valve guides and large valves.

Found a super nice overview of GSX engine specifications, weaknesses and differences here : https://suzuki-classic.de/phpBB3/viewtopic.php?f=10&t=5192&p=29371#p29367

I have found slotted cam gears : cam timing seems to be the main performance difference between 100 HP GS110X and 110 HP Katana GS110X engines. Pretty cheap upgrade.
The Martin 4-1 exhaust seems to be pretty free flowing with a quite big collector diameter.

Edited January 31, 2023 by Rijko

[cnap504]

You can get a little boost in compression by adjusting the valves to the loose side of spec.  They stay on the seats longer and trap more air in the cylinder.  Degreeing the cams will help a good bit too