GS 1000 engine in GSXR 1100 first gen frame?

[John Kat]

Back in the day, I know that Suzuki NZ's GSXR1100 used a Yosh pipe they had laying around which was originally for a GS1000...

If you want to stick with RWU forks, the best Suzuki ever made were the GSXR750J legs.

The GSXR 750 J is the 1988 model I believe?
The forks, I'm using are the GSXR 1100 K 1989 that must be identical as Suzuki carried over the design of the 750 to the 1100 one year later.
The offset might be a little different as the P/N differs for the top triple but who knows?
The reason it's a good fork is that it's the first one that was equipped with a cartridge type damper.
Tomorrow I'll get to see a GSXR 1100 exhaust and I hope that will settle the issue?

 

[posplayr]

Tomorrow I'll get to see a GSXR 1100 exhaust and I hope that will settle the issue?

What make and year?

 

[GregT]

The GSXR 750 J is the 1988 model I believe?
The forks, I'm using are the GSXR 1100 K 1989 that must be identical as Suzuki carried over the design of the 750 to the 1100 one year later.
The offset might be a little different as the P/N differs for the top triple but who knows?
The reason it's a good fork is that it's the first one that was equipped with a cartridge type damper.
Tomorrow I'll get to see a GSXR 1100 exhaust and I hope that will settle the issue?

Yes, 88 750 is the J model. In some markets the 1100K came with USD forks - which has caused quite some argument here in post classic race circles. I'm not sure that the 1100 forks are identical...the 1100 motor goes in the 750 frame, yes, but there's no room to remove the rocker cover so the 1100 frame is taller in the midsection. Whether this carries over to longer fork legs i don't know.
From memory, I suspect the 750 top yoke may have an ignition switch mount cast in where the 1100 has a separate switch assembly. I do remember cutting this off a 750 top yoke...

 

[John Kat]

What make and year?

Devil ( a french brand) for GSXR 1986 to 88

 

[John Kat]

I got an OEM GSXR exhaust (maybe from a GSXR 750 J 1988?) and a 17" GSXR wheel from one of my friends.
The good news is that the exhaust went onto the bike easily.
There is now plenty of room for the 18" wheel even with a mudgard.
The diameter of the exhaust pipes is apparently a little smaller than on the GS and I will need to sort out how to attach it to cylinder head.
There could also be a minute interference below the engine but I suppose I could take some material away from the fins.
At least there is no gaping hole!
One issue however the complete exhaust weighs as much as a dead donky...
I will definitely have to use another silencer.
Last but not least the quick fix would be to use the 17" wheel as you can see on the pictures.

 

[GregT]

I've machined up brass head to pipe adaptors previously. Sliding fit in the head, pipe sockets into it, about 3mm thick where it sits against the head. I've found that doing it like this, you don't have to use the crush/insulating washers at the joint as the brass seals quite well as long as everything is clean.
Brass as it's a bit stronger than alloy - and doesn't rust like steel would.

 

[steve murdoch]

Looks like you lose access to the oil filter and plug?
An okay trade-off if that system saves you some money for future snafus.

 

[John Kat]

I've machined up brass head to pipe adaptors previously. Sliding fit in the head, pipe sockets into it, about 3mm thick where it sits against the head. I've found that doing it like this, you don't have to use the crush/insulating washers at the joint as the brass seals quite well as long as everything is clean.
Brass as it's a bit stronger than alloy - and doesn't rust like steel would.

As the diameter of the GSXR pipe is smaller, I though of welding a kind of a large washer with the outside diameter corresponding to the exhaust port diameter ( ie the same as the crush washer) and the inside diameter corresponding to the inside diameter of the pipe itself?
Strangely enough the pipe goes down to a smaller diameter just a few mm further down?
I also noted that the actual diameter of the exhaust port is far smaller than the inside of the crush washer?
All in all I believe the diameter would be almost constant from the exhaut port to the GSXR pipe with only a small disruption where they join.
BTW, I thought of welding the "adapter" washer to the inside of the exhaust pipe in order to both fill in the gap and second to allow the "half moons" to sit neatly on the outside of the washer where it protudes from the GSXR pipe.
Not easy to explain.
Would a brass adapter washer be strong enough to hold the exhaust in place?
If that works, I found a neat muffler to go with the OEM pipe ( in fact it must be from a 1991 GSXR 750 )
http://www.ebay.com/itm/361333645938?_trksid=p2060353.m1438.l2648&ssPageName=STRK:MEBIDX:IT

 

[GregT]

A brass adaptor is strong enough to hold the pipe centered which is all you want it to do.
Don't reduce the ID of the pipe at the head joint...my experience is that this will have a noticeable effect on power.
I've had to make up half moons to suit odd pipes and retaining clamps in the past. Most automotive exhaust pipe shops will be able to form tube ends into the flange you need. Then it's just cut to length required and split the tube lengthwise. Given that they can also expand tube, a stepped half moon is possible with a little sweet talking to the machine operator...

 

[John Kat]

This is what I'm planning to do in pictures.
The OEM manifold as it stands

The crush washer simulating the flat adapter that will have a smaller ID to match the exhaust pipe ID

The half moon in place that will come against the adapter

 

[John Kat]

The project moved forward today as I mounted the carbs, the clutch cable, the rear brake and the 3 spoke 18" rear wheel ( thanks Jim).
No issue but I will have to relocate the choke cable.
On the "to do" list I need to buy the left footpeg plate, get the electrics done, secure the tank, buy the seat, buy a chain, buy the exhaust silencer...
I don't know if Pop Yoshimura would have a smile seeing the bike but I do!

 

[John Kat]

The project moved forward as I mounted the instrument panel from a GSXR 1100 K I had lying around.
Another major step happened when I realized I could use a GSXR 1100 K/L/M wire harness that I had purchased many years ago for another project.
The condition is almost new and it took a big weight of my chest.
BTW the battery that's used on the bike is the same as the one on the GS 1000's.
A new chain was delivered today and I will have to shorten it very slightly as it's slightly too long.
The exhaust manifold is taking longer than expected due to the holiday period over here.
Here are the latest pictures:

With the tank in place

Lots of wires

The throttle cable a little short of space

 

[ShadowFocus603]

Looking good John. Can't wait to see this all done up.

 

[John Kat]

I'm currently trying to get the electrics to work.
No big mental issue apart from sourcing the right connectors and terminals...
I placed an order for most of them to cycleterminal.com but where do I find the connector that goes to the oil pressure sender?

 

[GregT]

I'm currently trying to get the electrics to work.
No big mental issue apart from sourcing the right connectors and terminals...
I placed an order for most of them to cycleterminal.com but where do I find the connector that goes to the oil pressure sender?

It's possible to adapt the female part of a connector which uses a spade as the male part. They're usually open on one side which will let you tweak it to fit the shouldered pin on the oil pressure sender.

 

[John Kat]

It's possible to adapt the female part of a connector which uses a spade as the male part. They're usually open on one side which will let you tweak it to fit the shouldered pin on the oil pressure sender.

Good idea!
Thanks Greg

 

[Buffalo Bill]

It looks very good!
Because you mentioned Pops Yoshimura, I was reminded of all the mods he made under the valve cover to increase power and RPMs. Including: port polishing, springs, buckets and shims, timing chain idler sprocket, pistons, high lift cams, all things later incorporated as standard in the GSXR oil cooled engines.
John I don't expect you to do all those things, just curious if you were able to do any of them.
Thanks.

 

[John Kat]

It looks very good!
Because you mentioned Pops Yoshimura, I was reminded of all the mods he made under the valve cover to increase power and RPMs. Including: port polishing, springs, buckets and shims, timing chain idler sprocket, pistons, high lift cams, all things later incorporated as standard in the GSXR oil cooled engines.
John I don't expect you to do all those things, just curious if you were able to do any of them.
Thanks.

No I don't believe I have that kind of expertise.
I'm just an amateur mechanic really and while I'd like to have this done on my engine, I don't know who could do it around where I live.
As I'm lucky to have much more powerfull machines in my stable I'll do without.

 

[John Kat]

This is what I'm planning to do in pictures.
The OEM manifold as it stands

The crush washer simulating the flat adapter that will have a smaller ID to match the exhaust pipe ID

The half moon in place that will come against the adapter

I got the header back today with adapter welded into place and in no time flat I got it back on the bike.
Looks OK to me!
In fact this header would work on any GS 1000 in my view.
Last but not least there is still access to the drain plug!
The header will be painted later of course.

Plenty of space for the 18" wheel

Still the minute interference with the bottom case fins

 

[Buffalo Bill]

I just bought a complete OEM Katana 1100 exhaust for my 1127 swap into a 750 Katana. Those pipe ends look similar, and the ring clamps identical.
You just might try putting an OEM GSXR or GSXF exhaust on for a fitting test. It might work.