GS 1000 engine in GSXR 1100 first gen frame?

[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]

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

[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]

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%3AMEBIDX%3AIT

[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.

[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.

[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.

[John Kat]

What make and year?

Devil ( a french brand) for GSXR 1986 to 88

[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...

[posplayr]

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

What make and year?

[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]

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.

I think John has already decided on a stanchion, but also probably is using a GSXR 1100 RSU triple (second gen I think).
My suggestion was to go to a GSXR 750 with the same diameter RSU stanchion as it will likely have more offset.

John,
Here is a triple clamp for sale right now at Gixxer.com. You need a R (pronounced "red R"). If you look you might be able to find an vintage Yoshimura triple clamp for a GSXR750 in the same vintage and that (IMO) would be much more cool than that modern day CNC wet dream.

GSXR750Fork.jpg

[GregT]

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.

[dorkburger]

That is droolworthy....

[John Kat]

Looks like a custom set of tripple trees just may be in your future?

The solution is only 750 USD away...not including the forks of course

http://cognitomoto.com/products/gsxr-adjustable-offset-triple-tree-conversion-45mm-50mm-55mm-60mm