GS 1000 engine in GSXR 1100 first gen frame?

[John Kat]

I got my laser cut engine brackets back today and I tried a quick mockup of the engine in the frame.
It went like a charm as the engine is now solid in the frame.
The two front brackets will be done later as they must be done in 3D but only on the final set-up.
Next step will be to cut my "good" frame and to weld the aluminum extensions once and for all.

 

[posplayr]

Should be quite strong, I assem when you have it welded the welder will fillet in those sharp corners to reduce the stress risers.

 

[John Kat]

Should be quite strong, I assem when you have it welded the welder will fillet in those sharp corners to reduce the stress risers.

Yes, that's the idea.
With respect to strength, we are in unknown territory for sure but given that the upper beams are quite far apart the frame should not bend much around the vertical axis.
The concern as usual is any twisting effect between the triple tree and the swingarm axle.
Securing the engine tightly should help here.
On the other hand, some flex might be good to avoid disrupting your line at 60? of lean when you hit a bump.
I'll have to ask Valentino after he test rides the bike

 

[limeex2]

Not only is this an extremly interesting thread, but to have a shop that is made from limestone,carpeted and what appears to be speakers the size of a closet would be the ultimate man cave. Thanks for posting and inspiring others.

 

[John Kat]

Not only is this an extremly interesting thread, but to have a shop that is made from limestone,carpeted and what appears to be speakers the size of a closet would be the ultimate man cave. Thanks for posting and inspiring others.

Thanks, Yes I'm quite lucky to have this space.
In fact the house is built on the ramparts of a 13 th century city in the South West of France.
The updates will have to wait until I get the resolve to cut my good frame...

 

[tatu]

Thanks, Yes I'm quite lucky to have this space.
In fact the house is built on the ramparts of a 13 th century city in the South West of France.
The updates will have to wait until I get the resolve to cut my good frame...

Would you like me to send you one / some?
I find that in those plunge moments its best to take a deep breath and hold it till the first part is done then it kind of smooths out.

 

[posplayr]

BikeBook, Go troll someplace else, you're not welcome here.

There is a little triangle with exclamation mark. You can report it as "Spam" or anything else you like. I have already done so on this and the other one I saw.

 

[John Kat]

I finally decided to move forward with the project and I cut my good frame...
For the next step, I believe I will have the extensions welded in place but keep the two frame halves united only by a bolt in order to ride the bike down a slope to make sure everything is well aligned?
Before

After

Side by side with the prototype

 

[yoshisakan]

Why not just keep the 1100 motor? It's awesome.

 

[posplayr]

John, I think the only way to do this is to have a welder that also has a jig. That frame is going to warp when heated enough to melt the aluminum.

Alternatively you might figure a way to brace the individual members relative to the main mounting points to avoid warp.

My only experience with this was when I had bar clamps welded to by GSXR top clamp. The first time I did it I had a spare set of forks and brought the welders my forks with dual top clamps and fork braces all installed to keep the top triple from moving when welded. The Triple came back and it was all nice and straight.

After my git off on Camino Cielo, I bent that top triple and needed to get a new triple rewelded. This time I forgot about the extra clamping from the first time around and had it welded. When I got it back it was way way off. Fortunately I was able to manhandle it back into position. Point in that aluminum will be extremely malleable when it is hot and will shift all over in an entirely different way than steel would. Imagine trying to weld sheet metal, it will warp all over.

I'm not sure how much welding with just the cases in place will help, but that is a minimum. Perhaps, having a sacrificial set of cases that have enough room to make the cuts while the cases are installed. You don't even want to cut the frame unsupported. With full support you can also weld without worrying about the whole mess moving.

The more I think about your road test on the frame is going to be pretty meaningless. Any wheel alignment can compensate for frame twist that you will not be accounting for, and the road tests can't possibly account for any warping from the welding? So what the point? Keep it as straight as possible with bracing and then cut and weld it. Live with the results which should not be too bad.

 

[John Kat]

Why not just keep the 1100 motor? It's awesome.

The whole point of the exercise is to build a copy of the XR 41.
Beyond that it's a pure engineering exercise...

 

[John Kat]

John, I think the only way to do this is to have a welder that also has a jig. That frame is going to warp when heated enough to melt the aluminum.

Alternatively you might figure a way to brace the individual members relative to the main mounting points to avoid warp.

My only experience with this was when I had bar clamps welded to by GSXR top clamp. The first time I did it I had a spare set of forks and brought the welders my forks with dual top clamps and fork braces all installed to keep the top triple from moving when welded. The Triple came back and it was all nice and straight.

After my git off on Camino Cielo, I bent that top triple and needed to get a new triple rewelded. This time I forgot about the extra clamping from the first time around and had it welded. When I got it back it was way way off. Fortunately I was able to manhandle it back into position. Point in that aluminum will be extremely malleable when it is hot and will shift all over in an entirely different way than steel would. Imagine trying to weld sheet metal, it will warp all over.

I'm not sure how much welding with just the cases in place will help, but that is a minimum. Perhaps, having a sacrificial set of cases that have enough room to make the cuts while the cases are installed. You don't even want to cut the frame unsupported. With full support you can also weld without worrying about the whole mess moving.

The more I think about your road test on the frame is going to be pretty meaningless. Any wheel alignment can compensate for frame twist that you will not be accounting for, and the road tests can't possibly account for any warping from the welding? So what the point? Keep it as straight as possible with bracing and then cut and weld it. Live with the results which should not be too bad.

You are most probably right!
In both frames there was some remaining tension that got released when I cut the lower beam...
Luckily as the top frame beams were cut in the middle of a straight line, it will be possible to clamp the half beams on a flat surface and then weld them together.
This will be done with the engine cases bolted in place just like on the prototype.
In any case, I'll keep my fingers crossed.
Many thanks for the advice!

 

[John Kat]

I finalized the setting of the engine in the frame and it's now ready for welding...
In fact it feels so solid already that I'm pretty confident the frame will not twist on the road.

 

[GregT]

Are you going to cut pieces to cover the joint area from the other frame ? Done right it should finish up undetectable.
I think I'd have tweaked the lower rails into better alignment before making the lower middle mounts too, just my 2c...

Looks like it should be easier to get the motor in than the stock GS1000 frame.

 

[John Kat]

Are you going to cut pieces to cover the joint area from the other frame ? Done right it should finish up undetectable.
I think I'd have tweaked the lower rails into better alignment before making the lower middle mounts too, just my 2c...

Looks like it should be easier to get the motor in than the stock GS1000 frame.

I hadn't thought of that!
On the other hand there will be the weld that will remain visible but it should be doable.
Good idea for sure.
Taking the engine in and out of a GSXR 1100 frame is definitely much easier as one can unbolt the right hand lower frame rail.
In fact it's a must I believe as there isn't enough clearance above the cylinder head to move the engine out?
What's for sure is that you need to take the engine out to lift the cylinder head.
I agree that the junction piece between the lower rails doesn't look very sexy but on the other hand the protuding parts were most usefull when I had to to hammer the extensions out of the frame during the adjustment phase...

Beyond that, I'm wondering what wheels I should use?
GSXR 1100 18" 6 spoke or 3 spoke?
GSXR 1100 17" ?
I was planning to use a GSXR 1100 K front fork in any case as it was the first Suzuki to use cartridges in their forks: a massive improvement in roadholding!

 

[GregT]

Put it on 17's. Back in the day, I was part of a team here which built an 1100 using the same frame as yours. We put it on Marvic 17's, ran it on methanol. With the late Robert Holden riding it set lap records wherever we ran it in NZ. Admittedly Robert was a specialist on the GSXR1100 - he instructed at a race school in Aussie using them - but they really handle very well on 17's. Much better choice of rubber too.

 

[John Kat]

Put it on 17's. Back in the day, I was part of a team here which built an 1100 using the same frame as yours. We put it on Marvic 17's, ran it on methanol. With the late Robert Holden riding it set lap records wherever we ran it in NZ. Admittedly Robert was a specialist on the GSXR1100 - he instructed at a race school in Aussie using them - but they really handle very well on 17's. Much better choice of rubber too.

17" are the better choice but as I have some 18" available, I will try these first.
I can swop later on, if required, with the 17" that are on my Katana 1100.
I'm still undecided if I want to give the bike a period look or not?
For the period look I have some old 4 pot AP Racing ( AP 3369) calipers that were used I believe on some Yamaha TZ racers.
Are they any good?
Here are the bits and pieces for the bike:

 

[GregT]

The XR's used AP two pots but those 4 pots are a very good caliper...very good indeed.

 

[John Kat]

While I'm waiting for the frame to come back from the welder, I bought a fuel tank.
It wasn't cheap but the condition was very good with no rust whatsoever.
Not surprising considering it came from Greece.

 

[John Kat]

The frame has been spotwelded last friday ( sorry no pictures) and the guy will finish it by next monday.
I'm trying to get all the bits and pieces together to get it on its wheels before the end of the month...
I need to mock up the seat and the tank together and then the exhaust pipe before final assembly.
Here's the seat I'm contemplating to buy: http://www.poly26.com/produits/photos/selle329abmedium.jpg