GS 1000 engine in GSXR 1100 first gen frame?

[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...

[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.

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

[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

[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.

[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.

[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...

[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]

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

[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]

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.

[John Kat]

Is there any way you can reduce the curve in the bottom rails to put straight joiners in rather than the Z piece?
Will the frame be welded and fixed or will it be dismantalable to unbolt the two halves, or a mix like one side fixed and the other removable to make the engine in and outable?

Hi Chris,
It would be difficult to "straighten" the downtubes in order to align the bottom rails in my opinion.
All tubes will be welded to get maximum rigidity.
Suzuki took care of introducing the engine in the frame of the OEM GSXR chassis as the bottom right rail is bolted in place.
I will keep this feature on my frame.

[tatu]

Is there any way you can reduce the curve in the bottom rails to put straight joiners in rather than the Z piece?
Will the frame be welded and fixed or will it be dismantalable to unbolt the two halves, or a mix like one side fixed and the other removable to make the engine in and outable?

[John Kat]

I've ordered the brackets to support the engine in the frame but I won't get them until mid april...
In the meantime, I checked that the GS 1000 OEM air box ( at least the front one) will easily fit in the frame AFTER installing the carbs.
Very good news indeed when using CV carbs.
In fact, I also checked to see if the VM carbs would fit and the answer is NO as they hit the top frame rails.
So CV carbs it will be!
I'm still devising a frame alignment set-up fixture but if anyone had a good idea, I would be interested.
So far, I'm contemplating using a laser beam that would be attached to the middle of the swingarm pivot and aimed towards the front of the bike.
At first I would lift the beam to strike the middle of the bottom triple tree and then lower it to illuminate the front wheel axle.
If it strikes it in the middle both times, the frame is straight!

[John Kat]

It can be done
Not only can it be done but it can de done (almost) economically.
Of course it's not for the faint of heart as you have to cut a GSXR 1100 G/H chassis into two...
It's definitely a racing type bike as the fitting is very tight.
For instance the motor has to be assembled before going into the chassis.
Now I need to hire Valentino to test it out.
Next step is to design the gussets to hold the engine in place.
I will start with the top rear and the bottom front first as they will help align the engine in the frame.
Here's what it looks like so far: