Roadster/Interstate/Thruxton R tank (2020)

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Here's a bit of work I did earlier to accomodate the rear wheel and hollow axle.The rear wheel is actually a front wheel for a GSXR600, so more work remains.( Figure out sprocket and brake)
The hollow axle is too large in diameter for the Commando swing arm as is. It needed a piece added, then milling out.
The milling allowed for correction of the slots so that the swing arm pivot and axle are in the same plane.

Glen



This is a cut down GSXR 600 axle with a solid end added. The solid end is a couple of heavy washers and lots of Tig weld, all machined down
 
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Slots cut, axle before modification.

The wheel fits- sort of

With tire on there's not a lot of clearance but it will work.
Outer tire diameter is similar to a 100/90/19.
Width is quite a bit greater.
Hobot would call it a " Balloon tired corner cripple"

 
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worntorn said:
Slots cut, axle before modification.

The wheel fits- sort of

With tire on there's not a lot of clearance but it will work.
Outer tire diameter is similar to a 100/90/19.
Width is quite a bit greater.
Hobot would call it a " Balloon tired corner cripple"

Click to expand...

so your are going down to a 17" rear rim? how wide is the rim? i wish i had access to your shop! and your talent too!;)
 
The front and rear rims are 3.5x 17". Tires are 120/90/17 , about 26" diameter, similar to 100/90/19
 
worntorn said:
The front and rear rims are 3.5x 17". Tires are 120/90/17 , about 26" diameter, similar to 100/90/19
Click to expand...
I ran a 130/80/17 on the back of my commando it had a terrible weave above 90mph
Hope you don't have this problem
 
worntorn said:
Maybe I'll have it front and rear at the same time and it will cancel out? :)
Click to expand...
I tried that
I put a yam fzr 400 front wheel in to test the theory
That was a 120/60/17 made no difference
I had a pair of commando CMAs laying around with old ratty tt100s , can't remember the front tyre size probably 360/19 and a 410/19 on the back and no more weaving just hope you don't have the problems I had
I also tried a 120/18 in the back,it didn't like that either
 
If you see this bike listed in the For Sale section the day after it goes on the road, you'll know why!

Glen
 
baz said:
I tried that
I put a yam fzr 400 front wheel in to test the theory
That was a 120/60/17 made no difference
I had a pair of commando CMAs laying around with old ratty tt100s , can't remember the front tyre size probably 360/19 and a 410/19 on the back and no more weaving just hope you don't have the problems I had
I also tried a 120/18 in the back,it didn't like that either
Click to expand...
weaving is a result of a number of unwanted condtions. 1, lose bearings, 2, incorrect tire pressure, 3, bad shocks, 4, wornout isolastics, 5, tire carcase failure, have i missed any?.... take your pick
 
worntorn said:
Slots cut, axle before modification.

The wheel fits- sort of

With tire on there's not a lot of clearance but it will work.
Outer tire diameter is similar to a 100/90/19.
Width is quite a bit greater.
Hobot would call it a " Balloon tired corner cripple"

Click to expand...

Nice work. Glad you reinforced the swing arm before enlarging the slot. Back in the '80s I opened up the slot for a larger rear axle on my Production Racer (cast mag 18" wheel with 130 section tire). Worked fine up until the swing arm broke on the left side right through the enlarged slot.

Ken
 
850commando said:
weaving is a result of a number of unwanted condtions. 1, lose bearings, 2, incorrect tire pressure, 3, bad shocks, 4, wornout isolastics, 5, tire carcase failure, have i missed any?.... take your pick
Click to expand...
You missed out tyre width/diameter
As stated I changed from a 130/80/17 to a 410 X 19 and the weave went away
No other changes were made
 
baz said:
You missed out tyre width/diameter
As stated I changed from a 130/80/17 to a 410 X 19 and the weave went away
No other changes were made
Click to expand...
if we go further we take this thread off topic. I'd love to take this further but better in a seperate thread. do you wan to start it?
 
850commando said:
if we go further we take this thread off topic. I'd love to take this further but better in a seperate thread. do you wan to start it?
Click to expand...
Yep I think you are right there's enough thread derailment !
I've covered this subject and my findings in the past I'll see I can find it
Cheers
 
So after much Wheeling, tapping out minor flat spots, more Wheeling , tapping and then lots of hand sanding to remove the Wheeling ridges, it was time to fold a flange on the bottom edge. Once that edge is folded, the Ewheel cannot be used everywhere, although it can still reach most spots. Best to have that work completed.
I have used a small home made hand tool for the fold in the past. It is very time consuming and doesn't do a perfect job, but it is safe.
Less safe is to use the bead roller. The plus is that it's fast and it can make a perfect job.
Several years ago, I spent about 4 or 5 days building this bead roller, so I refamiliarized myself with it and put it to work. It went well.
The bead roller established the turn and put the new flange at about a 30 degree angle. I used the little hand tool to coax the flange to 90degrees, bit by bit. That only took about 20 minutes per side.

The hand tool



The powered bead roller. That's a Yamaha R1 throttle cable running the drill motor. Very high performance!



One edge rolled



 
Then on to forming the tank bottom. The bottom needs to be large enough and shaped correctly to clear everything down below, carbs, head steady, frame members etc. At the same time, any extra clearance means a loss of capacity. I want decent capacity, hopefully 16 litres +-.
The worst though would be to have inadequate clearance and have a spot that rubs metal on metal. The top of the u shape should be the only thing touching other than the two front mount bolt flanges.
All of those points will sit on rubber just like the standard tanks.
Getting around the frame members took lots of pounding.

 
I only see this thread now.
Fantastic job, Glen.
About your engine cradle: with some careful measuring, you don't need adjusters.
In my cradle, the top bolt sits in 2 slightly excentric bushes for final adjustment, 1 mm max.
Because not sure of the wear properties of aluminum, I riveted 2 SS thrust plates, which if needed, can be replaced.
In combination with thicker plates, it made the cradle 7 mm wider, but that can be gained on the swingarm and bushes.
In fact, I took the opportunity to move the arm a few mm to the left, and create more space for the chain.

Roadster/Interstate/Thruxton R tank (2020)


I also moved the swingarm spindle 5 mm up for more anti squat.
(+ extentions for the exhaust supports)
 
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worntorn said:
Slots cut, axle before modification.

The wheel fits- sort of

With tire on there's not a lot of clearance but it will work.
Outer tire diameter is similar to a 100/90/19.
Width is quite a bit greater.
Hobot would call it a " Balloon tired corner cripple"

Click to expand...

Wonderful stuff there Glen, I'm deeply impressed. If one were to do something similar here in Denmark, the whole thing would have to be assessed by an approved engineering consultant, with samples of the steel used, the welding x-rayed, etc., etc. It would be rather expensive to get it all approved.
On the other hand, very few non enthusiasts would probably notice this change.....
 
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