Topic: MessnerMoto - CB750 f2 - Some Parts are now available from build!!

[MessnerMoto]

Not sure which portion was moving and difficult to machine.  I would have milled it and not cut the round portion leaving the outside edge half cut with maybe 30-45 degrees or the cut not cut for the last 1/3 of the radiused end. Program the cnc to cut the sides of that section so you have parallel sides respective to the end for the boring.  Then the part free with edges squared to be able to clamp so your boring can be aligned to the end. You will of course have to check with a laser or plumb line  that your drill or milling bit is going to bore into the part straight. If it is off by much you may be able to see that with the bar ends attached.

Ideally you perform all the machining without removing the part of all the angles align. (Within the bounds of the programming...)
It is interesting,  I guess you have a strong desire to have something no one else has or you enjoy seeing designs come to life.

What is your testing method going to be for critical parts since you are reinventing/reengineering many parts on the bike?


David

Thats not a bad idea... but next time we will not bore a hole for forks. Where fork is supposed to be we will drill two smaller holes of lets say 10mm.... and two same holes on a tool. Tool is a cylinder of 50mm diameter so it will not interfere with part when we turn part for other side machining.

I like to design and if designed something nicer then I am really happy:). Seeing something you imagined in real life is rally rewording. And thats usually a point of custom motorcycle... Trying to be different

I always leave same  amount  or more material like in OEM parts. I always have some OEM parts next to meet for measurements. And if I really want to remove material as much as I can I use some FEA analysis... Like for top triple. And don't forget I am using 6082 T6 all the time. Higher yield strength then cast Al.





 

[754]

I think you meant forged aluminum.
 I suggest,
 The handle bar stub, leave it 1.5mm oversize,  then mount with the fork part INSIDE a large enough 3 jaw chuck.. Probably will end up not sticking out.
 Then machine your inside features, and face end with an endmill..dont hit the chuck.
 Now mount it on what you will, use for handle bars.. Back into lathe with fork part and stub clear of the jaws then turn to same O.D. As handlebar.... Have a radius on edge of tool facing fork part.. Get as close as you can then blend the rest..  It will, look slick...

[MessnerMoto]

I think you meant forged aluminum.
 I suggest,
 The handle bar stub, leave it 1.5mm oversize,  then mount with the fork part INSIDE a large enough 3 jaw chuck.. Probably will end up not sticking out.
 Then machine your inside features, and face end with an endmill..dont hit the chuck.
 Now mount it on what you will, use for handle bars.. Back into lathe with fork part and stub clear of the jaws then turn to same O.D. As handlebar.... Have a radius on edge of tool facing fork part.. Get as close as you can then blend the rest..  It will, look slick...

I was talking about clamps being cast alloy...

Stub area on part is close to 22mm... exactly 22.00-22.10. Ant is close to being perfect circle. When we finish drilling stub area on part for plug and threads we will screw in the rest of stub tubing. With the complete stub on we will do the polishing. So it will be almost seamless transition from part to rest of the stub.

The main problem in machining this part aries from 8 degree angle of stub. Maybe it was not clear from pictures I posted...





This 8 degree is because I want want handle bars to go low. I like a little bit more conformable riding position without that losing that clip on look

[754]

I know its 8 degrees , that. Wont matter when you machine it on the lathe, gripping with a 3 jaw. Faster to finish rounding it in a lathe than milling or hand finishing.

 I think most stock triple trees are forged, not cast.....look at the part line...  Way thicker than casting.
If they're cast  they would be much weaker..

[MessnerMoto]

I know its 8 degrees , that. Wont matter when you machine it on the lathe, gripping with a 3 jaw. Faster to finish rounding it in a lathe than milling or hand finishing.

 I think most stock triple trees are forged, not cast.....look at the part line...  Way thicker than casting.
If they're cast  they would be much weaker..

So you are talking about making big hole for forks at the lathe? Or about other roundness around fork hole?

For people who don't know what we are talking about here is a picture explaning how do make difference between cast and forged part



Looking at the part lines on GSXR k6 k7 clamps I can say they are cast. 



on bottom clamp part line is not even trimmed. And part lines are not even in one plane

[754]

Many trees the line is much wider.. Do you think cast would be safe. ? I do not....

 This may help if you build more..
 What i was talking about is holding the 8degree angled stub.....in a 3 jaw chuck on the lathe....the handlebar part is INSIDE the chuck .. This would require minimal rough miling on the stub.. 3 spots would do.
 Then machine the internal features of the stub.. Then take out of lathe, mount on handlebar..... Then clamp handlebar in lathe chuck... And turn stub round to match handlebar..

 On the ones you have now, instead of rounding by hand, machine inside of stub, mount on handlebar, then finish rounding on lathe..

[MessnerMoto]

Original cb750 top triple is also cast... Yield strength of cast part can go high. Dia casting can produce yield strength above bilet alloys yield strength(look at aa 390 cast alloy parts). Also castings can be hardend to t6.... But I think nothing fancy was done with triples. Cast a356 t6 alloy have yield strength around 160MPa

...for machining we will see how to speed up the process if we decide to make more. I admit the way we did it is currently not cost effective. I will tell abou the advices you provided to cnc shop guys. Pretty sure we can make it without all the extra manual work

[calj737]

If they're cast  they would be much weaker..

I've heard that debate for decades and have seen it dispelled time and again. Casting is certainly a very dependable process of the raw material and process is of quality. And there's heaps of methods for casting. A triple tree is a multi component assembly and casting/forging a single part won't change its overall strength much (in my oponion). I'd even wager many modern tops are cast and not forged.

[754]

The top tree is not the major concern.. The lower takes the punishment.
 On a casting the part line should be very thin, otherwise waste of material and extra cleanup cost.  A mm would be a lot.
Forgings go thru trimming dies.... Then it may get tumbled or ball burnished.. The part line then may appear untouched..
 Another issue is part lines on castings are easiest to  do if they are single plane...ie, a straight line. To change that part line to a curve or multi step on a forging, is of little consequence , but major deal when casting..
 Here is a pic of a Bultaco tree.. Note how thick the part line is... On many trees you can see evidence of triming dies on the part line.

[MessnerMoto]

The point is that I designed my triples according to gsxr triples. They are cast.

[754]

Hey,no problem in strength in what you are building, and its very nice work..

[MessnerMoto]

Hey,no problem in strength in what you are building, and its very nice work..

It ok I am always open for discussion. I am pretty sure we will use some of your advices for machining when when I remake this part

[MessnerMoto]

In the end this is how the ceiling was made. Not my idea



And we started immediately something new. Probably the last complex part I will make for this build.

[MessnerMoto]

I am getting close to finish all CNC stuff... Controls are still not polished... Finishing touches left for the weekend

[SOHC4 Cafe Racer Fan]

Amazing! 

[MessnerMoto]

Thanks Don

[Retro Rocket]

Amazing! 

+1, I love to see someone fabricating simply because they can...

[MessnerMoto]

Amazing! 

+1, I love to see someone fabricating simply because they can...

Speaking of fabrication... Things are speeding up.

With the help of my good friend munizabap(old soho uk forum member) and a rally excellent fabricator who has his own custom shop we started making some progress.
Majority of work went in to making one giant banding wheel. It has diameter of 360mm for 35mm tubing. If you want custom stuff you need to make your own tooling










So we did all the bends on one tube without banding. Thats some really nice skills by my friend. Pneumatic press....

[brandEn]

wow.....

[754]

Very nice, how thick is the wall of the tubing..?

[MessnerMoto]

wow.....

Thanks

Very nice, how thick is the wall of the tubing..?

The wall is 2mm thick. So there is no need for fancy bending tools because tube is not deforming. Diameter of banding and diameter(35mm) of tube are big enough so there is no need for mandrel tool also. Probably this setup for bending is good enough for 1.5mm wall. Everything below 1.5mm thickness would require mandrel tool insert in tube during bending... I mean tube is for sure deformed during bending but currently it is not noticeable

[SOHC4 Cafe Racer Fan]

The bracing looks excellent.

[754]

Where is your front master cylinder. Two bikes that had remotes were.. 80,s Beemers, and Z1R,s..
 ..I like the clean matched look... Better than hoses and mini reservoirs hanging in the breeze..

..Sometimes ..less is more.....

[MessnerMoto]

Where is your front master cylinder. Two bikes that had remotes were.. 80,s Beemers, and Z1R,s..
 ..I like the clean matched look... Better than hoses and mini reservoirs hanging in the breeze..

..Sometimes ..less is more.....

Front cylinder is missing from front right control because of 2 reasons. First because I it is currently beyond my design and production capabilities. I can make it but I need to draw a line what I will do for this build. If I don't do it I will end up designing and making every part of bike .

Second thing is the look. Yep it looks way better without front master. The inspiration came form CB750 cafe racer by Crowe/Tarantulas cb750 bike controls. I will reuse somehow front master from gsxr. Probably I will just modify brake leaver of gsxr cylinder so it is pulled by cable. Of corse it is all hidden under the tank.

The drawback is I am introducing one more system that can fail

[MessnerMoto]

I finished modeling assembly for light. All the parts will be 3d printed. Of corse skin will be hand formed aluminum. I am still waiting for led projector to arrive. I need to measure connecting points of led projector  and then I will make support for it....