Author Topic: Project "Laubfrosch" - the trials hybrid  (Read 3480 times)

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grumbern

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Reply #45 on: July 08, 2019, 06:09:36 PM
It's a "Rotenbach" AC/DC 200 P, 5-in-1. Basicly the standard TIG welder you get in different styles and brand names. What made me buy it instead of a different one was the posibility to use an air-powered plasma torch.


grumbern

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Reply #46 on: July 12, 2019, 01:47:15 PM
Engine plates type "Special" :)



grumbern

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Reply #47 on: July 14, 2019, 11:05:51 AM
Now, second layer of paint applied:




That's how they look on the bike. It's still missing the bolt to the gearbox and the one through the frame is too thin - didn't have anything fitting at hand right now. But you get the picture:




The bottom view shows the purpose of the latches. They give some more rigidity, but mostly a good posibility to mount the side stand and skid plate to:




I also melted some aluminium... Not exactly beautiful, but it's doing the job and to my defence I have to say, that a) welding a 20mm deep hole is darn hard and b) cast alloy, espacially these old ones are ugly to weld, bubble alot and contain a lot of junk.








Today nothing else will happen here, but next week I can start the machining.
So long,
Andreas
« Last Edit: July 14, 2019, 11:08:20 AM by grumbern »


Adrian II

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Reply #48 on: July 14, 2019, 02:43:36 PM
Quote
I also melted some aluminium... Not exactly beautiful, but it's doing the job and to my defence I have to say, that a) welding a 20mm deep hole is darn hard and b) cast alloy, espacially these old ones are ugly to weld, bubble alot and contain a lot of junk.
.

Once that is all cleaned up and re-machined it will look a lot better. Were the holes too damaged for helicoil inserts?

On the Bullet rear engine plates there are hexagonal holes to lock the hexagonal footrest bar in position, as well as a spacer tube between the plates, do you have some other arrangement in mind?

A.

Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


grumbern

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Reply #49 on: July 14, 2019, 07:48:57 PM
Yes, the threads were done for and I don't have any 5/16-BSF inserts nor tools for that. I didn't want to use M8, so this was the way to go.
The distance tube will be made from Aluminium and instead of the hex rod I'll simply use a round and shorter one. The footrests will be set backwards below the swinging arm axle, so there's no need for an unnecessarily complicated mounting plate with hexagonal cut outs.


grumbern

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Reply #50 on: August 08, 2019, 10:01:31 AM
It's been a long time since anything happened here. But as I am on vacation finally I have some time to concentrate on the Laubfrosch again.
So I first went with the fabrication of the axle and bushes for the front wheel. The DR's hub fits pretty well, but is 2mm less wide and only has a 12mm axle, instead of 9/16". So that's too thin for the Bullet's clamps. So I turned two bushes from Aluminium, allso providing the needed distance on the inner face. First reamed the bore to 12mm:




The outside is turned to 14,3mm (9/16"):




Finally slotted it using a hand saw, so the axle, simply a piece of 12mm 1.4301 round stock, can be clamped:




Thas looks pretty much like this:




I mocked up the Engine a bit more as well. Apart from the slender primary case, there's a nother fine detail that found it's way there. Can you find it?




And as the mail man brought some pieces of stainless tubing, I could start to try a little on the exhaust. I like how it turned out. Fit neat an tight, but has enough clearence to the carburettor and especially: The pushrod cover! I wouldn't want to block this by any means, because easy maintenance is a must!








I'm still a bit worried about the muffler though, because I don't need a fried leg! Well, it will get a shied anyway, maybe that's good enough.
So long,
Andreas


Adrian II

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Reply #51 on: August 10, 2019, 11:21:59 PM
DEFINITELY fit a heat shield. You could justifiably use exhaust pipe wrap for the middle section, but it wouldn't look so good. I usually had some bits of melted plastic to scrape off the old Electra-X's woodsman high-level exhaust pipe from boots or over-trousers. 

A.
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Adrian II

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Reply #52 on: August 14, 2019, 02:23:23 AM
If you were to make your exhaust system a copy of the Woodsman rather than the normal Trials type you could have the muffler/silencer further back where it would be more out of the way.

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Grumpy Brit still seeking 500 AVL Bullet perfection! Will let you know if I get anywhere near...


grumbern

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Reply #53 on: August 14, 2019, 12:01:13 PM
Yeah, I thought of this option, but it builds just so big. So I think I'll just go with the trials-type muffler.


grumbern

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Reply #54 on: October 05, 2019, 04:44:37 PM
The view inside the combustion chamber. All nice and new:




As my magneto is newly wound and re-magnetized I took care of the rebuild. First the old bearing races had to go, which wasn't that easy at all. Those races sit i little paper cups to insulate them and the rotor from the housing, as erosion caused by a missguided current could lead to premature waer of the bearings. Those cups of course were not to be used any more, and the one on the drive side was destroyed anyway when driving out the race:




First the measuring:




And then cutting new ones from a suiting piece of paper:






It wasn't easy to find a piece of paper of 3/10 of a mm, but I found a greeting card that had the right dimensions.
The new race titted with the paper cup:




And a picture of the rebuilt rotor. Primary and secondary windings, as well as the condensor were professionally replaced:




So long,
Andreas