What alloy does the MT9 engine use?

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Lmo
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Re: What alloy does the MT9 engine use?

Post by Lmo » Sat Aug 17, 2019 3:33 pm

Schlauen Deutschen!!
Lew Morris
Dnepr w/ '06 Ural Drive Train
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1973 BMW R75/5 (original owner)
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Snakeoil
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Re: What alloy does the MT9 engine use?

Post by Snakeoil » Sat Aug 17, 2019 3:43 pm

I agree with Jay that that split clamp an flange is a very elegant fix.
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Rob
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Re: What alloy does the MT9 engine use?

Post by jaybird » Sat Aug 17, 2019 3:49 pm

Snakeoil wrote:
Sat Aug 17, 2019 3:43 pm
I agree with Jay that that split clamp an flange is a very elegant fix.
It looks nicely made, but I have to agree with one of the posters in the BMW thread, it is a bit "butt ugly", beats the hell out of walking though!

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Jaybird
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Etc.

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Lmo
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Re: What alloy does the MT9 engine use?

Post by Lmo » Sat Aug 17, 2019 5:23 pm

but I have to agree with one of the posters in the BMW thread, it is a bit "butt ugly"
Butt ugly?!?! It's a Ural !!! :rotfl:

For those slaves of fashion they do offer this "upgraded" flange.

Image
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

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Re: What alloy does the MT9 engine use?

Post by Korto » Sun Aug 18, 2019 7:55 am

Lmo wrote:
Sat Aug 17, 2019 3:09 pm
Image

Image
They're not ugly, they're... they're...(sniffle)...beautiful.

But also bloody expensive in $Aus. I know you lot are saying what I was thinking of would be just as, if not more expensive, but my discussion with the welder never got as far as that.
I had thought it would be a reasonably simple job. No cutting the pipe ends off, just weld a couple of aluminium plates on the butt ends of them, with a hole through the middle to let the exhaust pipe through (I'm not saying I'm right in this thought, just what I was thinking). The exhaust pipes would have to be worked on, but I'm already going to have to do that, as after a change in gearbox (swapped out a ural for a mt9) the kickstarter keeps hitting the pipe, and the pipe gets in the way of where the sidecar bolts on to the bike anyway.
So there's definitely the feel that "If I'm going to change the exhaust, might as well do the lot"

But no, that clamp is beautiful. And expensive. And I can make one... Just need a 48x2 jam nut, cut it in half, and weld some nuts on the outside to tighten it together. Done.

In the meantime, I've cleaned the muck out of the thread, and I can get a good, solid bite in the last 5mm, which doesn't leave much room for any gaskets, but with some putty may do for the short term.

I'm starting to agree that the welder just doesn't want that particular job. He's an experienced welder who's done all the other work on the bike, but maybe he's had a bad experience in the past with old cast aluminium? Who knows.
Australia, Newcastle. 1972 Dnepr MT-9... mostly... I think...

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Lmo
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Re: What alloy does the MT9 engine use?

Post by Lmo » Sun Aug 18, 2019 4:14 pm

But also bloody expensive in $Aus.
This is why we all like to see member's location information posted in their 'signature' line. As close to east asia as you are one would think used Ural parts would be readily accessible.

As I mentioned, the exhaust stub on my R75/5 doesn't have many threads left, and it's holding its own. Just make sure to clean out the residual metal left in the thread of the "nut" and use a good anti-seize when you reassemble. And, you don't need to torque the bejeezus out of it either, just snug it down, and keep an eye on it.
Lew Morris
Dnepr w/ '06 Ural Drive Train
C5 Power Arc
125/42 jets
Drilled slides/
.030" shims

1973 BMW R75/5 (original owner)
1947 HD FL (long gone, forever regretful)

arbalest04062
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Re: What alloy does the MT9 engine use?

Post by arbalest04062 » Wed Sep 04, 2019 5:33 pm

I don't mean to be snarky with this answer, but the only answer to the question of "What alloy does the MT9 engine use?" is whatever crap aluminum the factory could scrounge up around the yard. The Dnepr had great engineering. Dnepr actually had a plain bearing crankshaft in their boxer twin before BMW. What they also had was really poor metallurgy and worse quality control. My Dnepr ate its pistons within 300 miles of new. I bought it from an excellent motorcycle mechanic that I have known for years. Cylinders were bored, new pistons installed. Then the cam lobes wore themselves round, cam followers wore out. Valves seized up in the valve guides multiple times. On examination, the valve train geometry was all wrong. The rocker arms worked on the edge of the valve caps, causing the valve caps to be spit off the top of the valve stem. The weird part is that the cycle parts were very robust. After I replaced the Dnepr POS motor with a BMW motor, the bike went like stink. I had no more problems with the bike. It's like the motor and cycle were made in different factories.
Once you go hack, you'll never go back.

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