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Author Topic: The Worlds Fastest NIMBUS  (Read 32493 times)
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wobblywalrus
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« Reply #15 on: August 22, 2013, 12:05:34 AM »

Lars!  It is good to hear from you.  That looks like a nice bike and a great excuse to spend some time over here in the US.
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peterdallan
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« Reply #16 on: August 22, 2013, 06:23:53 AM »

Hi Lars

Owner of a 1951 Nimbus Type 'C'. I've had a look too and there's definitely potential in that motor, the only bugbear seems to be shaft drive and gearing. Have you had new gears made up? I know there is/was an upgrade available from 3 speed to 4 speed.

Best of luck with it Lars, I really cannot wait to see it fly!

Regards

Peter
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« Reply #17 on: August 24, 2013, 05:44:52 AM »

Hi Lars, we missed you...

Welcome back from GB...

Tell us a bit more on this blown nimbus...

Patrick
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octane
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« Reply #18 on: August 25, 2013, 07:09:50 AM »

THANK YOU ! ..Franey, Glen, Tom G., TMan, Grumm, Fast Lammy, LSRJunkie, Stan Back, Old Scrambler, Bo, Patrick
for your kind words.
Ohh, it's good to be back here ! Thanks!

Hopefully this will be the beginning of an old dream...



...of racing a Nimbus, coming through.


Its GREAT to hear from you. A pair of Nimbi made it around the world a few years ago!

Yes, they certainly did;
The 'Contempt For Death trip, The Dumb Way Around'.

Those Norwegian guys are absofreakinglutely amazing and their trip...



..is a testament to the sturdiness and durability of these old Danish motorcycles.
I was there, at the Copenhagen Nimbus shop , the day they returned from the trip :



Now will ya' look at those machines !...boy'o'boy, had they taken a beating ?!:



Look at the head-light...ha ha ...it's a tiny flashlight:



Rim-inforcement Ukrania-style:



The frame broke and was "repaired" on every single continent they rolled over.
The last repair was just south of the border from Germany passing into Denmark.
The problem is that the frame is made from ( I think you call it ) spring-steel
which just about no-one knows how to weld properly...and it IS close to impossible



...but HEEEY! There's always something one can do to stay on the road:



Those guys are freaking brass-balled heroes.
I've had the pleasure of them visiting my workshop before their trip.
Here's Tormod checking the Indian:



The had a blog running throughout their journey. The way the described their massive insane troubles
was absolutely hilarious. Loads and loads of humor .

If you're in the need of a good laugh, please read this:

When we reach Mininia ( in Egypt ) it is a different story. We have to stop for the night,
 park at square in the center and ask for a hotel. Within 5 minutes it is 2-300 civilians around us,
 demanding to see our passports. Of course you don’t show your passport to strangers so I say no.
 The crowd get more and more aggressive, and accuse us for being spies from Mossad.
 Everybody knows the Mossad normally drives Nazi-style sidecar motorcycles from the thirties
 on their operations, but not Danish ones for God’s sake.

When they understand they will not get to see the passports they threaten to call the police,
 so I tell them to go ahead. First a uniformed officer shows up on motorcycle, and he is calm and ok.
 Then a plain-cloth officer come and demand to see passport. I ask for his ID, which he hasn’t.

Needless to say, no passport flashing. As the crowd get more and more “intense” I suggest
 that we take refuge at the police station, which the undercover cop think is a good idea.
 So off we go, with 2-300 nuclear researchers, a fair amount of neurologists, some brain surgeons,
 a few rocket scientists and a minority of camel f**kers running after us,
 shouting and hoping for the Israeli spies to get hanged at the spot.

At the police station they are polite, and serve us tea and cigarettes.
 However, their actions and questioning don’t impress in a positive way:
 What are you doing for work?
 Where do you come from and what is your nationality (while “reading” the passport)?
 Do you carry a lot of gold and diamonds?

They write down the information from the passports and when it is done they
 ask our names are again. Then they start to argue about who should have the
 paper where they have written down the information.
 After quite some time a bright mind recalls they have a Xerox machine so
 each one of they can have a copy, even of the passport’s front page.
 We are stunned by their ability to reason out this brilliant idea to take
 photocopies and just has to congratulate them.

After four hours of phone calls (but never to the Norwegian embassy which would
 be the easiset way to check us out from Mossad's payrolls) and clever cross-examination
 they take us to a hotel, where it is a tourist police that checked our bags.
 Just as well, we might have equipment and a desire to blow up the towns most ran down hotel,
 especially as we’re the only guests. Then they fetch us with a police car with flashing lights
 and siren to a restaurant, and back to the hotel and placed a guard for the night,
 in addition to the tourist police officer.
 The next morning they escort us out of town, and could proudly look back at another intricate case closed.



http://kccd.no/blog_en.html


Lars,
It sure looks beautiful!

Thanks Rex.

Quote
Can't wait to see what you have done the engine.

Nor can I
.-)
..as I don't have any yet. What you see on the picture is a collection
of junk-parts that I have borrowed from the Nimbus shop and from a friend



Good to hear from you Lars..............Love the Nimbus.....I had one I used to ride in the old country (Netherlands)............

Thanks Bak ! I'm amazed that in this thread alone I've meet one former and one present Nimbus owner.
Never thought that would happen.


Great to see another build from you Lars, I´ve been lurking around in your old build thread for some time and if this one is as interesting as the old one we are in for a ride! smiley..."

Tack så mycket Anders !
In company with Anders I feel like a retarded caveman banging away with his flint-ax
while looking at this brilliant Swedish guy quietly going about his business building a rocket-ship.
Your build in mind-boggling Anders ! I can only stand in awe.



saw the link the second time around.
that's quite some motorcycle.

it would be nice to have another build thread from you, Lars.

will you be building some salt covers for the rockers, springs and valve stems?

Nope. This baby can cope with it, and who'd want to hide away this magnificent sight:

http://youtu.be/OuMHdFsQeTU?t=25s


"The rumors of my death have been greatly exaggerated"

My contender for 2014. "Odins Fury"

Hi Lars,

Glad to have you back in land of the living.

Thanks Jim ! Glad to be back !

 
Quote
George mentioned what you were up to. We missed having you on The Salt for Speed Week this year

I SO missed being there. I did follow as closely as I could:
SCTA web-radio ( mmmmm, that was a somewhat , shall we say; mixed pleasure)
SCTA run and result lists
and constant updates from quite a few FaceBook pages,
George's friends Lee and Steve's among others.

Hi Lars

Owner of a 1951 Nimbus Type 'C'. I've had a look too and there's definitely potential in that motor, the only bugbear seems to be shaft drive and gearing. Have you had new gears made up? I know there is/was an upgrade available from 3 speed to 4 speed.

Best of luck with it Lars, I really cannot wait to see it fly!

Regards

Peter

Thanks Peter, a fellow Nimbus guy , no less !
I do have plans for the gearing ( more later ) , but as I see it the real problem
with the engine is the engine...ha ha !

It only has 2 main-bearing, though they look like something taken from a steam-train, or something
( these is NOT my photos, but they show what I'm on about )









...so I'm in need of a lot of good advise on how to handle that slight problem.,
and prevent it from jump-rope'ing' and ( Auuurgh !) breaking.

Lighten the (Clutch)-flywheel ? / dynamic balancing the crank ? / weight-balance the individual con-rod-pistons ?


Best of luck with it Lars, I really cannot wait to see it fly!

Thanks. Nor can I






OK: time for turning this into a real build-thread.
I have a whole'lotta' pics , descriptions and questions to ask.

Any help is truly appreciated.







« Last Edit: August 25, 2013, 07:29:32 AM by octane » Logged

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« Reply #19 on: August 25, 2013, 11:18:10 AM »

Well, well -- looks who's shown up.  Good to see your writing again, Lars.  As I look through this and see your next project - my question is if you're hankering for a spot on the next Salt Talks t-shirt.  I'm confident that you'd be the only Nimbus on the shirt.

Welcome back to the Forum.
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ol38y
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« Reply #20 on: August 25, 2013, 11:44:38 AM »

Welcome back Lars.  cheers

this looks like it's going to be an interesting build.
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Larry Cason
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2010 BUB 1350 M-PG record
2012 Speedweek  1350 A-PG record 169.975
2014 El Mirage Dry Lake  1350 A-PG  172.651
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« Reply #21 on: August 25, 2013, 02:57:06 PM »

If only we lived a bit closer Lars, then I would invite myself to a cup of coffee and some landracing chitchat. smiley
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octane
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« Reply #22 on: August 25, 2013, 03:35:51 PM »

Come ooooooon Anders, you do not need to invite yourself:



You are SO welcome, anytime !!!


..................

Thanks Larry !
« Last Edit: August 25, 2013, 03:37:40 PM by octane » Logged

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« Reply #23 on: August 25, 2013, 09:27:25 PM »

Lars,

take a look at http://www.uncommonengineering.com/index.html about 2/3rds of the way down the page the "Three Billet Steel Main Bearing Webs Added to 4 Main Bearing Block" *might* be something you could do to add additional main bearing(s)

roy
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« Reply #24 on: August 25, 2013, 11:16:55 PM »

Thank you Lars, I live up north in Östersund so it is quite a drive to Copenhagen but if I happen to be in the neighborhood I´ll send you a mail!

Sorry for the off topic talk by the way. smiley
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« Reply #25 on: August 26, 2013, 12:28:12 AM »

Welcome back Lars ,
                             You only need to adapt one of these .
http://muzzys.com/HayabusaCranks/index.html
Easy, like Bonneville records,,,,, wink
Oh, another thing too, a winning lottery ticket might help.
Tiny
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« Reply #26 on: August 28, 2013, 12:39:06 PM »

Lars,
After looking at the crank on the NIMBUS what is the rated max rpm? I can't imagine that it could be reliable at over 3000 rpm if that! Are the rod bearings lubed by "splash and clatter"? or do they have some pressurized oil fed to them? The large ball main bearings look very substantial but certainly will have a very limited rpm ability. It does look like you could add a center bearing to the existing crank with a little ingenuity which I know you have plenty of. What a project!!!!

Rex
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« Reply #27 on: August 28, 2013, 10:48:23 PM »

Great to see you back, Lars. I remember being sent the Nimbus Round The World links, and was really impressed. I`m sure I will be as impressed with your build as well. Have you considered a girdle a-la-Model A/B? That center main idea is a good start, don`t you think?
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« Reply #28 on: August 29, 2013, 02:56:10 AM »

Well, well -- looks who's shown up.  Good to see your writing again, Lars.  As I look through this and see your next project - my question is if you're hankering for a spot on the next Salt Talks t-shirt.  I'm confident that you'd be the only Nimbus on the shirt.

Welcome back to the Forum.

Thank you so much Jon !
Sorry ! ; for some reason I had overlooked you post.
A spot on the Salt Talk t-shirt is seriously an ambition worth pursuing,
but I'm absolutely certain others deserve such an honour much more than I do.
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« Reply #29 on: August 29, 2013, 04:03:06 AM »

Thank you Roy, Tiny and Kiwi !
Anders: there's PLENTY of room for off-topic's here !


Lars,
After looking at the crank on the NIMBUS what is the rated max rpm? I can't imagine that it could be reliable at over 3000 rpm if that!

Well, in fact it is.

The weird thing about these engines is, that if you look at the specs; ( which are VERY impressive for a 1932 engine )
hemispheric cross-flow combustion chambers , bevel-driven overhead-cam / valves , 4-cylinder in-line 750cc
you go: WOW, that must be one faaaast hi-bph engine
but it's not.....we're talking 23-24 bhp here.

On the other hand; riding this thing does NOT feel like riding a 24bhp bike,
it feels much stronger.
I guess it's in the way it delivers the power,
the way it zooooooooooooms up to around 4500rpm.

The 4500rpm is just where it runs the best in standard trim.
Daredevils have been know to tune them an run them up to 7200rpm (!)
without fatal consequences ( for the engine that is...ha ha )

Turn up sound on your PC, and listen and watch this.
That's a bog-standard Nimbus , (except it has the new (available off the shelve) 4-speed gearbox modification):



Nice, ei ?....Doesn't sound like a sluggish 23bph thirties bike, now does it?
No wonder everyone knows the Nimbus bike from it's nickname 'The Bumblebee' .

Quote
"..Are the rod bearings lubed by "splash and clatter"? or do they have some pressurized oil fed to them?

At first ( the first 250 bikes produced ) they had it, but it turned out 'splash and clatter' worked better.
This is not known to be a problem for these engines.

Quote
The large ball main bearings look very substantial but certainly will have a very limited rpm ability.
You are most probably right.
That's why my thinking is: if you want to blow an old engine to smithereens fastlike,
all you have to do is crank up the rpm's.
So what I go for here is along the same lines as on the INDIAN;
more torque / low rev grunt....and a high gearing...and keep the revs reasonable.
After all; the INDIAN was made with some anemic 13-14bph, and it now sports close to 40bph
( running with the hi boost ) on the rear-wheel .. and heeeey; it hasn't exploded .............yet.

I'm not really worried about tuning this engine with a relatively mild boost.
The Aisin AMR300 supercharger will run via a belt from a 'rearward' extension of the cam-shaft.
That's a modification surprisingly easy to do ( more later ).
It should be rather well-suited for a blower:
..low compression 5.4 : 1
..VERY little valve-overlap

These bike are hard to kill. Of the around 12.000 made, around 7500 are still in existence (!).
In Denmark alone 4500 are still road-registered (!).

Quote
It does look like you could add a center bearing to the existing crank with a little ingenuity which I know you have plenty of.
Oh, thanks Rex for your all too kind words, but I'm afraid it's way way beyond my capabilities.
There's a problem.
Rex, and others who have suggested the center-bearing solution, please have a look here
at my somewhat 'exaggerated' drawing of the crankshaft:



See the problem ?

My friend George has come up with a solution so way out-of-the-box, that I doubt he ever had any box to begin with.
.-)
but I'm afraid that solution too is just way out out what I can do with my flint-ax.
( More on that later )

Quote
What a project!!!
Thanks Rex.

I'm preparing a real build post.
Just need to upload a bunch of pics and stuff.

( I've been too busy making T-Shirts: http://www.landracing.com/forum/index.php/topic,13058.msg231299.html#new


« Last Edit: August 29, 2013, 08:09:10 AM by octane » Logged

"A designer knows he has achieved perfection
not when there is nothing left to add
but when there is nothing left to take away"

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