"the Holy Grail" of setting the gearselector Quadrant

Moto Rumi technical problems or solutions
Lasse
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Joined: Mon Aug 10, 2009 5:18 pm

"the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Fri Nov 27, 2009 3:56 pm

I Finally I found, what I guess, must be the "Holy Grail" of setting the gearselector Quadrant!
After a lot of trouble, a lot of help from "Club People in the Know" - I wasnt nearer in my agony, of NOT understanding, WHY I could only select 2. 3. & fourth gear - OR first - second & third gear - never all of the gears together!!!

I tried the "Fourth Gear" method - I tried the "All marks aligned in the middle" method - to absolute no avail...
Then I started thinking (yes - sometimes, not a bad thing) - really thinking of the theory behind selecting a certain gear.
Wearing my "thinking hat", I found much of the former "old wisdom" of no use.
E.g. the "rule" about the idler wheel MUST stand at a certain place - bullshit - because this wheel ONLY is for "transport" of movement to the selector drum!
It doesnt matter which teeth that does the mesh here...
Also, the selector drum can stay in (almost) any position - as long as you have 4 definitive and positive "gear-click"!

What I found (by thinking hard) were the fact, that the "detente quadrent" is the sole key to effective and right movement of the selector drum.
The "detente quadrant" consists of two springloaded "claws" - which MUST move by JUST ONE "click" for every movement of the gear-pedal - no more - no less!
On the back of those "claws" youll find two "fingers" - whose job is to "lift" one of the "claws" to allow the toothed part of the quadrent to move by ONE step - when the driver depress the gearpedal.

My bikes former owner had placed two thin washers UNDER each of those "claws" - then secured them finally by cotter pins.
By taking those two thin washers out from UNDER the "claws" - and placing them ON TOP of the "Claws" - and securing them there, I suddenly had a 100% normally functioning "detente" mechanism!
It was then a matter of minutes, using the simple "4.th gear method" - to have the gearselector cover in place again - and to feel the four nice clicks - when my gearbox, after many years malady, suddenly came back to "normal"!

So I am NOT going to use the winter months, to rip the whole motor apart, seeking for "gremlins" in the gearbox.
I hope that other Club Members can use this explanation?
If its too complicted - just drop me a Mail - and Ill try to explain further...

Lasse,
Denmark.

tony mooring
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by tony mooring » Fri Nov 27, 2009 6:49 pm

SUPERB Lasse, glad you finally got there!
Tony.

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Fri Nov 27, 2009 11:16 pm

Nice to hear that you’ve found a solution if only for your sanity! But for everyone a word of caution, the solution you found may be peculiar to your machine. :D

I would contend however that the marks on the idler gear are NOT a waste of time, no manufacturer is going to waste their time making such marks, for a start the bean counters wouldn’t allow it! They only like shiny gimjaws and kindred nonsense! :evil:

I do have to admit :oops: that I still haven’t sussed out the most probable way that the factory went about setting up the gear selection mechanism but I’ll lay odds that those much-despised marks are a key part of their method. Fortunatly for me it is 15 years since I needed to go inside my Tipo and as my memory is more RAM than ROM these days . . . (Switch off and everything that was in there vanishes.)!!!

It is true that the idler can be fitted in any position; its only function after all is to transmit rotary movement. All that is really required is that the selector shaft and quadrant are correctly aligned and gear selection can be expected to function correctly.

I’d also issue a care note about those marks, observe the marks on the idler gear carefully, you will find that one mark will be ON a tooth the other will be IN the gap. Reverse it and you’re half a tooth out. Another point is that, at least in all the machines I’ve been inside, it is clear that the marks were put on when the gears were in mesh so the complimentary marks on selector shaft and quadrant are OUT for IN and IN for OUT. One more point, I strongly expect that these marks were done freehand, (a quick dab with an air grinder I suspect), and will therefore be unique so if in any doubt a close examination with a magnifier should offer confirmation by comparing width, angle and grinding marks.

Ian Skinner
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Location: South Wales UK

Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Ian Skinner » Sat Nov 28, 2009 1:09 am

Hi All.

I agree with David, those marks are significant.

However, I do hope that this will not be another 'rat-hole'.

I enclose a copy of a relevant email sent by Gosta Karlsson after my item was posted on the uk club web site some years ago, regarding this matter, I trust that Gosta won't mind!

Here it is!

Dear Rumifreinds,
I have found Your page about the Motorumi clutchcover mounting and now I want to inform You little about this.
1953 when I begin to work and race with Rumi and first time I dismantle the engine and see the mark on the selektordrum ,Idler wheel and selektor Qudrant.When I mount the engine I put the gear after the mark ant put the selektorquadrant on the Idler wheel
and put the cover on.I never had problem with gearbox.When the Rumi factotydriver Gianni Zonca and his mecanic Forsella visit Sweden GP 1954 I ask Forsella about how he do when he put the clutchcover on,He told me that he make like me.Not first or fourth gear.But one problem I have seen many time are if You buildt up one engine from sparepartsengine and not check the distans beetwheen selektorDrum and backside Selectorqdrant You can get problem .First You must have the gasket thickness
genuine 0,7 mm.And the distans mast bee 0,5 mm .Do not use silicongasket Also must the selectordrum must go light .If not adjust with paper under the brassbearing .Sorry about my poor english.
Best regards Gosta Karlsson

Gosta Karlsson

Well, that's it folks! Ian.

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Sat Nov 28, 2009 10:36 am

Thank you, Gentlemen for your comments!
I should be polite and say: "I totally agree" - but frankly, I just say "I partially" agree...

1. The marking(s) on the idler wheel, why are they there?
In my (engineering) point of view - for nothing! because they indicates nothing - the idler wheel is ONLY there to transmit MOVEMENT - it can sit in ANY position, and still do its job!

2. Its true what Gösta Karlsson says: If the internals of the gearbox are sloppily put together, you could definitely have a problem!
But, considering you have four nice & positive "clicks" of your gears - and the gears stay in individual mesh, when driving, the focus must be directed at the "detente quadrant" - if problems arise around, FINDING & SECURING, the individual gears!

The "detente" mechanism is a very important part of the quadrant set-up.
Its job is to "lift" the "teethed half-moon" of the quadrant, one step by one step, - to transmit the appropiate movement to the selector drum.
The "detente" mecahnism is made in such way, that it can just move A CERTAIN DISTANCE (up or down).
This "certain distance" are guided by the "fingers" and the "half-round" slot in the bottom af the mechanism.
The key to the appropiate rotation of the selector drum cogwheel, is the measured movement of the quadrant!

So, my point is: If the "detente quadrant" mechanism is not in perfect order, you will never experience firm and positive movement (transport) to your selector drum!!
Finally, I consider the "fourth gear method" to install the gearbox cover, most adequate, and very easy to use...


This should not be a "rathole" - but a "loophole"

Lasse,
Denmark.

UHJ200
Posts: 544
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Sat Nov 28, 2009 12:50 pm

The point about the marks is that they create a “lock” in the angular disposition of the quadrant and selector shaft relative to each other. There is nothing unique about those marked teeth, the marks are there merely as a setting convenience, the equivalent of pencil marks on a wall when you are putting up and levelling a shelf.

I entirely agree that the selector pawl assembly is an equally important part of the gear selection assembly and must be in good order, no argument there, the difference is that when the off-side casing is removed there is no natural tendency of the pawl assembly to fall apart.

The most aggravating gremlin preventing correct reassembly and therefore proper function would seem to be that of the “I can’t see nuffink” exercise of relocating the quadrant shaft in its hole when the offside cover is being replaced without inadvertently displacing the tooth meshing between the quadrant and the idler.

What can help are a couple of strong elastic bands, you don’t even need to buy ‘em, just stalk a postman for a while! Tie a length of string tightly to them and stretch them over the quadrant and selector shaft, that’ll help keep the quadrant in mesh. When the cover is loosely on and you have a couple of the screws just in to maintain location you can pull on the string to expose the elastic band whereupon you can cut the band and finally nail the cover down.
This is one for the short tempered/five thick stubby thumbs brigade! :twisted: :lol: If keeping the cover really square to the crankcase, (it’s important!) when lowering it on it would be a good idea to make up three long studs to act as guides for the cover. If you want to be posh you could make them up from steel rod as long as you can put the threads on square but a cheap ‘an cheerful alternative is studding from a builder’s merchant or tool shop.

Janne E
Posts: 1
Joined: Wed Nov 18, 2009 12:13 pm

The Holy Grail

Post by Janne E » Sat Nov 28, 2009 6:45 pm

Hello Rumifriends
I`m from Gothenburg ,Sweden and I have watch this forum for a while.
I like it and I think it was a really good idea to start the forum, thanks.
As my contribution to the discussion, concerning assembling of the gear
selection parts, I hereby sending same photos showing the way I handling it.
Sorry for my poor English.
Best regards
Janne E
Attachments
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phpU1tkOMAM.jpg
phpU1tkOMAM.jpg (91.68 KiB) Viewed 25194 times

hugomez
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by hugomez » Sat Nov 28, 2009 8:35 pm

Hi Janne E,

Very welcome here, it's great that after a while visiting us you decided to participate.

Thanks for your contribution including those photos.

Welcome!!!

:D
OO
My little Formichino here: http://www.formichino.com/pictures1.html

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Sat Nov 28, 2009 10:31 pm

Well, there you go, "Great Minds think alike" , well almost anyway, the elastic band method works pretty much the same way. ;)

One other thing, if my Tipo was that clean I'd be scared to ride it! :roll: (I'll put the little green monster back in 'is box now shall I?!) :mrgreen:

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Sun Nov 29, 2009 1:40 pm

Hello "All" - this morning I pushed my RUMI out in the cold - to try my "new" gearbox with "motor-power".
(Because all I wrote previously were about a box, tested more or less by hand)

After all the replies & warnings - I were quite nervous.
Would it work?
YES - ALL 4. GEARS CLICKED HOME - going upwards & downwards...
I am relieved - to say the least - so now the bike is going into "hibernation" in my living room - for the winter.

Lasse,
Denmark.

Ian Skinner
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Location: South Wales UK

Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Ian Skinner » Sun Nov 29, 2009 9:23 pm

Hi Janne, it's great to see someone else coming to the same conclusion. Right on.

regards Ian

ps. I'm expecting that the next gear selection issue to be aired, will start with " My 1st gear keeps jumping out" Another 'loophole' most likely?

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Wed Mar 30, 2011 2:43 pm

Just a word of warning, to dthomas...
If you have an old gearbox, with "blended" internals - or worn ratchets or worn pawls - I am not so sure about the wonders of the "grind-marks-method".
I, for my part couldnt use it, even if I tried hard...
Pauls 4.th gear method saved the day for me, but only AFTER I got the selector drum position right.

Dthomas told us all a very important fact: His gearbox had ALL 4 gears in a good working order, BEFORE he had the (bad) idea, of touching the selector drum position!
So, without any doubt, his problem stems from a slightly wrong positioned selector drum - because everything were OK before.

I was told by Göran Persson, that even SLIGHT movements, up or down, of the selector drum in its slides, would have a dramatic effect on the shift pattern!
He told the truth...
Because going from a nearly useless gearbox - to a perfectly working gearbox - were under one millmeter of movement.
The worst thing in my struggle last year, when I certainly did a lot of "trialm & error", was the fact, that by a certain position of the drum, everything suddenly worked as it should!
Afterwards, I tried to write down HOW I did, but had to realise that I simply did not know why the box began to work again...

I my view, it was sheer luck, coupled with stubbornness, and a desperation to get the damn thing persuaded to work.
Dthomas must unfortunately endure more or less the same agony - untill suddenly, Bingo, the thing works.

I repeat (to bore many of you) ONLY trial & error will fix his box - there is no easy way out, no certain recipee.
He have to do it "by feel"!


Lasse.

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Thu Mar 31, 2011 1:16 pm

In the long debate asbout the "Factory Grind Marks" i suddenly got an idea - of which I would like to hear other "members" opinion?
Could the grind-marks have been put there, in order to ETABLISH THE WAY THE SELECTOR-DRUM WERE POSITIONED IN ITS SLIDES, AT THE FIRST PLACE - before the bike left the Factory shop floor, to get sold??

Because I found, by bitter experience, that just the slightest re-positioning of the selector drum had dramatic (bad) effect on the secure locking of the individual gears!
I.e. - if the drum did not have "the perfect/right position" - then one of the gears, would "jump out of mesh" (and for me, mostly second gear did just that...)

Think about it, when you move the selector drum "bearing" up or down, the "attack point" of the idler wheel will move quite a bit, resulting in another "turn-pattern" of the drum - thereby "disturbing" the proper lock position (sideways movement) of the various cogwheels inside the box, because of the pegs then will sit at different positions in those spurs, machined onto the selector drums surface!
The above, just a theory - but, please let us have YOUR opinion about if its just "balony" - or might in fact represent another sound view, of the "Factory Grind Marks"...


Yours,
Lasse.

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Thu Mar 31, 2011 2:37 pm

I'm as certain as I can be that the grind marks were put in the gears during final assembly as a part of the initial gear selector setting process.

I arrive at this conclusion because micro scratches within the marks transfer across from gear to gear so the marks on my Tipo's gears were clearly done at the same time, that is to say that the marks were put in while the gears were in mesh.

All of which still begs the question of exactly what was the setting-up process the factory adopted.

I'm pretty sure they didn't faff around with bits of knicker elastic or what-have-you to corral escape prone selector quadrants for a start! :lol:

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Thu Mar 31, 2011 4:20 pm

Hello UHJ - I agree, the Factory certainly made the grind-marks during (end)-assembly!
But could they also serve as reference marks, for the unlucky dealers, who sometimes had to repair or service the gearbox - in order to make it possible for such dealers, to be able to reposition the selector drum, at the same angle as done originally, at the Factory?

Lasse.

UHJ200
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Joined: Mon Aug 17, 2009 1:37 pm

Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Thu Mar 31, 2011 7:41 pm

I've a feeling that the mark on the idler pinion (part 13 pp 30) is supposed to align with the crankcase centreline. As everything is centred around the line of the crankcase split this makes sense if the quadrant is to be correctly aligned. It would also explain why it was desireable to make the bearing (part 1 pp 30) adjustable.

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Fri Apr 01, 2011 10:35 pm

Further to my last post, the more I think about aligning the pinion/quadrant mark on the crankcase joint line the more logical, (well to me at least!), it seems and what is more it explains the need for the idler pinion (part 13 pp 30) and the adjustable selector cam bearing (part 8 pp 30).

The selector cam itself is one piece so the relationship of the selector fork tracks (there are two) and the dedent cam (five positions) are fixed and therefore play no direct part in selector mechanism setting save for the marked tooth.

If this is the way what is the assembly sequence?

(1) The cam and associated parts are put into the crankcase with the marked tooth horizontal and facing foreward ensuring that the dedent pin (part 17 pp 30) is fully located in the concave location in the cam.

(2) The idler pinion (part 13) is fitted onto its pin (part 14 pp 30) it has two marks, ensure the correct mark is engaged with the mark on the pinion on the end of the cam.

(3) The cam bearing (part 1 pp 30) is adjusted up or down until the pinion to quadrant marked tooth is aligned with the crankcase joint (the centreline)

(4) The quadrant (part 28 pp 32) is located on the centreline axis with the tooth centred in the viewing hole located on the marked pinion tooth.

There still remain the vexed question of the best way to put the cover back on while keeping the quadrant engaged with the pinion and locating its hole (in part 26 pp 32) which is itself a part of the cover assembly and is thus inconveniently hidden as you try to put it on.

But then if you want an easy life go buy a bus-pass! :twisted: :lol: :lol: :lol:

hugomez
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by hugomez » Fri Apr 01, 2011 10:57 pm

Just to make easier to follow the explanation on UHJ200, I put here the page 30 and 32 of the manual.

Page 30:
Page-30.jpg
Page-30.jpg (105.94 KiB) Viewed 24786 times
Page 32:
Page-32.jpg
Page-32.jpg (91.42 KiB) Viewed 24786 times
;)
OO
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Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Sat Apr 02, 2011 8:11 am

Great work - great thinking, UHJ...
As I see it (and probably also you) its the IDLER WHEELS RELATIVE POSITION to the curved toothed "cam" driven by the shifter mechanism, thats the "secret" ofthe proper selection of each gear!
Therefore its not always understood by "innocent" prospective RUMI gearbox menders, that the position, up - or down, of the selector drum end bearing/idler wheel - is SUPER CRITICAL because just a tiny movement here, can have drastic (unwanted/unexplainable) results...

It took me long time (too long time) to understand the consequenses, of my adjustments of the selector drum.
Gösta Carlsson did help me to understand this, and also told me, that shimming of endplay of the selector drum had consequence upon the "change pattern" of the box!

About repositioning the clutch cover: When the selector drum is sitting in the right position, (and it MUST do so) - its very simple & easy to do this job.
Simply use the "fourth gear method" - works everytime...

So, UHJ, your theory about that all grind marks, should be sitting in a horisontal position, following the "split" in the two engine halves - must be right!!
This has not been an easy discussion, but I think now, conclusive, - but I fear that new members still must feel somewhat uneasy, before they dismantle their gearbox!


Lasse.

g. karlsson
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by g. karlsson » Sat Apr 02, 2011 7:08 pm

About gearproblem and and fitting of the clutchcover
Hello,
First, if the both springs for thegearshiftsegmemt in the clutchcover not are same lenght
and the segment not can return to middle you can get problem

Second, sometimes the brassbussing in the clutchcover can walk away up and down when you
change gear and there you also get gearproblem

Third,if you fitting the clutchcover with the fourth gearmetod you do not come in the middle of the qudrant ,you have missing one cog from middle in the qudrant.

So, I want to ask the fourth gearmecanic why the Rumifactory not have recomend other metod than the metod which Janne E show with his photo.
Sorry my poor english .
Regards
Gosta Karlsson

g. karlsson
Posts: 6
Joined: Thu Jan 14, 2010 1:20 pm

Re: "the Holy Grail" of setting the gearselector Quadrant

Post by g. karlsson » Sat Apr 02, 2011 7:41 pm

Hello again,
I meen the both springs number 33 and brassbussing number 22 from the spare parts pictures
Regards
Gosta karlsson

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Sat Apr 02, 2011 7:48 pm

Horskjer is right, getting that last pinion mark on the centreline is not quite the end of the story, after all we are dealing with machinery about half a hundred years old most of which will have had an uncertain past.

The position of the selector cam (part 8 pp 30) in the crankcase will have an effect on the angular position of the selector fork assemblies (parts 58 & 59, 60,61 pp32) and they in their turn determine the engagement or otherwise of sliding gears 26 & 50 (pp 30). As Horskjer says minimising selector cam end float is desirable as end-float will reduce the effective movement of the selector forks and ultimately the depth of engagement of the driving dogs. However the limited and relatively infrequent movement, compared with drive components like the mainshaft and layshaft, would not usually be expected to create much wear. For all that, eliminating unnecessary free-play isn't a bad idea -- a bit here and a bit there all add up!

When looking for wear and increased clearances the points to check are the selector grooves in the cam. Fortunately this component is fairly robust and short of defective heat treatment is unlikely to present much of a problem.

More of an issue might be the two pins (part 59 pp 30) as these are subjected to point loading in the cam grooves.

The two forks (parts 60 pp 30) are subjected to continuous movement and should be checked for axial clearance in their respective grooves in gears 26 & 50 (pp 30).

Another source of lost movement worth checking for is the fit of parts 59 & 60 in their holes in parts 58 & 61.

Moving to that part of the selector mechanism mounted in the right hand cover (part 8 pp 32) the condition of the pawls (17 &31 pp 32) should be checked for damage and correct action in conjunction with the mating ratchet teeth on part 28 (pp 32).

Pawl springs (19 & 33 pp 32) can settle over time and weaken even if they appear OK, replacement would seem to be the order of the day. Gosta has a point here and it is not just a matter of length but one of equal force. The simplest way of checking this is to place both springs end-on-end in a vice and compress them to their working length and then check that the compressed length of each is equal. For safety a loosely fitting piece of rod, just short of the compressed length of both springs, should be inserted to prevent the springs “pinging” out.

I have never tried the 4th gear method so cannot comment.

Finally I think the problem is that nobody really knows exactly how the factory did the initial assembly and I also suspect that there is something that we don’t know or have yet to divine.

Oh! b▫▫▫▫r it! I ‘fink I’ll just go buy a push bike!!! :lol: :lol: :lol:

tony mooring
Posts: 346
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by tony mooring » Sat Apr 02, 2011 8:38 pm

UHJ, You might well have to go and buy a push-bike the way fuel prices are going. I was of the understanding that Highway Robbery had been abolished, but the governments appear to have brought it back.
Back to the wear of gearbox internals, the biggest problem is that there are no new parts available any more.
Unless of course, there is somebody sitting out there holding a great stock of them.ha!ha! Waiting for them to develope into gold dust!
When I bought the stock from Stephen's Scooter Mart there was quite a number of gears that had been welded up and reworked with "dovetails" on the protuding "dogs" to try and avoid the jumping out of gear syndrome.

Lasse
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Sun Apr 03, 2011 8:12 am

With all respect to Gösta Carlsson (who gave me very valuable help) - I am not totally in agreement with his recommended method...
Why so?
Because I did follow Göstas method to the minute - first with a spring (which almost drove me crazy - by spinning away - again -& again) then, much better, with elasic bands.
It worked, the things slid home as they should - BUT, afterwards, the gears wouldnt change as they should (one gear missing out/and o,r second slipping out of mesh).
I faithfully repeated this method several times during a day - to finally give up!

Then Gösta told me, that just a minute "mal-adjustment" of the sliding end-bearing of the selector drum/idler wheel, could throw the gear-selection out of proper mode!
To give Gösta some credit for his method, I must admit that my gearbox are "composed" of gearwheels from at least 3 or 4 different RUMI bikes/scooters.
Also the "detente" mechanism is "unoriginal" and made up of different parts.
I guess that the "Gösta Method" will work perfectly, if you always could use Factory fresh new parts!

Unfortunately, many of us "RUMI menderes" have just old & worn parts to play with - so, our gearboxes here in 2011, might all be "individual creatures"...
Therefore, no fixed & 100% conclusive solution to gearbox repairs can probably be given to this Forum - I fear, we have to accept that "trial & error"- with the combined "wisdom" from members in this Forum, might be the only solution to a wellbehaving RUMI gearbox.

Lasse.

UHJ200
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Re: "the Holy Grail" of setting the gearselector Quadrant

Post by UHJ200 » Sun Apr 03, 2011 1:39 pm

It’s so blindly obvious that I hang my head in shame when I think just how long it took me to twig the centreline thing, particularly as I have an engineering background! My “eureka” moment then was the realisation that the selector assembly is designed around the join line of the crankcase; it is the centreline of the mechanism, the datum for the whole shooting match if you will.

The important point about the marks is not the marks themselves but the gear teeth they point to so to be properly set, or in the case of a 50+ year old partially clapped bit-o-kit your nearest best hope of not finding a box of neutrals is that the last tooth that engages with the quadrant must be set exactly on the centreline.

So to clarify:

1. Set the selector camshaft with the marked tooth horizontal and facing forward.

2. The idler pinion has two marked teeth; careful observation will show that the gear on the end of the camshaft has its mark between the teeth therefore the correct tooth on the idler to engage is the one that has the mark on the tooth. (See Janne E’s excellent pictures earlier in this topic for clarification).

3. Adjust the position of the second mark on the idler by rotating the camshaft bearing so that it is exactly on the centreline and tighten the three bolts.

4. Engage the central tooth of the quadrant as seen through the viewing hole with the marked idler tooth and replace the cover assembly.

It is interesting to note that in Janne E’s second picture the marked idler/quadrant tooth appears to be below centreline so presumably the image was taken before final adjustments were made.

One of the difficulties with replacing the cover is keeping the cover square while engaging the quadrant shaft with its mating parts hidden inside the cover. To this end I made up three long threaded rods as temporary guides. These are screwed into the cover fixing holes in the crankcase and the cover thus constrained should slide on easily. Anyone wishing to try this should note that the threads should be screw-cut rather than run on with a die as the thread axis needs to be kept exactly axial to the rod. The rods need not be a close fit in the cover holes and need only be screwed in finger tight, a little “wriggle room” is handy at times! When the cover is settled in place first put a couple of the fixing screws in just to be on the safe side and then the guide rods can be removed.

Lasse
Posts: 1501
Joined: Mon Aug 10, 2009 5:18 pm

Re: "the Holy Grail" of setting the gearselector Quadrant

Post by Lasse » Sun Apr 03, 2011 3:28 pm

Brilliant UHJ - many things seems to be so obvious, AFTER we got to understand the true meaning of some assemblings methods...
I have been somewhat stubborn as well - but I also "see the light" now!
Especially when I realised, that Jannes bike were lying flat on the garage-floor - probably to facilitate an easy way of putting the clutch cover onto the gearbox.

I am still a little suspicious, if this method will work on a "clapped out/worn/changed" gearbox - in theory it should! -But, after I, with much effort, made my box to work 100% as it should, no one can ever persuade me to pull the thing apart again, just to see if this (very sensible) "Grind Marks Theory" will work on my box!!!

But I guess, that DThomas will have instant & good results, if he follow the "UHJ/Janne/Gösta" method.
(And I hope we will hear from DThomas, and learn how he made his box behave - again)

Lasse.

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