RRT2 gearbox lay shaft won't fit

[Peter in Aus]

Has anyone got a RRT2 gearbox in bits or know the measurements of the lay shaft and gears on the lay shaft? The reason being is, I have been given a RRT2 gearbox to put together with all new gears and shafts and do not have the old ones to compare, and the lay shaft want fit, if you put the thrust washers (supplied) at both ends of the lay shaft assembly and put the inner cover on it won’t fit as the lay shaft assembly is at least 1/8” to long “see diagram”, if you fit the washer between 1st and third gear as in the SR boxers that makes it even worse, not sure if it should be there?
What I would like to know is the thickness of 1st and top gear, the ones I have are, top .776” including doges 1.069” and 1st gear .592”, also the measurement between the circlip (locating top B gear) and the end of the spline on the lay shaft.
If some one can help that would be great.
 Thank you
Peter

[JulianS]

Make sure that the fixed "B" gear is pressed on so that it seats against the circlip. Also make sure that the blind needle roller is pushed in far enough so that the layshaft is not touching the closed end when "B" and thrust washer in place.

Sometimes, if the shell has been converted from a bushed box, the recess for the thrust washer is not sufficient diameter or not deep enough.

You definately must fit the thrust washer behind "H" and with chamfer away from "H"

Can you post photos of your actual parts please.

[duTch]

 Julian rounded me up- no surprise, but this took a while so;

 G'day Pete, I'm happy to help but first up that's a hell of a sentence. I don't always get things right, but would appreciate if you can proof-read it a bit and fix some typo/spelling/punctuation errors, that'd make it a shitload easier to read (sorry-not sorry).

 

.....also the measurement between the circlip (locating 1st gear) and the end of the spline on the lay shaft.

  I think ^^that^^ may be an important factor.

Now for my typo/spello sesh -;

 The thrust washers each end on the layshaft are imperative- they have to stay as does the one between 1st & 3rd  - absolutely imperatively essential  (get the picture- don't ditch anything)

 First up, I'm not an expert on this, but I grafted my old RRT2 cluster into the Plunger box and lucky it worked ok, but for some reason (3rd gear whine ) I swapped it out for a standard box which turned out to be an early (pre '50) box..
  So when that spatshit- did jumping in/out of 3rd gear, I did some research into the RRT2 Graft & corruption and found that not only did I omit to use the 67-3203 thrust washer betwixt 'F' & 'H', but the rrt2 'B' gear is wider and I hadn't pushed it on as far as it needed to be (which probably saved an explosion/compensation for lack of thrust washer)
 
 Basically I think you need to assemble each shaft separately and check each move. There was a debate a while back when Pedrochapala was rebuilding his box and debating whether or not to use the  circlip you mentioned. If the gear is a tight fit he may have got away without it, but not recommended in my fickle mind...

 In summation, it seems the layshaft length is the current issue, so from memory if you can get it so it's just a few thou short of the main box is ideal.

 

What I would like to know is the thickness of 1st and top gear, the ones I have are, top .776” including doges 1.069” and 1st gear .592”, also the measurement between the circlip (locating 1st gear) and the end of the spline on the lay shaft.

 I think I may have those somewhere, but not tonight , but will help if you clarify which gears ('H'/'A'/? 'B'?)
 Have to admit that diagram is crap, looks like a complete cross-hatch gone wrong (maybe my current disposition?) there are better

[JulianS]

The circlip actually locates the "B" gear in the correct place, the gear is machined so it seats on the circlip.

Dont have measurements but photo shows the end of a needle roller layshaft. Note it has no oil scroll.

The layshaft used in plunger boxes is not the same as the swinging arm one, from memory, one difference is the location of the circlip. On the STD plunger box the "B" is a different part to the swinging arm, one difference being where it is machined to seat the circlip. You can see the difference in the photo. Plunger left swinging arm right.

So should you have a plunger layshaft it wont fit.

[chaterlea25]

Hi Peter,
I will dig out the RRT2 bits later (if I remember)
But there is often confusion over what thrust washers go where
There's a good reference posted on the britbike forum with the thicknesses and locations of the washers

http://www.britbike.com/forums/ubbthreads.php/topics/713333/pre-unit-transmission-info-swing-arm-models#Post713333

Its been a while since I looked at myRRT2 box in bits but I changed out first and third gear pair to STD
The dogs are different between first in RRT2 and STD sets, so you need to fit 3rd STD pair as well (these have the same tooth count as RRT2"

John

[duTch]

After I did my post I realised I didn't give where I garnered the information I used a couple of years ago, but John has provided some of that now anyway.
 I also found a similar but more specific thread with picures that was really handy...maybe the photobucket fiasco has made the thread unrecognizable

[Peter in Aus]

 

.....also the measurement between the circlip (locating 1st gear) and the end of the spline on the lay shaft.

 Sorry that should have read "locating top gear B" not 1st
Thank you for all the replies I will take some pic and post them later.
Sorry Dutch never was much good at school.
Peter



 
 

 

[Peter in Aus]

http://www.britbike.com/forums/ubbthreads.php/topics/713333/pre-unit-transmission-info-swing-arm-models#Post713333

[/quote]
 Thanks John for that, got some useful info from that, all the thrust washers measure up ok.
There seem to be some discrepancy with top gear B according to that link above it is to wide, but dose not account for all the clearances required.
I think the circlip grove in the layshaft could be wrong or could be some other thing wrong with the shaft (see sketch) hopefully some one can verify that.
I am adding a few pic so as to get a better idea of what I'm on about.
Peter 

[duTch]

 yo Pete  sorry if I may have sounded a bit harsh, I learned to read and spell at an early age, but it's all gone downhill since I left school...before the internet there was a gap of some years where writing was superfluous, and reading was on a 'as need' basis...and I think I'm half dyslexic/ocd/addhdcfknwhuddeva...

 anyway where was I ?..no great surprise, but the gears don't necessarily engage fully as the length/depth of the dogs, that is only determined by the throw of the cam-plate grooves, which is not as much as we'd think- I think I have it noted somewhere.
 So.. keeping that in mind, each gear fairly much needs to start at an ideal mark, and correspondingly finish/engage in also (guess ) and ideal mark- there's not much room fro variation with it.

 Best I can suggest is (stock up on ), and just have a play, and before you know it all will be revealed  .

 In all honesty , these boxes are not the rocket science that they belong to...

[chaterlea25]

Hi Peter,

I measure 2.730in. same as you
Length from groove to end of splines is 0.880
Length between shaft shoulders is 3.700in.
Layshaft B (18tooth) gear is 0.745 wide (Tooth) and 1.0625 including dogs
On my old layshaft that still has the B gear fitted the shaft protrudes through the gear 0.8-0.810in.
So the gear overhangs the end of the splined section by about 0.090
( I am unsure if this is correct but is as I removed it from a "working" gearbox

Layshaft H gear (1st) 24 tooth on RRT2 is 0.595 wide at boss and 0.545 at teeth

Overall width from outside of B to outside of H without thrust washers is 4.375in.

Hope this helps
John

[duTch]

 hey Pete, reading that reminds me that my 'B' gear was overhanging the spline too and the only way I could rectify it was to deepen the circlip landings inside the dogs with a dremel which was surprisingly easy.
 I would recommend checking each gear individually for clearance from others (in this situation, put the 'B' gear in the case-ideally on the layshaft with'D'- and the 'C' gear engaged with 'A' on the mainshaft with no selector forks for maximum potential, and ensure gears don't clash unnecessarily).
 I'm suggesting this off the top of my head from memory (maybe pulling from my idiot), so go steady and persevere, at least you have an inspection cover to look through.
 Keep in mind though that I had grafted the RRT2 cluster into a Plunger box, so a potential recipe for disaster, and haven't used the box since then...haven't looked for any evidence yet, I need to figure which old phone I used at the time and go through the pics

  Just suggestions

[Peter in Aus]

Thanks John & Dutch, that is what I was looking for, got some thing to work on now.
Club ride day to day so off out on the A10 will look at it tomorrow and let you know how I got on.
Thank again for all your input.
Peter

[Peter in Aus]

Problem solved, Thank to all for your assistance.
It turns out that the main reason for the problem was the circlup that locates top gear B on the layshaft.
When we got the order for the bits it came without the circlup so we used a circlup from another box fingering that it would be the same! “Not so” when it turned up it was about half the diameter (the wirer that it made of) of the one we used.
So when we fitted it the gear B went on nearly 1/8” further giving us the required end clearance.
So all good now, thanks for your help.
Peter

[duTch]

 Good stuff- I had a search of photos, but couldn't find any relevant nor my notes, but from memory that's about how far I needed to move mine (by different method- but not being a stock setup, no surprise).

 I was also thinking maybe that's why I didn't have the thrust washer between 'F' & 'H', but that was long ago when I knew even less...

 Just shows how something so simple can cause so much grief (and sometimes more)

[chaterlea25]

Hi Peter,
Glad you got it sorted
When in the final position how much is the B gear overhanging the splined end of the layshaft?

John