Date: 29-03-24  Time: 09:25 am

Author Topic: Roadside bodging (first and second gears not selecting)  (Read 9021 times)

Fazerider

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Roadside bodging (first and second gears not selecting)
« on: 08 June 2014, 02:01:37 pm »

The bike's been reluctant to select first when at a standstill for a couple of months now, an ailment it mysteriously developed whilst having the MOT performed. Well, it's been getting worse, to the point where I ordered some new detent and return springs for the gear selector, which took ages to come and then I sort of didn't find a suitable time to tackle the job... but I kept using the bike.
It's also started with the old 2nd gear problem; selects OK if you give it time, but if you're in a hurry it's likely to turn into a false neutral.
Last night I made the mistake of attempting to change down to first while slowing for some traffic lights, but was going too slow and there was nothing there... no probs, I thought, flick up to second and pull away in that gear again... except now I can't get 2nd either, lever just goes up and down without the normal accompanying clonk.
Shove the bike onto the pavement, raise onto centrestand, try and spin the rear wheel fast enough that things think they're moving whilst grabbing at the clutch and yanking at the gearlever. All this effort gains me is a muck sweat.
Either I take the clutch cover off and try to persuade the selector drum round or I call for some roadside rescue... it's nearly 1am, I'm knackered after a 12 hour shift and not really in the mood for delving into the engine by streetlight so I call the folks who gave a pretty good service last time the bike died and I needed a 30 mile recovery lift. "We're a vehicle short and all the rest are are out on jobs, it'll be a 2 hour wait. If you're lucky."
I decide I am in the mood for roadside motorcycle maintenance after all. With the bike on the sidestand, I get the cover off with no oil spillage. Can't see why the escapement mechanism isn't working the drum around because it's a) too dark and b)the clutch is in the way and pulling that off feels like it'd be more than I want to tackle. I try to lever the drum around with the screwdriver, but it's not budging... then my tired brain remembers the clutch is engaged: wind out the cable adjuster on the handlebar until it's disengaged and to my great relief find I can lever the drum round to second, and then third.
Then it was just a case of putting everything back together, shoving my oily hands back in my nice new gloves :rolleyes  and then spend another two minutes before I twig that the reason the bike won't start is that I'd hit the killswitch.
Ever tried riding in London, even late at night, without changing into 1st gear? It's bloody difficult, the moment you relax and have to slow to a halt your foot does what it's programmed to do and changes down. Despite my intention of staying in third or above, I went down to second at one point. Anyway, tl:dr ... finally made it home at 02:15, or about two hours ahead of my lazier self that would have preferred the Fazer shoved in the back of a Transit.
« Last Edit: 16 June 2014, 12:04:04 pm by Fazerider »

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Re: Roadside bodging
« Reply #1 on: 08 June 2014, 05:46:45 pm »
Respect for getting under way again with your own sterling efforts and tackling it at the roadside in the dark  :thumbup  .


Fazerider

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Re: Roadside bodging (first and second gear not selecting)
« Reply #2 on: 15 June 2014, 11:22:44 pm »

I finally got round to tackling this job over Friday and Sunday (Saturday I had to go and get deafened by some crusty old rockers in a polo field in Surrey… Procol Harem, Jeff Beck, The Who… it's a hard life sometimes).


To start, since I'd be working on the garage floor, I ran the bike up onto some bricks to give a couple of extra inches space underneath so I could get my head underneath.
The gear selector arm didn't appear to have anything wrong with it that I could see, no broken, bent or worn bits were obvious anyway. I figured a detent and return spring change wasn't going to help, but I'd already bought them so didn't have anything to lose by changing them.
The drum was pretty baulky when turning by hand so selectors were next in line for attention. Disassembly went pretty much as Deefer described aside from the upper bolt on the rear fork pivot retainer which doubles as the pin for the gear lever return spring: this was a bastard to remove as it's a low profile, pre-rounded hex head… your conventional 12-point socket just isn't up to the job of shifting it.





In the end I had to grind the tip and sides of my hex 12mm socket to get it to seat properly over the bolt head.
The other thing Deefer omitted was that the oil strainer/pickup is (obviously) totally in the way so has to come out: the cover levers off OK, but the two screws holding the main casting were very tight… fortunately they're Allen heads and undid after an alarming crack.





At this point I wondered whether his description was just a massive wind-up because the selector forks seem such a long way up inside, but despite appearances they are indeed accessible. The old ones were quite badly damaged and the drum had some signs of wear too… fortunately I'd picked up a complete gear assembly from a local breaker for £45 on Friday so had the drum and selectors ready. Getting them in looked like it would need two hands holding the forks inside the engine where there's barely room for three fingers plus another hand to feed the drum in. I fed some 2.5mm electrical cable in to hold the forks in, but out of the way while pushing the drum in.





Locating the forks is surprisingly easy, just slide then back and forth until they find the groove on the drum (doesn't actually matter what the drum position is).


The drum action was now noticeably smoother, I was able to clock it round from 1st to 6th and back with no problem, so with high hopes put everything back together, clicked it into neutral, rolled the bike off my poor-man's workbench and popped it up on the centre stand for a final check of clutch and gear selection before refilling with oil.
And that's where my self congratulation as an ace spanner monkey ended… no way would it select 1st or 2nd. Exactly the same foccing problem as when I started. :wall
So it must be the gear selector escapement mechanism that's at fault, despite looking OK. Unfortunately that wasn't a part included in my bargain bundle of gearbox bits or I'd have had another to compare it with.
Bollox… another few days commuting by car.  :'(
« Last Edit: 16 June 2018, 11:55:37 am by Fazerider »

Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #3 on: 19 June 2014, 01:08:55 am »
Thought I'd add some snaps of the bits that came out...
Here's the left selector fork, the worst of the bunch.





The drum also bore some wear marks, the scuffing on the tip of the nearest track corresponds to 2nd gear for the left selector fork.





As for the selection problem, it's still there. Second gear upwards select fine, it's just the 1-N-2 region that does nothing when the gearlever is prodded.
I've had the gear shaft back out again thinking that if the claw got stretched by my heavy-footed MOT guy, then the angle the shaft moves through might not be sufficient to nudge the pin on the selector beyond the neutral detent, yet still be able to work the higher gears because the pin doesn't need to be pulled quite as far (once it's beyond the middle of the movement the detent wheel will push it the rest of the way).
Despite having a closer look at the shaft, the mechanism looked OK, but in desperation I tried squeezing the claw in the vice to tighten the gap by 1.5mm. That too has made no difference.


I've uploaded a brief clip of the shaft failing to reach the selector pin when the drum's in neutral here. Aeva Media doesn't like .mp4 and I'm locked out of my own youTube account (due to having registered under an email address that is now extinct) so I hope Videobam works OK, I've not had time to test them against others.
 
« Last Edit: 16 June 2018, 11:52:25 am by Fazerider »

Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #4 on: 19 June 2014, 11:53:51 pm »
Today, unable to think of anything else, I revisited the breaker that did me the deal on the gearbox and picked up a gearshift shaft for £15.
Comparing the two side by side there was no difference that I could see apart from the claw on the old one being narrower… measured the gap on the new one and it was 20.0mm, exactly what the gap in the old one was before I gave it a squeeze in the vice.

Anyway, I stuck the new one in and the bike could tell the difference even if I couldn't. It worked. :woot

Bunged it all back together, went for a shakedown run and refuel… and cylinder number 2's exhaust clamp decided to snap. :wall
After a bit of hacksawing and drilling made a 'C' shaped bit of 3mm steel as a temporary clamp. I'll take a gamble on some Kawasaki exhaust clamps I guess (having run out of old Motad ones to modify).

Btw, if anyone else is too tight to buy a clutch holder tool, 30 minutes with a drill and file converts a 3U blanking plate from a 19" rack into a suitable tool that bolts on. The downside is it'll only suit clutches that have the same dimensions, but since this is the first time I've needed one in 30-odd years I may not need another.
:)

« Last Edit: 16 June 2018, 11:49:40 am by Fazerider »

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Re: Roadside bodging (first and second gears not selecting)
« Reply #5 on: 20 June 2014, 12:09:47 pm »
Well done ;) It's always satisfying when you figure out the head scratchers

Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #6 on: 21 June 2014, 03:11:23 pm »
Thanks, your Dudeness. :)


Can't claim to have really figured it out though... all I did was change parts until the fault went away, I can't see what was wrong with the old shaft.
I have the photos available at last (accidentally shot without the SD card, so it put the images on internal memory which I could only access once I'd found the cable that I'd carefully hidden from myself).


New item on the left, old on the right and, aside from the claw being a bit squashed after my little experiment, there was nothing to choose between them.





Still, having changed the bits that didn't cure the main problem at least second gear does go in more securely now. And hopefully this lengthy waffle might help anyone planning to make use of Deefer's cunning technique for changing the selectors. :)
« Last Edit: 16 June 2018, 11:47:53 am by Fazerider »

Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #7 on: 07 August 2014, 12:12:10 pm »

Update:
Selecting second gear soon became as likely to provide neutral. And this morning after a particularly clattery, cocked-up upshift from one set of lights, first became a bastard to select from neutral at the next lights. :'(
So it's only a matter of time before first and second vanish completely and I'll be stuck at the side of the road with the clutch cover off manually forcing the drum round again.
Foccing thing.
Time for a new motor I guess. Perhaps one made by a manufacturer who knows how to make a decent gearbox.

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Re: Roadside bodging (first and second gears not selecting)
« Reply #8 on: 12 October 2014, 11:13:52 am »
Well, I took the clutch off again to see if I could figure out what the foc was happening and had some success. The bent bit of the selector arm that forms the stopper for the return spring for the claw was colliding with the pins of the selector drum… presumably because the claw pivot has developed a bit of slack, requiring the arm to move a bit further before it's able to drag the drum round out of the neutral detent.


http://gfycat.com/UnlinedSoreElk



The solution seemed straightforward: pop it in the vice and increase the bend of the tang to 90º so that it has some clearance.






This worked brilliantly… nice positive engagement of first and second. Oddly though, over the course of the next two weeks the problem gradually returned until it stranded me on my way home from work at midnight again… fortunately this time at my local Sainsbury's filling station which is a) covered and b) brilliantly lit. So 15 minutes was all it took to get the cover off and manually prod the drum round to 3rd to limp home.


A bit baffled as to why the problem had come back when it had been so convincingly fixed, I measured the position of the tang and found it had crept back to the original position. Strange steel this thing is made from. So I repeated the bending trick, this time going a bit further so that it got the message… and discovered I'd now got a nice stress fracture across back of the bend. A blob of weld fixed that, and hopefully that will have got rid of the peculiar memory effect.






So far, so good. All gears select cleanly again.
I suspect that wear, or bending as a result of heavy-footedness, of the claw mechanism rather than any inherent flaw in the gearbox itself is the root cause of the model's second gear problem. Bending the tang, or perhaps chamfering the edges, allows the arm to move far enough to do its job. Excess movement is now limited by the main return spring stop.
« Last Edit: 16 June 2018, 11:36:09 am by Fazerider »

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Re: Roadside bodging (first and second gears not selecting)
« Reply #9 on: 12 October 2014, 01:08:36 pm »
Blimey sounds like you've had a nightmare with that. I'd not know where to start and would have either paid a dealer or sold for cheap. Hope this is the last time you have to have it apart! Nicely documented for others too.
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Re: Roadside bodging (first and second gears not selecting)
« Reply #10 on: 12 October 2014, 01:31:32 pm »
Bloody hell, what do you do with your gear lever?!?  :eek


Just out of curiosity, you do ride with your foot well clear of the shifter, right?
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Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #11 on: 12 October 2014, 02:01:27 pm »
Bloody hell, what do you do with your gear lever?!?  :eek


Just out of curiosity, you do ride with your foot well clear of the shifter, right?
If you keep a bike for a few years without writing it off, it's what happens... just normal wear and tear.
Though admittedly my MOT tester seemed to accelerate the process somewhat.
This engine has covered about 80,000 miles, about the same as my original one did  before the second gear selection issue raised its head.

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Re: Roadside bodging (first and second gears not selecting)
« Reply #12 on: 12 October 2014, 04:50:42 pm »
Bloody hell, what do you do with your gear lever?!?  :eek

Just out of curiosity, you do ride with your foot well clear of the shifter, right?
If you keep a bike for a few years without writing it off, it's what happens... just normal wear and tear.
Though admittedly my MOT tester seemed to accelerate the process somewhat.
This engine has covered about 80,000 miles, about the same as my original one did  before the second gear selection issue raised its head.

Bit catty, aren't we?  :b

I understand normal wear and tear, but as an engineer, I can't see why your shifters are failing compared to other high mileage bikes. My only conclusion is that you're either REALLY heavy-footed, that there's something wrong with the part (but two in a row?), or that you are putting the part under a certain amount of repeated strain. Hence my question about riding with your foot on the lever.
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Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #13 on: 12 October 2014, 05:35:17 pm »
Bloody hell, what do you do with your gear lever?!?  :eek

Just out of curiosity, you do ride with your foot well clear of the shifter, right?
If you keep a bike for a few years without writing it off, it's what happens... just normal wear and tear.
Though admittedly my MOT tester seemed to accelerate the process somewhat.
This engine has covered about 80,000 miles, about the same as my original one did  before the second gear selection issue raised its head.

Bit catty, aren't we?  :b

I understand normal wear and tear, but as an engineer, I can't see why your shifters are failing compared to other high mileage bikes. My only conclusion is that you're either REALLY heavy-footed, that there's something wrong with the part (but two in a row?), or that you are putting the part under a certain amount of repeated strain. Hence my question about riding with your foot on the lever.
Even if I did ride with my foot on the lever, which I presume nobody does since it's likely to result in unintended gear changes, I don't see that it would cause undue wear. As for the second shaft also succumbing within a few thousand miles... I've no idea how many miles it had done prior to my acquiring it nor how brutal its previous owners were. The fact that the mechanism clashes with the pins of the selector drum once the claw has a millimetre or so's free play and becomes an "end stop" long before the proper end stop comes into effect points to a design fault.

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Re: Roadside bodging (first and second gears not selecting)
« Reply #14 on: 12 October 2014, 10:04:28 pm »
Even if I did ride with my foot on the lever, which I presume nobody does since it's likely to result in unintended gear changes,

I agree, but you'd be surprised.

I don't see that it would cause undue wear.

If there is light pressure on the shaft, the moment may not be enough to change gear, but it's putting parts under greater stress. Hence the accelerated wear.

As for the second shaft also succumbing within a few thousand miles... I've no idea how many miles it had done prior to my acquiring it nor how brutal its previous owners were.
Granted, however, the fact that it was fine for a few weeks is puzzling. Could you have misaligned anything as you rebuilt the gearbox?

The fact that the mechanism clashes with the pins of the selector drum once the claw has a millimetre or so's free play and becomes an "end stop" long before the proper end stop comes into effect points to a design fault.
Agreed.
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Re: Roadside bodging (first and second gears not selecting)
« Reply #15 on: 06 November 2014, 07:53:04 am »
Quote
The other thing Deefer omitted was that the oil strainer/pickup is (obviously) totally in the way so has to come out: the cover levers off OK, but the two screws holding the main casting were very tight… fortunately they're Allen heads and undid after an alarming crack.



I did say that I might have missed a stage out as I was doing it from memory...... The oil strainer bolts are threadlocked in with a whole bottle of threadlock on each from the factory, so yes they do make an alarming crack as you undo them


Btw, if anyone else is too tight to buy a clutch holder tool, 30 minutes with a drill and file converts a 3U blanking plate from a 19" rack into a suitable tool that bolts on. The downside is it'll only suit clutches that have the same dimensions, but since this is the first time I've needed one in 30-odd years I may not need another.
Quote


Or use an air impact gun
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Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #16 on: 13 December 2014, 05:26:02 pm »

To complete this long-running tale I should add that the problem came back after a few weeks. :rolleyes
I extracted the shift arm again and even before measuring could see that the tab had unbent itself enough to collide with the selector drum pins again. The tension caused by the cooled weld had relieved itself by cracking the inside of the bend.
I did attempt to weld the inside of the corner, but a stick welder isn't the best tool for an awkward job like that and my skills certainly weren't up to it either. I discarded the ruined mess I'd made and tried grinding the top of the tab down a bit on another second-hand shaft.






This appears to be the best solution. The tab is still long enough to act as the stay for the claw return spring but is short enough to pass over the tips of the pins on the selector drum without hitting them. The metal is incredibly hard, a cobalt steel hacksaw made no headway through it, grinding it down was effective, though it takes a while to clean up afterwards. The pic should make things clear, I ground the tab down to about 8mm measuring from the tip to the back of the plate.
« Last Edit: 16 June 2018, 11:24:34 am by Fazerider »

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Re: Roadside bodging (first and second gears not selecting)
« Reply #17 on: 10 April 2015, 07:43:10 am »
Hi Fazerider,

I was googling "gearchange selector escapement" (I'm designing a bike and don't want to re-invent the wheel) and came across your harrowing tale. Very impressed at your tenacity in getting to the bottom of the problem. Also very handy for me in understanding the fundamentals of the mechanism. Good job.

But perplexing why that tang was repeatedly bending, given that it was so hard. Just case-hardened I guess, and the core metal a bit too weak for the job. A case of misguided weight saving.....?? 

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Re: Roadside bodging (first and second gears not selecting)
« Reply #18 on: 10 April 2015, 09:42:21 am »

Yes, it surprised me. Not just that it returned to the original position, but that it did so very slowly. Can only assume that the metal is so hard that even after the first attempt to bend it it was riddled with micro-fractures and that somehow accounts for the strange behaviour.
Good luck with your project… sounds like you're designing to a pretty detailed level.

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Re: Roadside bodging (first and second gears not selecting)
« Reply #19 on: 10 April 2015, 02:58:22 pm »
you could say that...

Fazerider

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Re: Roadside bodging (first and second gears not selecting)
« Reply #20 on: 10 April 2015, 06:39:34 pm »
Impressive CAD there!
What are the twin helical structures under the left of the motor?

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Re: Roadside bodging (first and second gears not selecting)
« Reply #21 on: 10 April 2015, 07:14:21 pm »
Interesting that you're using the BMW-style single sided swingarm!

What CAD program did you use for that?

Specs?
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Re: Roadside bodging (first and second gears not selecting)
« Reply #22 on: 10 April 2015, 09:36:35 pm »
The spiral things are the rotors of the supercharger. It's a sleeve-valve V6 2-stroke, more or less a copy of the Rolls Royce Crecy, which would have been the successor to the Merlin. This is just a scaled-down version. I'm guessing that modern metallurgy and fuelling technology (it's direct injection) would help it all along.
This thing is 800cc and would produce about 250bhp @8000rpm. This would have a bmep of just under 200psi, which isn't much. And without all the friction and pumping losses of a 4-stroke, the amount of heat produced wouldn't be excessive either. It works like
this
.



It'd just cost about 250,000 euro to make, which is why it won't happen. At least, not this year.  The CAD program is Solidworks.

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Re: Roadside bodging (first and second gears not selecting)
« Reply #23 on: 10 April 2015, 09:44:46 pm »
Beautifully detailled model!

Guessing you're a final year engineering student like me - where and what are you studying?
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Re: Roadside bodging (first and second gears not selecting)
« Reply #24 on: 10 April 2015, 10:26:43 pm »
Bloody hell, what do you do with your gear lever?!?  :eek

Just out of curiosity, you do ride with your foot well clear of the shifter, right?

Behind his head clear enough? Every biker should practice yoga

My only conclusion is that you're either REALLY heavy-footed.

Lay down and let Fazerider show ;)
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