Author Topic: Ratchet Woes? or Something else?  (Read 238 times)

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Unlucky_soul

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on: March 01, 2019, 03:23:41 am
This is pretty strange. Had to change the lay shaft and main shaft of a friends bike. Reassembled the gear box. While testing for correct gear changes (without the cover) all seems good... but when i put in the cover it doesn't shift properly, resulting in many false neutrals between 1-2 and 3-4. and occasionally between 2-3. Whereas it goes correctly when i shift gears using the neutral finder.

Maybe I did something wrong in the adjustment of adjuster plates? Or maybe its something else. At at my wits end.


mrunderhill1975a

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Reply #1 on: March 01, 2019, 11:10:02 am
Common problem when inner cover removed. Two likely possibilities, 1)the adjuster ratchet plates need to be moved slightly such that each caused more throw (moves farther to get into 2nd gear).  This is just a trial and error adjustment, keep at it and eventually you should get it right. 2)The detent plunger is too "deep" into the inner case and not landing on the correct notch. Did you count the number of turns on the detent plunger when you removed the inner cover?  If not, you will have to use trial and error to get the plunger to proper depth.

The photo below (from Hitchcock's tech pages) "shows the correct position for the ratchet where there is equal gap on either side of its teeth- main plate when gearbox in correct neutral. This can be fine-tuned by slackening off each of the backplate pillar bolts, then rotating the plate fractionally in the required direction. Remember the detent plunger must have its  adjustment screw tensioned no more than necessary for a light action gear change, but enough to make sure it doesn't jump out of gear.  Of course this implies more adjustment may be required after a road test."

« Last Edit: March 01, 2019, 01:15:26 pm by mrunderhill1975a »


mrunderhill1975a

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Reply #2 on: March 01, 2019, 12:40:30 pm
Here is some info from Pete Snidal:

Replacing the Detent Plunger

 In order to replace the GOSA, the shifter quadrant must first be
 relocated to the smooth spot between two gears, as detailed
 <file:///D:/DLX2013/9detent.htm#posn>above. (ie, between top and 3rd)
 so that the chisel tip won't be caught in a notch and prevented from
 turning, since it must turn with the threaded barrel. Engage the
 threads of the GOSA, and screw it down until it stops. Once the
 barrel has been threaded in to the desired (you think) tension
 position, moving the bellcrank by operation of the shifter mechanism
 will allow the tip to engage a slot.

 It is of course important that the chisel tip be positioned
 horizontally, so that it will engage properly with the notches, once
 the job is finished. Make a note of the angle of the screw adjuster
 when the plunger nose is horizontal, and ensure that when you replace
 and adjust, that the screw slot stays in this relationship. Usually,
 the chisel is parallel to the screw slot. When satisfactory action
 has been attained, holding the screw with a suitable screw driver,
 tighten the locknut.

 Once you have worked the gearbox through the gears a few times, and
 are feeling positive "stops" between them as the detent plunger
 engages the appropriate notch in the shifter bellcrank, reassemble
 and road-test. This procedure will correct the vast percentage of
 shifting problems. If shifting difficulty is still experienced with
 the detent plunger working properly, the problem can only be the
 linkage moving too far, or not far enough. For example, if difficulty
 is experienced getting into top gear from third, the linkage is not
 moving far enough in the upshift direction. If it consistently fails
 to get past Neutral from second, the difficulty is lack of sufficient
 movement in the downshift direction. Note also that not enough
 movement in one direction is often accompanied by too much movement
 in the other. For example, if insufficient downshift movement is
 experienced (missing first from 2nd), excessive upshift movement may
 make for attempts at 3rd from 2nd going past 3rd into the 3-4 "false
 neutral." To correct shifting problems once satisfied with the detent
 plunger, see the section on <file:///D:/DLX2013/9shftadj.htm>ratchet
 adjusting.
 -----
 Best of luck with it,


mrunderhill1975a

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Reply #3 on: March 01, 2019, 03:53:30 pm
Here is some adjustment information from Terry and Shawn

"Ride the bike and determine whether the gearbox shifts too much or too little. For example when shifting from 2nd to 3rd the gears pop out to a neutral between 3rd and 4th, it shifts too far (this was my rouble). Or for example when shifting from 2nd to 3rd the gears pop out to a neutral between 2nd and 3rd then it shifts too short. If you have to drive holding it in 4th gear with your foot it !probably shifts too short. If it seems to jump out of gear to neutrals both above and below your selected gear check the GOSA (see below).

Put the bike on the center stand so that the rear wheel is clear of  the cement and can be turned by hand. Remove the outer gearbox cover.
Check the spring loaded gear selector detent pin that is at the upper front under the outer gearbox cover. Jan's old posts call it a GOSA and you should be able to find it in the archives. The GOSA is what holds the gears in gear. There are 5 detents that the GOSA slips into in the inner "gear operator" (1st, neutral, 2nd,3rd,4th). If the GOSA is too loose, misaligned (slot and taper not horizontal), or the
taper is rounded off it will allow the "gear operator" to move and
gear to slip out. When the GOSA is over tightened the tapered face quickly becomes a rounded rubbing block rather than a tapered detent pin. Set the GOSA up correctly before adjusting the ratchet (below) and use Jan's posts and common sense to set it snug but not too tight. (The taper should not bottom the spring between the detents. the repair book had a terribly vague description of how to do it)

After the GOSA's in good working order... With the bike on the center stand and the outer cover off the gearbox re-install the foot shifter (this is easy with RH shift and may not be practical with LH shift)
You may have to reinstall the kickstart lever too. You should be able to turn the rear wheel with your left hand and shift up and down  through the gears with your right (or you may need an assistant with LH shift). As you shift you will be able to watch the ratchet that Terry's post talks about. You can loosen the nuts that hold the adjuster and move it on its slot to see how the adjustment changes how far it shifts.
If your bike was shifting too far the ratchet will allow the "gear
operator" to move past the GOSA's detent. For RH shift this means the shift lever is rotating clockwise and the solution !if I remember correctly! is to rotate the ratchet adjuster plate counter clockwise (sort this out for yourself by going through the gears a lot). In my case I could not rotate the adjuster plate enough and I had to file
the slots in the adjuster plate longer. I didn't do any filing until I'd adjusted it several times with plenty of riding on each change. (It's not a 1 day process unless you're REALLY in to it.) When the adjustment is close the bike was very ridable and only popped out of gear occasionally.
If your bike was shifting short the RH shift lever will need to move further. If I remember correctly (!) this means you need to move the ratchet adjuster plate clockwise.

Some other things could cause jumping out of gears... Worn gears, bent main or layshaft, or the detents worn out of the gear operator.

                Good luck and patience,

                Shawn

And below is some info from Terry:
Adjusting the shifter movement is not the easiest thing to explain and it's even more frustrating to do. If you have  a parts book please refer
to it while I try to explain the adjustment.

First thing to do is remove the gear box cover. The neutral finder
should come off with your fingers as it should not be completely tightened
down.
The spring holds it from loosening off. Remove the kick starter. Now
there are five screws to remove around the perimeter of the cover. The
small screw that holds the inspection cover in the top left corner is one of the
screws.
Now the cover can be slid off the kick start shaft and rotated around
so that you can pull the clutch cable from the lever inside the cover.

In the left hand top corner of the inner cover you will see the ratchet mechanism. As you shift gears the foot control ratchet (outer) will
rotate and engage a tooth of the inner ratchet. What happens if this
mechanism is not adjusted correctly is that the outer ratchet will just miss a
tooth on the inner ratchet and by the time it reaches the next tooth you have run out of movement on your foot shift; therefore the gear will not engage.

The very back plate is called the foot control adjuster plate and is
slotted to allow you to move it side to side in order to get the outer and
inner ratchets to engage properly. What you are trying to achieve is that
the outer ratchet catches the closest tooth of the inner ratchet as it
move  through the gears in both directions. Since you have a left side
shift lever you may need another person to help you.

The foot control stop plate which holds this ratchet mechanism
together has two holes in it which will allow you to see the inner ratchet. While
rotating the rear wheel have someone shift for you while you watch
the outer ratchet engage the inner ratchet. You should be able to see if the outer ratchet is slipping past a tooth on the inner ratchet. If so, the adjuster plate will have to be moved until the outer ratchet connects with theclosest tooth on the inner ratchet each time you shift gears. To adjust the plate you will have to remove the stop plate. There are only two small nuts holding it in place. The foot control adjuster plate pins can now be
loosened off so that the adjuster plate can be moved side to side.
You'll just have to play with it until it does what you want it to do. You
may have to assemble everything and ride the bike and come back and make
further adjustments to get it working right.

I hope all this makes sense to you. Let me know how you make out.

Terry"