Finding Neutral while stopped and in gear

[TwoManyXS1Bs]

Been doing a lot of town cruising, stop/go stuff.
Taking advantage of the last of our hot days.

I found my neutral!

Setting stopped, engine idling, clutch pulled, 1st gear:
A shoving nudge up on the shift lever and it goes into neutral.
No need to flick/tap, no need to rev the engine.

Same going down from 2nd.
Same when cold (60°F) and hot (205°F).

Not quite as slick as some period Hondas, but I'll take it.

Summary of what was done:

Shifter/starwheel area:
- New shiftdrum stopper plate
- Reconditioned later model indexing wheel
- Later model indexing spring.
- Polished neutral detent plunger tip, set spring length to 26mm.
- Meticulously recentered shifter claw (including lateral centering in the slot)

Clutch:
- Replaced sticky organics with Barnett kevlars.
- Still using the experimental plate spreader mod.
- Replaced the 'ultimate' clutch worm gadget with the modified MikesXS worm, using the 1.2" clevis hole.

(I installed thicker palmswell handgrips awhile back, and these reduced the clutch lever pull, producing only 0.040" of pressure plate travel. Now have 0.050" pressure plate travel.)

Other:
- Fresh oil, Valvoline 20w50
- Replaced Neutral switch.

I did the 4lb 1/2 gallon waterjug test on the rear wheel, with trans in 1st. Pulling the shift lever to neutral required about the same medium effort as the 2lb test when all this first started.

I believe that the most significant contributors to this improvement are the shiftdrum stopper plate, Barnett plates, and different oil (?).

I also believe this could be improved further, in the trans.
So, future plans:
- Later model trans.
- Later model shiftdrum, with its "behind the starwheel" roller bearing.
- Couple tricks I have in mind for the shiftforks and guidebar.

 

[MaxPete]

2M - you are too much! People have gotten Master's degrees in Mechanical Engineering for work and reporting like that.

Thanks very much for a genuinely interesting, useful and comprehensive post.

Pete

 

[ihaxs650]

Been doing a lot of town cruising, stop/go stuff.
Taking advantage of the last of our hot days.

I found my neutral!

Setting stopped, engine idling, clutch pulled, 1st gear:
A shoving nudge up on the shift lever and it goes into neutral.
No need to flick/tap, no need to rev the engine.

Same going down from 2nd.
Same when cold (60°F) and hot (205°F).

Not quite as slick as some period Hondas, but I'll take it.

Summary of what was done:

Shifter/starwheel area:
- New shiftdrum stopper plate
- Reconditioned later model indexing wheel
- Later model indexing spring.
- Polished neutral detent plunger tip, set spring length to 26mm.
- Meticulously recentered shifter claw (including lateral centering in the slot)

Clutch:
- Replaced sticky organics with Barnett kevlars.
- Still using the experimental plate spreader mod.
- Replaced the 'ultimate' clutch worm gadget with the modified MikesXS worm, using the 1.2" clevis hole.

(I installed thicker palmswell handgrips awhile back, and these reduced the clutch lever pull, producing only 0.040" of pressure plate travel. Now have 0.050" pressure plate travel.)

Other:
- Fresh oil, Valvoline 20w50
- Replaced Neutral switch.

I did the 4lb 1/2 gallon waterjug test on the rear wheel, with trans in 1st. Pulling the shift lever to neutral required about the same medium effort as the 2lb test when all this first started.

I believe that the most significant contributors to this improvement are the shiftdrum stopper plate, Barnett plates, and different oil (?).

I also believe this could be improved further, in the trans.
So, future plans:
- Later model trans.
- Later model shiftdrum, with its "behind the starwheel" roller bearing.
- Couple tricks I have in mind for the shiftforks and guidebar.

2M, Thank you for this interesting article. I am assuming that the shiftdrum stopper plate is the same as the anchor plate in the Haynes manual.. Looks very doable, within my limited mechanical ability! Did you order the shiftdrum stopper plate from Yamaha?

 

[TwoManyXS1Bs]

2M - you are too much!

Hey, Pete. Thanx for your support. Glad you enjoyed this exploit.

Yeah, too much. My ex-wife used to complain that that I was the kind of guy that when asked: "What time is it", would explain how the clock is built...

 

[TwoManyXS1Bs]

Hey, ihaxs650. Glad you enjoyed this, too. Hope it helps in your quest.

...I am assuming that the shiftdrum stopper plate is the same as the anchor plate in the Haynes manual..

I guess so.
I made sure that the part number appears in the pic of the new one.

... Did you order the shiftdrum stopper plate from Yamaha?

It comes up as 'obsolete' and 'not available'. Typical.
I found one of the last few NOS plates on eBay.

There's a lot of these stopper plates on eBay, used/pulls. Most appear to be in good shape. The critical area for inspection is that narrow contact ring on the inner edge. Here's another example of what to avoid:

 

[ihaxs650]

2M, I have yet to open the clutch side to a XS650. I am assuming their are 2 stopper plates to replace? I was able to purchase new NOS on ebay. Thank you!

 

[TwoManyXS1Bs]

... I am assuming their are 2 stopper plates to replace?

No, just the one. Part #25.

 

[SEd27]

Been doing a lot of town cruising, stop/go stuff.
Taking advantage of the last of our hot days.

I found my neutral!

Setting stopped, engine idling, clutch pulled, 1st gear:
A shoving nudge up on the shift lever and it goes into neutral.
No need to flick/tap, no need to rev the engine.

Same going down from 2nd.
Same when cold (60°F) and hot (205°F).

Not quite as slick as some period Hondas, but I'll take it.

Summary of what was done:

Shifter/starwheel area:
- New shiftdrum stopper plate
- Reconditioned later model indexing wheel
- Later model indexing spring.
- Polished neutral detent plunger tip, set spring length to 26mm.
- Meticulously recentered shifter claw (including lateral centering in the slot)

Clutch:
- Replaced sticky organics with Barnett kevlars.
- Still using the experimental plate spreader mod.
- Replaced the 'ultimate' clutch worm gadget with the modified MikesXS worm, using the 1.2" clevis hole.

(I installed thicker palmswell handgrips awhile back, and these reduced the clutch lever pull, producing only 0.040" of pressure plate travel. Now have 0.050" pressure plate travel.)

Other:
- Fresh oil, Valvoline 20w50
- Replaced Neutral switch.

I did the 4lb 1/2 gallon waterjug test on the rear wheel, with trans in 1st. Pulling the shift lever to neutral required about the same medium effort as the 2lb test when all this first started.

I believe that the most significant contributors to this improvement are the shiftdrum stopper plate, Barnett plates, and different oil (?).

I also believe this could be improved further, in the trans.
So, future plans:
- Later model trans.
- Later model shiftdrum, with its "behind the starwheel" roller bearing.
- Couple tricks I have in mind for the shiftforks and guidebar.

TwoManyXS1Bs,

Thank you for your detailed break down.

Can you provide some more input on the feel/ performance of the Barnett kevlars vs the stock discs?

I had looked at upgrading when I rebuilt my clutch, but read on 650 central that they were not recommended for street use.

 

[TwoManyXS1Bs]

Hey, SEd27. Thanx for your interest. Good question on the friction discs.

I'm not racing, just a sedate 'ol rider looking for pleasant clutch and shift operation.

Study this 'friction material' chart for a moment.
(Snippet extracted from: http://www.rbracing-rsr.com/clutchtech.html)

Cork composition plates have a higher 'wet' coefficient of friction compared to kevlars.
Kevlar plates can handle higher heat, which skyrockets during hot launches.
Kevlar plates need more pressure to match the corks.
Kevlar plates can handle much more clamping pressure than corks.
Kevlar plates have a better dimensional stability compared to corks (swelling).
The Barnett kevlars are made to a better premium quality, and cost more.

Well, that's the hard tech.
Next is my personal 'feel' on these Barnett plates.

While riding around on the 'sticky' cork plates, I would occasionally experience clutch jutter, and some subtle differences in clutch 'feel' in cold/hot situations. That's just my fussy 'deft touch' talking. Most may not notice this.

The Kevlars didn't produce any jutter, or different disengagement/engagement feel in both hot and cold conditions. The engagement zone (feathering zone) felt a little narrower, less wandering, to me. Engagement was smooth, clean, solid, no slippage. Higher rate clutch springs not necessary for me, I'm not drag racing...

 

[SEd27]

2M, This is awesome info. I may give these a try next riding season to further improve clutch operation.

(I have already replaced the sacked out original springs with Barnett units and installed the upgraded needle bearing)

 

[TwoManyXS1Bs]

On both of my XS1Bs, I've noticed that the neutral position seems to have a 'mushy' feel. Noticed it even more when doing the shiftdrum torque tests. Scanning for and collecting pictures of shiftdrums on the net, found a significant preponderance of indications of misaligned neutral detents.

Look closely at the neutral detent plunger's score lines on this shiftdrum:

It would appear that the shiftdrum's neutral notch and the plunger are mis-aligned by about a millimeter or two, creating this 'mushy' feel. Another item to investigate during overhaul...

 

[5twins]

Yes, but what could someone do to alleviate this? The neutral notch on the drum already looks to be as far to the left as it can go.

 

[member3480]

Two Many when I build race transmissions I have also seen that on many other trans. (not Centered) I wonder if you can spread that groove all the way across and if that would force it to drop into neutral. I have three trans here two 1977 and one 1981 and going to have to look at all three. Maybe I will cut one I don't care if it gets ruined they are all spares . I know on some of the other older trans. that someone told me they changed the spring to a stiffer one to help drop it in neutral while riding just don't know how that worked out. Need to make a slider clutch up for one of these like I have for the race bike HAHA

 

[TwoManyXS1Bs]

...I have also seen that on many other trans. (not Centered) ...

*whew* Thanx, DaddyG. Sometimes I wonder if I'm just seeing things.

A close-up of the detent marks show two little wear dots, where the plunger tip spends most of its time. The plunger doesn't drop anymore within this 'mush' zone, so the shiftdrum's position isn't fixed. The plunger would also experience side loads while in this zone, possibly interfering with exiting neutral.

... what could someone do to alleviate this?

...I wonder if you can spread that groove all the way across and if that would force it to drop into neutral...

I had thought about grinding the plunger's tip, to a more cone shape, so that the sides of its spherical tip wouldn't contact the side of the detent hole. But decided that's probably not a good idea, as it may make it difficult for the plunger to climb out of that recess.

All I can think of at the moment is to grind the recess. Would need to dress a rotary stone to match the existing recess, mount the shiftdrum on a X-Y table, bombsight align the thing, dial-in the proper offset (whatever that is), then have at it with the sparks we've all come to love. Kinda like this mock-up:

Of course, finish polish out the rough recess with Craytex...

 

[member3480]

You know sometimes if you polish both it may make it easy for it to go in and come out. Sometimes the bare eye cannot see what is hanging up. I have polished dogs after I cut them for smooth movement. Now you got me want to play with one HAHA

 

[TwoManyXS1Bs]

Have at it, DaddyG! Pioneer away on the thing.
For me, this project is buried a ways down on my todo list...

 

[Bob Kelly III]

Wow 2M Great work ! thank you ! bound to come in handy some day ...for sure ! it's alwayse a pleasure to read your investigations into the mechanical ! Keep it up ! I can't wait for the next one ! LOL
WELL DONE !!!!
......
Bob..........

 

[DanielBlack]

Kevlar plates need more pressure to match the corks.
Kevlar plates can handle much more clamping pressure than corks.

Higher rate clutch springs not necessary for me, I'm not drag racing...

It's been about a year, any change in feel?Clarifying, you're still using stock springs?

 

[TwoManyXS1Bs]

Hey, Daniel. Yes, still on stock springs. Feels about the same.
Lot better than it was, but still some more to go...

 

[xjwmx]

I'm not sure, but this might be like trying to fix your piano playing by working on the piano.