News:

This forum is run by RPM and donations from members.

It is the donations of the members that help offset the operating cost of the forum. The secondary benefit of being a contributing member is the ability to save big during RPM Holiday sales. For more information please check out this link: Membership has its privileges 

Thank you for your support of the all mighty FJ.

Main Menu

Clutch - how hard or smooth should the gearshift be?

Started by bwanapete, August 30, 2015, 02:12:33 PM

Previous topic - Next topic

Shane4371

Maybe we could brain storm and develop a clutch brake for our transmissions, I wrench on semis and when the clutch brake goes south.it causes engagement issues..I've been watching this post daily,I had the same issue but mine was cured with maintance, I hope you find the cure,please post how you resolve the issue.

JCainFJ

 I cured my FJ and my other Yamahas first gear clunk by installing the Factory Pro roller bearing shifter detent arm and spring, adjusting the chain to spec, and replacing the cush hub damper blocks in the rear wheel. Cynthia's TDM needed the APE heavy duty clutch hub springs too. My YZF600 is hard on clutch hubs and I am now about to install another hub along with a 3rd set of rear wheel damper blocks.
I want to try one of the APE Trac King clutch baskets the next time the FJ clutch needs service.

Pat Conlon

That's interesting Jon. Do you suspect wear on the FJ clutch basket is adding to the clunk?
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

JCainFJ

 Pat, Yes the springs on the back side of the clutch basket loose tension. The APE clutch hub springs that they sell for the FZR1000 are the ones I've used in the past. Cynthia's TDM hub was very bad,when I took it off of the engine I could twist it back and forth and it would rattle.
Also, when the rubber damper blocks in the rear wheel shrink and get hard with age, that lets the shift into 1st sound bad. The TDM is on its third set and the YZF needs new ones too.

ribbert

Quote from: JCainFJ on January 12, 2016, 12:39:35 PM
I cured my FJ and my other Yamahas first gear clunk by installing the Factory Pro roller bearing shifter detent arm and spring, adjusting the chain to spec, and replacing the cush hub damper blocks in the rear wheel.

Replacing cush drive blocks and tightening the chain are only minimising the effect and not fixing the cause.
The clunk is caused by the clutch dragging the gearbox around, even when it's disengaged.
It acts like a fluid coupler with the oil between the plates providing enough drag to keep the gearbox spinning while it has no load on it (in neutral)

As observed by many here, the behaviour changes from when the engine is cold to when it is hot, as the oil viscosity changes.

I can't see the connection between this and the shifter kit.


Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Pat Conlon

I agree Noel.

Driveline snatch is a different issue.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

JCainFJ

True that, all a person can do is try to minimise the clunk. I'm just stating what has worked for me.
The shifter kit makes every shift quicker and more positive, even the shift into first from neutral.

Earl Svorks

 Shane , ,,Your idea about rigging up a clutch brake has been rattling around my head for some time now. It would be the cure for the symptom regardless of what oil ,or clutch plate make. It would also be extremely  difficult to engineer. If I were to attempt this , the first detail in design might be to arrange that the brake be triggered by the neutral light switch. The device might be installed into the outer clutch cover.  It could make contact with the clutch pressure plate when the clutch was dis engaged, but only when the neutral switch is closed.   Before we get too excited, we're gonna' need to have someone tell us just exactly what is the function of this  plate on the inside of the clutch cover. WTF does it do?
  Also, Noel I agree  with you concerning the roller bearing detent not being involved in this issue. I modified my  detent arm with a generic open ball bearing whose OD matched the OEM roller. I have also found as many as 3 different springs of differing rates for this application.
  Simon

Pat Conlon

The key is in the name of the part. It's called a breather plate, per the parts listing.
I suspect it's function is to separate the blow by gasses from the oil, preventing oil from puking out the crankcase breather tube.

Just a hunch.

Randy will chime in.
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Shane4371

Quote from: Earl Svorks on January 13, 2016, 04:01:54 PM
Shane , ,,Your idea about rigging up a clutch brake has been rattling around my head for some time now. It would be the cure for the symptom regardless of what oil ,or clutch plate make. It would also be extremely  difficult to engineer. If I were to attempt this , the first detail in design might be to arrange that the brake be triggered by the neutral light switch. The device might be installed into the outer clutch cover.  It could make contact with the clutch pressure plate when the clutch was dis engaged, but only when the neutral switch is closed.   Before we get too excited, we're gonna' need to have someone tell us just exactly what is the function of this  plate on the inside of the clutch cover. WTF does it do?
  Also, Noel I agree  with you concerning the roller bearing detent not being involved in this issue. I modified my  detent arm with a generic open ball bearing whose OD matched the OEM roller. I have also found as many as 3 different springs of differing rates for this application.
  Simon

Shane4371

Its almost 5xs a week I get a driver complaining,ita hard to go in gear or the truck jps when I put it in gear.9 xs outta 10 somethings.outta adjustment, anyway,in relation to our clutchs,pulling the clutch lever disengages the clutch.we know this,so with the clutch lever pulled completely down how far should the clutchs move in relation to a clutch lever being fully pulled in.thier has to be a measurement thats within specs and outta specs.i hope you see were im going with this

Earl Svorks

  Thanks for that Pat. I also found info that backs this up in a drawing related to someone's carb issues elsewhere in the forum today.
  Shane,,it would be simple to measure clutch pressure plate travel with a dial gauge. Of course the outer cover would have to be off to accomplish this. Perhaps we can ask of anyone who reads this who has or plans to have their clutch exposed that they might take the time to measure their own clutch in this way. I am certain no specification exists in the available literature. We could compile our own database on the subject. This would certainly be interesting, at least. Perhaps helpful to others with clutch issues.
   Simon

ribbert

Quote from: Earl Svorks on January 13, 2016, 04:01:54 PM
.......rigging up a clutch brake has been rattling around my head for some time now. It would be the cure for the symptom regardless of what oil ,or clutch plate make. It would also be extremely  difficult to engineer. .........
  Simon

Simon, as the drag appears marginal, have you considered altering the fulcrum on the M/C to give you a bit more throw, or a different M/C, or a stepped slave cylinder, separating the plates a bit more, I don't reckon it needs much. If it throws the spring over centre you could try it with a modified coil spring unit such as the Barnett and pack the clutch cover out accordingly, probably only 5mm or so.

It would be a lot less engineering than a clutch brake if it worked.

Then there's the power assisted clutch I started making a couple of years back for an arthritic rider but he stopped riding before I got too far down the track with it. This could also tie in with a modified clutch as you would not want to lose any of the clamping force and presumably it would end up being heavier on the pull.

Interesting subject, I love these sort of projects but in this case, in theory only, I only go from neutral to first once a day.

Keep posting your thoughts.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Earl Svorks

 Hey Noel,
I have gone to some length to see that I am obtaining maximum piston travel at both ends of the clutch system. I do ,however think that I can get a bit more out of it with a simple modification that will be easy to execute. It involves a short, half round, or semi
circular shim whose inside radius matches the handlebar outside diameter. This shim would fit between the handlebar and clutch master cyl  outboard of the bolt holes to tilt the cyl,and it's lever  a little bit away from the handlebar. A 2 degree angle from the bar (this angle could be increased easily) will produce a few millimeters increase in the distance between bar and lever end.  The cap on the back of the mc could be shimmed at it's inboard edge if the ensuing misalignment was an issue. This should provide an increase in fluid displacement sufficient to increase pressure plate outward movement enough to make some difference. If this has the desired effect on clutch drag , then I will do something  permanent. If there's no improvement, it's simple to put things back as they were. No harm done.  I hope to eliminate , or better yet, confirm  this as  the  cause of that persistent clutch drag
     Simon

ribbert

Quote from: Earl Svorks on January 15, 2016, 12:28:17 AM
.....This should provide an increase in fluid displacement sufficient to increase pressure plate outward movement enough to make some difference....
     Simon


Simon, this had crossed my mind but I wondered about the limitations of piston travel inside the M/C and the clutch spring going over centre?  Anyway, easy enough to give it a try.

For the purpose of the exercise, you could just hold something between the nub on the lever and end of the m/c piston while you pull the lever in and select first.

Doing it this way you could just keep increasing the thickness of the shim until there is no more piston travel, or it works or there's a sudden funny noise from the clutch and it never works again. :biggrin:

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"