Clutch woes: Can't find neutral at a stop.

[LeeH]

Hey all,

Looking for some help here. When I purchased the bike 2 years ago I was never able to shift into neutral while stopped with the engine running.  

I gather from reading on the Folwick site this was an issue even when the bike was new, and know it's a problem shared by the 650s

Last summer, I installed an NOS clutch cable, made sure it was well lubed, adjusted it per the instructions in the repair manual, and VOILA! there's my missing neutral. 

The bike was winterized and mostly sat (started occasionally), until the weather got better.  

This summer, when I started to get the bike ready to ride again, I noticed that the clutch had gone out of adjustment so that the bike would die when shifted into gear.

I've managed to adjust it so that that issue is taken care of, but neutral is gone again.

I've spent the last two days trying to find the sweet spot again in the adjustment screw, to no avail.
Cable is well lubed and clean.

Anybody have anything i could be missing? Possible fixes I'm not thinking of? Just live with it?

Thanks in advance,
Lee

[bruno]

You'll excuse me for my bad English.
I bought a TX this year .... not working, leaking oil on all sides and had the bearing of a connecting rod seized.
So I rebuilt the engine myself, changed all the bearings. gaskets, all chains etc ... nothing complicated with the manual ....

The bike works well, I'm doing the running. Only problem .... the clutch. When coupling the first gear is a step forward, from cold you can put in neutral.... to warm no way.... I need to turn off the bike.
I'm working on ... I noticed that there are two types of rod. An old model in one piece and at the end a ball. A newer model with two shorter rods and two balls.
When I have time I will change these ... to see the result.

We will inform you later

[LeeH]

Thanks for your reply.
I've seen the 2 rod vs 1 rod swap discussed on the 650 forums.
Let me know how it goes!

[albaljeu]

All these TX's have that problem. The best way to overcome that problem is to just shift into neutral before coming to a complete stop. If that is not a solution for you, another way is to find a clutch lever that has a longer throw..... the distance from the lever's pivot point center to the cable end center.

[bruno]

Unfortunately I do not know if I can put photos here; apparently it is not possible ... or yes? Maybe.
I changed the clutch plates (with others, not new) and the rod with the ball (now 2 balls).
When the bike is cold it is perfect, when it is warm is a bit 'harder and harder to put on the neutral.

I think that there must be a solution, I want to find the solution.

I'm going to order a new clutch and I want to speak with a specialist oil Motorex.
My opinion, discs do not come off properly.

It will take a bit 'of time, perhaps a month. I will keep you informed.
Nice day
 This is the plates mounted before ....

This is the clutch plates other  mounted after


op the early rod, low new mounted

[pewe]

As albaljeu wrote, its typical for the TX 750. One of the problems is the material of the original Yamaha-plates. If they get in contact with modern oils they can swell when the oil gets hot. The XS 650 has similar problems. A guy in Germany solved the problem with aftermarket-plates.

Greetings
Peter

[vanislejay]

I don't have any problems with my clutch dragging, but finding neutral could be a pain in the ass I guess. I have ridden so many old bikes over the years that I never felt it was a real problem because all bikes have their quirks. If you stop before putting it in neutral, I find it's easiest to shift into second and then feather it down into neutral. I can get it like 90% of the time. I just noticed I do this last night on my ride home, I was paying extra attention because of this thread. Normally it's just muscle memory and I do it without thinking.

[bruno]

Yes, I also agree in saying that it is a question of material of the plates of the clutch.
By cold working, heat does not work. Therefore a matter of heating; and expansion of the materials and consequently the loss of quality.
Due to the quality of the oil is possible, in forty years, much has changed.
Replace the clutch plates with other aftermarket and I will give you news in 15 or 20 days.

Nice day

[pewe]

As you can see here and in the pdf-file the early TX 750 clutch had rubber made springs between the plates for better separation (part No. 11).





70-73_clutch.pdf (96.87 KB)

Peter

[bigskyforever]

Seems like everyone has an idea on the neutral issue. Some guys have put an additional washer on the tension spring to assist with more friction on the shift drum. I have a couple of engines torn down and when shifting it manually with the top casing removed it is easy to see that the outer shift lever with the larger roller plays little or no part in slowing down the shift drum as it passes by the neutral position. Also the neutral switch with it's angle position puts little tension on the sweet spot as the shift drum rolls by.

Now that you have good oil,modern discs and the problem is still there. I am contemplating to do three small mods which may or  maynot work. 
1. I will drill the shift drum slightly where the tension spring with the metal pin is supposed to contact the drum.

2. I will use a die grinder on the outer drum where the shift lever outer roller sits when in the neutral position which should increase additional tension to the shift drum  as it rolls by.
3. I will grind the outer neutral switch housing, slightly which should allow the contact switch to push against the side of the shift roller a little more and give additional friction in assisting the drum to slow down as it goes by neutral.

I do have donor parts so I think it is worth a try. I am quite certain that the focus on the clutch disc and oil can be an issue, but I have worked on other Japanese bikes with similar systems which do not have this problem. I did see the problem first hand with one of my TX750's prior to tear down and I do believe that this is a mechanical issue not a clutch issue.

Feel free to give me your feedback especially if you have tried a similar modification. 

Thanks

[bigskyforever]

Just another observation on the clutch issue. The metal spacer discs that are placed between the fiber discs are manufactured by metal stamping. If you pay attention you will find that you can feel the difference from one side to another. Take time to place them all in the same direction as you place them between the fiber discs. This will allow for a greater gap between the discs when you pull the clutch and reduce the drag.

[bigskyforever]

Hello again, just a brief update on the clutch mods. I completed. With new style clutch discs(aftermarket) I now can find neutral when I am stopped. The new style discs can take the heat and do not have the drag issue , which confirms that this is a mechanical issue not a clutch system issue.

[norwegian]

If you have a problem to get gearbox into neutral when engine is running and it goes easly to neutral when engine is not running, the problem is proberly the clutch basket. One or two out of Three clinker are broken and two demper springs are broken. See pictures

[bigskyforever]

For sure with the basket in this type of condition you would have issues, but I believe that the problem encountered is two fold. Expansion of the metal and fiber discs which can be an issue especially with old fiber discs and the detent spring seat. If you ever have the cases split on this engine you can remove the third fork cotter pin and slide the fork to the side and access the detent seat. Put a small amount of grease on the end of a drill bit and drill the seat another mm. or two. This will slow the drum when it is shifted up or down on the way by. This same style of drum was used by more than one motorcycle manufacturer in this era. If you have a look at a CB750 they used a similar drum, they used a large switch with a large spring loaded ball bearing to slow the shifting drum on the way by. It is obvious that the small spring and detent system used on the TX does not create enough drag on the way by. I have done this modification on a 73 TX and it has certainly made it easier to find even when the engine is very warm.

I have added some pics showing a similar shift drum and a CB 750 neutral switch of the 70's era  and the TX 750 light spring and small pin style detent. Pretty obvious which switch or detent will slow the drum on the way by.

Attachments:

[albaljeu]

bigsky , which clutch plates did you buy ?