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clutch engages very early

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chris wilson
(@wursthead)
Posts: 32
Eminent Member
Topic starter
 

I have a 78RS100R I finally got going thanks to the help of you guys out there!
one question..the clutch engages right away upon release. Is that an adjustment or maybe a deeper issue?

 
Posted : 12/06/2019 20:04
James Strickland
(@8053)
Posts: 423
Reputable Member
 

If it were a bike that was new to me, I would play with the adjustment of the clutch arm on the back of the transmission, and/or the cable at the handlebar end. If the clutch starts to engage with very little release motion at the hand lever, it would follow that there would be considerable free-play at the lever when fully released.

former Airmarshal, IL.

 
Posted : 12/07/2019 09:52
chris wilson
(@wursthead)
Posts: 32
Eminent Member
Topic starter
 

thanks James. Just to be clear because im not the best mechanic around or at all but pretty handy with taking direction..are you saying start with the arm on the back of tranny and the lever at the same time to get it right? is there a process in order to get it right?
I appreciate your time

 
Posted : 12/07/2019 14:47
James Strickland
(@8053)
Posts: 423
Reputable Member
 

To make a judgement about the clutch free-play, You start at the handle bar end. How far can you pull the clutch lever before you feel the tension increase when the clutch is about to be dis-engaged? If the lever gets half way to the hand grip before the tension takes up, there is too much slack in the assembly. Now then, on the lower right side of the transmission you can see where the clutch cable engages the little swing arm on the throw out mechanism. There should be a coil type spring pushing the arm away from the back cover of the transmission. Another way to assess the free-play would be to take your finger and press on the bare cable until you can feel the clutch pushrod start to push against the spring diaphragm inside the clutch assembly. The distance from the cable boss to the cable rest of the throw out arm is supposed to be 201mm. You can cut a coat hanger wire to make a 201mm gauge. Try to adjust the the handle bar end adjuster until the 201mm distance is established. The final adjustment of free-play is achieved with the lock nut adjuster higher up on the clutch release arm close to where the clutch arm pivot pin is fitted. You may not have to make an adjustment there after the 201mm is established. ( The 201 span is considered to be ideal to achieve the mechanical advantage of leverage within the limits of the throw out mechanism. I'd be surprised if the span was precisely 201mm on my bike.) What we are trying to achieve here is the tiniest bit of slack in the mechanism so as to achieve the greatest amount of push in the clutch assembly for the highest degree of dis-engagement between the clutch assembly and the friction disc that transfers motor torque to the transmission input shaft. The free play at the hand lever should be minimal. If the free play is too loose, you would not be getting the maximum dis-engagement when you pull the clutch lever. There is a small window of adjustment where you have your free-play and full disengagement. It is inside that range where you can try to position the clutch take-up where you want it. This range of adjustment is very small.

Actually, you can get the desired free-play using the handlebar end adjuster as long as you don't run out of threads on the adjuster. It's a sort of a "feel" thing.

If there is no slack or free-play, that means that the release mechanism is always pressing on the clutch assembly. This is bad. In a car or truck it would be called riding the clutch if you rest your foot on the clutch pedal and eliminate the free-play. This promotes excessive wear of the friction disc.

Be aware that I am completely self-trained and not a professional airhead mechanic. You might get somewhat different advice from more experienced pros.

If you want to speak with me directly, my cell phone number is 309-251-0877.

former Airmarshal, IL.

 
Posted : 12/07/2019 16:30
Richard W
(@wobbly)
Posts: 2591
Member
 

If there is no slack or free-play, that means that the release mechanism is always pressing on the clutch assembly. This is bad. In a car or truck it would be called riding the clutch if you rest your foot on the clutch pedal and eliminate the free-play. This promotes excessive wear of the friction disc.

You'll need "free play" in both the clutch cable AND the arm when the lever is fully released.

Typically, unless you have short fingers or weak hands, you want the clutch to engage as the lever is almost all the way out. This means the clutch is getting maximum dis-engagement when the clutch lever is pulled in. Failure to fully dis-engage will make the bike want to creep, which may end up walking you into a busy intersection. And we don't want that.

► Tip: For smoother clutch operation do this: 1) Hit the grease nipple on the throw-out arm with a grease gun. 2) Hit the "barrel" where the clutch cable goes into the lever AND the clutch lever pivot bolt with Motul Chain Lube. Click Here

Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.

 
Posted : 12/07/2019 17:00
chris wilson
(@wursthead)
Posts: 32
Eminent Member
Topic starter
 

thank you so much! this helps a lot!

 
Posted : 12/10/2019 15:37
chris wilson
(@wursthead)
Posts: 32
Eminent Member
Topic starter
 

this helps. thanks for your time and knowledge!

 
Posted : 12/10/2019 15:40

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