Sticky clutch (motorcycle)

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74Dusted

74Dusted

Stock Piler of 340's
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Ok it's not a mopar, but it saves me money, so I can put more in the tank of my duster :D

1978 Yamaha DT175E 2-Stroke (DT125 with an MX175 top end).

It sat for a long time, when I stopped riding it. Prior to that, it had little use (only driven in 1978, by the original owner, about 200 miles on the bike as of now)

I cleaned it up last year, put new brakes on it, new seals, repainted the body & frame, tuned it up (new wire, points, plug, etc). All to prepare it to ride on the street. Fired it up and the clutch doesn't disengage (worked when it had been parked several years before)

So I Cleaned & Flushed the Crankcase & Transmission out, filled it with fresh oil and tried to ride it again. Clutch still doesn't disengage and that's when I gave the bike the middle finger and walked away (several months ago)

Any ideas? I didn't find any water or anything in the crankcase, the clutch worked when the bike was parked the first time. Any of you older guys have some suggestions?
 
Mine's doing the exact opposite, the clutch is engaged all the time (grabbing) I have to start it in gear and hang on :burnout:

My grandfather told me it was from sitting too long, but didn't have any ideas how to free it up again.
 
There was little moisture in the trans oil but the plates have rusted where the air was humid above the oil. The steel plates have bonded to the fiber plates.

2 options.

Start it, block it nose first against something solid like a tree or public library, strap the front wheel down if possible. Pull clutch lever, rev piss out of it, jam in to gear. This MAY break the plates loose. If so, ride it a bit, and you're golden.

Or

Remove kickstarter, pull clutch cover, remove (using one turn per screw at a time) the 5 or 6 bolts with clutch springs under 'em.
Pry the plates apart gently. If fiber sticks to the steels, replace 'em all (Prolly $60). If they pop apart clean, jam it back together, torque the screws IN STEPS to spec GENTLYYYY (The little aluminum studs that they thread into like to break off) with a QUALITY torque wrench (not Harbor Fright).
Replace gasket, re-install cover, replace lost oil and ride the piss out of it.
 
jos51700 said:
There was little moisture in the trans oil but the plates have rusted where the air was humid above the oil. The steel plates have bonded to the fiber plates.

2 options.

Start it, block it nose first against something solid like a tree or public library, strap the front wheel down if possible. Pull clutch lever, rev piss out of it, jam in to gear. This MAY break the plates loose. If so, ride it a bit, and you're golden.

Or

Remove kickstarter, pull clutch cover, remove (using one turn per screw at a time) the 5 or 6 bolts with clutch springs under 'em.
Pry the plates apart gently. If fiber sticks to the steels, replace 'em all (Prolly $60). If they pop apart clean, jam it back together, torque the screws IN STEPS to spec GENTLYYYY (The little aluminum studs that they thread into like to break off) with a QUALITY torque wrench (not Harbor Fright).
Replace gasket, re-install cover, replace lost oil and ride the piss out of it.
Click to expand...

I'll probably pop the side cover off and see what's going on.

As much as I'd love to try "Option 1", I'm reminded of my childhood, when me and some friends thought it'd be a cool idea to use my ATV to "mow over" some small trees so we could build a fort/clubhouse... Parked my ATV up a tree :D
 
Don't be surprised if you don't find pins holding the clutch springs in place. Pretty sure my old dirt bike had pins in place of bolts....
 
When you have it apart check the free length of springs, after sitting so long they might be too short to keep clutch from slipping.
 
Well I pulled the side cover off. 2 things

The oil pump/mixer pump (for the 2-stroke mixing) area was filled with water? WTF? The 2-stroke mixer tank was full of uncontaminated oil, the lines & pump were full of oil, but water made it inside the case somehow (which is sealed separately from the main case, no water in the actual engine)

I haven't figured out how that one happened, but I'm going to use some RTV during the reassembly just incase.

second thing. The Drum, Clutches & Steels look brand new, no rust or noticeable wear. But the whole clutch assembly was filled with crud/gummy goo that must have lingered when I flushed the crankcase (it's what you'd expect 30+ year old oil to turn into)

So I'm cleaning everything up real good, otherwise the engine looks Brand New inside (to be expected, the bike has 200 miles on it)

edit : Oh man it's awesome, I got er back together and the clutch works, she shifts like a dream again! Come on summer, hurry the "f" up so I can ride!
 
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