Author Topic: 71 Cb350 Twin - Clutch problems  (Read 9736 times)

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Offline kine8282

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71 Cb350 Twin - Clutch problems
« on: August 16, 2009, 05:25:09 PM »
I just got my new bike started!!! thanks for all you help here on the forum, the bike idles nicely between 1000 - 1200. No problems, I put the bike back together but realized that the clutch doesnt disengage. Not sure if the PO had this problem since she wasnt running but i replaced the cable and the cltuch still wont disengage. I have the bike on the center stand and how I tested this is put the bike in gear (it goes in gear without the clutch...it this a problem?) and the rear tire spins but when I pull in the clutch lever the rear tire keeps spinning. I'm pretty sure I put the cable and clutch adjuster correctly but it still doesnt disengage the gears.

From what i noticed that the clutch lever basically moves out when you pull the cable and pushes the cltuch lifter rod right? I tried manually pushing in the clutch lifter rod but it doesnt even budge...is this because its messed up? any advise would help.

I changed the oil on this and the oil that came out looked OK, i'm sure it was old but I got out a little less than 2 qt so the motor didnt dry up and according the odometer it only has 13K miles. not sure that helps
1975 CB550K aka "Nefertiti"
1978 CB750K aka "Kate"

Offline Tnutz

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Re: 71 Cb350 Twin - Clutch problems
« Reply #1 on: August 16, 2009, 06:11:40 PM »
i am having the same prob with my cb500/4.  Sometimes with time and sitting to long they will stick together.
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Offline kine8282

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Re: 71 Cb350 Twin - Clutch problems
« Reply #2 on: August 16, 2009, 06:35:17 PM »
How are u goimg to fix or have fixed your clutch problem?
1975 CB550K aka "Nefertiti"
1978 CB750K aka "Kate"

Offline Bill/BentON Racing

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Re: 71 Cb350 Twin - Clutch problems
« Reply #3 on: August 16, 2009, 08:56:05 PM »
Both models use a #8 bearing inside adjuster,rides against pushrod,make sure it didn't fall out.Bill (# might be wrong)
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Offline kine8282

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Re: 71 Cb350 Twin - Clutch problems
« Reply #4 on: August 17, 2009, 07:32:55 AM »
the bearing is still there.

set it up again yesterday and made sure that the left cover was screwed on tight. turned the clutch adjuster screw until it made contact with the rod and felt some resistance screwed ehte lock nut, i can hold the clutch lever all the way down so i guess that since the clutch lever moves out, this means that the lifter rod is getting depressed right? i mean i can't depressed the rod manually but its because its not enough pressure to push this with my arm?

the clutch still wont disengage...any other ideas?
 
1975 CB550K aka "Nefertiti"
1978 CB750K aka "Kate"

Offline ohiocaferacer

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Re: 71 Cb350 Twin - Clutch problems
« Reply #5 on: August 17, 2009, 07:57:11 AM »
You cant depress that clutch rod with just your hands.....to much pressure with those clutch springs on the basket.

Also.......your rear will always turn and rotate with the clutch in and the bike up on the center stand.

To test if its engaging properly....have the bike on the ground running....pull clutch in.....shift into gear....slowly let the clutch out and bike should start to move with lever travel out about halft way thru.

Hope this helps,
Greg

Offline kine8282

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Re: 71 Cb350 Twin - Clutch problems
« Reply #6 on: August 17, 2009, 11:18:05 AM »
greg, thanks for chiming in. I'm stuck at work at the moment so can't try that but will try later. I've switched the cables on my 550 as well as my 750 and every time I've tested the clutch they were both on the center stand and although the rear spins while on the center stand i would hear or feel a difference while I pulled in the clutch and released it. The feeling was like the gear was engaged and i dont have that same feeling with the 350, are the clutches different?

Couldn't I test the clutch while its on the center stand by using the throttle? ie put the bike in gear, pull in the clutch and then twist the throttle and if the rear wheel moves with the twist that means that my clutch isnt disengaging right? I'm a little hesitant to try this on flat ground because if the clutch is screwed and i pop it in gear - I'll have a run away bike and will have more problems.

From what I have written does this sound like a cltuch problem or just an adjustement problem? I really hope its the latter
1975 CB550K aka "Nefertiti"
1978 CB750K aka "Kate"

Offline kirkn

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Re: 71 Cb350 Twin - Clutch problems
« Reply #7 on: August 17, 2009, 11:22:23 AM »

Also.......your rear will always turn and rotate with the clutch in and the bike up on the center stand.

To test if its engaging properly....have the bike on the ground running....pull clutch in.....shift into gear....slowly let the clutch out and bike should start to move with lever travel out about halft way thru.


+1 on all of that.  

You can't press the rod in by your fingers.  Clutch springs are WAY too stiff.

The wheel will always spin with the bike on the centerstand.  Or, at least, all of my bikes will unless you hold the rear brake on.

So, if the clutch still won't disengage, and you've fiddled with the cable/adjusters/etc., my favorite technique to free sticky clutch plates is to start the bike, pull in the clutch lever and, holding it pulled in, duck-paddle the bike forward a bit and stomp it into first gear.  Ride around the yard / drive / neighborhood streets for a few minutes, getting on and off the throttle all the while holding the clutch lever in.  After a very few minutes of this, the clutch will unstick and function normally.  I've done this any number of times on resurrection projects and never failed, and never damaged anything.

It reads more difficult than it is.  You won't have a runaway bike because you can always hit the kill switch and chug to a stop.  And, of course, don't do this while aiming at a telephone pole, or onto a busy 4-lane street during rush hour or anything...   ;D

Good luck with it,

Kirk

Offline kine8282

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Re: 71 Cb350 Twin - Clutch problems
« Reply #8 on: August 17, 2009, 12:52:10 PM »
thanks...i'll have to try those tricks when I get off work, i hate having this addiction to these bikes and not being able to get my fix! I've also read that if the kick start works while I pull in the clutch then that means that the plates are stuck, can someone verify this?
1975 CB550K aka "Nefertiti"
1978 CB750K aka "Kate"

Offline Green550F

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Re: 71 Cb350 Twin - Clutch problems
« Reply #9 on: August 17, 2009, 08:34:37 PM »
Note that the cable pulls on a cam that has an adjuster. The adjustment seems backwards at first. If you turned the screw in to take up the gap between the pushrod and cam, you accidently went the wrong way and increased the gap to the point where the cam won't push on the rod.

The screw is captive between the case and the cam. So as you "back out" the screw, the cam rides forward and closes the gap to the rod. A little odd at first, but it works!
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Offline lordmoonpie

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Re: 71 Cb350 Twin - Clutch problems
« Reply #10 on: August 19, 2009, 04:44:18 AM »
if the bke has been stood for a whiel the oil on the clutch plates gets sticky and stops them disengaging even with a correctly adjusted clutch. You can sometimes spin these free by runnign with the bike in top gear, dumping the clutch and keep running. I free mine up on the powered starter but in extreme cases (my old wet sumping XBR for example) I'd often take the plates out and clean with brake cleaner prior to starting.

One thing also worth noting in the CB350 clutch push rod is a composite item - the tip and shaft are made of different materials and expand at different rates. A correctly adjust clutch at cold can lead to clutch drag in a hot engine. There's a modification doem here in the UK by the likes of Les Bibby to replace the tip with a different metal of more equivalent thermal expansion rates to the shaft to resolve this.

I once had a "fun" time being held on the start line at Darley on a red flag restart on my K4 with the clutch dragging like a beggar. Two of us K4s stalled finally as the clutch drag overcame the stall point just as the restart flag went down! Half a lap down before I even moved LOL!
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