CB175 Clutch Issues

L

leadscentral

New Member
Hey guys,

I am finally finishing my rebuild of a 1970 K4 CB175 but I am having issues with the clutch. Have read through as much as I can on here but cant seem to fix the problem.

I split the cases to replace the kick start shaft. this was successful and the engine has been put back into the frame. The bike can now be started both by kick start and electric start when I can eventually get it into neutral.

The problem is I cannot seem to change gears and get the clutch working properly. I have had the chain off and when the bike was in 'neutral' the neutral light was on but the front sprocket would turn when the engine was running
I couldn't get into first gear but when I went to second the sprocket would stop. Its almost like the clutch is always engaged.

Today I put the chain on and was unable to roll the bike even with the clutch lever pulled in nor change any gears.

If I try kick start or electric start now the bike will try to pull forward

I have tried all of the clutch adjustment procedures on this forum. It either wont even let me roll the bike at all and I have had to drag it back into the garage or when I had the clutch cable as tight as it would go the bike would roll but not very smoothly

I thought it was the bearing in the clutch adjuster so I pulled the left cover to check, to me it looks like its in there, I was unable to get it to move to come out please tell me what you guys think as I'm not sure if that's part of the worm gear or the bearing (images below)

I don't think the clutch plates are stuck as I have been able to kick start the bike OK.

Not sure if I now need to pull the right cover and do some work on the shifter and clutch, have included some photos of them before the covers were put back on.

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4.JPG
 
You probably assembled the clutch wrong somewhere, you had to remove it when you split case so plates shouldn't be sticking.
It's most likely the inner hub binding beacuse you fitted thrust washers in the wrong order, center should spin pretty free with the plates removed
You may get output shaft spinning due to oil drag, it's fine when everything is assembled correctly
 
Hey mate thanks for the response.

Just did some cleaning and digging around and can confirm that the ball WAS in there on the adjuster, not sure what to do next.

What are the thrust washers? Will start pulling the right cover now...
 
Exactly what they sound like.
Should be one up against the bearing, spacer for clutch basket, then another before the clutch hub
Haven't had a 175 since 1977 though so working from memory
 
OK so I pulled the right cover, oil filter, pump and clutch. Clutch was assembled correctly.

Whats not making sense is I cannot turn the gear change rotor at all. The shifter mechanism appears to be installed correctly and even after removing the detent wheel and putting the gear shift lever on the other side it will not budge.

The corresponding side is the neutral switch rotor.

de.JPG
 
Does the shift drum try to turn when you operate gear lever?
Either the gear dogs are butted against each other or a selector isn't located properly
Bearing locators are properly set?
There is a pin on the small bearings and half ring on the large ones
Just took a better look at pics, the locator roller is in the wrong place, it should be on the outside, on the 'star', earlier pic shows correct place
Is the oilway blocked on oil pump mount?
 
Does the shift drum try to turn when you operate gear lever? No it doesnt
Either the gear dogs are butted against each other or a selector isn't located properly
Bearing locators are properly set? As far as I can see yes
There is a pin on the small bearings and half ring on the large ones
Just took a better look at pics, the locator roller is in the wrong place, it should be on the outside, on the 'star', earlier pic shows correct place - the locator roller is completely removed on the latest image
Is the oilway blocked on oil pump mount? - No all looks good


Thanks again for your help
 
Is it possible the stopper is causing the problem here? The gear shift linkage will not turn the shift drum at all no matter what i try...

Part 8 I have taken off but part 7 is still there, I am wondering if part 7 is making it stick somehow or is in the wrong place. I don't recall removing it when i split the cases but something may have moved when I put the linkage back on..

1d.jpg


1c.jpg


1a.jpg


1b.jpg


Can anyone see if something is in the wrong place here?

If its not these parts all I can think is that something was moved in the tranny when I put the new kick start spindle in and i will have to split the cases again however I have been able to kick start the bike successfully and have the motor running and change 1 or 2 gears yesterday although it was very difficult and it all feels jammed.
 
Does the pivot bush (#12) have a spigot on both ends?
The small roller holds neutral position, the large roller holds gear, both have to be free to rotate on bushing/spacer.
Unfortunately it's about 37 yrs since I last had one apart.
Try sending 'Teazer' a PM and ask him to take a look at your pics, he's raced 160~200 and probably can tell you any issues with assembly
 
Yep the pivot bush does have a spigot on both ends, made sure the neutral stopper was surrounding it correctly. Will try and get onto Teazer thanks a lot
 
Ben, The detent rollers look right. The inner connects to the Neutral detent and the outer one works on the "star" to position teh cam at teh correct points.

Let's deal with shifting issue first and the clutch later. Can you rotate the input shaft (the one the clutch sits on) and the output shaft that the sprocket is on? They should both rotate reasonably easily. If it's in gear, both will rotate.

Next, try to shift while you rotate the input shaft. What happens inside the box is that one gear moves along a shaft and the dogs on the gear engage with dogs on the matching one on the same shaft. When the engine is running that's easy but with the motor stopped, the dogs are often facing each other and it's impossible to shift until the shafts are rotated a few times.

So please rotate a shaft and see if you can change gears.

If the shafts do not rotate or the gears will not engage, something is wrong and we'll tackle that next
 
Hey thanks for helping me out!

Can you rotate the input shaft (the one the clutch sits on) and the output shaft that the sprocket is on? Yep both rotate fine and smoothly

I cannot shift whilst rotating the input shaft at all. I wasn't sure if the neutral detent was stopping this from happening or its something else
 
Next step: Does the shift lever move up and down slightly or is it stuck tight and not moving? If it is really tight, remove that shaft and lever and see what's binding first. As the foot lever moves up and down, the claw tooth selector should move left and right and should try to rotate the shift cam.
 
The neutral detent appears not to be sitting down in the scallop and that suggests that maybe the shift cam is sticking for some reason.

Can that detent roller and lever be moved downwards slightly with a screwdriver? It almost looks as if it's binding on the cam.
 
If that detent roller is free to move and not locking the shift drum, the next place to look is the neutral switch on the other end of that cam shaft. Undo the small mounting screw and see if that let's it shift.
 
The shift lever moves up and down and isnt binding the selector tries to rotate the shift cam, catches in the right spot but the shift cam will not budge one bit.

I have pushed the neutral detent down and out of the way but was still unable to move the shift

The neutral switch has also been removed and no luck...will try again
 
This is all good. It eliminates a whole bunch of variables. You could try to remove the retaining plate - that's the half moon plate with 2 countersunk screws and see if that frees things up. That might be revealing.

If not, something was misplaced or bent when it was assembled, and if that's the case, the motor will have to come out again. Drag it out and slap it on its back on the bench and remove the bottom crankcase half to see the shafts and selectors.
 
Would it be worth trying to remove the neutral detent altogether to see if that frees it up? Just wasn't sure how to get that spring out
 
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