Hi Fellas, i have a DT 175 model A 1974 that i am trying to restore . i have put a replacement clutch cable on today but it appears to be to long as it just takes up the slack in the actuator arm not actually moving the plates .am i missing something obvious or have i been sent the wrong cable ?

There's an adjustment that raises or lowers the arm & raising it makes the lifting part get closer to the pushrod so effectively making it start from further back which takes up cable slack. That's in a perfect world so i'm only guessing at the moment.
How does it compare with your previous cable for free inner cable.
Just a note--with the adjuster you can just see the off center peg on it in the drawing & you only get half a turn of adjustment to fully raise or lower the arm. Bit hard to explain but from bottom to top--is half a turn--then back down the same way if you need to & if you go over the top & keep going clockwise to bring it down you'll run out of travel as the off center pin will bottom out in the groove.
Maybe someone else can explain better.  

thanks for your reply. yes i can see the adjustment mechanism and it looks ok. the range on that is fairly slight .there was no clutch cable on it when i bought it so i dont have any reference . just to clarify on this engine there is no ball between the rod and the plunger as on the ct3 etc ?

I can only go by the parts pic but for that to work [no ball] the pushrod would need to be round ended--which it appears to be in the drawing. It must be round ended anyway to work the lifting end so 'yes' rounded both ends is my thought.
I guess you're asking that in relation to getting the arm to move further back & take up free cable?.
There will be a casting mark somewhere for the arm to be about 'there' for the best angle of lift so wouldn't want to end up too far away from that mark. Too far before the mark.

with the new cable i have 110 mm of overhang on the inner cable ??

Mine is a 1975 175B but i believe they are the same. I think when I took mine apart there was a ball between the two clutch rods. Number 12 and 18 in the diagram. The diagram for the 1975 does not show it in the picture, but I believe it was there. I could be wrong as one of the other bikes I had a while back definitely had one. (not a Yamaha). I could not get the clutch adjusted on mine, I replaced the clutch, the plates were all in spec but I replaced them anyway. But my clutch springs were all out of spec. and I think that was a big part of my problem.
Good luck.

Jim

    does this cable and actuator position look right ?i can move the actuator arm about 15mm anti clockwise before i feel it start to move the push rod ??

Just be careful adding a ball bearing. If the pushod is rounded both ends the it ain't going to work & shouldn't have one.
But if it's flat one end & rounded the other then rounded end goes to the lifting arm & flat end has ball between it & the mushroom rod.
Ok i'll post this now i've typed it. But i found a new pushrod of the correct part number on ebay & 'is' rounded both ends. Go to listing number eBay item number:322494700931 or maybe someone can link it direct--i'm hopeless at that with ebay. You can use their magnifier to get a good view. Rod looks larger than the i'd expect of the mushroom rod in which case it'll only go in from the left on assembling motor. But i could well be wrong. Pic coming.

 

I see ya pic now i look lol. I was going to say it looked pretty good where it is, but 15mm further forward, i don't know. Should be a mark somewhere around to give best arm starting point. Maybe i'm thinking if other similar motors. If all else fails can you melt the solder & slide the nipple up a bit.