RogerD Posted August 24, 2009 Posted August 24, 2009 I have 2 1974 DT 360's. The clutch won't engage on one of them I am restoring. The lever on the engine bottom moves freely - almost too easily, like it is not engaging the push rod. I have the clutch cover off and see no movement when the lever is pulled forward. Any ideas?
Moderator Airhead Posted August 24, 2009 Moderator Posted August 24, 2009 I have 2 1974 DT 360's. The clutch won't engage on one of them I am restoring. The lever on the engine bottom moves freely - almost too easily, like it is not engaging the push rod. I have the clutch cover off and see no movement when the lever is pulled forward. Any ideas? sounds like something is missing...like a ball bearing perhaps!...Just a guess...
RogerD Posted August 24, 2009 Author Posted August 24, 2009 sounds like something is missing...like a ball bearing perhaps!...Just a guess... I was thinking the same thing, but couldn't figure out how it could happen. An way to check without cracking the cases open? I just got it running after 2 days of cleaning out a mouse nest in the air cleaner, cleaning the carb, and cleaning all the coil and flywheel surfaces. It almost took my leg off(decompression valve didn't engage - had to pull the cable by hand - will fix next) but it fired up and sounds strong! This is my third resto on the '74 360 and I've never had this clutch problem....
Moderator Airhead Posted August 24, 2009 Moderator Posted August 24, 2009 I was thinking the same thing, but couldn't figure out how it could happen. An way to check without cracking the cases open? I just got it running after 2 days of cleaning out a mouse nest in the air cleaner, cleaning the carb, and cleaning all the coil and flywheel surfaces. It almost took my leg off(decompression valve didn't engage - had to pull the cable by hand - will fix next) but it fired up and sounds strong! This is my third resto on the '74 360 and I've never had this clutch problem.... The thing is...you dont know what the previous owner did..is there a ball i assume there is in your manual. you will have to drain the transmission oil and remove the clutch cover case i suppose, then pull off the pressure plate to gain access to the rod and bearing..
RogerD Posted August 24, 2009 Author Posted August 24, 2009 I guess I'll have to. I already have the tranny drained and the cover off..
RogerD Posted August 25, 2009 Author Posted August 25, 2009 The thing is...you dont know what the previous owner did..is there a ball i assume there is in your manual. you will have to drain the transmission oil and remove the clutch cover case i suppose, then pull off the pressure plate to gain access to the rod and bearing.. I pulled the pressure plate and used a magnet to pull long rod out. There is no bearing between the 2 rods. The long rod is flat on the lever end - is this correct? The rods move when the lever is moved forward, but not far enough to release pressure on clutch plares? Could my rod be too short from wear?
jordanscycles Posted August 25, 2009 Posted August 25, 2009 you could try adjusting the clutch adjuster on the opposite side cover from the clutch plates, should be the side cover that covers the front sprocket. you should loosen the nut, then screw the screw in until it hits the rod then tighten the nut to make it stay. might be covered by a rubber cap, might be underneath the plate, but I think that it's your problem.
Moderator Airhead Posted August 25, 2009 Moderator Posted August 25, 2009 I pulled the pressure plate and used a magnet to pull long rod out. There is no bearing between the 2 rods. The long rod is flat on the lever end - is this correct? The rods move when the lever is moved forward, but not far enough to release pressure on clutch plares? Could my rod be too short from wear? I would expect a bearing but like I said its a guess, what does your manual show? the answer will be in there...
blackhat250 Posted August 25, 2009 Posted August 25, 2009 I would expect a bearing but like I said its a guess, what does your manual show? the answer will be in there... Yip " the pushrod is in 2 parts , the ball is in the middle , [allows spinnig of clutch]
RogerD Posted August 25, 2009 Author Posted August 25, 2009 you could try adjusting the clutch adjuster on the opposite side cover from the clutch plates, should be the side cover that covers the front sprocket. you should loosen the nut, then screw the screw in until it hits the rod then tighten the nut to make it stay. might be covered by a rubber cap, might be underneath the plate, but I think that it's your problem. I have adjusted the adjusting screw all the way in and it still won't move far enough to move pressure plate. I even took the push lever axle out to check it, and it seems fine as well....
RogerD Posted August 25, 2009 Author Posted August 25, 2009 Yip " the pushrod is in 2 parts , the ball is in the middle , [allows spinnig of clutch] Yes, the push rod is in 2 parts, but the schematic shows no ball between them. Instead, the end of the long push rod is rounded to fit into a depression on the short one to allow spinning. I still suspect the long rod somehow got damaged - it is flat on the sprocket side end, and I think it is supposed to be rounded there as well... I scanned the page from the service manual but can't seem to paste it into this window - it shows no bearing between the rods.
Moderator Airhead Posted August 25, 2009 Moderator Posted August 25, 2009 Yes, the push rod is in 2 parts, but the schematic shows no ball between them. Instead, the end of the long push rod is rounded to fit into a depression on the short one to allow spinning. I still suspect the long rod somehow got damaged - it is flat on the sprocket side end, and I think it is supposed to be rounded there as well... I scanned the page from the service manual but can't seem to paste it into this window - it shows no bearing between the rods. so no bearing anywhere then in the manual?
RogerD Posted August 25, 2009 Author Posted August 25, 2009 so no bearing anywhere then in the manual? Nope, no bearing - just the rounded end of the rod acts as a bearing. I was hoping to avoid taking my other bikes clutch apart to see the rod in it - but I'm almost curious enough to do it. I can email the schematic if you want to see it. By the way...sorry about your bike - hope you get it back.
Moderator Airhead Posted August 25, 2009 Moderator Posted August 25, 2009 Nope, no bearing - just the rounded end of the rod acts as a bearing. I was hoping to avoid taking my other bikes clutch apart to see the rod in it - but I'm almost curious enough to do it. I can email the schematic if you want to see it. By the way...sorry about your bike - hope you get it back. I just had a look on bikebandit site, looked at 1973 DT3, it shows a ball !! not sure its relevant to you, it was only ever a guess but still sounds like something is missing By the way...sorry about your bike - hope you get it back. ???
RogerD Posted August 25, 2009 Author Posted August 25, 2009 I just had a look on bikebandit site, looked at 1973 DT3, it shows a ball !! not sure its relevant to you, it was only ever a guess but still sounds like something is missing Look at the clutch schematic for a 74 dt175 - it shows the same as my manual drawing - no ball..unlike the 73's and earlier ones. For some reason, all the microfiche file for the 74 DT250 and DT360 are messed up and unattainable - Don't know why. Go here for good clear pictures of yamaha parts drawings :
805comtech Posted August 27, 2009 Posted August 27, 2009 I am having the exact same problem on a 75 DT250. I have taken it apart to the clutch plates to expose the push rod end. I removed the bearing and checked the internal rod. Everything looked good so I re-assembled it. Still wont engage. I removed the actuator from the bottom of the engine and cleaned everything. It appears to be beveled at the contact point and is adjusted by rotating a cam type threaded adjuster. I adjusted it all the way down for maximum contact. Still wont engage. Tomorrow I plan to change the cable in case someone before me put too long a cable on it. If that doesn't work I guess I will need to split the cases and see if the internal rod is damaged. I think the 250's and 360's work in the same manner. If you succeed will you post the outcome? I will do the same. Thank you Bill
RogerD Posted August 29, 2009 Author Posted August 29, 2009 I am having the exact same problem on a 75 DT250. I have taken it apart to the clutch plates to expose the push rod end. I removed the bearing and checked the internal rod. Everything looked good so I re-assembled it. Still wont engage. I removed the actuator from the bottom of the engine and cleaned everything. It appears to be beveled at the contact point and is adjusted by rotating a cam type threaded adjuster. I adjusted it all the way down for maximum contact. Still wont engage. Tomorrow I plan to change the cable in case someone before me put too long a cable on it. If that doesn't work I guess I will need to split the cases and see if the internal rod is damaged. I think the 250's and 360's work in the same manner. If you succeed will you post the outcome? I will do the same. Thank you Bill Your 250 should be identical to my 360"s. I'll measure the long rod tomorrow - I believe it should be 6 3/4" long. Roger
RogerD Posted August 29, 2009 Author Posted August 29, 2009 Your 250 should be identical to my 360"s. I'll measure the long rod tomorrow - I believe it should be 6 3/4" long. Roger Sounds identical to my problem. i also took the pressure plate off to check the rods. I also took the actuator out like you did. If your clutch pressure plate doesn't move when the lever beneath the engine is pulled forward, it's not a cable problem. From the shop/ service manual and comparing to my other DT, the clutch pressure plate should engage with only a movement of only @ 20 degrees - from 10 degrees to the rear to 10 degrees forward. I think our long rods are too short. Can you measure yours? Or did you put it back together? I can get to my non-working one pretty easily to measur. I'll let you know. Roger
RogerD Posted August 29, 2009 Author Posted August 29, 2009 Sounds identical to my problem. i also took the pressure plate off to check the rods. I also took the actuator out like you did. If your clutch pressure plate doesn't move when the lever beneath the engine is pulled forward, it's not a cable problem. From the shop/ service manual and comparing to my other DT, the clutch pressure plate should engage with only a movement of only @ 20 degrees - from 10 degrees to the rear to 10 degrees forward. I think our long rods are too short. Can you measure yours? Or did you put it back together? I can get to my non-working one pretty easily to measur. I'll let you know. Roger
805comtech Posted August 29, 2009 Posted August 29, 2009 Friday night. 10:00 PM. I think I know the problem with mine although its not pretty. Removed the clutch basket down to just the shaft at the clutch side of the cases. With the bearing and external rod removed i attempted to remove the long internal rod with a magnet. When I did it moved the entire shaft with the rod. First time I had noticed this. I think the internal push rod is stuck to the clutch shaft. Hope not do not want to split the cases as this engine runs pretty good.
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