Finding a skilled mechanic who specializes in clutch repairs can be beneficial in diagnosing and resolving issues with your 1983 Honda CM250C. While I can provide some general guidance, it's important to consult with a professional for a more accurate assessment and resolution of your clutch problem.
Here are a few potential causes for the symptoms you described:
Clutch Cable Adjustment: Ensure that the clutch cable is properly adjusted. If it is too loose, it may not disengage the clutch fully, resulting in the bike stalling when you try to engage first gear. On the other hand, if it's too tight, the clutch may not engage properly, causing the bike to jump and stall.
Clutch Plates: Over time, clutch plates can wear down or become glazed, reducing their ability to engage and disengage smoothly. This can result in the symptoms you mentioned. Replacing the clutch plates might be necessary if they are worn or damaged.
Clutch Springs: Weak or worn clutch springs can cause similar issues. When the springs lose their tension, the clutch may not fully engage or disengage, resulting in a lurching motion or stalling. Replacing the clutch springs could resolve this problem.
Clutch Basket or Hub: In some cases, the clutch basket or hub may be worn or damaged. This can cause the clutch to grab or slip, leading to the symptoms you described. Inspection and potential replacement of these components might be necessary.
It's worth noting that these are just a few possibilities, and an on-site inspection by a qualified mechanic is recommended to accurately diagnose and address the problem. They can examine your clutch system and perform any necessary repairs or adjustments to get your motorcycle running smoothly again.
Remember to communicate the symptoms clearly to the mechanic, as it will assist them in troubleshooting the issue effectively.