[wardus212]

Hi, I'm having problems with my honda cb250 G5 1974

It won't select first gear. I have removed the clutch to gain access to the selector rod and drum. Here is a video of what is actually happening. Ive been through the gearbox itself and nothing it sticking out to me as being wrong or worn

If I turn the rear wheel as I'm spinning the drum it tries to select the first gear but doesn't quite slot correctly into the drum first time. This is causing a grinding noise as I pull away until it slots into gear

The rest of the gearbox selects fine, its just that first gear

Any help on this would be greatly appreciated!

 

[mike in idaho]

The lever isn't going down far enough to engage the gear. Look at the pin in the centering spring on the shift shaft, is it bent or loose? The pin on the end of the shift drum should be in the center of the opening on top of the shift arm with the shifter at rest. Some bikes have an eccentric shaped pin, with a lock nut, in the middle of the centering spring to make the lever position adjustable. I can't remember if the CB250 has an adjustable one or not.

 

[wardus212]

When you say the pin should be in the centre of the opening which pin are talking about?

 

[mike in idaho]

The pin is under the star shaped piece on the end of the shift drum. #25 in this diagram: https://www.cmsnl.com/honda-cb250-general-export_model50695/partslist/0054.html#.W0Ywrzq0Wpo The centering pin is #14.

 

[wardus212]

No broken centering pin, shift shaft arm is straight. The pins on the drum look good. Any more ideas on what this could be?

 

[wardus212]

Heres a link to a video which shows me selecting first gear manually, I have to put a fair amount of force on the drum to get the gear to select

https://www.youtube.com/watch?v=nLijjDMw224&feature=youtu.be