Loss of 4th gear

[Lester]

Hi all,
Its been a long time since I was last on here, I even had to add a new user account. I am after a bit of advise following a bit of an issue yesterday.
On an upward change on a ride yesterday it didnt feel like it fully went into gear, this was followed by a mechanical knock. I changed up again and initially it seemed ok. I moved up and down to the box to make sure everything was ok. When I selected 4th there is no drive at all, it just revs as if it is in neutal. I am thinking that I have snapped the end off of one of the selctor forks or something - any one got any ideas on the basis that all other gears are perfectly find but with no drive in 4th?
I am guessing that if it was the gear cluster it would more than likely have taken a tooth off and would therefore give a grinding in 4th rather than a complete lack of drive.
Really after an idea on where to start and whether I remove the selector drum, etc with the engine in situe or whether its looking like a complete strip down.
Any advise much appreciated, getting a little worried about this one and want to start taking it apart to find out what I am up against.
Cheers all,
Lester

[CRM]

sounds like a drum / selector arm / dog issue.
fact is its going to require an engine out job and strip to be sure.
do an oil change first and see what comes out, good chance its all in the strainer now anyway.
may be cheaper and less stress to find a good used engine from someone on here who can assure you the motors good.

[Lester]

Thanks for the reply. I was think that one of the dog legsl/selector forks had broken away, but wasnt sure if that would only effect one gear, I was thinking more like 2 gears but not sure why I have this in mind. I understand you can remove ther selector drum with the engine in situe, so I figure I may as well do this first and see what I find. Before doing this I will also drop the sump and see what lies inside. I am sure that what ever has broken away will now be sitting in the sump - this will probably give me an idea of what I am looking at. Watch this space for the pics of what I find.
If anyone does have an engine, or parts for sale realted to this thread drop me a PM.

Cheers all,
Lester