Dude where's my first gear?

[mysta2]

Back when I was first trying to resurrect my '75 SOHC 750 from its junk yard days I needed to break the corroded clutch plates free. The way I usually do this is to hold the clutch lever in with the bike in gear and rotate the rear tire in short jolts until it frees. Well maybe I hadn't gotten enough sleep that previous night or something, because I forgot to hold the clutch lever in... and it broke free. Since then I had no first gear. The shift lever seems to snap into what should be first, but the tire spins freely (possibly second also, it's hard to tell)

At this point I have the motor torn down completely, and can not see any obvious problem. Forks look to be straight and in what I have to guess is the proper position. No teeth missing from any of the gears. No metal in the pan.

Any clues what I could have done to this thing, and what I should take care of before bolting the thing back together?

I'm not sure if this is related but it does look as if fourth gear is dragging on the right lower fork. So, how do I fix that? I'm guessing that it must be bent... I'll try and post a pic.

 

[mysta2]

I can't seem to figure a way to post a pic from the apple-verse (iPad/phone) so that will have to wait till tomorrow.

 

[Tim]

Get Tapatalk and access the forum through that on your iPhone. You can post pics.

 

[warthogcrewchief]

If it's anything like my '72 CB 350, it's almost like a double-clutch. You need to release the clutch, then re-engage it to shift. I've found it's more pronounced in 1st and sometimes 2nd.

 

[mysta2]

Yeah, I tried tapatalk a long time ago and didn't like it. But I reloaded it so here goes.

Drum shows no wear that I can see. The anodize on it I think would make it obvious. The dogs on what CMSNL identifies as fourth gear show a lot of wear on one side and a bit on the other. As you should be able to see the fork itself (lower right (CMSNL)) is pretty badly burned up.

I think I uploaded four pics that describe the situation.

 

[mydlyfkryzis]

Since you have it apart, I would replace the gear and the fork. The worn dogs probably forced the gear against the fork, bending it...

Typical scenario.

Usually happens on the 2 second gear, as that it the gear that many abuse when accelerating rapidly.... By the time you get to fourth, the "race is over"

 

[joea]

your shift fork should not be galled,over temped (blued) and the gear dogs are worn excessively....change the shift fork and both (mating )gears and check circlips tight and in place,transmission bearings, shift mechanism and springs, and the shift lever return spring screw is tight.
joe