Topic: Bike popping out of gear? Update!

[75 super sport]

So, say it is #1, where would I start? Could it be that I'm not engaging my clutch fully, and it is not allowing it to go all the way into gear? Or what are the possibilities. About #2, the thought has always been in the back of my mind that the bike sat because of an issue. Usually things do not get put away and abandoned for no reason. I really hope it's #1, but #2 makes sense too unfortunately.

[goldarrow]

Is anything coming to your head scottly?

3 things come to mind:
1. You are not fully shifting the bike into gear.
2. I hesitate to post this, but perhaps the reason the bike sat unused for so long was due to the same shifting problem. Some bikes came from Honda with improperly installed snap rings on the transmission shafts, which could pop out of their grooves and allow erratic transmission operation. I was unfortunate to have one of these, which decided to shift into gear by itself while cranking the motor, folding up the kick-stand and falling on top of me. The fix was to split the cases and re-install the snap rings in the proper direction. Hopefully your problem is #1. 
3.  PO raced the bike and hard shifted, not using clutch

FTFY

[scottly]

Popping out of gear under heavy load is usually due to worn dogs, not worn or bent forks, in my experience with 750's. Even worn dogs don't cause popping out of gear under light loads.

[75 super sport]

That's why I was curious too. Even letting out the clutch to start going it pops out. 

[goldarrow]

Popping out of gear under heavy load is usually due to worn dogs, not worn or bent forks, in my experience with 750's. Even worn dogs don't cause popping out of gear under light loads.

My 75 750k popped out of 2nd under light load, splitter the cases and found worn shifter fork and drum.  Here's my project thread if OP wanted to read about it. http://forums.sohc4.net/index.php/topic,114817.175.html

[scottly]

So, say it is #1, where would I start? Could it be that I'm not engaging my clutch fully, and it is not allowing it to go all the way into gear? Or what are the possibilities.

Once moving down the road, you don't even need the clutch, if you know what you're doing.
I would rule out the easiest first: the external linkage. If no fault can be found there, the next step would be to remove the shifter cover and inspect the shifter mechanism where it operates the shifter drum. This doesn't usually cause problems, unless someone has messed with it before and screwed it up.

[75 super sport]

The external linkage? Are you referring to clutch cable?

[scottly]

No, the external part of the shifter. The clutch isn't suspect in any way.

[75 super sport]

Ok. What should I keep my eye out for?

[scottly]

Just take a picture of the external shifter for now. When and if you have to remove the shifter cover I can give you specific things to check.

[PeWe]

Washer in clutch correctly mounted? It is convex, it grow outwards so it will work as a spring. Or if a washer is missing so the main shaft can move more than it should??

It was a thread about gear problem where the entire transmission was investigated. You might find something here.
http://forums.sohc4.net/index.php/topic,138663.0.html

[75 super sport]

Almost positive the washer is in there right, but now I am second guessing myself. Could this be a culprit to my issue? For future reference what's a good way to keep the clutch basket from spinning when installing the clutch basket nut?

[PeWe]

Easier to do the clutch nut when engine is in the bike with drive chain to wheel. 5:th gear in and wheel to floor. I have used a piece of wood between case and front sprocket too.

[przjohn]

Is the bike popping out of gear or is the clutch slipping, do you know the difference?

All this talk about the clutch seems like you are chasing butterflies if the bike is popping out of gear.

 Once power has been transmitted through the clutch it is effectively gone past that part of the system and the popping out of gear problem then would be past the clutch, meaning the transmission or the transmission operating system.

However, if the clutch is slipping than the power never makes it to the transmission. This usually appears under a load and is felt as a gradual feel in power loss and not a sudden stop in power like popping out of gear.

Since you state the bike is popping out of gear under no load it sounds like a transmission related issue and not a clutch issue.

[75 super sport]

It's definitely popping out of gear. It will pop out, then I have to put it back in to gear

[Kickstart]

+1 to what przjohn is saying... unfortunately.

You most likely are going to have to crack the case and see what's going on in there.  But before you do that, I would take a close look under the shift cover. 

Maybe the shift linkage arm is bent preventing the drum from shifting/turning all the way... long shot, but worth looking into before you crack the cases open.

[strynboen]

thek that the small spring holds the roller arm dovn to the drum...if that is gone,,the drum vill turn free..and any load vill pressm it in free gear..im a 550 man ..but think you can get to the drum end,,just take the cover off.
.a easy fix..ve can hope

[75 super sport]

You guys are awesome,  thanks so much for all the input

[75 super sport]

Does the motor have to be removed to take the shift cover off?

[PeWe]

Just to be clear and no missing clue: Earlier mentioned washer in clutch has nothing to do with slipping clutch, gear problems as the Flybox1 thread had. Quick and easy to check.

Then the gear mechanism that strynboen mention. This should keep the drum that control the forks which gears in place.
see another thread
http://forums.sohc4.net/index.php/topic,60626.msg658199.html#msg658199

[pmanning]

I used to work with a guy that used his 750 for unsanctioned, privately organized, and highly illegal drag racing on weekends. (This was Birmingham, Al in the 1970s.)  He was quick but hard on his equipment.  He went through three or four transmission rebuilds in a year and probably less than 1,000 miles-bent shift forks, broken shift fork pins, rounded engagement dogs on gears, and wallowed out engagement slots on mating gears.  Since you don't know what kind of riding the bike was subjected to in those 13,000 miles it is hard to rule anything out.  You might pull the oil pan and see if there are shiny metal bits or chunks lying about there.

[70CB750]

Does the motor have to be removed to take the shift cover off?

no, but there is oil behind it.

Check out Dino's documentation, it will help you understand how the shifter works:

http://hackaweek.com/hacks/?p=1649

In the worst case scenario, transmission can be dealt with from the bottom,  engine out of the frame and flipped over.  Done it myself to make the F3 engine shift to 3rd and higher.

[75 super sport]

I have never split a case, it sounds terrifying to me haha

[75 super sport]

Would anyone be interested in walking me through the process on a weekend for $100?

[MoMo]

Would anyone be interested in walking me through the process on a weekend for $100?

location???  and it does seem internal but check the linkage before pulling the motor...Larry