Topic: Transmission causing stall?

[laser145]

The bike: 76 CB750k

My bike stalls when I try to start moving. At idle, I pull in the clutch, shift to 1st gear, apply throttle and release clutch... it moves a couple of inches, then kills the engine. The bike won't roll freely while in gear (as it shouldn't) and it does roll freely in neutral (as it should).

It does the same thing if I try to start from 2nd gear.

On my final ride before breakdown I thought the bike was slipping into neutral when I shifted from 1st to 2nd... but I was wearing very thin shoes (vans) and thought that maybe they just weren't as thick as my boots and would require me to lift my entire foot off the footpeg when shifting to ensure full operation of the shifter... When I did this, and made a deliberate effort to shift solidly, it seemed to work fine.

I've asked about this in another thread as I though the problem was my clutch, I'm opening the clutch anyway...but I'm just not sure.

What causes this stall? I've searched threads about slipping gears...but nothing about the bike stalling...

Cheers

[77cafe750]

my 750 did this on occasion before i rebuilt the carbs and it onl;y did it when it was cold

[laser145]

my 750 did this on occasion before i rebuilt the carbs and it onl;y did it when it was cold

So you couldn't make it drive with the engine cold, but you let it warm up and it would pull away?

My carbs aren't synced perfectly I think... but they're clean. The bike idles around 1200-1400 smoothly, and revs up nicely.

the other thing is these was a rattle coming from the motor while idling in neutral...when I pull in the clutch it goes away...

[77cafe750]

yea when she was cold i could not move her at all after she warmed up no issue rebuilt carbs and resynched no problem now

[laser145]

yea when she was cold i could not move her at all after she warmed up no issue rebuilt carbs and resynched no problem now

Really!?!? In my mind that just seems crazy! I would be delighted to know it was that simple. So yours would just stall when you would hit the throttle and drop the clutch... did the throttle rev up smoothly when it was in neutral and cold?

[77cafe750]

yes
she would rev very smoothly in neutral

[MCRider]

my 750 did this on occasion before i rebuilt the carbs and it onl;y did it when it was cold

So you couldn't make it drive with the engine cold, but you let it warm up and it would pull away?

My carbs aren't synced perfectly I think... but they're clean. The bike idles around 1200-1400 smoothly, and revs up nicely.

the other thing is these was a rattle coming from the motor while idling in neutral...when I pull in the clutch it goes away...

As to the rattle, on a CB750, if it goes away when you pull in the clutch, as you say it does, it is completely normal. Don't worry about it. Its part of the accepted noise package.

[laser145]

Well I was/am hoping my problem is the clutch... http://forums.sohc4.net/index.php?topic=74777.0

The pics seems to show it pretty worn in a few areas. Once I get more answers on it, then get it buttoned up, I'll mess with my carbs before I get into the transmission.

[laser145]

my 750 did this on occasion before i rebuilt the carbs and it onl;y did it when it was cold

So you couldn't make it drive with the engine cold, but you let it warm up and it would pull away?

My carbs aren't synced perfectly I think... but they're clean. The bike idles around 1200-1400 smoothly, and revs up nicely.

the other thing is these was a rattle coming from the motor while idling in neutral...when I pull in the clutch it goes away...

As to the rattle, on a CB750, if it goes away when you pull in the clutch, as you say it does, it is completely normal. Don't worry about it. Its part of the accepted noise package.

Good to know, thanks. This is my first SOHC and none of my friends own them, so I don't have any ideas what "normal" is...

[MCRider]

The CB750 clutch rattle is a badge of honor. Wear it proudly! 

[laser145]

The CB750 clutch rattle is a badge of honor. Wear it proudly! 

I want to! Just need to get her back on the road!