Air in clutch symptoms

[Blackpowder70]

Hey guys I recently changed my clutch fluid out on my 2005 ST. The master cylinder was dark and there was allot of muck at the bottom. I cleaned it all out then proceeded to bleed the system using the clutch lever and I pushed allot of dark out the bleed valve. Did not see a ton of bubbles.

Well the bike sat for 4 days due to work. When I took it out it seemed to shift ok but after about 15 min it started to shift kinda hard and had started to smell odd. I pulled off a side street and it would not down shift to first. So I could start it and when I release the clutch it would stall.

After a bit it went into first and I drove it home. I then bought a vacuum bleeder and new fluid again and I got a bunch of air out. Had to run 4 master cylinder levels through till I got no air.
My question is would the excess air cause the inability to down shift and also the odd smell at a stop? And after bleeding with a vacuum bleeder will this cure the problems? I drove it around the neighborhood after the final bleed and it seemed ok. I don't want to drive to far again and have a issue.

 

[Bmacleod]

Beware that a vacum bleeder will sometimes, or in my case, almost always pull air in around the loose bleeder, making it look like there is lots of air, when in fact, there may be none in the system. I have a vacum bleeder and I dont have much use for it for this reason. I will sometimes use it to pull a volume of fluid through the system, realizing that I have to disregard the air, before finishing up with other bleeding methods, so I can watch for bubbles after using it. Some people wrap teflon tape around the bleeder to try and seal the threads of the bleeder... i dont bother.
Could the smell have been fluid dripping on the exhaust from not tightening the bleeder after the first flush? Was the fluid low when you started the flush the second time. Yes, a defective clutch or slave cylinder can cause the issues you had.

 

[Blackpowder70]

Beware that a vacum bleeder will sometimes, or in my case, almost always pull air in around the loose bleeder, making it look like there is lots of air, when in fact, there may be none in the system. I have a vacum bleeder and I dont have much use for it for this reason. I will sometimes use it to pull a volume of fluid through the system, realizing that I have to disregard the air, before finishing up with other bleeding methods, so I can watch for bubbles after using it. Some people wrap teflon tape around the bleeder to try and seal the threads of the bleeder... i dont bother.
Could the smell have been fluid dripping on the exhaust from not tightening the bleeder after the first flush? Was the fluid low when you started the flush the second time. Yes, a defective clutch or slave cylinder can cause the issues you had.

The fluid was not low the second time it was at the level mark. I know that when I stopped due to it not down shifting to first It had resistance pushing it to the road side with the clutch pulled in. But after a few minutes off looking for a issue I started it up and it went into nuetral fine and then first. I then drove home and did not smell anything on the way home. When I pulled new fluid through with vac pump it was not clean and clear. But it is all clear now after running a bottle through it. The lever feels good and it shifted fine around the neighborhood and no smell. Just the whole situation caught me off guard.

 

[Jethro]

For stubborn bleeds I will "back bleed" from bleeder at slave cyl. With a pump (manual) that attaches to a 1 gallon brake fluid can. Brake lever held so that compensation port is open. Slow & easy! Have any painted surfaces protected.You start with an empty master cyl reservoir,, keep an eye on the level . Hope this helps.

 

[Blackpowder70]

Great advice guys. And I do think old fluid on the pipe was the smell. I ordered a one way bleeder valve for the last conventional bleed with out the vacuum pump. Gotta get my girl ready for this upcoming spring weather in a few weeks. Thanks so much for the help.

 

[TerryS]

I also think a vacuum bleeder is useful to pull fluid through during a from-dry first fill, but not so good for flushing old fluid out of the slave. The vacuum bleed does not cause the slave piston to move, unlike a conventional squeeze the lever/crack the bleed nipple action. With the conventional method, there is fresh fluid pumping in/out of the slave in the chamber piston area, which will be more successful at flushing out any goo that was making the slave piston sticky.