B12 notchy-shifting FIXED.. NO REALLY!

[China Greg]

After two years of teeth-gnashing and replacing of numerous parts, I finally discovered why my 1st Generation B12 was shifting like a bread truck:

A small pushrod-shaft that actuates the clutch (incorporating a small thrust-bearing, on the right side, residing within the inner clutch hub), had a defect: The bevel on the leading edge had a bit of a sharp edge, causing the shaft to hang-up under load inside the shaft. This often resulted in blocking the clutch from disengaging all the way, making shifts clunky and "sticky".

I polished off (de-burred) the leading bevel edge of the pushrod and now the bike snicks through the gears sweetly. Hallelujiah. It's a milestone, and now the bike is a keeper.

[BanditoNova]

Sounds like that might help quite a few folks on this board. While my 01 B12's shifts aren't that rough, they could stand to be a bit a bit smoother. Any chance of posting a diagram showing the part?

 

[China Greg]

re: posting a diagram..

Well, err... I'm not eggzactly the SHARPEST tack in the box, when it comes to posing such technicalities.. (hell, i can't even post a photo of any kind here).

It's a short (2") shaft, with a "deck" for the thrust bearing, sticking out of the right side end of the countershaft; the last piece in the end of the (inner) clutch hub.

To get to it, you'd need to drain the oil, remove the clutch cover, and pull the big circlip on the little aluminum "pressure plate". Under that is the thrust bearing and the pushrod shaft I mentioned, which just slip out easily. Not a difficult job, if you have a good set of slightly-large circlip pliers for the pressure plate. You MAY be able to salvage the clutch cover gasket, (they are fairly tough material), but you can't be sure, so you'd better have a new one ready, or have the time free to order a new one if your old one rips.

PLEASE NOTE: This was done on a 1998, 1st Gen bike. I don't know about later versions.

BUT, one thing has been made clear to me: anything that impedes the clutch from FULLY releasing will result in "sticky" or clunky shifting. If you have been doing a lot of wheelies or burnouts, your clutch hub and/or basket may have developed ridges, holding back smooth operation.
Again, ANYTHING that impedes total clutch release, (even very old clutch fluid) can result in sticky shifting.

Wow. This one has been a LESSON learned! I replaced all kinds of components before finally stumbling on this tiny flaw, (which IMHO I think is Suzuki's fault for making that shaft edge bevel too steep).

[BanditoNova]

Thanks Greg, I'll try to locate it on an exploded diagram. 

[Banditmax]

http://www.cmsnl.com/suzuki-gsf1200-1998-saw_model13549/partslist/FIG17.html which number on that link.

[BanditAllan]

To access inside the clutch cover you dont have to drain the oil, just place the bike on the side stand and then a piece of stable wood about 3 inches high under the rear wheel.
This tilts the bike over enough so the oil doesnt run out the clutch side cover when its removed.
Use sound judgement here and realise you cant lean on the bike or push on it while its in this position and all should be fine.

[BanditoNova]

Maybe on this page? #4 clutch push piece? This is a 2001 manual.

http://icandesign.ca/images/clutch_page54.jpg 

[China Greg]

...tilt the bike over enough so the oil doesnt run out the clutch side cover when its removed.

Yeah, I used to do that, but it got messy for me, (maybe the board under the back wheel makes the difference).

I just drain the oil into a clean pan and pour it back in again later!

[BanditAllan]

Well id changed the oil when id gotten the bike used and then found the clutch was toasted. So instead of drain it out again i opted to tilt it over a bit more and replace the clutch plates and diaphram spring.
The three inch high piece under the rear wheel is just enough that the oil doesnt reach the edge of the lower case to spill over, but the lean angle looks quite steep.
Its still reasonably secure, but you just need to remember its tilted over more in that temporary position.
*Of note here is that an air tool and socket will remove the clutch basket centre nut without the special holder, and refitting is easy by just remarking the original location of the nut.
CAREFUL use of the air tool is required to send it back into the original position before locking it in place*