gearbox / clutch issue - loud shifting

[maanieek]

Hi,

I would like to know how the gearbox in a GSX 1400 should typically operate. I have one with 90,000 km on the clock, and I am a bit concerned about how the transmission feels.

First gear engages very hard and loud – which I understand is quite normal for these bikes – but the subsequent upshifts are also very loud and clunky.

The clutch seems to be working properly, at least at a standstill. The motorcycle starts moving when the lever is released to about 3/4 of its range, and there are no fluid leaks or air in the system. As for the gears themselves, they all engage fine and don't pop out while riding. The only issue is those very harsh, loud noises when shifting.

When downshifting with rev-matching, I occasionally manage to avoid the clunk. Interestingly, the smoothest shift happens between first and second gear when the engine oil isn't fully warmed up yet.

I have a feeling that something might be wrong with the clutch itself, as if it's not disengaging completely. However, as I mentioned, I haven't noticed the bike creeping forward when the clutch lever is pulled in.

Any advice or insights would be greatly appreciated.

Best regards,

[KiwiCol]

Hi Maanieek, welcome to the forum.  We prefer new members to do a bit of an introduction to the group in the intro section here: https://gsx1400owners.org/forum/index.php?board=20.0   Have a read so you get the idea.

Now as for the clunky gear shifts, you probably have hit the nail on the head here when you say the smoothest shift is 1st to 2nd shortly after start up before the oil has warmed up.  To me, this is your smoking gun, the oil.  What oil are you running in it?  Not trying to baby it with Full Syn are you?  or Motul 7100? 

[GSXKING]

G'day mate and welcome to the nuthouse. Normally I wouldn't respond until you introduce yourself. Thanks Col.
I think you should buy some professionally fitted earplugs and all that noise will miraculously disappear 😎.
They're old school motors and are designed to last, not be smooth or quiet. Trust me my bike is as noisy today as it was 25 years ago. 🕐

[Stevel3]

I'm on my 4th GSX1400 now and I haven't had noisy gear changes on any of them. On this last one the clutch does feel a little bit heavier than I thought it should. I also think it is mostly down to what oil you are using. My bike is going in for a full service and check over next week.

[Eric GSX1400K3]

Gday Maaniek, looking forward to your introduction.

Have you tried holding the clutch in for a count of 10 and rolling the bike forward then select a gear?

I'd also suspect the oil, the clutch plates can stick together if the oil isn't thick enough, this then gives the feeling of a partially releasing clutch.  The above check allows a bit of time for the plates to separate.

Also check the slave cylinder for correct operation, and clean the push rod that goes through into the engine.  A popular mod is to fit a hayabusa slave cylindervseal, this stops crud from going into the slave and onto that pushrod.

Also check lever at the perch, the small bronze bushing in there can wear out, but it seems like you've got full range of lever travel as the bike doesn't creep fwd.

Change the oil to a semi sun 10W40 JASO MA2 spec and she'll be right

[Tony Nitrous]

I have a few big Suzuki's, it's pretty normal to feel / hear the bike going into first from neutral on most of them. It's just normal to me and not a big deal.

Up or down through the gears is a lot less defined and harsh.

Personally the biggest downside to many big Suzuki's for me is the BTL / Back Torque Limiter / poor version of a slipper clutch which does riding no favours at all.

[grog]

Clunk into first is normal, every 4 cyl jap bike I've owned same. I hardly touch the clutch changing gears,changes fine for me🤷🏼 Change the oil, ear plugs, practice a bit more👍

[Phill P]

I found mine quite clunky, rebuilt the slave cylinder once and it helped a bit but then changed it out the an Oberon slave cylinder, much improved

[Eric GSX1400K3]

I found mine quite clunky, rebuilt the slave cylinder once and it helped a bit but then changed it out the an Oberon slave cylinder, much improved

more progressive feel or lighter? Can you give some detail on the improvements at all? Im thinking of doing the Oberon upgrade as well.

[Phill P]

I found mine quite clunky, rebuilt the slave cylinder once and it helped a bit but then changed it out the an Oberon slave cylinder, much improved

more progressive feel or lighter? Can you give some detail on the improvements at all? Im thinking of doing the Oberon upgrade as well.

Slightly lighter although I did fit new lines and fluid at the same time, definitely smoother, wouldn't say more progressive. Definitely better than before, although a brand new normal slave cylinder may give the same result 

[maanieek]

Yes, you're right—I used Motul 7100 15W50. Even so, I wonder if clutch wear at this mileage might be the cause.

[Barbastro K6]

With the motorcycle raised on the center stand, try changing gears.

Clutch state: You should be able to stop the wheel with your foot.

[KiwiCol]

Yes, you're right—I used Motul 7100 15W50. Even so, I wonder if clutch wear at this mileage might be the cause.

Ok, pretty sure that's it.  These engines don't sound good on 7100, there have been other members who were using the same oil, thinking they're looking after the internals better by using Motul 7100, but it's noisy and clunky.  Change your oil to a semi syn 10w/40, probably the cheapest you can find and try that.  Now doing an oil change never gets out all the oil, so you'll still have about 1L of 7100 in there, so don't be surprised if it's still a bit clunky. Do a 2nd change to get all of the 7100 residue out and fill with a good semi syn 10w/40 and see how it sounds and feels then.  It's 1 oil filter and 2 packs of oil to try, so not that expensive really.

[maanieek]

Okay, if it's not too much trouble, let me know what oil you use. I'll give it a try.

[KiwiCol]

Well, living in NZ, I use Gulf Western Synex 3000, but doubt you'll have that available in Poland.  I know a lot of the UK guys use Halfords?  Is that one you have?