Slipping clutch Kawasaki GPZ500?

Flearoy

Hi all

After changing the oil and filter on my recently acquired Kawasaki GPZ500 (D1 model, 1994/5) the clutch has been prone to slipping at higher revs, especially with a pillion or on hills.

As far as I can tell, my clutch is correctly adjusted at the lever.

Gears engage smoothly too.

I don't know what oil the bike had been run on before I got it, but the oil I used is a fully synthetic type of the appropriate grade.

Any suggestions? I thought I might change the oil for a mineral oil, given the miles on the bike (33k), its age, and the fact that I don't mind changing it frequently. I'm concerned that new fancy oil might have caused the clutch to slip.

Any advice appreciated,

Flearoy

marlot

You didn't use car oil, I hope? Many car oils contain friction reducing chemicals which don't work well with wet clutches. You need an oil which is specifically marked fro bikes - look for JASO MA marking.

fivetide

I think you might be right. Chances are that bike likes semi-synth at best, don't forget it is an older design.

Any owners club you can check on?

5t.

Flearoy

marlot wrote: »

You didn't use car oil, I hope? Many car oils contain friction reducing chemicals which don't work well with wet clutches. You need an oil which is specifically marked fro bikes - look for JASO MA marking.

No, proper bike oil, cheers though.

marlot

its possible the clutch is coming to the end of its life. But before replacing it I'd try changing to a semi synthetic oil.

boyse7en

Does it slip only when hot?

I had the same issue on a Ducati Monster that slipped its clutch after I replaced the oil. I'd used a bike specific semi-synth recommended for V-twins (think it was Motul 3100, but I might be wrong). It was fine until the engine got good and hot - worst was after a longish run at speed, like on a motorway, and then stopping. The heat-soak due to the lack of cooling meant the oil got even hotter and I could barely pull away from the petrol station. Once it got moving, it got a lot better.

I'd go to a local bike dealer and ask what oil they would recommend for your bike and try that.

fivetide

marlot wrote: »

its possible the clutch is coming to the end of its life. But before replacing it I'd try changing to a semi synthetic oil.

I must be on the OP's ignore list or something.

marlot

boyse7en wrote: »

Does it slip only when hot?

I had the same issue on a Ducati Monster that slipped its clutch after I replaced the oil. I'd used a bike specific semi-synth recommended for V-twins (think it was Motul 3100, but I might be wrong). It was fine until the engine got good and hot - worst was after a longish run at speed, like on a motorway, and then stopping. The heat-soak due to the lack of cooling meant the oil got even hotter and I could barely pull away from the petrol station. Once it got moving, it got a lot better.

I'd go to a local bike dealer and ask what oil they would recommend for your bike and try that.

I thought a monster had a dry clutch?

boyse7en

I thought a monster had a dry clutch?

Some might do. They have done dozens of variations of different engines etc. over the models lifetime. My Y2k one was definitely a wet clutch though.

Flearoy

fivetide wrote: »

I think you might be right. Chances are that bike likes semi-synth at best, don't forget it is an older design.

Any owners club you can check on?

5t.

Agree, it is a pretty ancient design now! I've had a dig around, and it seems semi-synth might be the way to go. Think the old GPZ might be a bit passed getting the 'racing technology' benefits of the newest oils!

Cheers all

Flearoy

boyse7en wrote: »

Does it slip only when hot?

I had the same issue on a Ducati Monster that slipped its clutch after I replaced the oil. I'd used a bike specific semi-synth recommended for V-twins (think it was Motul 3100, but I might be wrong). It was fine until the engine got good and hot - worst was after a longish run at speed, like on a motorway, and then stopping. The heat-soak due to the lack of cooling meant the oil got even hotter and I could barely pull away from the petrol station. Once it got moving, it got a lot better.

I'd go to a local bike dealer and ask what oil they would recommend for your bike and try that.

Good question, I'll take it out for a ride and see if the slipping is more pronounced when it's hot. Cheers for the pointer.