Piston slap

[nick31]

Hi, in my continuing search for a Monster i have come across a '98 600 Dark, 22k miles and piston slap has been diagnosed.
My understanding is that its quite a common problem. With these bikes is it something that can be left? If so does it get worse? Or is a new barrel and piston the way forward?

I'm handy with the spanners so i would be capable of sorting it myself, plus the bike comes with low mileage barrel and piston from a 600ss.
Other than that the bike seems to be in good condition, serviced, etc etc. I havent seen the bike yet, its a couple of hours away so before i make the trip i thought i would ask on here.

(It may even be being sold by a member on here..?)

Thanks,
Nick

[Sirc]

it's a controversial issue Nick - or how long's a piece of string even.. If it were lower mileage and the sound all but disappeared when hot then it shouldn't cause concern but if you think it's been doing it for a few thousand miles and LOUD then it's worth checking just to be on the safe side as once the piston(s) and/or barrel(s) start to scuff up badly (some do, some don't) then the engine can eventually suffer anything from low compression to ring breakage. If you plan to run it then oil changes are more important than usual. As you say, it's a known problem (seems to affect front cylinder more than rear) so much so that Ducati changed later bikes to a forged type in an attempt to improve the situation.

[Nickj]

Sounds like a bit of mending might be in order if it's still there when the motor is up to temperature.
Once done go for the regular oil changes at 3k and a new filter at alternate changes, you don't need the real fancy oils just a regular semi-synth. I got my 750 with under 2K on the clock its now up to 45K and running nicely on Tetrosyls 'Carlube' branded 10/40.
Doing a regular thousand miles a month I use a fair bit of oil :(

[nick31]

Thanks guys.
The seller says that the compression is fine, and it only does it at idle. Hopefully i will be able to speak to him on the phone soon to find out a bit more.
Incidently, its a 600 Dark, 22k miles, and he would accept £1000 - does that sound a bit much considering its 'problem'?

Thanks,
Nick

[Kato]

The "early" pre 98 600’s, had pistons that make the horrible slappy noise when cold, not that it gets much better when they warm up. Sounds like the insides are trying to get out, most will tell you "they’re all like that". If you pull it apart, chances are there will be nothing wrong with it. Just very short piston, it can be almost cured by replacing the piston on that cylinder with a piston from a later model (which supercede from the early ones anyway) chances are it will be quieter but never fully cured and you will just get used to it after a while

[Zimbo]

As Kato says, earlier 600 monsters did slap horribly when cold, if the noise goes away when warm it shouldn't be anything much to worry about.

[Dookbob]

these monsters are fetching more now than they were two years ago, at £1000' assuming its not a nail, it,s a bargain.

[pegboy]

I think my M600 was probably the loudest with piston slap. I brought a second hand engine while rebuilding the original engine. The noise was there cold and even louder when hot. It was still going strong after 3 years of running, went to France, few track days, commuting to work, 24m round trip, then the ride outs, tunnel runs etc. i think you get the picture. There us proof they can last a long time, but then there is I'm sure proof that the will go bang, every engine is different and you take a chance everytime you ride it. I must admit I did change oil every 2500-3000 miles including oil filter, but then again i do that with both my bikes.

[nick31]

Thanks guys.

I went to view the bike yesterday, it does sound like piston slap to me. It goes away a bit when its warm, but not much.
But having said that the motor pulls strongly, the rest of it looks good and it has been looked after so i handed over some notes for it.

I was grinning all the way home with the noise coming out of the Remus pipes. :mand:

No doubt i will be asking lots of questions in the forum from now on, the first being regarding rev counters/shift lights..

Thanks again,
Nick