Madgadget
07-08-2011, 08:13 PM
Hi All,
This is my first posting here, so I must apologise for the length of it, but I've been trying to solve a particularly tricky problem.
I've been bitten by the monster bug several times now, the first was a rebuild of a rather shabby looking M600 1995 model year (which I will be posting up some pictures of the rebuild shortly) and the second was a recent purchase of a really sweet sounding 696+ with termi's :)
The M600 has been running well and shifts up and down quite nicely, and has a good turn of power about it, however, it's just started to develop a rather nasty sounding metallic knocking/ticking. This ticking doesn't immediately appear when started from cold, but comes in after about 5 seconds and then continues until the engine is warm, where it quietens down.
I've done a number of tests on the engine, checked the oil for signs of swarf, foreign particles etc, the engine did have that commonly occurring loose alternator nut which has now been tightened up, but it's still got a ticking/knocking sound.
It appears to be coming from the horizontal cylinder as far as I can tell using a stethoscope. I've checked the valve clearances on this cylinder and they are within the normal tolerances (inlet 3-4 thou on the opener, 6-7.5 thou on the closer, Exhaust 2 thou on the opener and 4-6 thou on the closer - which according to the book is a little on the high side, but not too much).
So, I'm left with either a fuel problem, although the plugs seems on the dark grey/black side, not light brown and not oily, a big end going (but nothing obvious in the oil filter etc) or a piston slap problem- from what I have picked up from reading through previous postings.
I've got an MP3 of where the sound is most prominent: http://www.ps-l.com/monster/Monster%20600%20metallic%20sound.mp3
Anyone heard this before?
I'm toying with having to strip the engine completely down thinking it's either piston slap or replacing the main bearings, or should I just by a second hand motor off of fleabay....?
The thing is, the engine pulls fine, the compression is good, and it goes well. In the rebuild of the bike, I did put in a new washable filter and cleaned down the carbs, and the only thing different from the norm is that I replaced the rusted old exhaust cans with some sweet 696 cans - would that have meant that the fuel is now lean? although the plugs don't show anything odd about them.
Any help, or guidance greatly received as I am pulling my hair out here !! :(
This is my first posting here, so I must apologise for the length of it, but I've been trying to solve a particularly tricky problem.
I've been bitten by the monster bug several times now, the first was a rebuild of a rather shabby looking M600 1995 model year (which I will be posting up some pictures of the rebuild shortly) and the second was a recent purchase of a really sweet sounding 696+ with termi's :)
The M600 has been running well and shifts up and down quite nicely, and has a good turn of power about it, however, it's just started to develop a rather nasty sounding metallic knocking/ticking. This ticking doesn't immediately appear when started from cold, but comes in after about 5 seconds and then continues until the engine is warm, where it quietens down.
I've done a number of tests on the engine, checked the oil for signs of swarf, foreign particles etc, the engine did have that commonly occurring loose alternator nut which has now been tightened up, but it's still got a ticking/knocking sound.
It appears to be coming from the horizontal cylinder as far as I can tell using a stethoscope. I've checked the valve clearances on this cylinder and they are within the normal tolerances (inlet 3-4 thou on the opener, 6-7.5 thou on the closer, Exhaust 2 thou on the opener and 4-6 thou on the closer - which according to the book is a little on the high side, but not too much).
So, I'm left with either a fuel problem, although the plugs seems on the dark grey/black side, not light brown and not oily, a big end going (but nothing obvious in the oil filter etc) or a piston slap problem- from what I have picked up from reading through previous postings.
I've got an MP3 of where the sound is most prominent: http://www.ps-l.com/monster/Monster%20600%20metallic%20sound.mp3
Anyone heard this before?
I'm toying with having to strip the engine completely down thinking it's either piston slap or replacing the main bearings, or should I just by a second hand motor off of fleabay....?
The thing is, the engine pulls fine, the compression is good, and it goes well. In the rebuild of the bike, I did put in a new washable filter and cleaned down the carbs, and the only thing different from the norm is that I replaced the rusted old exhaust cans with some sweet 696 cans - would that have meant that the fuel is now lean? although the plugs don't show anything odd about them.
Any help, or guidance greatly received as I am pulling my hair out here !! :(