please excuse me sticking my oar in, like you say not worse clutch ever seen, at first I thought this might be case of poorly set up adjustable levers, yours appear standard, is this starting from cold? (is the fast idle / cold start engaged?) because having watched the video it seems as if the clunk is caused by the stall not vice versa. (what happens if you try this with bike on the stand?)
This really is an odd one. The every third attempt bit is what puzzles me. Sorry to say it, but I think that Left Hand case cover is going to have to come off for a better look. It may well be easier to feel/see if it's a gear selector issue with the selector mechanism in front of you.
you could be right, and ideally you would experiment more out on the road to see what happens if you ignore the clunk and restart and carry on (as said in a p.m.) and so frustrating that this isn't possible right now, but I think @witchellski can possibly still confirm if bike physically stops abruptly rather than revs lowering and stalling (and then clunking).
yes, sadly it's best to "get into the bowels" now, and selector side would be first side to look for me also.
I did have the bike out on the road very briefly a week or so ago, but had to bring it back in because it was really not happy (also totally illegal ). I actually thought my front brakes had seized because it wouldn't drive forward. It just stopped dead when I put it in gear. This was when I realised there was a definite problem. When I run it on the stand it will go through the gears (rear tyre off the ground), but is really vibey. It was almost like the swingarm / rear shock was loose. They aren't cause I checked. Might be time, as suggested for the engine casing to come off. I don't really want to run it anymore for fear of doing more damage!
I'm almost certain it's the mechanical clunk that's causing the stall. Without more road time it's difficult to know for sure. I had tried more revs and more clutch slip, but that made the clunk more severe. Like a stick in the spokes!
I'm in no hurry to get the thing back on the road, so I might just leave this hanging and see what others think... Then the spanners will need to come out! Thanks for all your comments so far. Really, really helpful.
quite right, re: doing more damage, you've fully confirmed now, I wasn't sure if you'd ventured out further.
I have the same thing on my ST4, then if I use a paddock stand (supports the swingarm) vibes dissapear.
Draining the oil and having a look at it might reveal something. Check the drain plug magnet for metallic evidence of the ferrous variety too.
So, I dropped the oil to find no evidence of debris on the sump plug. a bit dirty, but definitely no shards or shrapnel. I proceeded to take the left side cover off the engine, which I am glad I googled first, because I would have missed the casing bolt under the clutch slave cylinder! Once removed, again there was no evidence of damage. The selector spring and arm looked normal to me, but I took a couple of videos just to share in case there is something obvious in there I missed. The first video is just a tour and the second is me selecting second and neutral. The selector is at a jaunty angle to avoid the ABBA stand mount. Let me know what you guys think, before I start pulling the other side off. I'm now thinking I should remove the clutch basket and inspect the gears on that side.
Sorry that the cause of the problem is yet to be revealed, have you managed to replicate the "catching" sound with this cover off out of interest?
When it stops, is it an engine stall or the gearbox jamming causing it? Asking because (not wanting to worry you) my Monster sheared 4 teeth off the 6th primary gear and aside from a rhythmic rumbling when in 6th gear, it would sometimes jam up when pulling away in 1st due to the idling 6th gear cogs locking against each other. Here's what it looked like; Though I did find more evidence on the sump plug than yours; As for it breaking, there was no drama, no noise or anything. It was just good one minute and clunking the next. But, as I said, I don't want to worry you...
Gulp… I really hope that’s not my problem. Certainly sounds like the same symptoms though. I’ll split the other side and see what that uncovers.
Just a thought, but could it be electrical or fuelling? Such an abrupt cut out sort of feels like something cutting out… Anyway, further investigating to follow.
Hopefully nothing that serious. I removed the clutch plates and the chain/sprocket so that I could spin the gearshaft freely. Used a socket onto the clutch hub nut with a battery drill to see how smoothly it spun in gear, it would jam every so often in most gears and even in neutral. But if it's a damaged gear you won't see it (other than maybe hidden shrapnel) through the side cases, I had to remove the rear cylinder to see the full horror although dropping the oil told me all I needed to know. More info here if you want to hear about it; http://www.ukmonster.co.uk/monster/showthread.php?t=59257
If you have an endoscope camera, you could probably get a decent look at the gears through the side of the engine under the cases without much dismantling? Although I've got one I didn't try as it was obvious from the crap in the oil that I needed to split the engine.
It does feel like an engine stall. I’ve been watching my video over (certainly don’t want to run it any more) and it feels like it’s instantly losing power, rather than drive if that makes sense.
Happy New Year to you all... I couldn't keep away from the bike today, so I thought I'd do some further investigation. I have a late 90's 900 Monster, which is next in line for a rebuild, so I have been systematically robbing things off it for the ST2. The latest theft is an Odyssey PC680 battery. Far superior to the OEM Yuasa and bags of power. Watching the videos I took I just couldn't get it out of my head that there was a potential electrical fault with the system. This is by no means conclusive, but I swapped the battery out and started the bike up. The first thing that struck me was the difference with the starter motor. It span up really easily, unlike the Yuasa battery which caused a sluggish start. Also the neutral light came on. I ran the bike and popped it into gear and pulled away in first. It managed to do it 4/5 times without stalling. This is a vast improvement, but could it be the solution? If the battery was dud and wasn't taking a charge it would only take a few starts to pull the charge down enough to affect the rest of the system. As I said in an earlier post, it just felt like a dead stop, or cut-out. Anyway, I have ordered a new (more powerful battery) that fits in the space left behind by the OEM one, so I will report back once I have fitted it. The Odyssey won't fit unfortunately. Fingers crossed this does the job... At least I have a bit of peace of mind about the mechanicals (for now).
