I've had a strange problem with my bike twice in the last week. Both times I went over a large jolting bump (train tracks and a speed hump) and the bike lost connection between engine and rear wheel. Both times I was in 3rd or above, so it couldn't have bumped into neutral. I revved the throttle and without touching the clutch, it was just as if the clutch was in. I pumped the clutch lever a few times to see if it was stuck, but that did nothing. After about 10 secs each time I got it to reingage by pulling the clutch in and tapping the gear lever up or down until I finally got some power back. btw, the bike wasn't stalled, engine was still running. This could potentially be a very dangerous problem if I lost power in a bad situation. Does anyone have any ideas? A worn/broken clutch or gearbox?

cheers,

tone 

any thoughts ?? 

I don't know if there is much of a relationship between this and the oil, but the oil was changed soon after I got the bike, so it might have had something to do with it (cause god knows what was in it). It can't hurt to stay away from anything with friction modifiers in it - a lot of car specific oils have these in them, and they certainly do nothing for a wet clutch. 

It is obviously safe to go for motorbike specific oils like castrol 4t (i think), or the one I am using is Shell helix plus 15w50 which seems to be perfect for motorbikes, is a high quality semi synthetic, and it's relatively cheap.

cheers
michael

check out this guzzi page for info regarding the mechanics of it-

http://www.geocities.com/guzzitech_pages/GearboxClunk-Pete_R.html

Thanks, that seems to make sense with what I have been told from others. The problem didn't occur when actually trying to change gear, but I think I am having a similar problem where a big bump causes the gearbox to move into a false neutral between gears. It is interesting that you mention the change of oil, because I changed it not long before the problem started (although i've only been riding the bike for a couple of weeks, so it is hard to tell). I put in a 4X4 oil (because it matched the spec on the filler cap, 10W-40 i think). I have since found out that I can use a better oil, as suggested in your reply. I might drain it out and give this a try.

cheers,
tone 

I have to agree with Michael though, after I changed the oil in my bike (Motul) it made my gear changing a lot nicer. 

Cheers, Nathan