Knock Knock... Whats there

OK. I got my first XJ650RJ courtesy of Craigs list and after cleaning carbs fluid changes etc got it to fire and run briefly. noticed valve noise so checked clearances. All but one measurement indicated low clearance. Pulled the head and am in the process of lapping and adjusting valves but While I was searching for proper compression just prior to pulling the heads I ran into another problem/concern. While you are cranking this bike over there is a knocking noise that fades in and out. It will turn over about 10 or 15 revsjust fine and then it starts to knock louder and louder for about 10 - 12 revs then it fades away just like it started and will crank nice and quiet like for another 10 - 15 revs and then it starts all over again. Never heard anything like this before and it has me shaking my head. Any suggestions?

 

OK had to reply to myself to get the message back to the top of the board. I really need help on this one. Anyone have any ideas? any at all? Intermittent clunking noise when the motor cranks? The guy I bought this bike from said it ran great when he put it away, he just wanted to get a bigger bike. He's got the BMW k1200 to prove it. He loved his seca so much he couldn't part with it, but after 4 years sitting in the garage he couldn't justify keeping it any more. I know the guy through work so I trust his version of the story. When I tore the bike apart I found valve clearances were too low pretty much across the board and the cam chain tensioner went clunk when I released the lock nut but when I removed the tensioner to pull the head off, the tensioner did seem a little sticky. I want to turn over the motor without the head to find out if the clunk is in the bottom end or if it's gone now that the head is off. How do I do that without screwing up the cam chain that is hanging loose? What else should I check?

 

The fact that it comes and goes is strange, but the bike should turn over in 5-6 spins, tops. If I'm reading your post correctly it sounds like youre turning it over 30-42 times? Have you been able to isolate where the noise is coming from?

 

I'm not cranking the bike over to start it. The coils are disconected, the plugs are out and the valvecover was off to inspect clearances. The thunking noise was loud so it was hard to locate. When it was running it sounded like a rattle at idle and was coming from the top right side of the motor

 

I'm wondering if it's in the starter clutch mechanism.

 

OK.. I will try turning over the motor without the head on this evening. If the clunk is still there I will turn the motor over by the end of the crank and see if it is the starter clutch.

Anybody know the best way to keep the cam chain out of the way or supprted so as not to FUBAR the whole works.

 

Starter clutchs will make lots of various noises that could easily sound like your are describing. just check the oil and make sure it doesn't look like you are panning for gold (spun bearing) and you should be fine.

Sean

 

When I swapped the fluids before I started her the first time it was beautiful. Old as hell (you could smell it) and a little dark, but you could still see through it (sort of) and no metal to speak of beyond the normal fine silt on the magnet.