I found this in my sump..!

Had teh clutch out of my 550 (YX600 engine) to try and cure a rattle, and while peering into the sump I found this piece which I manoeuvred (?) out with a small tool I had to make. I'm thinking its a piece of HyVo tensioner guide and I'm also thinking its probably the main cause of the low speed (sub 1200rpm)'chugging' rattle.
I see on the shaft model you can just about replace this without a complete strip down (just the sump & lower crankcase half?) Is this also possible to do this on the chain models?

It's been like this since I put the motor in (maybe 3k miles) so I'm not too concerned but if I get a few rainy days it could be something I fix.

 

I have not been inside a chain drive XJ engine but that looks like the nub off the end of the starter chain tensioner that fits into a place in the engine case. Without the tensioner doing its job the chain rattles around and will hit the engine case and also oil spout that sprays the starter chain.

 

Chain and shaft driven bikes only difference is the final drive. I would be surprised if you couldn't get to the guide just by splitting the cases. Don't know if anyone on the forum has done this.

 

I don't know what it is but according to esteemed member Bigfitz52 the chain guide is not going to crumble in the 550 - plus in the 550 the chain is a true drive that is hydraulically tensioned and not gear driven like the shaft driven XJ's. Unfortunately, photobucket strikes again as the image is missing, which might have given some confirmation to the part.

https://xjbikes.com/forums/threads/xj-550-engine-noise-please-help.40470/

https://xjbikes.com/forums/threads/rattling-noise-on-idle-550-primary-chain-hi-vo.33497/

 

Here's what the 550/600 hy-vo tensioner set looks like..

 

I suspect my chunk is part of the lumpy bit - question is does any one know if it can be accessed with only a partial strip (remove engine flip it over and remove sump and lower CC half.)

 

Yes, it can be accessed from just the bottom the bottom half. I just did a 750 for the starter clutch and put in a new chain tensioner and glad I had planned on it as the old one dissolved as I was removing it. Still a fairly involved job but not terribly difficult if you pay attention to the details as you should anyway. Consider changing the chain as well if plenty of miles on the engine.

 

Thanks but the chain drive models are different to the shaft 650/750/900 s so the question remains I think. Actually I recall also have a 'scrap' 600 bottom end so I might just end up pulling that apart to check what's what. If I do I'll take pics aong the way.

 

I am trying to find the xj website we use with all the factory manuals. You should get the details there if l can find it.

 

I have a PDF of the factory manual courtesy of the old guru Brian.. However the picture of this aspect are minimal and not very detailed. Photography has come a long way inthe past 45 years!