550 Owners worried about primary chain noise READ

Let me begin by saying a real factory service manual is a wonderful thing, as is eBay where I found mine for $15. Careful study of the lubrication schematic reveals that the Hy-Vo primary chain tensioner is OIL PRESSURE FED. Specifically, it is referred to as the "oil pressure tensioner." Which explains why the clatter and clamouring from below decks shuts up as soon as any revs go on the clock. I love my factory book (it also has full cable and wiring routing diagrams.)

 

OK, sounds like you were going somewhere with this and stopped in the middle......

 

nope. There have been a lot of posts from folks worried about the noises coming from the engine room on the 550's especially hot and idling. I myself wondered about just how "automatic" whatever was supposed to be tensioning the Hy-Vo chain actually was. There is NO MENTION of the tensioner other than making sure the plunger is installed correctly. It was a mystery to me as well, until I got my factory service manual. The functionality of the pressure tensioner is now demystified a bit, and I thought I'd share.

 

Ok, I kinda wondered about mine anyway.
And you're right; you probably shouldn't have sold the Triumph.......

 

I too have noticed alot of bottom noise after warm up at below 1000rpm.
It's got me worried actually. I was wondering If I have a bad bearing or worse.
The xj550 I had had some noise under 1000rpm too but I don't think it was as bad.

Anyway's , What are the charicteristics of a crank or rod bearing failure so I can try to elimiate that possibilty from the mix?

BTW- what exactly does the HY-VO chain do? What does it relate to and what does it drive?

Thanks

 

that's good info, as my 550 also makes a racket at idle. It dies down if I pull the clutch in... But almost 6K miles later it still sounds about the same, so I figured it was a "factory" noise

 

The Hy-Vo chain in the 550/600 is the "primary" drive; it is how the crankshaft drives everything else. It runs from the center of the crank to a "jackshaft" or "countershaft" that has the clutch drive gear on one end and the alternator and starter geared off the other end. My '81 (18K mi) makes a bit of a racket (not bad but noticeable) that changes when you pull the clutch in, and goes away above 1200 rpm or so, and is only there at all when the engine is warm. Now that I know about the hydraulically-operated tensioner, I have quit worrying about it. I can only talk intelligently about the 550/600 in this regard, I'm not 100% sure how the other XJs are configured.

 

On mine I got a spinny thing behind the motor with a metal pipe hooked to it which connects to another spinny thing at the rear wheel. ("Captain Dummy Talk" for shaft drive).

 

I was referring to chain primary drive vs. geared primary drive... I'm not 100% sure if all the XJs use a primary chain, or if some of them might be all gear-driven. I'm relatively new to XJs (not to bikes) and all my "course work" has been on the 550s as I try to learn everything there is to know about them... and about which spinny thing spins which other spinny thing...

 

As far as I can tell from the manuals (someone please chime in), 650 and 750 motors have a direct gear drive from the crankshaft to the clutch assembly. What they call "primary chain" seems to be going from the crank to the starter clutch, which also has the ACG rotor mounted to it. It seems strange, but somehow beautiful

 

thanks so much for this thread bigfitz52. My 550 has the exact same noise as described above. only at idle,warm bike,goes away with rpm increase. it is quite loud and I have been extremely concerned about it ever since I bought it last june. after reading this thread I'm not nearly as concerned as it looks like it is a factory noise.Whew! feel much better now.

 

catdawg You might want to pull your clutch cover, undo the pressure plate bolts, lift out the pressure plate and check the clutch hub NUT.

Quite some time after I posted that, when I went to rebuild the clutch, I discovered the NUT was LOOSE and only the poor battered tab washer was holding it together.

It quieted down considerably after the clutch rebuild; the loose clutch HAD to be contributing.

Upon reassembly, ensure the dot cast into the pressure plate is aligned with the dot cast into the basket. If you have to pull the clutch down, take careful note of the placement of the plain plates and their tabs.

And always run 20W something oil, either 20W40 or 20W50.