Engine problem in Carolina

[Shovel Jockey]

Looking for an experienced XS650 mechanic in upstate South Carolina, Western North Carolina or Northern Georgia to help diagnose an engine noise that's bad and getting worse. I've done all I know to do. Hughs Handbuilt is covered up and can't get to it. It's pretty deep and although I'm a decent wrench I'm not sure I can take one of these apart and put it back together. Thanks, Joe

 

[angus67]

I never rebuilt an engine before my rebuild in 09. It isn't really that difficult, plus, yours runs. Mine had a busted grunion, and the rod jammed the piston up into the head. I rebuilt it to 680cc chopped it and it's a blast!
There isn't much to these engines. They are roller bearing ( no babbit bearings) low oil pressure, a great forum to reference. Parts to get up and running are cheap, and when you can afford a true Yamaha piece instead of a cheap knockoff,
You just replace it. The rebuild kit for the top end can be had relatively cheap. I baught a piston kit from mikesxs.com for 550$. I took the kit to a shop, they checked out the parts, and for $45, they skimmed the head, lapped the valves, and made sure ring gap was good.
You can do it with simple
Tools. The most technical part was using a torque wrench. Shoot.....I installed my Pistons in the bore while
Watching tv in bed!!
The most aggregating part was when i ripped my base gasket sliding it down the studs, then waited a week for a new one.

 

[member3480]

What kind of noise is it??? KNOCKING GRIDING SLAPPING????
Hugh is not that far from you
These motors can have bad cam guides that make noise crank bearing noise clutch noise?
Does it start up easy and does it have power?

 

[Shovel Jockey]

Thanks for the vote of confidence Angus; maybe i'll give it a shot. If I get into it I'll probably keep the rebuild down at the shop behind the house though; the only jugs I want to be handling in bed belong to.......well, never mind.

 

[Shovel Jockey]

Knocking daddycycles. seems to go with the crank revolutions. I bought this 78E model 4 years ago out of a collection with less than 500 miles on it. It's ran flawlessly for over 21k miles. I've done all the maintenance, tuning and most of the upgrades myself. a couple of months ago I heard some noise starting around the camchain; adjusted it like I always do but no improvement. drained the oil and found pieces of the guide or tensioner in the sump and a little metal in the side filter. Researched a bit deeper and realized I had one of the dreaded "D" type cam chain tensioners (without the locknut), and it was overtightening itself after I would set it each time I installed the acorn nut. BEWARE THE D TYPE CAM CHAIN ADJUSTERS!. Took it to a shop that deals with Harleys and vintage metrics; no XS experience though. They replaced the guide, rear tensioner & chain. They also said it needed new rings and valve guides, decarboned the combustion chamber and lapped the valves. I got the bike back and after I reset the timing, which they had off, It ran ok but was making a pronounced noise I had never heard before; and it's gotten worse. I took it back to the shop and they said it was piston slap due to the Hastings? rings they installed and to ride it till she started smoking and they would rebore it. I'm not so sure about that and think I'd better get a second opinion; ya know? PS, I upgraded to the "E" type cam chain tensioner thanks to Doncon on this forum. Simple swap.

 

[member3480]

Well if is a bearing knock then its time for a complete rebuild. I do these all the time and you are dealing with a 20 plus year old motor. Putting rings in a motor with out cleaning up cylinders is not helping you. I do rebuilds and a lot of these older motors need to be tested for crank play and should have been done when it was tore down. It hard to tell what is wrong without a tear down if the noise is loud. If you break it down you can always contact me for advise because I am in NJ but do go to my sons in NC (Carolina beach ) offen. Sound like you got some work to do.