Classic
rackin' up the miles
I just took out my filter and found quite a bit of my cam chain tensioner in it. I was just wondering how much longer I have before it is necessary to rebuild the motor.
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My method.........Check the compression.....140-150 throttle open and about the same on both sides is good....the pistons and cylinders may be fine......in that case I would pull the pins and leave the pistons in the cylinder as to avoid a fresh break in and assoiciated wear......if you have to pull the cylinders.....valve seals and lapping is always good to do.........flush the junk out.........check oil pump and clean...remove carbon from the combustion chamber........
Good way to check piston wear is with the head off and not removed.....force the top of the pistons front to back with your hand......if there is just a tiny bit of movement that is pretty much normal........lots of movement and the pistons, rings and cylinders need to be inspected for clearance and wear......might save a bunch.............especially if it not a high mileage engine.......
xsjohn
Good way to check piston wear is with the head off and not removed.....force the top of the pistons front to back with your hand......if there is just a tiny bit of movement that is pretty much normal........lots of movement and the pistons, rings and cylinders need to be inspected for clearance and wear......might save a bunch.............especially if it not a high mileage engine.......
xsjohn
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Sundie
Jabroni
John, can you define that front to back piston movement in measurements? Like, is 1mm gap okay?
Classic: it's probably not your tensioner (at the back of the engine) as it is the guide (at the front). Which is good, because you can replace the guide without taking the jugs off, (just take the two bolts out the front after you have the head off) but the tensioner *requires* taking the jugs off.
Classic: it's probably not your tensioner (at the back of the engine) as it is the guide (at the front). Which is good, because you can replace the guide without taking the jugs off, (just take the two bolts out the front after you have the head off) but the tensioner *requires* taking the jugs off.
Sundie......As many times as I have seen this movement I should l have come up with some measurements......since it was for my use I just kinda learned what I might find when I went farther or the need too.......to tell you the truth most bosses in bike shops would rather you go all the way so you could charge more......imagine working all day and parts eveywhere as he notices and then later there was 4 valve seals 1 head gasket and 1 front guide and 2 quarts of oil on the ticket....and if he didn't like that what would happen if it did come back smoking......kinda different when it's your own and you know some history..........
Hell you can take a mag light and a screwdriver and go down the spark plug hole and try to wiggle the piston front and back and find something out.........beyond shade tree there....
Little bit ok ......a lot not good......and did it have piston noise when starting off cold tells you something......little bit there and it goes away as the engine warms and the piston head swells then it's ok but wore slightly.......if it doesn't after a half a mile or so thats not too good ...never leaves not good...........that's the rock you are judging by forcing the piston front to back with the head off....and the rock may not be totally the piston or bore........worn rings maybe........
xsjohn
Hell you can take a mag light and a screwdriver and go down the spark plug hole and try to wiggle the piston front and back and find something out.........beyond shade tree there....
Little bit ok ......a lot not good......and did it have piston noise when starting off cold tells you something......little bit there and it goes away as the engine warms and the piston head swells then it's ok but wore slightly.......if it doesn't after a half a mile or so thats not too good ...never leaves not good...........that's the rock you are judging by forcing the piston front to back with the head off....and the rock may not be totally the piston or bore........worn rings maybe........
xsjohn
Sundie
Jabroni
Well, the one thing is true - no piston noise when started up at all. I'm assuming you're talking about slapping/knocking.
Classic
rackin' up the miles
I've got just over 140psi in each cylinder and the motor is just about to turn 17,000. I'm pretty sure those black plastic pieces are the plastic guide part of the tensioner. I'll see if I can make time to rebuild the motor. It will be difficult though as the XS is my only vehicle and I work a lot.
Sundie
Jabroni
Classic: both the guide and the tensioner have those black plastic pieces. But the guide is just more prone to delaminating from the aluminum mount it's on.
Also, with 140psi... I'd leave it alone, and just check your oil/filters often. You're in Minnesota, fix it when the snow flies again.
Also, with 140psi... I'd leave it alone, and just check your oil/filters often. You're in Minnesota, fix it when the snow flies again.
Sundie
Jabroni
i like adjusting it while the engine's warm and running, and get it sort of in the middle of whatever the vibration is. Messy though.
Classic
rackin' up the miles
michael Rides
XS650 Member
Regarding cam chain tensioner, Is there an effective way to see the condition of the forward tensioner without taking the rocker cover off. When I got the bike (81 special ll) the Motor hadn't been run in 15 years. Got it running, warmed it up and changed oil, filter and sump filter. I had one 1/32 x 1/32 by 2 inch sliver of black plastic in the sump filter. Got it running again, adjusted the chain and rode 10 miles. Changed the oil again and found no additional pieces. Concluded that either i am good or there is no black plastic left to break free and that the chain is rubbing on aluminum (hope not). With the sump filter off, I cant really see much. Any ideas. Was hoping to get some miles in before winter when the major overhaul will happen. Previous owner says he never saw any tensioner in his oil changes (told me the truth about everything else so tend to believe him). Any thoughts?
No, there's really no way to visually inspect the front guide short of a teardown. The front guide is channel shaped and what you discovered is a piece of the lip running down each side. It's common for that part to break off first. It doesn't necessarily mean the guide is totally shot yet, just that it's started down it's "road to destruction", lol. You should be OK running it for the rest of the season.
michael Rides
XS650 Member
Thanks for the quick comment. Dont like the sound of a road to destruction. I will avoid that street sign>
I just replaced mine and like 5twins said it was just the lips off the side. It produced a lot of plastic which made me pretty worried. When I pulled it, all of the main part in the middle was intact. Wish I had waited and made it a winter project... spent my summer on a honda elite scooter haha
