HELP! I might have Killed my Engine?
Posted January 04, 2002 - 08:58 PM
So I'm fairly new to the XR thing and I treat it like my old liquid cooled CBR. That is, I ride it hard and don't worry about much else.
Anyway, after a long hard day of riding (hot engine most of the day) the engine starts making a light tapping noise. I check my oil and sure enough it's 3/4 a quart low.
Well stupid me, I ride to the nearest gas station to buy oil. That's probably not the stupid part, but what is... is I rode HARD to the nearest gas station.
I filled it up with semi-synthetic which is what it had in it, then called it a day and rode the 75mph 15 mile trip back home.
When I got home, it was tapping again. LOUDLY!
I changed my oil tonight and started it up and it's still tapping, LOUD!
Seems to be coming from either the upper cylinder area where the cooling fins are, or from the bottom front area of the engine just below the header tubes.
Does anyone have any ideas? Or is this a tear-it-apart and figure it out type of thing?
How much would a complete rebuid cost me? Ballpark figure?
Posted January 04, 2002 - 10:25 PM
I wish you luck.....things could get spendy.
Posted January 05, 2002 - 05:52 AM
your XR seems to be needing some valve adjustment!
Beware of one thing: a french dirtmagazine warning refered the third gear breakage on stock 600 XRs in case of excessive road use of the bike...but I suppose that yours demultiplication isn´t the original and it's longer!!!In that case I think you shouln't worry.
Great rides and happy new year for you
Posted January 05, 2002 - 02:21 PM
Posted January 05, 2002 - 03:50 PM
Well I took the XR over to my friends house and he adjusted the valves for me while I watched and learned.
one needed a bit of adjustment, one was perfect and two others REALLY were out of adjustment. I mean wiggly like.
After he put the bike back together I started it up and it ran PERFECT with no tapping at all. BUT.... about 30 minutes later some of the tapping came back. An hour or two later the tapping was actually loud again, though I can't hear anything at idle where as before it was very loud at idle.
Posted January 05, 2002 - 10:39 PM
The piston and rings are cheap and the nykasyl cylinder probably won't need replacing but the valve parts on top may get pricy. Did you change out the old oil and check the filter and screen for metal particles? Probably not but that is a good place to start looking for serious wear and tear.
That old bike is not worth much on the used market so you really have to conseider how much it is worth to yourself before getting into a major rebuild.
Posted January 06, 2002 - 07:14 AM
Did find that you could pull the offending rocker and run as a 3 valve motor to get home. (two days back to the truck in Baja)
Posted January 06, 2002 - 03:26 PM
I herd XR600's making a loud tapping noise because of the decompression cam. I would check the valves again, your friend might not have tightened everything well enough. You can also take a valve cap off and start the bike to see if it's getting oil. It should make a mess.
If you pull the valve cover off inspect the top end and look for lack of oil damage. If your not getting oil the screens could be pluged.
How does your plug look? Is it all white? I wounder if it's pinging. I could here my bike pinging and making noise unless I ran 95+ octang when it's hot. This bugged me for years.
Posted January 06, 2002 - 03:50 PM
Mostly because I was coming off a "real" street bike (4cyl CBR900RR) and didn't realize that keeping the revs up would kill the motor. Also thought it had about 4 quarts of oil instead of the 2.1 that it holds.
The decompression lever and stuff is no longer on the bike. The previous owner (who also beat the bike) took all that and bunches of other stuff off the bike to get it as light as possible. No battery, electric starter, tachometer, odometer, etc.
After riding all day today I can say that the noise is definately back. Though still not as loud as before.
I'm going to look at the valves again tonight. Does anyone know what the clearance is? My buddy did 4 and 5 for the clearance and after reading my manual I think that's wrong.
Do I still need to adjust the front right valve differently even though it's no longer setup as a decompression?
Posted January 06, 2002 - 04:51 PM
Posted January 06, 2002 - 06:24 PM
Of the two that were previously loose, the left front was loose again. The other was fine.
So I adjusted that one valve clearance and took it for a test ride.
Some of the tapping was gone, but for the most part it was still tapping pretty bad.
I can't afford a top end rebuild right now, much less a new cam.
Posted January 06, 2002 - 08:11 PM
Posted January 13, 2002 - 09:51 PM
Took the valve cover off tonight. The CAM looks GREAT! and FEELS okay. I felt the "tiniest" amount of wiggle at the end cam bearing. Sort of the same amout of wiggle that you feel at the valves are at TDC of the comression stroke.
The left front <larger> ROCKER or LIFTER is GONE! Absolutely worn THROUGH!
The other seven large and small rockers are fine!
So can I can just replace the one rocker without a problem or will that screw other things up?.
Anyone got a used one for sale, or know a place on the net that sells them? I can't find rockers for sale ANYWHERE on the net.
Posted January 14, 2002 - 04:27 AM
Posted January 14, 2002 - 04:50 PM
Just bought a rocker... $42 at Honda.
Thanks for the help everyone, I'll give you an update when the rocker goes in.
Posted January 14, 2002 - 07:38 PM
returning the bike to service, I would suspect that you are having a problem with the valve
train. Something is wearing out causing the valve clearance to change rapidly. Sub rocker
arms are a problem on the RFVC motors, the adjuster screws actually drag across these
rocker arms and when it starts to wear the valve clearance will change rapidly. If I
remember correctly the sub rockers are about fifteen bucks each and can be sent out and
heat treated for twenty bucks each, the adjuster screws should be heat treated as well. Or
something else is going away in the valve train, one of the various rocker arm pins, the
valve cover itself, or it’s fixen to swallow a valve. Either way don’t run it any more until
you remove the valve cover and find out what is going on. A factory service manual will
help a great deal with top end service.
Posted January 14, 2002 - 07:44 PM
you can get all of this stuff heat treated (harder) but is not necessarily a required process.
What is a must on the RFVC motor is fully synthetic oil to keep that monkey motion valve
Posted January 15, 2002 - 12:38 PM
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