427 replies to this topic

[Alex DeFreitas TT Bronze Member]

HELP NEEDED

I own a 1996 xr650l. I replaced my 45t rear sprocket with a 40t sprocket from drive systems. On the highway the other day I was full throttle in 5th and my engine blew something. Important to note what happened.

**** The best way to describe it is what happens when you hit reserve on the highway. 60mph or so and then all of a sudden it sputtered and lost all power. I had just filled up the tank so I knew something was off. I pulled over and couldnt get it started again. After 30 tries I finally got  it to roar back.

****THE ISSUE: Now there is a high pitched rattling coming from somewhere in the engine block. It is hard to diagnose eaxactly where it's coming from but I can assure you it is a new noise.

I have stripped this bike all the way down to the frame MINUS TAKING OFF THE ENGINE.

I find it ironic that this happens right before my spring break so this is my question to you guys...


SHOULD I TAKE THE ENGINE OUT AND BREAK IT DOWN SERPERATLY

OR

DO YOU THINK IT IS PERHAPS SOMETHING THAT COULD BE "EASILY" FIXED WITH THE ENGINE STILL ON THE FRAME.



I am prepared to take the engine off but I must admit that I have never rebuilt an engine and don't even have any ideas on how to lift it out.


Any advice appreciated.

[Alex DeFreitas TT Bronze Member]

*****ALSO

my pig still rides. there is that high pitched rattle but i was able to ride her off the highway before trailering her home. figure this might be important to note.

[Horri TT Titanium Member]

Any chance of a tape/vid of the motor running with the noise??,,Might have had a mild seizure or some such thing.,Being able to restart it after a while cooling downs sort of maybe an indicator of a possible partial seize..Then again maybe the small ends given way or less likely the big end..Guessing really though..

Edited by Horri, 08 March 2012 - 05:56 PM.

[Alex DeFreitas TT Bronze Member]

I will take a video tomorrow and post it on. The noise to me sounds like a nut fell off and is rattling around somewhere. That is the sound at least.

[dubkatz TT Silver Member]

if the sound is coming from the case your gonna have to pull the motor and split the cases. or at least i would bet money thats the case. What ever you do dont ride it. If something is loose and you ride it you risk lunching your tranny. Either way get the car keys cause your bikes going to be out of commission for a while.

[ThumpNRed TT Titanium Member]

You likely seized your motor. You are going to have to pull the motor and do a complete tear down to know the extent of the damage. Have you drained your oil since the bike crapped on you? I bet the oil is "black water" nasty and the filter may even harbor a surprise or two for you. DO NOT get fooled into running it again as any damage that's already been done will not cure itself. Bruised engines don't heal like bruised biceps.

[Alex DeFreitas TT Bronze Member]

doesnt seized engine imply that its stuck? mine still works ... im not that educated in engines.... im studying mech engineering but cant say ive ever torn an engine apart... first time for everything

[ThumpNRed TT Titanium Member]

It doesn't have to seize tight. Usually if a rod seizes tight on the crank, the crank and rod bust and eject out the side of the case.... the internal combustion grenade (not a pretty sight). In your case, it sounds like something got tight but continued to turn due to the rotating mass. The increased friction caused the bike to lose power. Once everything cooled down, you were able to get it started again. The fact that you have a new noise, leads one to believe that it is bruised and needs attention.
Check the oil and filter. I suspect you may learn more

[thestuz TT Gold Member]

its prob just the rocker set chewed out on the cam from prolonged, high rpm.
ive got a ported head with new valves installed from a 98xr600 and a rocker cover for a decent price if its what you need.

[ThumpNRed TT Titanium Member]

thestuz, on 08 March 2012 - 11:13 PM, said:

its prob just the rocker set chewed out on the cam from prolonged, high rpm.
ive got a ported head with new valves installed from a 98xr600 and a rocker cover for a decent price if its what you need.

I thought the same thing, but the fact that it would not start until after it cooled down makes me wonder if it is not something in the bottom end. The end rersult is the same either way though... motor needs to be sitting on the workbench.

[cyclewizard TT Bronze Member]

ThumpNRed, on 08 March 2012 - 07:03 PM, said:

You likely seized your motor. You are going to have to pull the motor and do a complete tear down to know the extent of the damage. Have you drained your oil since the bike crapped on you? I bet the oil is "black water" nasty and the filter may even harbor a surprise or two for you. DO NOT get fooled into running it again as any damage that's already been done will not cure itself. Bruised engines don't heal like bruised biceps.

What ThumNRed said....got hot and seized...

[XR650L_Dave TT Addict]

Maybe it dropped a valve seat?

[HeadTrauma Get Help Now]

Seizures among RFVCs most often happen between the piston and bore and stem from abnormally high piston temperature...which is usually caused by a lean mixture. Lubrication-related seizures don't typically occur before the valvetrain comes unglued first. Ironically, the "Achilles' valvetrain" of these engines often survives even extreme overheating when oil flow is not disrupted. Since these engines have a roller bearing on the rod big end, they don't seize down there. The bearing cage can break up and wipe out the bottom end, though. A wallowed-out small end will produce significant knocking.

If all you did was stick it and just scuff up the piston, then there's a chance you could fix it without opening the cases. If the piston lost a bunch of metal, then it's a good idea to make sure it's cleaned out of the bottom end. Dave makes a valid point; very high head temps can sometimes cause an exhaust seat to drop out, too.

Lifting out the engine isn't real hard. Just pretend you're lifting a 110lb block of cement because that's how much the engine weighs.

Whatever you do, find the root cause and fix that first.

[150ron TT Titanium Member]

how many miles are on it?

[jtf1307tie TT Member]

HeadTrauma, on 09 March 2012 - 10:17 AM, said:

Lifting out the engine isn't real hard. Just pretend you're lifting a 110lb block of cement because that's how much the engine weighs.

99.5 lbs    just weighed mine while it was out!

Edited by jtf1307tie, 09 March 2012 - 05:58 PM.

[Alex DeFreitas TT Bronze Member]

thanks a lot guys... i have an update

spent 3 or 4 hours on it today. broke it down all the way to engine. took out carb etc. it took a while taking off all the electrical components.

Question 1 : I decided to rip off the exhaust and replace it entirely. every bolt and the flange?'s are rusted as shit. While socketing out the nuts on the bolts that stick out of the CAM head plate? Or the front of the engine. Well like 3 of them broke. So where do I have to get to in order to replace these bolts coming out of the front of the engine.

UPDATE: cleared oil finally and none came out of the first bolt 8)..... maybe a cup or two came out of the bottom bolt by the drive sprocket... did a lot of work and had oil sitting for next change.... I know its a newbie move but the owner before me effing changed the stock dip stick for a temperature reader.... so i never really could check the oil level.

****responding to earlier post YES the oil is black. no suprises in the oil filter tho lol...


So im thinking it has something to do with siezing due to overheating????

But regardless there is a rattling noise coming from the engine so I need to find it. Suggestions / Thoughts?

someone said exhaust port or something like that?

[Alex DeFreitas TT Bronze Member]

1996 xr650l

bought with 7340 miles
odometer stopped working last summer at 9430 miles
I approximate it at 12,000 miles

I dont know how long it sat outside before I bought it last spring. I fell in love the second I saw it

[Alex DeFreitas TT Bronze Member]

ALSO

Following my clymer manual (dont shit on it im not buying the honda one)

It mentions lining up the alternating rotor to some T mark. I cant find this mark no matter how many times I turn the bolt. It turns and then "unwinds" real quick and I never can seem to line it up which they claim you have to do in order to move all the valves or some shit like that

[HeadTrauma Get Help Now]

Alex DeFreitas, on 09 March 2012 - 07:30 PM, said:

UPDATE: cleared oil finally and none came out of the first bolt 8)..... maybe a cup or two came out of the bottom bolt by the drive sprocket... did a lot of work and had oil sitting for next change.... I know its a newbie move but the owner before me effing changed the stock dip stick for a temperature reader.... so i never really could check the oil level.

****responding to earlier post YES the oil is black. no suprises in the oil filter tho lol...

So im thinking it has something to do with siezing due to overheating????

Uh.....no, it sounds like you ran it out of oil. WAY out of oil.

What "first bolt" are you referring to?

[Alex DeFreitas TT Bronze Member]

the one on the down tube.

i had done two oil changes before so i know it was real low. like i said one of the two owners replaced the dip stick with a temp gague