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mtn500 09-29-2008 09:30 AM

i hope i didnt ruin my engine
 
hello all
a few weeks ago i started the venture of replacing the clutch in my xl500s. got that done but decided i would do more "maintenance" to the bike since i was already doing it, so i removed and rebuilt the swing arm and worked on the exhaust system. i put everything back together, minus the muffler, and rode it to my neighbors house so he could weld a bracket back onto the frame that secured the muffler. after the bracket was welded on, i rode it back home and finished the assembly of the bike. i checked and double checked everything to make sure all bolts were correctly torqued and nothing was left off. rode the bike around the yard...it ran/rode great. so i took it on a short trip into town (3 miles from home) and back, it ran great then too. i was both satisfied and happy that it was back together and running great.
so my girlfriend and i take a ride and thats when it happened. we had stopped on a dirt road to look at something and i could hear a clicking sound coming from the engine; nothing major but enough to make you notice it. the bike was still running fine so i didn't dismount and try to pinpoint the problem, i just decided to head home and look at it ( i was ~1 mile from home). while riding the bike home i noticed that the bike felt like it was losing power going up a hill so i down shifted and when i pulled in the clutch lever i immediately noticed the engine wanting to stall. my first reaction was i was out of gas, but i knew i shouldn't have been, so i twised the throttle and heard the engine rev but it sounded different, like it was hesistant to rev and after the throttle was let off it idled back down and died quickly. i still had the clutch disengaged when it died so i stopped as quickly as i could to see what happened.
first thing i noticed was the enging smelt hot. my next reaction was to check the oil. when i pulled the dipstick, i could see a creamy colored smoke in and rolling out of the crankcase. i was not happy. checked the oil level and it was ok. the oil was brand new but was so hot it appeared to have the viscosity and color of water. i gently tried to kickstart it but there was a large amound of resistance on the kickstarter, kinda like there was no lubrication between the cylinder wall and the piston. WTF! we stood there for a minute while i was thinking what could have happened and then i heard it; a mechanical click sounding like something had just been "freed". what was running through my mind was somehow the engine had gotten too hot and locked up. i hesitantly remounted the bike and tried to kick it over again. there was still resistance when i initially kicked it over but after the first revolution of the crank it felt like it freed itsself and started turning fine. would it crank? i kicked it over twice and it fired right up with no strange noises at all. rode home slowly with no problems. checked oil after cooling down and level was fine and it was not discolored.
so im stumped.

i know that was a long post/explanation of what happened but i wanted to be thorough.
what could have happened? clutch related? clutch plates were soaked before installing and everything was lubed prior to reassembly. could something have happened that stopped the oil pump from pumping oil into the cylinder? any particular areas i should pay special attention to?
thanks for any suggestions

DAKEZ 09-29-2008 10:14 AM

I'm not a Master mechanic but it sounds like a valve issue... (stuck/bent?)

I look forward to hearing what the problem was/is.
Good luck.

Pablo83 09-29-2008 11:17 AM

sure sounds like the engine overheated. If some debris were left in the case from the clutch rebuild it could have clogged an oil passage and caused the cylinder to not get properly oiled. If it were me I would tear down the engine to check for damage. Lots of work, but better than completely destroying in engine in the middle of nowhere.

Good luck

mtn500 09-29-2008 06:11 PM

it could be a stuck valve, i will certainly look into that. as for something clogging an oil passage....thats not unreasonable. im pretty sure i didn't leave debri in the case, but im not perfect. also, as this was my first time working with/on a clutch, i was ingorant to the fact that a new lock nut would probably be necessary, which it was. due to not having a new nut i was halted mid-job for a couple days for the part to come in. i have to work mainly at night so during the summer months there were bugs flying around and at night more than i wanted were in the garage flying around the lights. i covered everything up well after each work session, but i would not say it was impossible for a bug to find a nice dark place somewhere in the crank case and hide out there without being seen.
as it is, it sucks ass. i have no time during the week to work on it so i guess i get to worry about it all week.
i'll post back if/when i find the problem

mtn500 10-01-2008 09:36 AM

i had some free time last night so i decided to check a few simple things on the bike.
i pulled the plug and inspected it; it looked fine, great even.
drained the oil, not so good. the oil was very dark and has what appeared to be metal flakes in it. it appeared to have glitter in it.
here is picture of new 20w50 compared to the 20w50 that had ~10 miles on it.

http://i136.photobucket.com/albums/q...0/100_1887.jpg
the clutch plates had similar material impregnated in them
http://i136.photobucket.com/albums/q...0/100_1798.jpg
http://i136.photobucket.com/albums/q...0/100_1799.jpg
i refilled the case with new oil and hesitantly started it up. it started up and ran fine. i held my hand on the upper part of the block next to the cylinder as long as i could to see if i could feel any clicking/knocking and none could be detected.

im guessing its a clutch issue. it will be until this weekend before i get any more time to mess with it.
i'll let you know what i find out.
thanks

XRsteve 10-01-2008 09:52 AM

That could be a lack of oil getting to the cylinder head, causing things to heat up. Make sure you didn't lose any o-rings or seals when you had the clutch cover off. I don't know much about older xl500s, but on the newer xr's there's a seal between the case and cover that if missing it would cause low oil pressure.

mtn500 10-01-2008 12:02 PM

i definitely suspect there was a lack of oil to the cylinder, but i don't think it was from a missing gasket. i installed a new crank case cover gasket when i put everything back together. not to say it in a cocky way, but im pretty sure that i didn't put it back together with parts missing; though i am not perfect.

if no oil was getting into the cylinder, wouldn't the rings get damaged first? and if the rings did get damaged, would't it then start to burn oil which would be evident in the exhaust gases?

XRsteve 10-01-2008 12:15 PM

Quote:

Originally Posted by mtn500
if no oil was getting into the cylinder, wouldn't the rings get damaged first? and if the rings did get damaged, would't it then start to burn oil which would be evident in the exhaust gases?

The cylinder is probably lubed by splashing oil from the crankcase. If the head isn't getting oil, it would sound like what you described. I've seen that personally and the end result isn't pretty.
I'm not sure what year your bike is, but I just did a little research and couldn't find any seal that could be left out. So that probably wasn't it. I can't find out how oil gets to the top of the head. If it's like later XRs, there's an oil line going up to the top. You loosen the bolt to check oil flow. Maybe the same would work on your bike.

mtn500 10-01-2008 01:16 PM

my bike is a 1980 model. if what you mean by "oil line" is a physical tangible line that can be seen on the outside of the engine casing, then no, there are no oil lines on the engine on my bike; all oil is circulated using inside "canals" for a lack of better terms.

the clutches will be the first thing to check because i can do that with the engine in the frame. the cylinder head on the other hand is a different story. the bike has to be disassembled and the engine removed from the frame to remove the cylinder head for inspection/service; as much as i "want" to do that, finding the time right now is going to be an issue.

kdxkawboy 10-01-2008 07:36 PM

It sounds like you overheated and mildly seized the piston/rings. The mild seize would result in the engine not producing enough power to overcome the resistance when you were idling, Could be a bent valve, but unless the engine stopped at TDC, pressing against the valve that wouldn't explain the resistance to kicking it over. when you seize an engine the piston expands to the point you loose all clearance between the piston and cylinder. Most definitely time to tear down the engine and with any luck you'll need to do nothing more than hone the cylinder and put in a new piston and rings.

If you have a decent dealer they will let you study their shop manual and photocopy a few key pages. Your bike has an oil pump and I would expect its gear driven and it's gear is located near the clutch. I suspect in working on the clutch something happened with the result the pump no longer pumps, meaning you weren't getting oil up between the piston and cylinder wall.

montesa_vr 10-01-2008 08:31 PM

Great job on your detailed description of how this happened and your follow up photographs. Really bum luck.

I'm not at all sure what happened here. It's not clear to me whether your engine overheated due to lubrication failure. If you replace the clutch on an XL500S you have to remove the automatic decompression cable that opens the exhaust valves to make starting easier. If the adjustment of that mechanism was altered by removing and replacing the cable, and the exhaust valves are being held open, that would certainly cause overheating.

If the problem is really oiling, a couple of things to follow up on: the little oil control pipe, which goes in the middle of that upside down triangle, just below the primary gasket surface and right in the middle of the cylinder. It would be easy to leave out -- or the oil screen that fits horizontally into that big oval shaped opening at the bottom of the primary case.

You sound too careful to have overlooked any of these things, but I don't see anything else in the manual to explain your problem. Good luck. I'm afraid more than once I have maintained something right into a state of non functioning. I feel bad for you.

motojunky 10-02-2008 06:27 AM

I'm in a hurry, and only quickly skimmed through the replies... hopefully I'm not missing key info before making a suggestion.

I once had a 1983 XL600 that had just gotten a clutch job. It had metal in the oil much like yours. I took it apart to find that the kickstarter idler gear had been installed backwards. It was machining away at the back of the clutch basket. I flipped it around the right way, changed the oil a couple of times and proceeded to abuse the bike for many miles afterward. For the first several hundred miles I kept expecting the clutch basket to explode but after a while I forgot about it. It never gave me any trouble.

I don't know if the same could be possible on your XL500, but it's something to check out anyway.

My memory might not be 100%, but I'm pretty certain it was the kickstarter idler gear. In any case, it was obvious once I started poking around. If yours is something similar, it'll be easy to spot.

Good luck!

mtn500 10-02-2008 07:20 AM

Quote:

Originally Posted by motojunky
I'm in a hurry, and only quickly skimmed through the replies... hopefully I'm not missing key info before making a suggestion.

I once had a 1983 XL600 that had just gotten a clutch job. It had metal in the oil much like yours. I took it apart to find that the kickstarter idler gear had been installed backwards. It was machining away at the back of the clutch basket. I flipped it around the right way, changed the oil a couple of times and proceeded to abuse the bike for many miles afterward. For the first several hundred miles I kept expecting the clutch basket to explode but after a while I forgot about it. It never gave me any trouble.

I don't know if the same could be possible on your XL500, but it's something to check out anyway.

My memory might not be 100%, but I'm pretty certain it was the kickstarter idler gear. In any case, it was obvious once I started poking around. If yours is something similar, it'll be easy to spot.

Good luck!

thank you everyone for the suggestions. in order to remove the crankcase cover to access the clutches, only the kick starter lever itself needs to be removed from the kick starter shaft. none of the gears involved in the kick starter were touched or altered in any way.

as for the starter decompression cable, yes it had to be completely removed to access the clutch so re-installation and adjustment was necessary. the manual calls for 1-2mm of free play at the decompression lever at the cylinder head. the lever is adjusted to within those specs but initially, after i first got the bike put back together, when the engine was running you could see the lever slightly moving in synchronization with the engine running (if that makes sense?); in other words you could see everytime the exhaust valves were opening because the decompression lever would move very slightly even though the free play was within tolerance. the manual didn't say anything like you should able to see it move, so i adjusted the lever (to still within the 1-2 mm tolerance) so that it was not moving when the engine was running.
could that possibly be a source of problems? does anyone know if the decompression lever at the cylinder head should be visibly moving when the engine is running? my memory says that it didn't move in the past but my memory is not perfect? again, by moving i don't mean the lever moved 1-2 mm with every engine rotation, but it slightly actuated (maybe .25-.5mm movement); if you were standing 6 feet from the bike you would not see the movement, but sitting on it looking down at the lever it was hard not to see movement.

montesa_vr 10-02-2008 04:07 PM

Moto, I never paid enough attention to my old XL500 to notice whether the decompression levers moved with the engine, but a compression test would be a quick way to settle it. If your exhaust valves are being held open, compression will be lousy.

Following that, you could disable the decompression and just kick it the hard way and see if compression improves. But we're all guessing here.

JeffS77 10-02-2008 04:24 PM

ok i own a '82 XL500R. pretty much the same motor i belive except for the charging system.. I had the same thing happen a few years back the dude i bought the bike from put a pipe on it and a uni filter but never jetted it. it ran fine around town but once i hit a 30mile stretch @ 70-75 mph it REALLY over heated lost all power climbing a hill and cut out..pulled over.. tryed to kick it and it didnt want to budge..sat for 20min or so then it kicked over and ran fine.. when i got home i checked the jets and had to go WAY up. i did notice a little metal in the oil shortly after when i changed it and compression was a little low but still runs fine and does not blow smoke..it was just way too lean and got way too hot...since then i have put a few thousand on it and have noticed what sounds like a little piston slap..top end rebuild pretty soon.


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