| Author | Message | ||
     Reepicheep |
Man, I am the luckiest unlucky guy on the planet. I pulled the head off the KLR-250 *again* to replace the head gasket to try and address my *burp* (pardon me) and overheat problem. I break out the new Harbor Freight blasting gun, fill it with baking soda (great tip by the way, found it here on badweb), and blasted that sucker clean as can be. It looked *great*. Or at least all the chewed up spots are now shiny, instead of being all carbon-ey.  During the detailed cleanup after the fact, I notice a spring looking... wrong. Rotate back the rocker arm, and sure enough, one of the valve keepers is half gone. It was wedged in there and chewed up, but intact. So the valve looks OK, and I have another spare head with full parts (so I have plenty of springs and keepers I can pull, and none of the parts went on walkabout. I was very lucky to stumble on it when I did. No damage done. Would not have taken long though. Who knows what the ultimate damage would have been. In terms of root causes, I am open to input. Either I did not seat the keepers all the way (very possible, this was the first time I ever attempted it), or they had some kind of debris in there that kept them from seating correctly. Thats a possibility. But that was also the valve under the locknut that *did* leave to find itself for a while (requiring a lot of the bottom of the engine to come apart, but that's a different thread). So maybe during it's extraction, or as a result of that adjuster being *way* beyond out of spec, one keeper worked its way out. So its even further apart tonight... but headed the right direction. And the head and gasket did show signs of possible exhaust gas leakage, so hopefully I am on the right track with that as well. It'll be a wonder if this thing goes back together and stays together. It has been quite the saga so far, and I have been exceptionally lucky. And take note folks, even though this is a 23 year old dirt bike, it is fairly state of the art. 4 valve overhead cam, water cooled, and only 250cc. Only about 25 HP at the *crank*. Thats like 17 HP at the wheel. It has now had both a bottom end and top end rebuild in 10k miles, and the dirty little secret of thumpers everywhere (even the Honda's) is that more then 15k-20k miles out of a motor without significant work is unusual. The fact that these aircooled blasts are happily hitting 20k, and that the XB's (which are really 500cc thumpers welded together) are regularly hitting 30k and 40k, is quite an accomplishment. Buell and Harley (credit where credit is due) have really accomplished something with these motors. I kid my Honda buddy about my unreliable import (to which he tells me not to confuse Kawasaki's with Honda's, and he has a point). But it's true. 23k miles on the XB now, and the only "work" done to it is painting the exhaust and replacing a broken exhaust stud. No valve adjustments, no chain maintenance. I replaced the plugs at 20k becasuse I felt guilty. They were ugly, but the bike was running fine. Its also a problem with the mechanic (me), and I am glad I am learning so much so cheaply on a $561 ebay special, rather then a perfectly good Buell. As experience goes, this is the best and cheapest education I have had in a while. Anyway, kudos to Buell and Harley for making such a reliable, simple, easy to maintain, and enjoyable motor. | ||
| Oldog |
hey Bill when you did the lower end did you find any loose metal? (glitter) I was wondering about the oil pressure / pump Oh and If I wind up with a dirt bike Its your fault  | ||
| Reepicheep |
Yes, there was some. I assumed it was the material removed from my cam bearings. If you want to start with a 1986 KLR-250 frame, its sitting out in front of my garage behind a bush, just come and get it.  | ||
| Glitch |
The fact that these aircooled blasts are happily hitting 20k, and that the XB's (which are really 500cc thumpers welded together) are regularly hitting 30k and 40k, is quite an accomplishment. Buell and Harley (credit where credit is due) have really accomplished something with these motors. Really? I had no idea. I've well over 58K on the clock, and that's going a whole summer without a speedo before I figured out how to keep it fixed. Thanks to your posts by the way. So I'm guessing I actually have well over 60K on her now. I too have been bitten by the "little bike syndrome".  | ||
| Reepicheep |
The image didn't load... so what did you get Glitch? When people talk about Japanese thumpers, its all sunshine and roses. But I have known 3 different people first hand, and they all rebuilt top ends, pistons, and jugs around 15k miles (and those were Hondas). Then I watch adds, and it seems there are a LOT of thumpers (perhaps the majority) that have been rebuilt one or more times, but have less then 20k miles on them. Granted, a dirt bike has a duty cycle somewhere between "staggering" and "insane". But on the other hand, the ride that killed my KLR was one that would have been "a nice trip to take before lunch" on the XB. On the other hand, they are really easy to rebuild and parts aren't terrible, and come in multiples of 1 instead of 2, 3 (for our triumph friends) or 4. | ||
| Reepicheep |
Oh, and don't get me wrong. This KLR-250 is a great little bike and a great hobby. A fine adventure. You buy a dirtbike in a bucket, and you get a dirtbike in a bucket. I now have a complete bike that is very close to be running again, a nearly complete parts bike, and a partially complete bottom end, and I probably have less then $1200 invested in the whole mess. There has been a LOT of labor invested as well, but as this is my first time to go that deep, I consider that a "break even" education investment. Better to make these mistakes on a $500 dirtbike then a $5000 street bike. Or even a $3000 dirtbike. And it's a hobby, the way I relax. And they are unbelievable fun on the dirt for just playing around. | ||
| Ceejay |
glitch-does that count as dragging a knee? | ||
| Road_thing |
Looks like he could probably drag both knees at once... rt | ||
| Tm74 |
It depends on which class of thumpers you're talking about. I haven't seen this with a majority of the dual sports of any size. I've seen several of the 650 thumpers with well over 50K miles and a ton over 20K. I've also seen several 250 dual sports over 20K. I bought a DR650 and shortly after sold my xb9sx. I was planning on the DR being my only bike. Engine life was a concern for me so I did a lot of research before I bought it. I didn't find anything that threw up a red flag and I looked into pretty much all the dual sports. | ||
| Glitch |
 I was dragging knees all that day. There are a bunch of us that get together and take over a parking lot and "race" One of our friends says it looks more like a circus than anything else! It's a Honda 50 with aftermarket everything. Wish it were mine, for the time being I'm only borrowing.  | ||
| Reepicheep |
I love that red one! | ||
| Glitch |
That's Charlie's (New12r) Z-50. Mike (Shred) has one also. They're so much fun we're hoping the government doesn't find out and make 'em illegal | ||
| Deadduck |
don't worry, the gov. won't make em illegal, they'll just tax the poop out of em | ||
| Reepicheep |
Update! It is back together with a new head gasket, and has taken a few shakedown runs and done a few thermal cycles, and all seems well. Still not enough milage to declare total confidence, but I suspect it is fixed. This latest round found stripped threads where the banjo bolt for the oil line goes to the head, so that was another $40 heli-coil set (and a tricky install, as I did not want to pull the head again to repair it). And as previously mentioned, it involved replacing a couple of keepers. The cam chain tensioner from the parts bike was a mess (the 1985 Kawasaki setup was a hack to begin with, including a big blob of weld to lengthen the tensioner). The one from the parts bike had been brazed... badly.. then a hole drilled in the end and a big screw inserted  The front brake switch is a truly idiotic design, with two thin metal tabs that stick down to hook up the brake light. They just hang there, brittle metal, and about the third time you connect and disconnect them, they break. And the switch from the parts bike (which I used) was not dimensioned quite right, so I had to put a blob of epoxy to "lengthen" the brake lever switch engagement post. I think I mentioned earlier that two cam cap bolts pulled free of the head, in spite of careful use of a torque wrench. So I had to heli-coil those, and the bolts bound up near full depth, so I had to run a tap through the heli-coil to clean up the deeper threads. Then I swapped over a sprocket guard that was on the parts bike, but had apparently been removed from my bike. The coolant pump was missing a shim, so I had to put that on from the parts bike as well. I'm ready for this bike to just run for a while... It was fun, but a lot of time and work, and stupid little incedental stuff gets expensive ($40 head temperature sensor, two $40 heli-coil kits (odd sizes), gaskets, yamabond, etc). All part of the adventure | ||
| Oldog |
Bill i am glad that you were able to run it down, I wonder if the banjo let the oil leak out. I was out running saturday and almost found a new home for a 200 suzuki I must not buy a dirt bike yet | ||
| Reepicheep |
Hrrmph. Rode it hard last night, and it burped again. I'll swap the radiators and electric fan (about all that is left and I have a pair on hand) and see if that helps. I should check the oil pump as well... I don't think the banjo bolt would have let the oil out, it is on the back of the motor and would have oiled down my boot and tire. I did check the head when I pulled it last time, and I could see no warping, and looked pretty hard for cracks and did not see any. | ||
| Oldog |
not trying to be an ass here are you sure that all of the air is out of the head? | ||
| Reepicheep |
I appreciate all your help Oldog and welcome every suggestion (obvious or not). Problems almost always come down to something stupid and painfully obvious... to *somebody* *somewhere*. It's just a matter of finding it. I followed the factory manual "burp" procedure, which really isn't anything more then "run it a few times". When I swap the radiators and fan out, I will have to drain the system again, so I will spend extra time making sure that little bubble trap in the head is clear before my next run. That'll kill two unknowns with one drain and test cycle. At this point, I am more interested in it being fixed then it being correctly diagnosed Any good tips for checking oil pressure? This bike has no oil pressure gauge / sender / idiot light. Just a temp gauge. When I pull an inspection bolt in the head I get plenty of fresh oil drooling out, so it is getting *something* up there. It has a hard oil line with a banjo bolt running up the side that supplies all the oil to the head... but that would be a pain to tap into. I'll check the service manual and see how hard it is to pull the oil pump. A visual inspection of that would probably go a long way. | ||
| Reepicheep |
Hmmm... Went to swap out the radiators, and noticed some "goo" in the overflow hose where it went to the nipple. Went to dig that out, and found a "stiff spot" a bit up the hose. The goo looked almost like sand or sawdust. There was a decent amount of it. More then enough to block the line for at least 1/2 inch. The stiff spot in the hose turned out to be the old nipple from the old radiator... and it was also filled with goo. No idea how long ago it broke off and was working its way up that hose. I would wager the obstruction was at least 90%. And given its nature and position, I could *easily* see it forming a sort of one way valve. It certainly would not flow well. A previous test involved me blowing into the vent line with the radiator cap off, and I could move coolant through there, so I assumed the line was clear. This turns out not to have been true, and the direction I was "testing it" was the direction the one way valve could let stuff flow (into the radiator). So I cleaned the line, checked everything else out, buttoned it back up and refilled and re-burped it. So far (idling in the driveway for a long time) so good, but I have been fooled by that test before. It will take a good 20 mile ride to feel any level of confidence in the thing. But its something significant in a place near where I think the problem could be... so I am once again cautiously optimistic. This could have been the original failure mode as well. The poor thing just overheated, and I reacted poorly. Good to learn these lessons on a cheap old dirt bike... | ||
| Court |
Ya gotta love the KLR . . . I have these two "project" KLR's sitting here and it's fun to have a bike that I'm willing to do things with I never would on a $15K-$25K Buell. | ||
| Reepicheep |
 KLR: Once you learn to like the pain, they can't hurt you anymore... | ||
| Road_thing |
Sounds like you had your "A-HA!" moment. I suspect your troubles are over. At least, your KLR250 cooling troubles... rt | ||
| Reepicheep |
Well, it was an A-HA moment, but like every other A-Ha moment sbefore and after, I found something screwed up, fixed it, and the problem persisted. Replaced the radiators back to the originals. That cap worked better, but again, it was still a problem. I probably did about 7 other things... still overheating. So working my way down the list...
So I went to harbor freight, and got an oil pressure gauge (actually got a oil pressure / temperature / amp gauge for $16... figuring I could re-use them). So I hooked it up, and fired the bike up. Like 80 PSI at 8000 RPM, and 40 PSI at 4k RPM (spec says 15 PSI at 4k RPM). But the bike warms up, and the pressure drops. And drops. And drops. I did not push it to the "burp point", but it was down to about 9 PSI at 4k RPM, and still appeared to be dropping (and I wasn't even at the burp point yet). I am running Mobil 1 15w50 in it when it does this, which is between the recommended viscosities for the bike. So I'll tear into the pump, or maybe look for a clogged screen somewhere. Whee. Old bikes. So it looks like I get to tear apart yet another side of this engine... If it's like everything else I have done, I will find some screwed up thing in there, fix it, put it back together, and it will continue to overheat :/ | ||
| Reepicheep |
Significant new development... Old oil pump was beat up, put in... well... other old oil pump. Still burp coolant. I did a real methodical test, and found something really important. The burp is not related to temperature per se, I can let it idle in the driveway for an hour, until it is up to full operating temperature. Looks like it could basically idle there forever without the problem.  But if I start with a cool bike, and ride 2.8 miles from my house, I get a first "burp". The second is about a mile after that, and thats when the left radiator is basically drained. Stopping immediately and measuring everything (right at the point of burp) shows (first burp / big burp) Gauge temp: 168 / 185 Head temp left: 145 / 165 Oil sump temp: 146 / 153 Oil pressure at 4k RPM: 15 PSI / ? PSI (I missed getting the last PSI reading, but I think it was still decent, though a little anemic). That is 15w40 dino oil in there, and the manual calls for 10w40 or 20w50, so I ought to be able to go up a little and get a bit more pressure back. So anyway, the "event" happens only under load, and it happens at a temperature well below where the bike can idle happily in the driveway. Thats a little encouraging to me, as it seems to suggest something simpler then an oil pressure initiated problem. Suggestions o motorcycle guru's? (Message edited by reepicheep on August 02, 2008) |
