| Author | Message | ||
     Hangetsu |
So has anyone out there has issues with Buell XB head gaskets? It seems to me an engine with only 38,000 miles and ridden almost solely as a commuter should not blow a head gasket, but I think mine might have. I recently had a new ECM installed, and since that time the bike has ran well, if not a bit richer than it did with the stick ECM. I actually get a bit of brown smoke from the exhaust on a cold start, the idle has been a bit lower and rougher than before, and it’s a bit harder to start. Otherwise, it seems to have been running fine – until a couple of days ago. Last Monday, I set out for, what I intended to be a nice cool holiday ride. At it has been doing since the new ECM, it took a few cranks to before it would fire, and when it did, it died after a few RPM’s. The second crank will usually fire immediately though, and them run as it should. This time, however, when it fired, I heard what seemed to be a small backfire, but otherwise, it remained running and seemed to be running fine. I left home and header for the Columbia Scenic Highway, destination, Hood River. But I didn’t get far before I detected something wasn’t quite right. I didn’t get more than a few miles before I noticed a slight scent of burning oil. There was no smoke coming from anywhere, so I didn’t pay it much mind. However, when I stopped at a diner for a quick breakfast, I noticed a significant amount of oil had coated the oil pump cover, some splashed on my “comfort kit” exhaust heat shield, and quite a bit covered various other bits around the front cylinder. All of the oil-coated areas were close enough to the network of oil lines at the front of the engine that I thought the “backfire” might have created enough pressure in the crankcase to blow some oil out of the joints in the oil lines, but the location of the coated areas seemed all wrong for that to have been the case. I wiped down most of the oil covered areas and chose to keep my ride closer to home so I could keep an eye out for new seepage, but when I returned home, there didn’t seem to be any fresh coverage. However, when I peered around the front cylinder under the right-side air scoop, I noticed a fresh coat of AmsOil all over the fins of the front cylinder head. The oil coating the head fins formed a perfectly straight line where the head meets the cylinder. Both the cylinder and the valve cover are clean, but along the left side from the header to as far back as I can see, the cooling fins of the head are coated in fresh oil. So that’s my tale of yet another frustrating development on this machine that I so love to ride. I’m trying to keep my faith that this was a bike that would make the long haul, but that faith has been shaken with this new, potentially expensive event. Anyone have any similar experience? I would love to hear your comments and thoughts on what might be happening here – blown head gasket, or (hopefully) something else. Thanks in advance for your ideas. A- | ||
| 651lance |
Do you have any detail pictures? It not common to blow a head gasket. There isn't any oil pressure going through the HG just return oil. I've blown out a HG before and you can hear exhaust coming out and then would be discoloring in that area. Clean all the oil off and start your bike and get I good and hot sitting still. At that point you should eye the leaking spot. Most likely is the rocker box or push rod cover o ring. Not saying it can't e the head gasket it just not that common. | ||
| Hughlysses |
+1 to what Lance said. I don't think I've ever seen a report of a blown head gasket here, and if the head gasket did blow, I don't think it would result in a steady stream of oil. | ||
| Reepicheep |
As stated, you probably have a rocker box leak, not a head gasket leak. A head gasket leak probably wouldn't release much oil anyway, that's all up in the rocker box. An easy fix, and basically a right of passage on the old tube frame models that came with the paper Harley gaskets (what was Harley thinking?). The rear would go at about 6k miles, and the front would go at about 9k miles. The XB's are pretty remarkable in comparison, but can still loose rocker box gaskets. The new factory gaskets from HD are solid, but confusing as heck (they have a kit with parts for like 3 generations of evo motors, and crap instructions about which to use where). The Cometic gasket kit is at least as good as the HD kit. Neither kit is cheap, but having been a victim of HD "saving money" on the old paper gaskets, I try not to whine about the price of a quality part that solves the problem well. | ||
| Pontlee77 |
The 2007 bikes were the more prone to the leak from the rocker box cover, but 2008 had solved it with a better gasket (2006 had an old version gasket that didn't leak). | ||
| Tootal |
If you blew your head gasket you would know by all the noise! Blew one on my Harley years ago right as I pulled up to the dealer. A voice came from the service area that said, "sounds expensive!" It was real loud so I don't think that's your problem. The rocker is probably leaking on the intake side and dripping on the top of the cylinder and then running "down hill' toward the front of the cylinder. | ||
| Sagehawk |
The only blown head gasket I've ever seen was on a tuber that a friend's son owned. Rear head twice. First time was under warranty as a fluke. Second time I told Bob to pull the boys keys, and take his wallet for him to pay up. Something about cold motor and the front wheel being in the air just didn't add up to me or bob. After darren learned you have to warm up a motor some before you hammer on the thing, no more head gasket issues the rest of time he had the bike. I guess we were a kid once ourselves, right? | ||
| Hangetsu |
Hey Everybody. Thanks for all the great insight. This evening I removed the right-side air scoop to get a better look at the area in question, and it seems some of you were right. The leak seems to be coming from the pushrod cover. The area around the rocker box is pretty clean, but the upper part of the pushrod cover has a light coating, and the area just where it joins the rocker box is glistening with fairly fresh oil. What I find interesting is the suddenness in which the cooling fins between the header and pushrod cover, the oil pump cover, the header pipe, and other parts around the front of the engine became so saturated, where now there seems to be no fresh leakage. So this begs the question: could the backfire I mentioned earlier have caused oil to blow past the pushrod cover O-rings due to a pressure surge in the rocker box? And if the place the oil escaped from is the upper o-rings of the pushrod cover, and the problem persists, is this something that can be fixed without dropping the engine. Or am I looking at a complete disassembly of the front half of the bike? Another question while I’m here. There is a bit of oil seepage coming from the oil lines that enter and exit the engine cases near the oil pump. The seepage is coming from the oil lines right at the fittings and it’s enough to keep the engine case around this area as well as the oil filter pretty grimy. There is also some movement of the lines in the fittings when I wiggle them around. Is this movement normal, or should this junction be tight and stable? Thanks again for all your great comments. Cheers! A- | ||
| Hughlysses |
There is also some movement of the lines in the fittings when I wiggle them around. Is this movement normal, or should this junction be tight and stable? I'd think the fittings would allow some movement. There have been a few cases of the retaining spring in these "Snap Tite" fittings breaking after many miles,which can allow the fitting to come apart. Not sure if they rub through or just fatigue. So it might not be a bad idea to remove and replace the retainers and install new O-rings while you're in there. That may take care of the issue. | ||
| Steveford |
To replace that sealing ring for the pushrod cover the motor has to come down and you'll want a head gasket kit. It's not especially difficult, just time consuming. | ||
| Reepicheep |
Before I pulled the heads and bought a $100 head gasket kit, I would remove the rocker box, then carefully clean then apply RTV from the inside pushing it into the places where that O-Ring sits. I pinched one of those rings on reinstalling my rebuilt Uly heads, and instead of pulling the head I did that and it has worked fine. The engine builder that recommended it to me says they do this every time they rebuild anyway as it can be hard to get that o-ring to seal. Unless you see big chunks of a broken o-ring sticking out somewhere. Then you are probably stuck pulling the head if you want it reliable. | ||
| 651lance |
If the o ring is leaking give yourself a project for a few hours and do it the correct way. The oil passages on these motor are too small the have any rtv floating around in the engine. If the rtv comes loose in the pushrod tubes it goes right down to the lifter and the oil return passages. Bring it over I need a fast fun project. | ||
| Arry |
I had both rocker box covers develop leaks (should have done them both, the first time). Mine is an '07 so, I guess that's a bad year for those gaskets. Both times it was a very slow leak, that made a mess over a course of time. Sounds like you have a faster leak. As 651 lance said, clean it up good, then you might see where it's coming from, when it starts leaking again. Another thought, maybe the "small backfire" blew something loose in the crankcase breathing system. (?) P.S. Watch out for ice in "The Gorge". | ||
| Reepicheep |
Interesting topic. When I bought my 07 Uly used, I noticed it had a previous rocker box replacement (which included a bit much RTV for my tastes but was holding). I was surprised that an XB motor needed a rocker box fix in the first 10k miles. 07 was a bad year for XB12's. | ||
| Dan_m |
A piece of advice: when installing the pushrod cover o-rings, do not follow the procedure described in the service manual because chances to damage them are very high, that is because the manual specify to firstly install the o-rings on the top of the pushrod covers, and if you will examine the slots from the cylinder head where the o-rings are seated, you will notice that the edges are very sharp, thus the risk of damaging. Instead, i used a procedure that i've read in an article from twin motorcycles, iirc. This procedure refers to install the o-rings in the slots from the cylinder head, firstly. And don't forget to apply some engine oil on the o-orings, before installing. | ||
| Reepicheep |
Nice tip Dan, thanks. | ||
| Griffmeister |
Dan, I wish I knew that trick when I first put my heads on. I messed up the O-rings on both my heads without knowing it right away. I might also add that when the O-rings properly seat, you can feel the head settle into place quite smoothly. Then be sure to take a good look top and bottom where the O-rings sit to be sure they are not displaced before you torque the nuts. It's better to try a second time before you crush the gaskets and have to order new parts. | ||
| Tpehak |
I do not know what you mean blown head gasket, but bad head gasket can be the source of the leak. It seals not only cylinder head combustion chamber but also oil channels around the combustion chamber. The seal around those oil channels is so thin that it can easily start leaking. It happened on my 2009 Buell XB12Scg with new James Gaskets I installed on cylinders. My front cylinder head gasket is leaking right in the oil channel area. Anyway you have to replace the cylinder head gasket to fix the oil leak. I probably would not recommend you to use James gaskets, they leaked on me many times. Install OEM Buell gaskets, at least cylinder head gaskets, or maybe try Cometic gaskets.  |
