| Author | Message | ||
     Barrick09 |
ok where to start. about 3 weeks ago my 99 X1 blew a front head gasket, almost a 2 inch section was on the outside of the engine! also the carb had a huge crack. well after fixing all the problems the bike ran like it never has before! about a week and a half later (last night) im riding home when i down shift and the bike makes a huge bang sure enough the front head gasket blew again! The first time there was a loose head bolt on the section that had blown out, not sure if that was cause by the blow out or the blow out caused by that? i check the heads to make sure they were smooth to 6 thousands of an inch as said in the manual i believe. bolts torque to the right amount and everything. I alway let the bike warm up till the heads are hot to touch before taking off, i do ride a little hard, i do an occasional wheelie, but i never redline the engine or bang it up. What could cause 2 major blow outs like this in such a short time? Thanks in advance to any suggestion and opinions. ill get pics of the head gasket up asap. | ||
| Richsm2 |
in the past i experienced this in cars and mc.until i saw a tag on a ford factory rebuilt engine that said to retorque after the first full warmup, have done that ever since,that means I brought the temp up, not run the engine under load. also the beam type wrenches can be held at torque value , i have had them jump at torque value when held momentarily. where as the click only reaches the value. torque at least three times thru the pattern. i never reuse gaskets that are under pressure.check your surfaces for flatness, use a keen eye , anything you can see tells some tale. do not pull the upper gears until you are certain all is well,NO leaks. | ||
| Two_seasons |
Never reuse head bolts. Not saying you did, but reusing them is bad practice, as they are "stretched" when at the proper torque value. | ||
| Edv |
When you torqued the heads did you lubricate the threads of the head bolts and also contact area of the heads where the bolts make contact? this is very important | ||
| Rich |
Pulled a stud, possibly? | ||
| Fahren |
Where have I been? Never heard not to re-use head bolts... | ||
| Bluzm2 |
Me either. Cars yes, HD motors, no... | ||
| Thejosh |
Never reuse head bolts!! Heat, torque, and all of the stress causes them to stretch!! Especially on high compression motors such as the Buell. | ||
| Barrick09 |
I believe we did reuse the head bots. When taking the engine apart we had to use a cheater to get the head bolts out becuase they were so tight. Just incase this was not the case. What else could have cause it almost 2 weeks after replacing it. I figure if it would have been that it would have went in the first couple days??? | ||
| Greg_cifu |
SOME headbolts and studs are designed to 'torque to yield' but, not all and certainly not these engines. I checked BOTH factory service manuals and they said nothing about replacing the studs. When in doubt, I'm going with the service manual. Too many variables to know what happened to yours. Here are some possibilities. Take your pick of whatever you like: You could have had a failing gasket and it just let go and you made a mistake installing the second one. So it really was just one mystery failure that followed a routine failure. You could have roughly dropped the front end from one spectacular wheelie and it overstressed the studs on the front cylinder (the entire weight of your engine is hanging from those front studs). Those studs are now stretching and/or pulling out of the engine cases and the new head gasket let go when the studs or threads yielded again. You could simply have the studs pulling out of the cases. Were the lower shoulders firmly seated when you took it apart? The manual says they are supposed to be thread-locked and torqued into the cases at 10 ft/lbs. If the upper nuts were that tight, you might have had rust or something that caused the lower threads to rotate when you took it apart. And that gets to the torque issue already mentioned: were the threads clean, free of rust and lightly oiled before you torqued them? If not, you got a false torque reading before the gasket was actually compressed the prescribed amount. Finally: if you have a clicker wrench, ditch that thing for a simple beam wrench. The clickers need to be sent out for calibration regularly. They're handy for doing a bunch of bolts over and over but, I prefer the simplicity and repeatability of a simple beam torque wrench. I just don't trust the mechanism in the clicker-type wrenches for critical torque values. | ||
| Thejosh |
I got a clicker wrench that I use routinely. That is a bunch of B.S. about them needing to be cal'd. I work in a hangar that uses clicker type torque wrenches everyday and we have a cal station that measures the torque of the wrenches. I have never seen one fail, in fact for giggles I brought my craftsman torque wrench in to see how off it would be and it was 2 inch pounds off at different intervals. Granted the wrench measures in ft lbs and the calibrator reads in inch lbs, I had to do some calculations but the old craftsman was actually more accurate than the Crap-On's that we use for the aircraft. Someone lied to you because you are quite mistaken Sir, it is the beam style that get overstressed and misread. I would trust my torque wrench better than a beam style any day of the week, in fact, every engineer and tech that I know wouldn't trust a beam style torque wrench for anything. | ||
| Bluzm2 |
Gotta go with Greg on this one. I checked 4 service manuals (just to be sure my memory wasn't messing with me...), there is NO mention of replacing the head bolts or "nuts". Like Greg said, there are some types that are single use. The HD head bolts are NOT that type. Most auto engines now have single use head bolts that are designed to stretch a set amount when torqued. This keeps the clamping pressure constant. HD motors do not have this type of bolt. I've done more top ends than I can count. I've never used new bolts (studs really) unless one was damaged. I've never had a head gasket leak afterward using either the new style HD gaskets (o-rings not needed) or Cometic sets. If you use HD gaskets, follow the service manual. If you use Cometic's use their install procedure, it's a bit different that HD's. | ||
| Oldog |
I put a top end in my bike 20K ago (cracked bbl & broken motor mount bolt) I wheelie my bike Oh and Im a good size guy if you used standard parts and followed a manual then you have other issues, I would be looking at the whole thing as I tore it down for the re-do, The mitsu powered chrysler I used to have was supposed to have new bolts in the head, I did not do that and had no problems, Also the manual does not call for re-torque, once set they dont require attention, I would be checking the studs in the case... My ).02$ YMMV | ||
| Barrick09 |
I cant imagine it was from laying a wheelie down hard. I weigh about 130lbs and they are usually 1st gear clutch ups that i always set down easy. Not to mention the bike ran great all day i did wheelies earlier in the day but at that moment i had done any for hours. I was downshifting and boom. Not sure if this matter but i have 42mm mikuni carb and when the first gasket went the carb also had a huge crack in the backside. Nothing wrong that i can see with carb this time other than when the gasket went the second time it was shooting some serious smoke and vapor, didnt do that last time...could they be related maybe the carb causing the blowouts? (Message edited by barrick09 on October 24, 2011) | ||
| Greg_cifu |
OK, now you know one. I'm an aerospace engineer on some major programs and it was our cal lab that said what I posted. What engineers and supervisors don't trust is how a tech will use a beam wrench. People tend to read the scale, then give it a little 'umph' with their tongue strategically sticking out of the corner of their mouth.  If you read the scale and use it properly, the beam type is more trustworthy. Yes, you are correct that premium clickers are very repeatable and it's very easy to teach somebody to use one (process repeatability is very important in a production environment). Unfortunately, not everybody buys the premium wrenches and the one our cal lab specifically mentioned was the Craftsman Digitork. Friction in the mechanism made it very unreliable at low torques--150 ft/lb rated wrench that wasn't very accurate at under about 40 ft/lbs. The real answer is, "it depends." The torque values I was seeing in the manual were very low compared to the range of most 15-18" torque wrenches. To accurately torque something in that low of a range, it's best to use a smaller wrench, using a larger percentage of its rating. Back to the original poster's problem: did you follow the procedure in the manual? The 2001 manual has a specific procedure for incremental tightening to a certain level, completely loosening them, going through the sequence a second time, to a low torque, then turning the final 1/4 turn visually. I think they're trying to pre-crush the gasket, let the studs shift around and the nuts to seat themselves, then retorque to final value. As an aside: BMW Airheads actually call out breaking and retorquing the head nuts at every valve adjustment. They have virtually the same problems with weeping base gaskets after cold-engine, hard running. | ||
| Firemanjim |
One thing to look at is the stock cylinders are an iron liner in an aluminum outer, and are known to separate. When they do they raise a section of the liner and blow the head gasket.Look at the cylinder--- And another thing--the new stock head gaskets DO NOT use an o-ring like the earlier ones. If you put in an o-ring like the manual tells you it will blow the gasket! (Message edited by firemanjim on October 24, 2011) | ||
| Thejosh |
Been working as a tech in aerospace now for 10 years, on both military and private jets and have never seen a beam style torque wrench, why, cause they SUCK. And yes, clicker torque wrenches were designed to reapply torque over and over and over in much the same way that a cam was designed to lift a valve over and over and over. I have never seen a clicker wrench out of cal, at our hangar we check them everyday. Honestly I couldn't find a jet engine mech that would use a beam style either, why would anyone voluntarily use outdated torquing methods? | ||
| Greg_cifu |
No, because most techs can't be trusted to use them properly. Smart people have taken the responsibility of reading the tool properly, out of your hands: require a repeatable tool, require it to be calibrated, require a QA sign-off. They designed an entire process to ensure that the torque values are met. Take out a piece of that process and it's no longer the same. Hey, I wasn't any more fond of this finding--especially after blowing $150 on my clicker torque wrench--the old $60 would have done the same job with less risk. As I posted before, the right tool for the job depends on a lot of variables--most of which are outside the control or verification of the average home mechanic. http://www.garagejournal.com/forum/showthread.php? t=2980 | ||
| Fahren |
I really like my "split beam" type torque wrench. It's quality, and different from either type you are discussing here - here's a review from web bike world: http://www.webbikeworld.com/r3/torque-wrench/ I also have a dial type inch-pound unit from Precision. | ||
| Thejosh |
QA only needs to witness torque on production A/C. Techs go to school to learn how to use tools so I'm pretty sure someone straight out of school with a license could use a torque wrench. In service centers a licensed tech can sign off on a torque, so there goes that theory. The problem with beam style is that they fatigue and are temp sensitive. Clicker style take the "human" element out of the equation giving every single bolt the exact same torque, even if it is off by 1 or 2 lbs, it will deliver the exact torque, beam style relies on the human eye and arm to torque. Basically, your information is wrong, in this industry I have never seen a beam style torque wrench, and not because we don't know how to use them, but because it is old worthless technology that has been proven to be flawed. I would never use one on an aircraft or my bikes, they are garbage. | ||
| Reepicheep |
Bringing this back to head gaskets....  I had a KLR 250 do just what you described. Blow a head gasket, rebuild, blow it again in a week. I fixed it by doing the job "better" the second time. Pull the head, "machine" the mating surfaces with 1000 grit paper flat on my table saw machined surface (flates think I could find in my house). Just lay the paper flat, hit it with WD40, and go in circles. You will see the high spots get polished, and the low spots stay dull. Go until the dull spots are shiny. I think this may be as much about removing old goo as it is about machining surfaces. Then I did the reassembly, did a heat cycle, and disassembled and retorqued (PITA on overhead cam motor). That fixed it for me on the KLR. | ||
| Fast1075 |
Nobody mentioned parallax. Clicker tools cannot suffer from parallax. | ||
| Two_seasons |
Parallax error has been around forever. You get parallax error when you read an analog meter too. Either way, both work. Either way, I'm changing the dang head bolts. | ||
| Barrick09 |
So it was a ln o-ring style gasket with my understanding is to avoid right? I didnt machine the surface but it was mirror clean. How ever one head bolt was loose when the gasket blew and the others tight. Maybe if it was loose for a while it added a slant to the head and over the corse of the week shifted the gasket out of center and cause the blow. So now new head bolts and case bolts just in case, non oring style gasket, Machine the head. I did lub the bols last time and torqued corectly in the pattern to 10lbs. Any suggestions for breaking it in or a break in period? | ||
| Fahren |
O-ring.... made some dim recollection snap in my head - something about o-rings omitted if using cometic gaskets. Someone needs to remember this better than I can.... may not be an/the issue here, but still, pertinent to the subject. | ||
| Firemanjim |
Cometic uses no o-rings and has actual torque specs unlike the stockers. Older stock gaskets used an o-ring, the "new" redesigned stockers use NO o-ring and look a bit different around the hole that used to take the o-ring. Read the included instructions. And your manual has the instructions for the old style gaskets and calls for the o-ring. Clean all threads well and follow the instructions for oiling surfaces detailed in manual. Not unusual to find a head bolt loose and the area blown there,seen it more than a couple times. Did you look at the top of your cylinders to see if your liner had shifted? | ||
| Thejosh |
Head warpage could be an issue, I would definitely check. Josh | ||
| Preybird1 |
I re-used the front head bolts and it was a mistake. one of them when i torqued it down, it felt soft all of a sudden and then CRACK it snapped right in 2. It is cheap insurance and peace of mind. firemanJim is spot on and has been doing this for a long. | ||
| Barrick09 |
So can anyone confirm what was said about the oring gasket? Should i avoid this and get a different kind? If so what do you recommend. @firemanjim I did check the inner and outer lining they were fine. | ||
| Firemanjim |
Just get Cometic. | ||
| Fast1075 |
Back the nitrous nozzels down 3 sizes and the fuel nozzels 2 sizes. Pull the timing back 4 more degrees at 5200. Opps...wrong post  | ||
| Rick_a |
I jump my S1 daily...head gaskets won't be affected by wheelie landings. You'll break the front cylinder, mount, and/or bolts first. The head and cylinder surfaces are what I'd be looking at. | ||
| Fahren |
I'd concur with Fireman Jim on the Cometic. |
