| Author | Message | ||
     Blake |
If it's a metal gasket, well... Aaron, I'd at least like some BBQ sauce on that crow.  | ||
| Leveg |
I have just machined my heads for twin plugs - I know there are differing opinions on whether this is worthwhile, but I wonder if anyone else has done it, and has any thoughts on how it affected their ignition timing requirements. Also, does anyone have experience with a Crane HI-4E ignition? Thoughts and opinions?  | ||
| Reepicheep |
OK.. My front rocker box leak started right on schedule (7k miles, about 3k after the rear leaked). I already had the parts, and should be able to finish the job tomorrow night. About a four hour job if you go slow. I shot some pictures of the leaking gasket. Mine looks like it shrank and deformed, and pulled away from the sealing surfaces. Right where the leak was is the place where the gasket is the most deformed.   And on the other end, it looks like the gasket actually tore from shrinkage. You can tell by the darkened color that it was an existing tear (as opposed to the fresh tear from removal that is just to the right of it that is a lighter color).  So on my 2000 M2 anyway, it looks like at least some of my leaks were caused by deforming gaskets. Bill "who has to laugh at himself for being so uptight when this first happened to the rear rocker box" Kilgallon | ||
| Sportyeric |
I'm finding I'm getting pretty good at them! On the positive side(for me) I changed the plugs while they were out and it seems like a whole new motor. SMOOTH! Unfortunately, I cheaped out and used the Harley paper gaskets on the assumption that a complete rebuild would be needed shortly. Purrs like a kitten now. But I'm afraid to rev'er for fear of blowing the gasket again. | ||
| Reepicheep |
I used paper gaskets when my rear rocker box gasket went the first time (nobody local had the James metal gaskets in stock) just to get back on the road, and with carefull installation they have held well for 5000 or so miles now. When I went to do it, a local independent shop that drag races sportsters said they used these same paper gaskets to solve their leaking problems on the drag bikes, so I figured it was worth a try. He pulled them from a stack that were hanging on the wall loose, and threw them in a custom chrome bag, so I don't know if they were Harley or Custom Chrome or whatever, but either way they are some kind of paperish fibre and they have held up for 5000 miles on the rear rocker box. Looking at my shrunken warped gasket above (note: those are the original factory gaskets, not the replacement ones I got), it makes me think that the material was just wrong for the application, or that I may have baked them at some point this summer on a hot day before I rejetted (cooling down the engine). I switched to full synthetic as well, but have a hard time believing that could have damaged the material. Besides, the rear went before I switched anyway. Heck. Now the whole job is kinda fun. Better then watching TV anyway. Bill | ||
| Javahed |
OK, Tell me about these James Steel Rocker Box Gaskets. I just hit 4000 miles on my Y2K-X1 and noticed my rear rocker box is leaking. I'm bringing her in on the 3rd of October. Should I purchase the above mentioned gaskets rather than letting Harley replace 'em with paper ones? Do I pay for labor on a warenty repair? Is it an easy job that I should just do myself??? God - I thought my baby would never leak (yeah right) Thanks in advance! Dan | ||
| Aaron |
Dan: Yes, IMO do whatever is necessary to get steel gaskets in the motor, even if it means you have to forego the warranty repair and do it yourself (it's easy). Call Tat, I hear he carries the steel gaskets now. You don't really need the rubbers, and the gaskets alone are really cheap. He also carries the low profile wrench you'll need. Or, wait a couple weeks for some news on this issue. AW | ||
| Reepicheep |
Dan... Tat has them (American sport bike, link on lefthand bar). It's really an easy job, just take your time and use the manual and common sense. You might have a little trouble getting the torque wrench on one or two of the bolts. I just torqued the ones that were easy to get at, and used my mark I calibrated thumb to make the others match. Once you torque the one, you can then back it off a half turn or so by hand and re-tighten to get a feel for how hard to turn. Then just make the others match. If you don't get the tool from Tat, you may also have to cut down an allen wrench with a hacksaw. Also an easy job. I look forward to hearing the news that Aaron is hinting about. I wrote in my profile a year ago under what I want from the factory: "would it kill you to use the metal gaskets rocker box gaskets at the factory"... Hopefully thats what the news will be (though it won't do me a lick of good). Bill | ||
| Javahed |
Thanks for the advice ya'll!!! Dan | ||
| V2win |
I did not check to see if anyone posted this yet, but, Buell will be using a new (to them) gasket on the XB bike. It will be a steel shim with rubber coating similar to the James gaskets. Also you will be able to retro fit the 2-piece covers to replace the 3-piece we use now. The 2-piece has a hole for a pvc type breather one top and will elimate one set of gaskets. | ||
| Schemky |
Quench/Squish Question, Does the Thunderstorm engine use "squish" or "quench" type methods to introduce turbulence in the combustion chamber? I am quite familiar with the quench method used in the SB Chevy V-8. If the Buell uses quench, is the recommended clearance .038 - .042, like the SBC? I am about to order a set of replacement pistons and everyone makes a 10.0:1. I want to bump the CR up to about 10.5:1 since the duration of the camshafts I intend to use will bleed off cylinder pressure at lower speeds. Since all modern engines use "production" tolerances, it may be possible to mill the cylinders a sufficient amount to attain a static CR very close to 10.5:1 (with an advertised 10.0:1 piston). Milling the heads approximately .020 would provide a CR very close to 10.5:1, therefore if the top of the cylinders could be milled a like amount I could possibly accomplish my objectives and create a more flexible and efficient powerplant. | ||
| Aaron |
Schemky, Yes, there is a small shelf in the head that matches the dome on the piston. See the pic of the dual-plugged head at the top of this page. The factory tolerances dictate a pretty big gap, mostly they're around .050 from what I've seen. People commonly mill things to get it down around .025-.030. Remember this is an aluminum cyl and it grows. The bad news is that the shelf in the chamber is cast in, not machined, and as such, there's error in it's location from what's commonly referred to as "core shift", more accurately referred to as machining shift. In other words, when they machine a raw casting there's some tolerance on the starting point and therefore anything left cast-in has some range of possible placement. So some hand fitting, or getting the chamber shaped in a lathe, is required if you really want to do it right. Consider carefully how much to mill from the head versus the cylinder. If you do it all in the head, you'll end up with a pocket at the extreme o.d. that's the thickness of your gasket. IMO, you really want the whole squish band even or slightly tapering larger toward the center of the chamber, to help shove the fuel at the flame front. To know how much to mill from where, you really need to make measurements first. Nallin Racing offers a 10.5:1 piston that has a slightly altered dome shape to better match what most of the t-storm heads look like. He also offers it in a 3-9/16 bore, with matching cylinders, that can be installed without case boring, giving you about 1247cc. Axtell offers a variety of pistons and you *may* talk them in to cutting the chamber for you to match the piston, not sure. They offer some machine shop services to people but I'm not positive that's one of them. Mostly they specialize in pistons and cylinders. Good luck, AW | ||
| Schemky |
Aaron, Thanks for the information. I intend to take the top-end down as soon as the riding season ends in my neck of the woods (November). I'll measure as needed to determine how much of what needs to be cut/removed to attain a quench of around .030. | ||
| Axtell |
I have info on this also--- I have done what you are trying to do--call and I'll help---Ron | ||
| Aaron |
I didn't want to say this without knowing for sure they were offering the service to everyone, but about a year ago, Axtell sold me a set of pistons (Big Twin) and cut the chambers to match, and I was astounded at how perfect the fit was. The squish had a very slight taper, getting larger toward the middle, and it was absolutely even all the way around the dome. I'm convinced that getting this right is a big contributor to power, and it reduces detonation too. Someday I'll get the dyno sheet up here for that bike. It really runs. AW | ||
| Caveman |
Vacuum Leak? After a long ride, my 98 S3 now "pops" and "Crackles" from the exhaust like a street rod during deceleration / engine braking. It never did this before. Also, I noticed that when I "blip" the throttle (not driving) it does not come quickly back down to idle. I think I have seen ppl speak of this b4, but plz remind me of where to look. Exh flanges were kinda loose, so I tightened them with a torque wrench (6 - 8 ft/lb)doesn't seem very tight, and dbl nutted them, still no change. TIA jim | ||
| Blake |
Caveman: Check your intake seals. | ||
| Jmartz |
Aaron: When you say the squish band area enlarges towards the center of the chamber, are you talking about a shallow cone? I've always thought this shape to be a good idea since it has the potential to "focus" the charge but it is not clear to me if it would actually have time to work. The purpose of the "squish" is to create a denser area of air and the fire event and TDC piston residence are very quick. There is also the draw back of increased surface area on any piston that is not flat with the potential to collect more heat reducing the useable full thottle time. The old lightning chamber seemed like a very good design if the compression was higher and the squish band tighter. Flat top pistons and a squish band that gradually gave rise to the chamber. | ||
| Aaron |
Jose, yes, I agree. You see it in stock car racing all the time, flat top pistons with small chambers, for the reasons you mention. As I know *someone* on here would explain to all of us, the problem with flat tops and a flat squish band is raising compression. Sticking a dome in the way of the fuel being squeezed out is not the greatest thing in the world. They appear to be doing this on the Firebolt. Possibly a cost thing? I would think making a flat squish band is easier to do accurately in a production environment. Room for us to improve it? I would think so. AW | ||
| Road_Thing |
Caveman: Backfiring on the overrun can be caused by leaky exhaust header gaskets. Since you mentioned that your ex. flanges were "kinda loose" I'd suggest you pull your pipes and change out the little woven metal donuts in the exhaust ports. r_t (...of course, a LITTLE popping sounds pretty cool...) | ||
| Bull |
Hi Guys, My rear rocker box cover is beggining to "sweat"... theres oil film around the rear parts of the cover, not much, but anyway. Will the gasket blow or will it stay in place?? I guess it's hard to state, but i've heard a lot about these rocker covers, so someone would be able to tell me what to expect... Cheers/ Jojje | ||
| Pangalactic |
If you've got the stock paper gaskets, expect a gusher the next time you ride... | ||
| Pangalactic |
BTW.... Is there a trick to getting the rubber gaskets on the top piece to seat properly? I am having a heck of a time getting it to stay in the groove cut for it. I go a set of Cometic metal gaskets, and did the front ones first (even tho it wasn't leaking.......yet) and thought the rubber gasket was a pain in the arse. But it sealed. The rear set, I've put on twice. While both the bottom and the top were both an equal pain to set, only the top one is leaking. Do I possibly have a defective set, or is this pretty common- and I have to play with it till I get it right? | ||
| Pangalactic |
Maybe the rocker box gaskets needs it's own thread? Seems like thats about the only thing we talk about in here... | ||
| Aaron |
I'll tell you what, ask BuellieDan about this. At Breckenridge, he put in a full set of Cometics. The rubbers didn't fit worth a damn. I believe he ended up putting the originals back in. If they're not torn, they last almost indefinitely. | ||
| Tim |
In the past someone mentioned throwing the rubber gaskets in the freezer for a while. Tim | ||
| Blake |
Bull: I had some serious weeping on my '97 M2, even thought it had progressed to a full blown leak. I rode the thing with the tri-state trash, noticed oil burning smell when I arrived at our meeting place, a place called The Brass Ring in NJ. I said what the hell, beat the heck out of it riding with a bunch of maniacs, washed it up good when I got home. Hasn't shown any sign of weepage or leakage in over 4,000 miles since, and I run Mobil-1 15W50. Fine by me! It had been overfilled when I picked it up from the previous owner. That probably contributed to the come and gone weepage scenario. Not that I strongly recommend it, but I used the pressure wash at the local car wash to clean up the weepage. Looks brand new again. I'd say that if you are planning a long ride away from home, go ahead and change gaskets. Otherwise, wash her up good and wait and see what happens. Blake | ||
| Bluzm2 |
Bull, I just replace my front r-box gaskets last night. I wanted to wait a couple of weeks, but it was getting VERY messy. I replaced them with the stock paper units, no one in town had the steels available. I have around 10,500 on my M2, the rear let go at about 4200, the front about 10,200. I used stock HD rubbers with no problem, they came as a set with the gaskets. I saved the old ones just in case I need them. They probably would have worked fine. The main pain was the left front allen bolt. Not much room to manuver a allen wrench and the angle is too steep to use a ball end wrench (locktite grabbed a bit too much). Don't forget to use Locktite blue on everything. Both front and rear started out small and within a few hundred miles really let go. | ||
| Blake |
New rubber gaskets are fairly cheap. | ||
| Sportyeric |
New rubber gaskets are NOT cheap (up here, anyway}. I find if you compress them immediately after removing the rockerbox (by reassembling it while you scrape the old gasket off}, they will fit back in. If you leave them out they expand and can't be used again, though I never tried freezing. I may just have more time than money but I've never had a rubber gasket leak but am now on my third paper gasket. (I know I should have used Cometic.) I'm trying Aaron's recipee of extremely clean surfaces and someone else's hint of carefully balanced inital tightening. |
