| Author | Message | ||
     7873jake |
Have the engine rotated down and the rocker boxes and covers off. Have cleaned the surfaces, cleaned up some edge imperfections that were sharp and just ugly, cleaned all of the hardware and have basically gotten to the point of installing gaskets and buttoning the old girl back up. Trying to clean off the old burnt oil marks and leave the areas clean so I can track future leaks. I've got the Cometic gaskets for the base of the rocker boxes and noticed that while the OEM units are flat with a thin uniform layer of RTV, the Cometics aren't flat and not coated. (See pics) Any sage wisdom re: whether the ridge in the gasket goes up or down? Does it need a thin bead of RTV around it or does this unit have enough crush to it to seal because of the ridge?    | ||
| Ratbuell |
IIRC they are stamped with an "UP"...at least, the sets I've installed have been. They install dry. As long as your mating surfaces are still flat and you didn't hollow any of them out when you cleaned up the edges, the bead will compress. Its compression makes the seal, warm or cold, and being a compressed bead it will expand/contract with heat and maintain seal. | ||
| 7873jake |
I was expecting to see an "UP" or some such other stamp on them...alas it was just the Cometic USA stamp and a part number and no other indications. I have sheets of 1500 and 2000 grit sandpaper. I shoot a piece of plate glass with spray adhesive and stick the paper to the glass. Spray the surface with a little water and gently float the rocker box in a figure 8 to clean the mating surface and take some of the machining/casting edges off as well. After that, I have a few pieces of 1/2" x 2" aluminum stock that I glue a cut piece of the 2000 grit to and work the long areas of the head on the bike where I can, finger smoothing with the 2000 the rest of the surfaces where the block won't fit. The 2000 really just removes the old oil marks and gasket without even touching the material, I hope.  In the service manual, I did notice that on page 3-44, fig. 3-57 references fasteners 1 and 3 and the instructions seem to have a misprint about which ones need to be removed in which order as well as the qty of fasteners, etc. Just an interesting discovery. (Message edited by 7873jake on March 16, 2014) | ||
| Reepicheep |
The flatest surface I could find in my shop wasn't a plate of glass, it was the machined surface of my table saw. FWIW. | ||
| 7873jake |
I never even thought of the table saw! I have a 2' x 2' x 2" plate glass slab (from where I'm not sure) but my Powermatic PM2000 table saw has one heckuva nicely machined flat surface! | ||
| Reepicheep |
Plate glass might be flatter. Use a machined straight edge, put it flat on the surface, and see how big a feeler gauge you can get underneath it. A 2" thick plate of glass would be a cool thing to have laying around regardless. I went hunting for the same reason you did... only mine was for a KLR 250 that blew a head gasket. Took me forever before I finally looked over at the table saw and did the ole forehead slap. | ||
| Natexlh1000 |
I used to sharpen stuff with 300 grit paper and my dad's tablesaw. 12X12 paper + masking tape = Huge whetstone | ||
| Teeps |
You could contact Cometic Cometic Gasket 8090 Auburn Road Concord, OH 44077 Toll Free: (800)752-9850 Sales/Tech: (440)354-0777 Fax: (440)354-0350 Email: sales@cometic.com Hours: Mon-Thurs: 8:30 - 5:30 Fri: 8:00 - 4:30 | ||
| Tootal |
I don't think it matters which way you put them. The crush ring will do it's job either way. | ||
| 7873jake |
That's what I figured initially and then got the "let me see what the vault at BW says" in case I was mistaken, not an uncommon thing. I buggered up an allen bolt in the removal of one of the rocker boxes and went to Seminole H-D to see if they had any of the 1/4-20 x 1 3/4" in stock (grade 8). They did so I bought 4 new ones for $1.11/ea (part #4718A common to H-D bikes) and I ran in to a guy who I recognized as one of the Buell guys I'd dealt with before on the ECM issue. Asked him and he said the same thing Tootal said. Keep it dry and torque it to spec. My OP was born out of a Sunday desire to wrap things up. Once I abandoned that unfounded push to hurry up and finish, my life got easier but the curiosity remained. | ||
| Mark_weiss |
The Cometics may well have a Teflon-ish coating. | ||
| 7873jake |
They look and feel that way. | ||
| Mark_weiss |
The coating does two things for you. One, it helps the thin areas of the gasket to resist squirming out of place when the parts are tightened together. Two. The soft coating flows a bit to fill tiny voids and seal air ( and oil ) tight. |
