| Author | Message | ||
     Thomas_lindemann |
Im starting my winter project, Im basically gonna blue print the top end on my low mileage XB12 and Ive got a couple of questions 1. how tight can i run the deck height on it? .040"? 2. what is the thickness of the stock base gasket? 3. do the dowels come out of the top of the cylinders? 4. has anybody ran total seal rings in stock bore stock piston motors? | ||
| Hobanbrothers |
.040 should be fine as long as that is your min. many different base gaskets from .005 to a typical .020 or so, you must use final crush thickness. yes yes | ||
| Sarodude |
Thomas- I've been told by some reputable, knowledgeable builders that Total Seal rings seal so tight that they pull oil right past the stock valve guide seals. Apparently there are some tighter sealing versions out there - but I think the matching of the valve seal to the rings is something best learned from experience. I think I've heard of guys running these tighter seals with stock-ish rings and screwing up their valve stems & guides 'cause then not enough oil gets pulled through. I dunno. I just collect data and try to do my best. -Saro (Message edited by sarodude on October 31, 2005) | ||
| Thomas_lindemann |
Thank You for the info. I got the motor out and apart this weekend. The stock base and head gasket there was no way to save to get dimensions so I guess I will order some new so I can dummy up motor to set up deck. Im not gonna build a racer but can see there is room for improvement. here is what I was going to do. set deck at .040 take .010 off heads blend the seats into the port, radius the bowls a little, streamline the area around the guides, match the intake to the port. polish and cc the chambers radius valve job set spring pressure | ||
| Hogs |
Wonder why you wd. just take .010 off the heads, is that for just to clean up as far as performance increase goes will do nothing, I wd. think atleast 50 to 60 wd. be more in line...as Long as you clay the pistons first to see what ya got to work with.. | ||
| Rocketman |
You need Denish's V Twin tuning guides or at least one of them. Complete with formulas, building and tuning math with Harley \ Buell info such as gasket thickness you seek. Better than buying stock gaskets to take measurements off. Rocket | ||
| Thomas_lindemann |
Thank You again for the info, I just ordered two of William Denish's V twin Tuning Guides I appreciate it! | ||
| Sportyeric |
I think 40 thou is conservative. I'm going with 30 thou., but you do have to be careful to warm it up before hitting the rev limiter. The Sportster Performance Handbook says the cylinders grow 40 thou when hot, so you would end up with 80 thou squish, which, they say, is pretty much ineffective. If I remember correctly, the stock base gaskets crush to 15 thou. Rather than swapping out for thinner ones, you might want to turn down the bottom of the cylinders. I've smoothed the corners on my stock manifold, where the center 'pipe' section from the carb joins to the 45s of the individual runners and feel happy about it. There were big humps there. | ||
| Rocketman |
You can't beat Cometic gaskets and they come in a range of thicknesses. You'll enjoy the Denish books. Easy written and explained in layman's terms. Rocket |
