| Author | Message | ||
     Bomber |
cross posted in the KV, and here for greater visibility In this, the latest chapter in "As the Buell Turns" or, in this case, as it doesn't turn ;-} - 2000 M2 cases,, crank, conrods - CP pistons (10.5:1) - Millenium 1250 CYlinders - XB heads - Cometic gaskets (pn 160-050) Upon assembly of the engine, the piston contacts the head for approximately 10 degrees on either side of TDC -- contact point is on the left and right sides of the piston/heads, 90 degrees from the valve locations should I: install a second basse gasket? get thicker base gaskets? turn the entire project into a planter for magnolias? thanks, all, again, for your help == | ||
| Ratbuell |
If you have XB heads, you have to have pistons to work with XB heads. Contact Millenium, tell them you are using XB heads with their cylinders, and they should be able to specify the correct pistons for you. It's all in the shape of the chamber and piston dome. | ||
| Aaomy |
sounds like thunderstorm pistons with xb heads,, any picks of the pistons? they should be flat topped rather than domed. two possible corrections.. one new pistons,, two have thunderstorm tapers cut into the xb heads.. then figure out new compression ratio. three,, most recomended option,, package up everything and send to me.. i have a better looking pot for your magnolias,,,,,, | ||
| Rick_a |
It's the pistons. Those CP pistons are domed and designed to work with Sportster 1200 hemi chamber heads. Like stated above, you'll need either domed Thunderstorm 1250 pistons, the cylinder heads cut for the 15 degree chamber dome, and the chamber volume adjusted for your desired compression ratio (expensive but worth some 5+ HP) or just get the matching XB 1250 pistons. | ||
| Loki |
If not using a flat top piston with the XB head. Or either of the XB pistons. One must have the head cut for your piston of choice. | ||
| Mmmi_grad |
who told you these would work? CP pistons (10.5:1) ? Try and match your components next time. Good job catching the problem. | ||
| Bomber |
All -- pistons are entirely flat, with the exception of the valve pockets . . . . still, I'm thinkin it IS the pistons, and other ones may be necessary -- MMM1 __ great thinking! ;-} | ||
| Spiderman |
Did you get the XB 1250 kit? | ||
| Ratbuell |
Remember there's another measurement on pistons besides dome shape and size - deck height. It's the measure of whether the piston comes up past the top of the bore (positive deck height), or stays below the top of the bore (negative deck height). I don't know the specs on XB vs. T-storm, but it sounds like the XBs have a neg or neutral deck measurement, and the Tstorms may be a bit positive (maybe in the name of compression on the older motors?). | ||
| Rick_a |
Proper 10.5:1 pistons for those heads will have a slightly raised oval-shaped dome in the center roughly matching the chamber. Something like this, but with less of a dome:  A flat top would not get 10.5:1 with that bore and those heads. | ||
| Phat_j |
i have the xb 10.5:1 kit and my pistons are slightly domed such as these....http://www.revperf.com/default.aspx (Message edited by phat_j on April 16, 2007) | ||
| Sportyeric |
The dome on stock Thunderstorm pistons is very subtle and could be mistaken for flat-top at a quick glance. A fifteen degree angle for about 1/4 inch around the outer perimter. I have to look twice at my shelf full of crap to pick the right ones. Don't know about 1250. | ||
| Firemanjim |
That's odd,John as I thought those were supposed to be for my XB headed bike.It may have been an error on Rev Perf from the very start.Didn't I suggest a call to Brian at the time? | ||
| Bomber |
yep -- ya did -- we all have lapses from time to time, so no foul on anyone's part -- lil more research on my part is in order, then the course forward will be clear |
