| Author | Message | ||
     Hogs |
I asked this on the Regular Forum,Perhaps I Should have asked in here? http://www.badweatherbikers.com/buell/messages/32777/235065.html?1161109260 (Message edited by hogs on October 17, 2006) | ||
| Hogs |
well I guess no difference then.. | ||
| Davo |
Hogs, I do not know the difference and I am interested in knowing as well. We have discovered some high compression issues with (some)06 Uly's. 150 psi is a good benchmark for a compression test and my 06 is 170-175 in the rear cylinder and 180-185 in the front. There is a problem with compression. Starting issues and more active fan operation also tell the tale. The factory is curious about the problem but nothing "official" has been published as a remedy. If I get a set of new heads they will be 07 heads and I will post the difference after I compare them to my high compression 06 heads. I am wondering if some of these early bikes left the factory with 9 heads. That would explain the compression. I am sure that my stock engine is not EPA compliant. At the stock timing setting the engine is trying to self destruct. Late timing is the only remedy to pre-ignition. If I could get some 98 pump fuel I think the bike would grow wings. | ||
| Yohinan |
Hogs, the only piece of advice I can offer is to call someone (maybe one of the Buell friendly dealerships or Buell hqts themselves) and ask them what the part number is for an 07 Ulysses TB and then what is the part number for an 05 XB12S TB. Obviously if they give you the same part number then it's the same. Different PN then they are different. If they are in fact different then someone will have to chime in that has first hand knowledge that has held both parts in their hand to comment on what in fact the differences are, if in fact any. HTH | ||
| Alex |
Davo, up to 07 the 9 and 12 heads are exactly the same so there is no high compression head. I don´t know if there is a change for 07 but I doubt. Regards Alex | ||
| Davo |
Alex, Thanks for the info. The pistons must be different then. The 12 has to have more volume in the combustion chamber than the 9 @ TDC in order to have the same 10:1 ratio. I am trying to figure out why some Uly's have higher compression. | ||
| Alex |
Davo, that´s correct. The pistons are different. The 9 piston has a high middle dome while the 12 piston is almost a flat top. I don´t know if or why some Ulys have higher compression but cranking pressure (that´s probably what You´ve measured) is dependent on many things like cam timing, piston ring seal, static compression and maybe even head flow numbers (probably even a weak battery or starter will show different results). So there are a lot of reasons for different pressures. I´m sure You are interested in the question if there is an intended difference from the company (like using different cams or pistons or heads) but unfortunately I don´t know. First I would take a look in the parts books if there are different numbers for different engine parts but I doubt. Good luck for Your search. Please let us know if You find anything. Best regards Alex |
