So far the little digging I could come up with is that the EPA versions are U.S. versions to comply with changing EPA regulations. The "non EPA" versions were international versions, which received revision based on changes made to accommodate the EPA phase II changes. I haven't figured out what changes were actually made part-wise yet to comply with these changing regulations. I suppose some of the porters might be able to answer if they notice differences in jugs or across saws of different years.
Other than that I think parts are often improved, superseded or changed out on any given model. I believe all the earlier 395XPs are compatible with the latest part version... My guess right now is that the 2001-1 (Jan)/2003-10 (Oct)/2005-5 (May)/2007 -1(Jan) revisions maybe only badge/stamping of meeting EPA certification changes which end-users don't really care about.
Here are the regulations (if you follow the link, just look for Table 1, lower part which includes handhelds class III, IV, and V)
http://www.fs.fed.us/eng/pubs/html/02511204/02511204.htm
EPA- and CARB-Compliant Chain Saws
Chain saws used in wildland firefighting are classified as handheld equipment. Class III saws that are less than 20 cc typically are not used in wildland firefighting. Most chain saws are classified into class IV, with 20 to 49 cc. Some of the larger saws are in class V, with more than 50 cc engine displacement.
The EPA divides engines into classes based on whether they are handheld or nonhandheld and on engine displacement. Classes I, I-A, I-B, and II are for nonhandheld equipment, while classes III, IV, and V are for handheld equipment.
EPA Phase II standards become effective in model year 2002 for engines in classes III and IV and model year 2004 for engines in class V. The new rules will make it difficult for chain saw compliance because of the unique operating characteristics of the saws.
CARB Regulations
In addition to the EPA regulations, the CARB has developed regulations in accordance to the California Clean Air Plan. CARB Tier II regulations are currently more stringent than EPA regulations for both handheld engines under 65 cc and nonhandheld engines and will continue to be more stringent until 2003.
Starting in 2003, the EPA handheld standards will be more stringent than the CARB standards, depending on engine displacement. Proposed Tier III CARB regulations however are more stringent than the EPA regulations after 2005. These drafted regulations are scheduled for CARB action in December 2002.
Pumps with engine displacement of 40 cc or greater are exempt from CARB emission requirements. Chain saws over 45 cc are limited to Federal EPA control. CARB has authority over all handheld engines, except those established as farm and construction engines.
EPA Regulations
EPA Phase I emission standards, referenced in 40 CFR Parts 9 and 90 of July 3, 1995, have been in effect since production model year 1997. (The most recent version of the EPA emissions regulations is found in 40CFR90 of July 7, 2000.) The EPA estimates that Phase I regulations will reduce hydrocarbon pollution from engines by an average 33 percent, compared to hydrocarbons released by unregulated engines.
EPA Phase II emission standards, which are more stringent than Phase I standards, are expected to further reduce the hydrocarbons and reduce oxides of nitrogen by an additional 59 percent beyond the reduction resulting from the current Phase I standards. EPA Phase II also changes engine classes and adds a required useful life period determination. The Phase II standards are scheduled for phasing in between 2001 and 2007. The first year of Phase II is similar to Phase I except for additional durability testing. In the second year and in subsequent years for particular models up to 6 years, the emission standards become increasingly stringent. See table 1 for emission by engine displacement and classification.
Engines powering equipment defined as handheld:
Class III—engines less than 20 cc in displacement; or
Class IV—engines equal to or greater than 20 cc and less than 50 cc in displacement; or
Class V—engines equal to or greater than 50 cc in displacement.
The EPA anticipates that implementation of Phase II standards will generate significant reductions in emissions from the seven classes of engines with small increases in cost. It estimates the average price increase for handheld equipment to be $20 for Class III, $23 for Class IV, and $56 for Class V engines. (See the March 2000 EPA fact sheet, “Final Phase 2 Standards for Small Spark-Ignition Handheld Engines,” EPA420-F-00-007.) Engine manufacturers, however, have stated that the actual cost will be significantly higher than the EPA estimates.
The phase II changes for handhelds are similar to the phase I for non-handhelds, and for saws greater than 50cc, this worked out to the following changes
2001 : Phase I
2002: Phase I
2003: Phase I
2004: 143 g/kW-hr, CO=603
2005: 119 g/kW-hr, CO=603
2006: 96 g/kW-hr, CO=603
2007: 72 g/kW-hr, CO=603
opcorn:
