Some parts are designed to be used on multiple models. The inner guide plate also has a classification number of 664 because it's mounted right next to the spiked bumper (i.e. Other parts which are related to each other usually have the same classification number so that they are stocked in the same area on a dealer's shelf for ease of finding. It had a part number of 11, the first in this part series. The spiked bumper available on the first model of saw in this family, 064, was a small part that was quickly rendered obsolete because it didn't function well. 11 which is a spiked bumper suitable to a number of saws, like the 034/036, 026/MS-260, 040, 041, etc.)Ġ506 indicates a part series number, advanced numbers of which indicate a superseded part or an 'improved' part which has replaced previous parts. Spiked bumpers for other models of saws will also have the 664 part classification number (i.e. This is the part number for the inside HD felling dawg (spiked bumper) on an 066/MS-660.ġ122 indicates the model family which is 064/066/MS-640/MS-650/MS-660.Ħ64 indicates a PTO side part family grouping number, in this case a spiked bumper. So let's look at a part number and break it down:ġ1. the numbers cast into crankcase halves and certain large plastic parts like fuel tanks. Sometimes the part series number is only used for reference at the factory, i.e. The last four numbers are a part series number. The second set of three numbers is a part classification number. The first four numbers are a model family number. I've been dealing with Stihl's numbering system for 20 years and here's what I've learned about it:

That's not completely true, and there's been a lot of speculation about what part numbers mean in Stihl's system.

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