| 1978 H-D MX-250 ENGINE ON A BOSS FLAT TRACK FRAME |
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| 1977 HARLEY-DAVIDSON DT-250 |
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Dirt Track Engine - By the second half of 1977 Harley-Davidson introduced a new owners manual just of this engine which included both Dellorto and Mikuni carburetor specification. Many of these engines came out of MX-250 motorcycles and others were spare MX engines or surplus engines from bikes that were never completed by Aermacchi. To determine what is the difference from one MX particular engine came out 1978 MX-250 motorcycle that was probably butchered to extract the engine. This was very common and engine to another, first, we need to study the engine VIN#. If the VIN# follows the rule discussed under the 1978 MX-250 tab, then this particular engine came out 1978 MX-250 motorcycle that was probably butchered to extract the engine. This was very common and started in 1977 since sales of the 1978 MX-250 was not sufficient, because the bike was more expensive and heavier than the competition. H-D also converted most of the spare engines for this. These engines have similar VIN# as the ones mounted on a completed bike. But they changed the first sequential production number. Example; 7D90001H8 – The number “9” represents a spare engine. Only engines that start with a VIN# of a 7D1XXXXH8 (X = to the actual sequential production number) are an original engine from a complete build motorcycle from Aermacchi AMF Harley- Davidson Italy factory. I would like to add that I have seen VIN# that have a number “4” after the “9”. I do not have an explanation for this, but just that they were making and changing VIN# as those engines were assembled and sold. This added to the continued confusion we have today. But if you think this stops here, you are mistaken. By 1979 H- D needed to compete in ¼ miles Flat-Track racing that they made hybrid engine out of spare MX-250 and SX-250 engines. Some of also have a different VIN# production year; “J0” for 1980. this engines are missing the complete engine sequential production number which is discussed under the 1978 MX-250 tab, and they also have a different VIN# production year; “J0” for 1980. Because of the VIN# year production, I have desired to call these engines; “Hybrid MX-250”. H-D sold the Aermacchi Italian factory to Cagiva group in mid 1978, so how they could have manufactured this engine with 1980 VIN# in the Italian factory? The only explanation I have is that they used the surplus from both the SX and MX 250 engines. Moreover, even though I can not prove it is my strong belief is that Cagiva could have sold spare parts to Harley since Cagiva was producing their own version of the H-D 1978 MX-250 and SX-250 in Europe by 1979. Harley-Davidson Flat Track prototype engines - By the mid 1977 H-D was experimenting with the surplus of their MX-250 engines by moving the transmission shifter to the left side of the engine. The first engines had the shifter on both sides; right and left side of the engine. These converted engines were sold over the counter by H-D dealers or through special order. Because these engines were done in Wisconsin, H-D stamped with a VIN number. I only know of two engine stamped with a VIN number with a (VERY RARE) H7 = to 1977. Their were some stamped with a (RARE) H8 = 1978, but with a different type of VIN sequential number. They have the "9" for a spare engine, but also a "5" after the "9", which is my guess estimation for converted Flat Track engine or DT-250. (see photo) Flat Track Race Frame - Harley-Davidson never came out with a mass production combination frame and engine bike. More over their factory team used several different after market frames; Champion, Boss, Track Master, Red Line, KR, etc. Some of their factory rides consist of Randy Goss, Ricky Graham, Ted Boody, Scott Pearson and Jay Springsteen who won the Houston short-track race in 1977 with combination of a Track Master frame and a 1978 MX-250 engine. Moreover, the MX-250 did extremely well in dirt track racing across the country all the ways to the early 1980’s against modern water-cooler Japanese engines. |
