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DT360,DT400

  • topcop911
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DT360,DT400 was created by topcop911

Can anyone tell me how a 1973 DT360 makes 30hp and the 1977 DT400 only makes 22hp,I guess I did not word my question correctly.
What did they do to the DT400 to detune it?
Last edit: 23 Jan 2015 10:50 by topcop911. Reason: more information
20 Jan 2015 10:55 #1

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Replied by RALPH on topic DT360,DT400

My quess is the US gov
20 Jan 2015 11:17 #2

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Replied by Makotosun on topic DT360,DT400

That would be correct. The 77-78 models were detuned in order to meet the EPA standards for the last couple of years they were brought to the states. The 400 was not able to meet the EPA after 1978 and was discontinued here. There was also a move by Yamaha to push their XT/TT/IT bikes, so the two stroke enduros kind of petered out.

Though the motor is detuned from the 76-77 models, the better suspension makes those bikes more pleasant to ride. I can tell you that I have never run out of power with my 78, so the HP is not as big of an issue for recreational bike.
IF it isn't one thing, it's another.
20 Jan 2015 11:29 #3

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Replied by Enduronut on topic DT360,DT400

.

Also, if I'm not mistaken . . . didn't the industry standardize or mandate the way horsepower was taken & reported sometime during the 1970's?
In other words ..... A previous years 30 hp engine would only equate to just 22 hp under the new rating system . . . . as in .... crank hp converted into rear wheel hp.

.

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20 Jan 2015 11:55 #4

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Replied by RALPH on topic DT360,DT400

This is getting interesting.
20 Jan 2015 12:40 #5

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Replied by bluntz465 on topic DT360,DT400

HP figures are pretty meaningless as everyone played with them for one reason or another not least of which was insurance costs.The better value is the torque figures.Remember there is no substitute for cubes. B)
1957 Cushman Eagle 1969 Honda 90 ATC 1969 Honda CB250
1973 Yamaha AT3 1974 Kawasaki KH440 1974 Honda XR75
1975 Suzuki TS75 1975 Kawasaki GreenStreak 90 1975 Suzuki GT550
1975 Suzuki TS250 1976 Suzuki GT550 1976 Indian Chief
1976 Yamaha YZ80 1978 Yamaha IT175 1980 Suzuki GS550
1982 Yamaha IT465J
Last edit: 20 Jan 2015 14:46 by bluntz465.
20 Jan 2015 14:45 #6

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Replied by MarkT on topic DT360,DT400

Enduronut wrote: .

Also, if I'm not mistaken . . . didn't the industry standardize or mandate the way horsepower was taken & reported sometime during the 1970's?
In other words ..... A previous years 30 hp engine would only equate to just 22 hp under the new rating system . . . . as in .... crank hp converted into rear wheel hp.

.

.


+1 on this. :likey
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
20 Jan 2015 17:11 #7

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Replied by Hammer on topic DT360,DT400

bluntz465 wrote: HP figures are pretty meaningless as everyone played with them for one reason or another not least of which was insurance costs.The better value is the torque figures.Remember there is no substitute for cubes. B)


Yes, there is; technology. This is why Yamaha 250 and 350 road racers blew the doors of there competitors for ages with much smaller engines. The 250cc engine is only 15 cu. in., whereas the Harleys, Triumphs, etc. of the day were 750 cc (45 cu. in.). Don Vesco, Kel Carruthers and their folks were absolute magicians with the Yamaha twins! Could you imagine if a Harley 350 Sprint had to race against Yamaha 350s? From 1972 through 1984, if you didn't ride a Yamaha, why bother to show up?

Hammer
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21 Jan 2015 02:37 #8

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Replied by Devin on topic Re:DT360,DT400

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21 Jan 2015 03:13 #9

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Replied by bluntz465 on topic DT360,DT400

Hammer wrote:

bluntz465 wrote: HP figures are pretty meaningless as everyone played with them for one reason or another not least of which was insurance costs.The better value is the torque figures.Remember there is no substitute for cubes. B)


Yes, there is; technology. This is why Yamaha 250 and 350 road racers blew the doors of there competitors for ages with much smaller engines. The 250cc engine is only 15 cu. in., whereas the Harleys, Triumphs, etc. of the day were 750 cc (45 cu. in.). Don Vesco, Kel Carruthers and their folks were absolute magicians with the Yamaha twins! Could you imagine if a Harley 350 Sprint had to race against Yamaha 350s? From 1972 through 1984, if you didn't ride a Yamaha, why bother to show up?
Hammer

Ah yes well there is that of course....even if it was made from rpm torque is still key.But I wonder do you think that 350 stands a chance of taking a VMAX?
1957 Cushman Eagle 1969 Honda 90 ATC 1969 Honda CB250
1973 Yamaha AT3 1974 Kawasaki KH440 1974 Honda XR75
1975 Suzuki TS75 1975 Kawasaki GreenStreak 90 1975 Suzuki GT550
1975 Suzuki TS250 1976 Suzuki GT550 1976 Indian Chief
1976 Yamaha YZ80 1978 Yamaha IT175 1980 Suzuki GS550
1982 Yamaha IT465J
Last edit: 21 Jan 2015 19:41 by bluntz465.
21 Jan 2015 19:39 #10

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