facebook1 youtube1 twitter1 instagram linkedin1 pinterest1

NOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community! REGISTER AND MAKE THIS BOX DISAPPEAR!

×

Pictures Posting Not Working (12 Jun 2023)

Picture uploads is again unavailable. We are working on the problem. Thanks for your patience.

Makotosun

DT360,DT400

  • 's Avatar Topic Author
  • Visitor
  • Visitor

DT360,DT400 was created by

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 . Reason: more information
20 Jan 2015 10:55 #1

Please Log in or Create an account to join the conversation.

  • Posts: 131
  • Likes received: 25

Replied by RALPH on topic DT360,DT400

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

Please Log in or Create an account to join the conversation.

  • Posts: 4575
  • Likes received: 2207

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

Please Log in or Create an account to join the conversation.

  • Posts: 915
  • Likes received: 1252

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.

.

.
Control your thoughts . . . or your thoughts will control you!.!
Don't aim . . . and you'll hit your target every time!
A wise man knows . . . he isn't!
Failure squared . . . equals success!
The following user(s) Liked this Post: Makotosun
20 Jan 2015 11:55 #4

Please Log in or Create an account to join the conversation.

  • Posts: 131
  • Likes received: 25

Replied by RALPH on topic DT360,DT400

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

Please Log in or Create an account to join the conversation.

  • Posts: 734
  • Likes received: 169

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

Please Log in or Create an account to join the conversation.

  • Posts: 13392
  • Likes received: 9259

Replied by MarkT on topic DT360,DT400


+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

Please Log in or Create an account to join the conversation.

  • Posts: 392
  • Likes received: 248

Replied by Hammer on topic DT360,DT400


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
Who, More than Self, His Country Loved.
The following user(s) Liked this Post: Devin, mdscott
21 Jan 2015 02:37 #8

Please Log in or Create an account to join the conversation.

  • Posts: 945
  • Likes received: 431

Replied by Devin on topic Re:DT360,DT400

This image is hidden for guests.
Please log in or register to see it.




Sent from my iPhone using Tapatalk
21 Jan 2015 03:13 #9

Please Log in or Create an account to join the conversation.

  • Posts: 734
  • Likes received: 169

Replied by bluntz465 on topic DT360,DT400

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

Please Log in or Create an account to join the conversation.

Moderators: yamadminMakotosunDEETVinnieJames Hart