OzVMX Forum

Marque Remarks => Yamaha => Topic started by: steve7406 on February 16, 2012, 07:40:58 pm

Title: Whats the difference
Post by: steve7406 on February 16, 2012, 07:40:58 pm
Whats the difference between a 1975 mx 250 and a 1975 yz 250 which is better.
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 07:56:59 pm
ones a production bike and the other isnt :o
Title: Re: Whats the difference
Post by: John Orchard on February 16, 2012, 08:15:00 pm
Really?  I thought they were both proddy bikes; one in yellow with thermal-flow rear shocks and the other grey with cantilever ?
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 09:53:58 pm
Really?  I thought they were both proddy bikes; one in yellow with thermal-flow rear shocks and the other grey with cantilever ?

first cantilever was a mx250 B in 75 ,it was white.MX250A was 74 yellow ,twin shock. no?
Title: Re: Whats the difference
Post by: BETRIC on February 16, 2012, 10:07:54 pm
73/74 MX250 had the twin shocks, the YZ250 monoshock was a 74 model in OZ, but it was a 75 model in the USA, in 75 we got the MX250 monoshock only, 74 YZ, 75 MX used the same basic frame but with different motors, 74 YZ used the same style motor as used in the 73 YZ250, 75 MX used the same motor as was used in the 76 YZ250C, so I would say that the 75 MX had a better motor than the 74 YZ, the MX250B should have been known as the 75 YZ250 model, the USA and OZ both got the YZC in 76, the YZC still used the same basic frame with a different style rear swing arm ????????.
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 10:26:04 pm
I think the earlier chrome bore 8 bolt YZ's were superior to the later 75MX and 76YZ 6 bolt steel liner jobs.

Whats the diff in the swingarms ?
Title: Re: Whats the difference
Post by: JohnnyO on February 16, 2012, 10:41:27 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 10:51:14 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C

yep,hence my first post.
 :D
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 11:05:08 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C

except how many YZB's came here in 74? , not really available unless your name was Trevor Flood.
Title: Re: Whats the difference
Post by: JohnnyO on February 16, 2012, 11:05:39 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C

yep,hence my first post.
 :D
The '74 YZ250B/360B was a production bike available in limited numbers mid '74
Title: Re: Whats the difference
Post by: JohnnyO on February 16, 2012, 11:07:12 pm
A couble of Qld B graders had 250B's in '74, i think you had to be someone to get a 360
Title: Re: Whats the difference
Post by: motomaniac on February 16, 2012, 11:14:13 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C

yep,hence my first post.
 :D
The '74 YZ250B/360B was a production bike available in limited numbers mid '74

Yer I know . but in 75 an MX250 was a production bike and a YZ250 wasn't ::)
Title: Re: Whats the difference
Post by: JohnnyO on February 16, 2012, 11:29:05 pm
The first monoshock was the YZ250B/360B in '74, the '75 Yamaha was the MX250B/400B and '76 was the YZ250C/400C. There was no YZ in '75 in Australia other than the YZ125C

yep,hence my first post.
 :D
The '74 YZ250B/360B was a production bike available in limited numbers mid '74

Yer I know . but in 75 an MX250 was a production bike and a YZ250 wasn't ::)
True
Title: Re: Whats the difference
Post by: Freakshow on February 16, 2012, 11:50:10 pm
THE 73-73-75 call it what you will yz motor is better than any MX any year.  Apart from the lighter weight the YZ motor is sweet to ride.  the mx a or B still feels like an MX but the later one just might have a softer ride as a plus.

I got A and B and there all bike, no flim flam.  i know what id choose
Title: Re: Whats the difference
Post by: Nathan S on February 17, 2012, 01:48:48 am
YZ-B motor is the last of the old DT1 type, MX-B is the later 'long case' motor that was first seen in the DT-A and MX-A.

Title: Re: Whats the difference
Post by: maico police on February 17, 2012, 07:37:50 am
Early Yamahas are so confusing ???. Still don't know which is what?
I guess Montesa having two VB models is a lot clearer..... :-X
Title: Re: Whats the difference
Post by: Wendell Clark on February 17, 2012, 09:30:44 am
YZ-B motor is the last of the old DT1 type, MX-B is the later 'long case' motor that was first seen in the DT-A and MX-A.


From what I have seen and owned , Nathan S is spot on.
Title: Re: Whats the difference
Post by: JohnnyO on February 17, 2012, 11:15:34 am
YZ-B motor is the last of the old DT1 type, MX-B is the later 'long case' motor that was first seen in the DT-A and MX-A.


From what I have seen and owned , Nathan S is spot on.
yes he is
Title: Re: Whats the difference
Post by: bigk on February 17, 2012, 05:27:07 pm
So is a YZ250B a pre'75 bike or a pre'78 bike?
K
Title: Re: Whats the difference
Post by: Noel on February 17, 2012, 05:39:30 pm
 from 2012 Moms

18.5.4.9 Acceptable follow on models pre 75
a) Honda CR125M1, XL250K1,
XL350K1, MT250 and MT125,
b) Yamaha YZ360B, DT250B,
c) Suzuki TS400 (all).

Interestingly doesn't mention the YZ250B

Noel
Title: Re: Whats the difference
Post by: JohnnyO on February 17, 2012, 08:21:06 pm
So is a YZ250B a pre'75 bike or a pre'78 bike?
K
It's a pre '75 bike.. it was approved for pre '75 years ago.
Title: Re: Whats the difference
Post by: albrid-3 on February 17, 2012, 10:20:13 pm
I was race at Accu Park S.A easter week end, South Australian Titles, in 1974 my friend and I went to Pitman on the Saturday and view the all new YZ250 B first of the mono shock they retailed for $1750 dollars that same weekend Dave basham and Trevor Flood where racing them. both 360. I just wanted one so bad, but my wage was $80 dollars a week, so I couldn`t afford one. I was contented
racing my Honda Elsinore 125.
Title: Re: Whats the difference
Post by: bigk on February 17, 2012, 10:32:21 pm
So are they any good? I have been offered one to ride but declined because I thought they were pre'78 bikes, that and not really being a Yamaha fan. Might have re-think though.
K
Title: Re: Whats the difference
Post by: albrid-3 on February 17, 2012, 10:43:12 pm
The YZ 250 B and A, that I owned was very nice to ride, and great to look at, I think they are one of the best looking pre 75 bike on the track.
Title: Re: Whats the difference
Post by: VMX247 on February 17, 2012, 11:00:45 pm
So are they any good? I have been offered one to ride but declined because I thought they were pre'78 bikes, that and not really being a Yamaha fan. Might have re-think though.
K

Can't say they are a stand out podium taker, at the Classic Nats for the last five years or so..
Excluding the Herbert Brothers  ;D  ;)
Could be a change in the wind now with the split Nationals.
cheers US2
Title: Re: Whats the difference
Post by: albrid-3 on February 17, 2012, 11:04:59 pm
With the right jockey on board, they are a good unit.
Title: Re: Whats the difference
Post by: Nathan S on February 18, 2012, 02:17:58 am
Speaking with all the knowledge of someone who has never ridden one: ::)

I think that a YZ-B that's been limited back to 4" of rear travel is a good pre-75 bike, not an exceptional one.

Brakes are great, motor is great, forks are good. And regardless of your opinion on the old Yamahop stuff, the stock shock is very primitive compared to the modern twin shocks that 'every' other serious pre-75 bike runs nowdays and becomes the bike's weakest point.