Author Topic: tm 250  (Read 5029 times)

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oldfart

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tm 250
« on: February 19, 2008, 06:47:26 pm »
Is this the correct swing arm for a TM 250 . If I was to change the arm to a 74 model would the bike then be eligible to be ridden in pre 1974 class ???

 

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« Last Edit: February 20, 2008, 08:57:20 pm by oldfart »

Offline Tim754

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Re: tm 250
« Reply #1 on: February 19, 2008, 06:53:20 pm »
No you can't ::)   Well yes you can   :-X   OK so it looks like I was wrong  ::)  :-[ :-*
« Last Edit: February 22, 2008, 11:01:43 pm by Tim754 »
I may not agree with what you have to say, but I'll defend to the death your right to say it.
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oldfart

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Re: tm 250
« Reply #2 on: February 19, 2008, 06:58:20 pm »
The only difference that I can pick up is the swing arm
« Last Edit: February 20, 2008, 04:39:03 pm by oldfart »

Offline Tim754

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Re: tm 250
« Reply #3 on: February 19, 2008, 08:28:21 pm »
OK "suck it and see " ;)  I am sure they do not fit up easily.
« Last Edit: February 20, 2008, 08:54:20 pm by Tim754 »
I may not agree with what you have to say, but I'll defend to the death your right to say it.
                                                   Voltaire.

oldfart

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Re: tm 250
« Reply #4 on: February 19, 2008, 08:35:24 pm »
suck what  ???

Offline Freakshow

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Re: tm 250
« Reply #5 on: February 19, 2008, 10:43:45 pm »
Wont fit.  if you can make it i have 3 75 frame here you can convert for me.   cheers.
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

pbear62

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Re: tm 250
« Reply #6 on: February 20, 2008, 12:12:04 pm »
The '75 swingarm appears similar to the '74 except for the shock mounts being further forward. Fairly certain though that the '75 has a larger diameter pivot bolt (& different bushes etc) & that the pivot bolt holes in the frame obviously are larger too. Not sure of any other differences though - I would have thought that by replacing the swingarm it pretty much 'converts' the bike to '74 specs? Maybe Tim can share some light on other differences?

Doc

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Re: tm 250
« Reply #7 on: February 20, 2008, 06:56:13 pm »
pretty sure the pivot width is different too. The frame I have for my project 'I assumed' to be a '75 but in fact is a '74 with modified top mounts so she'll be modified back to stock and remain pre'75. This means all I thought was isn't so I've given you a bum steer or two along the way sorry Stew. Why don't you just put it together and ride it in till another frame happens along or you find/fabricate a swingarm to suit. I can't see any other differences between the '74 and '75 either, in effect side by side you won't pick the difference unless you know the manufacture date/chassis numbers off the top of your head. Not that many '75 TM250's around and it would save a lot of stress  ;) 
« Last Edit: February 20, 2008, 06:59:27 pm by Doc »

oldfart

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Re: tm 250
« Reply #8 on: February 20, 2008, 08:21:34 pm »
I've  got the good oil on what to do :)  Yep I will be keeping it as a 75 model  until a 74 frame surfaces with a swingarm .
Hey Freaky you greedy sod , 3 -75 and still can't jag a 74  ;D





Maico31

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Re: tm 250
« Reply #9 on: February 20, 2008, 09:05:10 pm »
I thought that the top mounts on a '75 TM were about an inch or so further forward than the '74 model.

Offline halo1963

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Re: tm 250
« Reply #10 on: February 20, 2008, 11:22:03 pm »
I was under the impression that you can race the 75 TM250 in the pre 75 class

Can anyone confirm that you can't or is it different for certain events

I have both 74 and 75 and I can check any measurements you want to compare on the two
will have to wait for the weekend to have them side by side

Regards
Halo1963
 
Regards
Halo1963

Offline Freakshow

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Re: tm 250
« Reply #11 on: February 20, 2008, 11:39:39 pm »
I was told in n uncertain terms any frame over 4900 ( for example) 1975 was not eligible, having said that the motor was allowed in a 74 frame as it was identical.  I have a complete 74 TM i raced Dt on last year and a 74 with a 75 motor i did the MX rounds on.

IF MA changes the rules so you can ride 75 model TM frames in Pre 75 i have 3 bikes ready for sale and also the 74 frame i got Quicky painting.  Being able to use a 75 frame would have saved me a lot of pain hanging onto these 75' model bikes as i have been rooting out 74 frames to make em legal for a long time.

I Would say for local club rounds of DT you should get away with a 75 on 12-13" shocks as most wouldnt pick it and you have no real advantage, but im not so sure on MX if you brought a 75, rules are rules and the travel would make an unfair advantage, they ride like differant bikes on an MX track.  they are not identical.  well at least they dont feel it, maybe short shock would change it some but still they are 75, if you let that in see what else then make it in MXB  thats 75.  Chance it and see but if its allowed then it should be changed in the rule book so every one is clear, not just a few i the no
« Last Edit: February 22, 2008, 12:08:22 am by Freakshow »
74 Yamaha YZ's - 75 Yamaha YZ's
74 Yamaha  flattracker's
70  Jawa 2 valve speedway's

For sale -  PRE 75 Yamaha MX stuff, frame, motors and parts also some YAM DT1,2,A and Suzi TS bikes and stuff

firko

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Re: tm 250
« Reply #12 on: February 21, 2008, 12:01:52 am »
1975 TM Suzukis have always been allowed to race in pre 75 as long as the 4" and 7" suspension limits are adhered to. That's usually done by fitting a '74 swingarm or relocating the lower shock mounts. The M model generally accepted as flow on models.

oldfart

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Re: tm 250
« Reply #13 on: February 21, 2008, 07:59:53 pm »
Firko - Just to clear the air, if I was to change the swingarm to a 74 model and leave the top mounts alone , and adhere to the suspension travel limits ........this makes it legal to race ????  not that I'm going to be at the front of the pack  ;D



Doc

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Re: tm 250
« Reply #14 on: February 21, 2008, 09:31:52 pm »
sounds that way to me oldfart..just don't go west young man  :D