OzVMX Forum

Clubroom => Tech Talk => Topic started by: Dono113 on September 04, 2013, 08:21:06 pm

Title: Legal Pre-70 front ends
Post by: Dono113 on September 04, 2013, 08:21:06 pm
Just looking for a few options to upgrade the front end off my 69 TS 250, just picked one up off Ray Atiken and its got a TM set up at the moment.
Title: Re: Legal Pre-70 front ends
Post by: jimg1au on September 04, 2013, 08:54:35 pm
cz front end
betors
some husky can amm i think they are betors anyway
all 35mm forks
Title: Re: Legal Pre-70 front ends
Post by: firko on September 04, 2013, 09:25:20 pm
I'm not certain if the TM forks are legal for pre 70 or not. If they're basically the same as pre 70 TS forks they're OK so then all you have to do is fit YSS PD valves or Race Tech Gold valve cartridge emulators. I've got Gold Valves in a set of 34mm Yamaha forks and YSS PD valves in a set of 35mm Cerianis. Fitting cartridge emulators and uprated springs to the Suzuki forks saves a lot of trouble and work and will perform much better than standard Betor, CZ or Ceriani's anyway. It's the single best suspension mod you can do to a 7" travel vintage racer. 

That TS of Rays is a good bike....built by Eddie Brook back in the 90's and the winner of a lot of pre 70/250 races during its time.
Title: Re: Legal Pre-70 front ends
Post by: SON on September 04, 2013, 09:45:16 pm
Besides the 67/68 twin pipe TM 250 all other TMs are post 1970
Title: Re: Legal Pre-70 front ends
Post by: Dono113 on September 04, 2013, 09:46:30 pm
Cheers Mark, Ray thinks it won't be legal at titles, got spare complete motor and a spare TS in the deal. Thanks Jim too, look
 Forward to next weekend at the WSDT rd3
Cheers
Bret D
Title: Re: Legal Pre-70 front ends
Post by: farmer58za on September 04, 2013, 09:53:23 pm
Montesa Betors.

http://s215.photobucket.com/user/farmer58za/media/IMG_2776.jpg.html?sort=3&o=65

They will need a new steering stem though.

Regards
David
Title: Re: Legal Pre-70 front ends
Post by: firko on September 04, 2013, 09:58:49 pm
Quote
Besides the 67/68 twin pipe TM 250 all other TMs are post 1970
But are the pre 70 forks the same as post 70 Graeme? I'm curious myself.
Title: Re: Legal Pre-70 front ends
Post by: SON on September 04, 2013, 10:32:59 pm
No Mark completely different
I have a 69 TS and a factory race kit so I am going down the same road
I know all the Euro forks are better than the steel Japanese but they just don't belong
Title: Re: Legal Pre-70 front ends
Post by: firko on September 05, 2013, 09:42:58 am
Quote
I know all the Euro forks are better than the steel Japanese but they just don't belong
I've got YZ250-A Yamaha forks on my TM400 so I reckon anything belongs if it's legal and works. ;D
Title: Re: Legal Pre-70 front ends
Post by: Tim754 on September 05, 2013, 01:46:09 pm
Thanks for the info SON .Would it be possible to put up a photo compering the forks?  Tim754
Title: Re: Legal Pre-70 front ends
Post by: Freakshow on September 05, 2013, 03:26:53 pm
I can swap you a legal 69 TSfront end
Title: Re: Legal Pre-70 front ends
Post by: SON on September 05, 2013, 08:21:18 pm
Thanks for the info SON .Would it be possible to put up a photo compering the forks?  Tim754
Sorry I am no good at posting photos
I'm sure someone can do that
Title: Re: Legal Pre-70 front ends
Post by: firko on September 05, 2013, 10:17:34 pm
 There doesn't appear to be much of a difference going by these two photos.                                                                     
                                                                              (http://i1112.photobucket.com/albums/k495/firko2/TS250_Savage1969_zpsf1d944ae.jpg)
                                                                              (http://i1112.photobucket.com/albums/k495/firko2/tm2501975_zpsd77d9f3c.jpg) (http://s1112.photobucket.com/user/firko2/media/tm2501975_zpsd77d9f3c.jpg.html)
Title: Re: Legal Pre-70 front ends
Post by: Tim754 on September 05, 2013, 10:25:58 pm
Agreed Firko. I might even have both of those about to physically compere. Lets face it neither  would in "bog stock form" offer any real advantage over the other.
Title: Re: Legal Pre-70 front ends
Post by: firko on September 05, 2013, 10:38:32 pm
Quote
Agreed Firko. I might even have both of those about to physically compere. Lets face it neither  would in "bog stock form" offer any real advantage over the other
Tim.....I suspect that they're probably pretty damn close, if not identical inside, a bit like pre 75 34mm Yamaha forks, which, after the original steel legged '68 model, are all pretty much the same except for a bracket casting here or there. I haven't seen anyone object, or even notice MX250 forks on a DT1 in Pre 70. Having said that, if there is a difference, all it takes is one pedantic finger pointer and your whole race meeting could turn to shit with a protest. 

Title: Re: Legal Pre-70 front ends
Post by: Freakshow on September 06, 2013, 02:54:55 pm
not even close....... ones Ali for a start the other is a lead weight in steel.    im sure there differant daimete as well, i have a pair sitting in the corner with the bones of one i stripped out.   and the forks dont even look the same.  its like saying the DT1 steel forks are like the Alimunim ones, pick a set up in your hand, other then going up and down, you cant say there the same forks.
Title: Re: Legal Pre-70 front ends
Post by: firko on September 06, 2013, 03:30:09 pm
That's what we wanted to know, thanks Freaky. For what its worth the steel DT1 forks are pretty much the same internally as the alloy version. Perhaps Suzuki are the same. They're both made by the same factory. The best way to get them working is to fit cartridge emulators, if not ditch em and fit a set of Betors.                 
Title: Re: Legal Pre-70 front ends
Post by: euro bikes on September 06, 2013, 04:11:14 pm
If everyone ran their bikes the way they were made in that era wouldn't that be what riding old bikes is about, with their shitty handling and power but all would be the same for everyone. Probally be abused for this i suppose!!! Cartridge emulators just wern't around then.
Title: Re: Legal Pre-70 front ends
Post by: bazza on September 06, 2013, 04:19:40 pm
euro bikes makes a good point,if emulators were not around and yet your rules ban period swing arms at the other end of a bike??
Title: Re: Legal Pre-70 front ends
Post by: euro bikes on September 06, 2013, 04:23:40 pm
This why i have given it away ,they are not what i used to race back when they were new . The fun is gone for me.
Title: Re: Legal Pre-70 front ends
Post by: firko on September 06, 2013, 04:24:40 pm
Quote
yet your rules ban period swing arms at the other end of a bike
No they don't. You can run any period swingarm you like. Non period isn't allowed because it affects the look of the bike. Emulators are unseen and even if they were declared illegal, how would you enforce it? This subject and other like it have been flogged to death and I haven't got the patience of Nathan to argue the pros and cons any more. It is what it is.
Title: Re: Legal Pre-70 front ends
Post by: euro bikes on September 06, 2013, 04:26:38 pm
But dose that make it right!
Title: Re: Legal Pre-70 front ends
Post by: bazza on September 06, 2013, 05:13:54 pm
Like a period alloy suzuki swingarm, yeah right
as for external not seen so ok, lets run 175cc in our 125cc you cant seeit, i dont think so
Title: Re: Legal Pre-70 front ends
Post by: Dono113 on September 06, 2013, 06:15:51 pm
Rights fellas we can run down the road of changing sleeves to higher cc and their are who believe its "run what was available time" if I change it will be period correct, I have a spare set of stock forks I just thought I could hear from fellas how have done the hard yards.
Cheers
Bret D