Vintage Dirt Bike Q & A

Hi guys.
I have a Thor swing arm on my '79 125 and want to put it on my '80 model. I am confident it will fit but will it work properly as i will be racing it and don't want to be going backwards in the handling, especially as it is such a sweet handling bike already.
My aim is to put trick parts on both my 125 and 250 RA so what would be the best rear end for both? The shocks are 17.5" long ( on both bikes) ,are they to long for the '80? My idea would be to fit a Thor to both to keep them the same as ik have Simons for the front as well.
Any feedback is welcomed !
Cheers, Brad

The Thor swingarm should be a bolt and go for your '80 CR. Check the length of the Thor against the
stock swingarm to make sure they are the same length as the '80 stock swingarm was one inch longer
than the '79. For shocks I would go with either Fox Airshocks or a set of piggyback Ohlins. Both are
big improvements over stock. Combine the swingarm/shock upgrades with your Simons forks, fiddle with
the adjustability a little and you should have a sweet smooth (relatively speaking) ride.

dogger

_________________
1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

Sound a slightly backward step to me.
Yes you will have the advantage of a lighter stiffer and longer swingarm.
But you would be going from a rising rate suspension layout on the 1980 CR125
and converting to a falling rate system as used by the 1979 CR125.
I'd go for a aluminium s/Arm that is made specifically for the 1980 and use the shorter
shocks eg Ohlin's YSS or Fox.
This is the way I intend to go and I have owed and raced both the 79 and 80 CR125's