Hi All
please can anyone one help with any information how to get my rear shock’s working better as they are to soft and keep bottoming out. Or do I have to get aftermarket ones ?
I want to keep as original as poss
its a 1975 dt250 512
thanks for any help

I think that wessi and a couple of others might have rebuilt them.

The problem is they are undersprung for the weight of the bike and rider. If you remove the 32mm cap from the reservoir and drain them and wash the out with brake clean you can get most of the debris out. This will not clean the bottom of the shock body. You need to unscrew the shaft seal holder and remove the piston out of the shock and clean the sludge at the bottom. 20 weight shock oil works good with a heavier spring which is hard to find ,, it says in the manual to use 10-30 motor oil and it works but not great. I believe they just used heavy oil to compensate for to light of spring rate. If you get a SHOCK WITH THE CORRECT SPRING FOR YOUR WEIGHT THE BIKE WORKS MUCH BETTER. These bikes will rearrange your skeleton if you try getting air so just stay low and be happy Soug

Thanks for getting in touch with your information 
do you recommend any after market shocks
thanks Billy

Billy   Old koni's or Boge mullholland if you can find them  They were for the motocross bikes from that era and the were heavier sprung and work much better.. 
Doug

Thanks Doug
Top Man

Maybe some of our members in the UK can recommend something... if I remember correctly there are several shock manufacturers there that will build vintage shocks to your specs.... YSS, IKON, Falcon, are names that come to mind.

Many here in the US have posted about finding NOS Redwing shocks on ebay... it's been mentioned many dozens of times if you do a search.

If it is truly just the springs, Cannon Racecraft in the US will make you whatever you want to your specs if they don't have anything in stock. www.cannonracecraft.com/ They are great to work with... I've used them to make springs for my bikes.

Check this link out if you're UK. Just don't pick a set that's too short. Those bikes could do with an inch or so more height at the back.
Gas/oil shocks keep better constant damping but if they're gas immersion you'll need to run them inverted. Think Hagon took over the Gas Girling shocks of which i'm familiar from the "70's.

www.hagon-shocks.co.uk/

Warning: useless trivia follows...

You need to run regular shocks with the (relatively heavy) body down and shaft up.

Gas shocks can be run upside down with the shaft pointing down...  or can be run with the shaft pointing up like a regular shock.  Doesn't matter to a gas shock. 

The reason most gas shocks are run with shaft down is this greatly reduces unsprung weight...  the heavy shock body is stationary while the light shaft moves with suspension.  But if you really wanted to you could run a gas shock with body down like a conventional shock. 

One caveat, if they are "emulsion" shocks (no piston that separates the gas from the oil in the shock) if bike sits a long time mounted with body down, the gas will all rise to the top and you'll have an brief initial damping "dead spot" where the shock piston is moving through the gas and not the oil.  It doesn't take but one good bounce and the gas and oil will mix again...  and stay mixed for a long time...  hours. 



 

Thanks MarkT I just learned something I didn’t know