Corte & Cosso De Carbon shocks?

[crash carden]

Hello fellow POGERS! I have purchased a 1977 Penton GS 250 it has Corte & Cosso De Carbon shocks on it. They have a small oil reserve canister attached to each shock with about one foot of rubber hose. I am guessing they are not a gas shock as there are no valves. They seem to work fine with no leaks. However I would like to flush them out and change the fluid,any advice would be great. Also what type of chain guard should be on this model of Penton,plastic,alloy? The parts manaul does not say. It also shows Marzocchi shocks as stock item,so no help for the shocks I have on it. What type of skid plate should be on this bike as there are no mount ears for the old style skid plate. Anyone have the proper skid plate for this beast that they would sell? Or advice on making one. Thanks for any help, Crash Carden -GO Team Penton!

[wildman]

I think all Decarbon shocks are gas charged. The corte-cossa shocks that came on Maicos were rebuildable. You might look for a metal cap on the reservoir with a valve hidden underneath. hope this helps. Dan

1975 250 Cross Country, 1974 175 Jackpiner, 1975 125

[farmer58za]

Hi Crash
If those shocks are Maico units then they definitely are rebuildable.
I rebuilt a set on my '80 model. The caps on the reservoir are alloy push-fit and can be pried off with a screwdriver. Underneath is a convex cap held with a circlip. This is the outer cap to the Nitrogen reservoir. If there's a valve, you can release the pressure. If not, drill out the centre of the convex cap with a hand drill and 1/8 bit.
You can then remove the circlip. Screw the reservoir off the hose and you can push out the floating piston and end cap by poking a small drift into the reservoir. If the hose is a swage fit on the reservoir, I think that pumping the shock may also push the piston out.
I drilled and epoxied two car tyre valves into the caps to be able to refill the Nitrogen.
Good luck

Regards

David
'75 KTM GS175
'75 KTM GS250
'75 KTM GS400

[crash carden]

Thanks,Wildman,Farmer,you have both been a big help. The shocks seem to be in good shape. I just removed them to clean them up and paint them. I think I will remount, test them out and see how they perform before go any farther. At least now I know what to do to repair them if they need to be. Thanks again,Crash Carden GO TEAM PENTON!

[rob w]

Question for ya'all:

On the '74 1/2, '75 KTM/Pentons with the first multi-position/lay-down rear suspension, they came with silver rebuildable Ceriani shocks.

 On these Ceriani's, they also say Corte & Cosso De Carbon on them.
So...was that another company that made the shocks for Ceriani, or what does that mean?

 Also, I'd be happy to find out someday where I can find parts or info to rebuild these shocks.

Thanks
Bob

[farmer58za]

Hi Rob
Just went to the garage and pulled out the stock shock from my '75 GS 250. It's a Marzocchi with a piggy-back reservoir - silver in colour. I've seen these shocks on other 250's from the same year. Could be that non-US bikes got the Marzocchis.

It's likely that Corte-Cosso could have made units for Ceriani.

I think Dr De Carbon was the inventor or patent holder for the gas charged shock.




Regards

David
'75 KTM GS175
'75 KTM GS250
'75 KTM GS400

[rob w]

Hi David,

The Ceriani shocks I'm speaking of were used just previous to the arrival of the reservoir Marzocchi's. Frame numbers apx. 412.....

Bob