RM125B rear shock rebuild

[John Orchard]

Has anyone had a stock set of RM B shocks apart?  I want to re-oil and gas my stockers, I need to know if I can just drill down through the top of the reservoir to release the gas, undo the stock hose and change the oil, then tap a thread back in the top of the reservoir to fit a valve stem for re-gassing.

Thanks, John

[Doc]

Brent J in Darwin has played intimately with RM shocks but I haven't seen him for a while...

[Nobby25]

Has anyone had a stock set of RM B shocks apart?  I want to re-oil and gas my stockers, I need to know if I can just drill down through the top of the reservoir to release the gas, undo the stock hose and change the oil, then tap a thread back in the top of the reservoir to fit a valve stem for re-gassing.

Thanks, John

John, I would like to do the same with my RM250N shocks. have you had any advice?
Who is Marty Orchard? back in the eighties i went on a caotic trail ride around Woods Point,floods,snow, lost.
Have this pic I had written on the back Marty Orchard someone elses bike sept 83

[vmx42]

Has anyone had a stock set of RM B shocks apart?  I want to re-oil and gas my stockers, I need to know if I can just drill down through the top of the reservoir to release the gas, undo the stock hose and change the oil, then tap a thread back in the top of the reservoir to fit a valve stem for re-gassing.

Thanks, John

It all sounds good until you try to refill with oil. You won't have any way of bleeding the air from the system or setting the remote reservoir piston in the correct position prior to regassing. Most shock guys have a pressurised oiling system that would probably work.

I would give your local guy a call to check it out first.

[John Orchard]

Has anyone had a stock set of RM B shocks apart?  I want to re-oil and gas my stockers, I need to know if I can just drill down through the top of the reservoir to release the gas, undo the stock hose and change the oil, then tap a thread back in the top of the reservoir to fit a valve stem for re-gassing.

Thanks, John

It all sounds good until you try to refill with oil. You won't have any way of bleeding the air from the system or setting the remote reservoir piston in the correct position prior to regassing. Most shock guys have a pressurised oiling system that would probably work.

I would give your local guy a call to check it out first.

You undo the hose from the reservoir/nitrogen chamber, make a make-shift reservoir (funnel will do) and top it with 5wt suspension fluid, then stroke the shock remembering that any air in the shock will rise (so remember to position the shock so all air will rise up to the make-shift reservoir), once all bubbles stop coming up, shock is bled.  Drill a hole in the top of the nitrogen chamber of the reservoir (prepared previously), drill and tap a thread for an air valve stem, position the floating piston (that is inside the remote reservoir) at aprox mid way in the chamber, tip the reservoir upside down, fill it with oil.  Now bring the shock hose (with oil filled to the end) and the reservoir (also with oil topped to the max) together and tighten. Now put 1000kpa's of nitrogen in through the air valve stem...... done !!   :-)

[John Orchard]

But that is only for a re-oil & gas, my experience doesn't really go as far as pulling the shock bodies apart.  I have just bought a pair of RM250B rear shocks which I am going to disassemble to see how it all works.

[John Orchard]

Has anyone had a stock set of RM B shocks apart?  I want to re-oil and gas my stockers, I need to know if I can just drill down through the top of the reservoir to release the gas, undo the stock hose and change the oil, then tap a thread back in the top of the reservoir to fit a valve stem for re-gassing.

Thanks, John

John, I would like to do the same with my RM250N shocks. have you had any advice?
Who is Marty Orchard? back in the eighties i went on a caotic trail ride around Woods Point,floods,snow, lost.
Have this pic I had written on the back Marty Orchard someone elses bike sept 83

Hmmm Marty Orchard, Marty runs the KTM & Husaberg dealership in Frankston.  Marty competes in enduro's, he use to import Honda NSR250's from Japan through his company 'NSR Import'.  He use to own Frankston Kawasaki and Top Gear Motorcycles (Frankston Honda & Suzuki dealers).

Marty use to test enduro bikes for Trail & Track magazine at the same time as I was testing the motocross bikes for them.  Marty's dad was named John orchard, they are no relation.

[LWC82PE]

I would like to do the same with my RM250N shocks. have you had any advice?

Open them right up (bodies and reservoirs) and do them properly. They are 30+ years old and there will be shagged bits inside.
The owners manuals gave instructions on rebuilding (changing the oil only really) on some of the RM shocks which may have been ok within the first few years of their life but many years on now they should be totally stripped and have parts replaced.

[brent j]

I’ve rebuilt quite a few of these type of shocks but I only do them for myself.
There’s not much point in explaining how I do it unless you make the same parts as I do to reassemble them.

Mine are modified to make them rebuildable and adjustable.
I spend more time than is practicable doing the work but I don’t mind as I’m having a great time playing with different damping settings etc. I don’t need to justify the time or $ as it’s a part of my hobby I enjoy. I’m also a machinist by trade which does help.

If you want to get your shocks rebuilt, I’d suggest to go to one of the established outfits as they seem to have a workable procedure to do the job and can supply parts for repairs/resealing. I’m not sure what the rebuilders use for pistons but the original one is not a good design especially in regard to the rebound damping system. My mate had a set rebuilt for his KX250 and I wouldn’t even try to match the price they were done for. I’m guessing these guys have the parts to do the rebuild on the shelf and they probably get them made in bulk.

If you are keen on having a play then cut them open but be prepared that you may cut in the wrong place and end up with something that’s not practical to fix.

Even if you re-gas/re-oil them think about why the gas and oil leaked out in the first place. Oil and gas won’t fix a leaky seal
You’ll also end up with a shock that is, at best, no better than original and in most cases they weren’t that good to start with

[Nobby25]

All great advice to consider, I might have a play with the originals one is fine and i suspect the dodgy bros who did a resto before I got the bike may have undid a res hose to paint them  I will save my pennies for something better

Thanks Nob

[Nobby25]

John, I remember him telling me he was a test rider so I thought it may have you nic-named after Marty Smith
Cheers Nob