Progressive Springs for Showa MG9-951

[Oldnag]

I am looking for some information on the springs I need to get to replace the springs inside my Showa MG9-951 air shocks. They are off a 1985 GL1200 LTD.

I thought the springs would be the Progressive 00-1170, but these are for the GL1100 and do not fit inside my air shock.

Can anyone point me in the right direction as to which replacement springs I should be using for this?

[Oldnag]

I have also seen that the Progressive 00-1172 are supposed to fit the 1985 GL1200 LTD - but I have my doubts from the picture. On the Showa MG9-951 the white cap (no idea what this part is actually called) fits inside the inner spring. The way I knew the 00-1170 was not going to work was that the white cap didn't fit inside the inner spring. From all the pictures I have seen of the 00-1172 it looks identical to the 00-1170 so now I would like to get the dimensions of the diameter of the inside of the inside spring.

On another note, this may all be a moot point since I can't find any 00-1172 springs anywhere. I found some fork springs with that part number, but no rear springs that I can find.

So 2 questions:
1. does anyone know anything about the fitment of the Progressive 00-1172 springs in the Showa MG9-951 shock?
2. does anyone know where I could get my hands on a set of Progressive 00-1172 springs?

[Rednaxs60]

Winter project I suspect. I have the springs, bought because I thought I might put the air shocks back on, but have a set of Hagon shocks on the rear of mine. PM me.

[donens]

Can the MG9-951 be rebuilt? Structure differs from any of the youtube air shock rebuilds I've seen. Those all indicate a snap ring, not a spring ring. Does it need the backup ring pressed for the spring ring to be removed?

[Oldnag]

Yes they can be rebuilt. I have had mine apart completely. That little clip is a pain to get out, but if you compress the washer behind it you will have space to pull it out with a pick or something like that.

Feel free to PM me if you have any questions at all about this. The thing I DON’T know, which happens to be the subject of this thread, is what spring to use for the replacement. I ruled out 00-1170 and Rednaxs60 and I have successfully determined that progressive spring kit 00-1172 will NOT work on the MG9-951.

[donens]

Thanks. Currently building spring compressor today. Any idea when spring replacement is necessary? What causes the springs to require replacement?
Keep me in mind if you guys find spring kit that will work.

[Oldnag]

I was having an air leak issue so I took the shocks halfway apart the first time. I replaced the oil seals and put everything back together. I got the system so it would hold air nicely, but I was still bottoming out even though I had a ton of air pressure in there. That’s what pointed me in the direction of springs.

[Rambozo]

Thanks. Currently building spring compressor today. Any idea when spring replacement is necessary? What causes the springs to require replacement?
Keep me in mind if you guys find spring kit that will work.

Springs need replacement when they no longer do their job. Springs go bad from age and use. Typically they can be checked by measuring free length, or better by measuring spring rate.

[donens]

Any idea on free length spec. Not sure how to do measure spring rate. Any help would be appreciated.

[Rambozo]

Honda often has the free length for springs in the service manuals. Spring rate is done on a spring tester. A makeshift one can be a drill press, tape measure, and a bathroom scale.
A quick and easy test is just to compare the two springs. If the free length is different, they are used up.

[donens]

I've checked the service manual. It provides free length for fork springs but nothing for the rear shocks. Based on the manual it appears they don't want you to disassemble that portion of the rear shock.
Any help on spec much appreciated.

[donens]

In addition, the LTD supplement manual does not even show the LTD 951 shock. Different air hose adapter.

[Rednaxs60]

The 951 shock is shown in the parts fiche, but no springs are shown. Have checked the fiche for the other years and models and there are no spring sets shown.

The spring kit 00-1172 outer spring may work, but it's the inside spring that is the wild card. Honda has a good habit of not reinventing the wheel so to speak, so it would not be too much to expect that the outer spring of the 00-1172 kit would be the same. The wildcard is the inner spring. This would be a research project.

As has been mentioned this is a project. Determining the spring rate and getting the appropriate springs to suit is the issue. I have read other threads where the person has tried to use a shock from a carb model and the shock was not up to the task - thinking it is the inner spring that makes the difference.

The other alternative is to change to a non-air shock, and this is still a bit of a crap shoot. The Progressive non-air shocks are about 1" longer eye to eye, and this raises the bike a bit, does not affect handling, but does affect the distance the rear tire is from the floor when on the centre stand, BTDT. These work very well on max preload riding solo or two up. Can put the bike on the centre stand, but used a jack to raise and take the bike off the centre stand.

Have changed to a custom set made with the correct eye to eye distance with a remote preload adjuster by Hagon. Have a set on my '85 Limited Edition. I would imagine there are other aftermarket shock manufacturers that can do the same. Downside - expensive.

[donens]

Thanks Rednax. Don't this I want to go to longer eye to eye. I have enough trouble getting the LTD on center stand, at 70+ years.
Guess I'll keep looking. Thanks for the info, invaluable.

[Rednaxs60]

Check out these shocks from Wilber The LDC self-levelling. Great concept.

https://wilbersusa.com/wilbers-ldc-self ... gJPnfD_BwE

[donens]

Yes, great concept. Great price as well. Thanks!

[donens]

On related topic. Views and pitfalls of switching to a manually adjusted progressive shock. Realize adjustment, would require saddlebag removal.
Concerned of effect on remaining air suspension system. Can the 3-way be simply blocked, thus retaining system function?

[Rednaxs60]

You can get to the manual adjustment of the shock with the saddlebags on, not easy but can be done. The air system does not need to be blocked off, tied up out of the way. Best to find a shock with a remote preload adjuster if possible.

The effect on the front forks is negligible. To compensate for new shocks, would recommend new front fork springs in the 1.1/1.2 kg/mm straight rate - Sonic springs come to mind, 1.2 kg/mm would be best. Most of us cannot feel the difference between a progressive or straight rate spring. The OEM springs are quite soft and after some 37 years or so, an upgrade would be very beneficial.

I have Race Tech front fork springs - 1.0 kg/mm and Race Tech emulators. Had to enlarge the OEM holes in the lower damping rod and add 2 extra holes per rod - 1/2" diameter. Don't use any air in the front forks. Time to change out the front fork springs this winter - expect I'll use the 1.2 kg/mm Sonic springs.

[julimike54]

Why not use Sonic Springs for the rear shock also?

[crazzy450z]

I know this is an older post, but can anyone comment on if there was a spring setup that was confirmed to work?

Yes they can be rebuilt. I have had mine apart completely. That little clip is a pain to get out, but if you compress the washer behind it you will have space to pull it out with a pick or something like that.

Feel free to PM me if you have any questions at all about this. The thing I DON’T know, which happens to be the subject of this thread, is what spring to use for the replacement. I ruled out 00-1170 and Rednaxs60 and I have successfully determined that progressive spring kit 00-1172 will NOT work on the MG9-951.