gonna try building a custom shock.....sorta.

[great white]

First of all, I've got all these parts lying around already from other projects so it costs me nothing more than some time in the shop. No need to comment on "why" or "just go buy XX". This is as much for the fun of making stuff as much as installing a better rear shock.

My 89 still wears it's original shock. I can feel that it's pretty much "sacked", but it's still somewhat ok for the infrequent blast I do on the FJ from time to time.

But I'm sure I can build better. I just don't want to spend a grand on something aftermarket. I'm in Canada, so after excahnge and shipping, you're not likely to get anything worthwhile under a cool G CAD.

I've got more than a couple CBR600RR/900RR shocks lying around. Leftovers from my VF750F project:



Honda actually put pretty good quality shocks on their RR series bikes. But with the reservoir mounted as it is, there's no way that shock is going to fit in an FJ chassis:



900 on the left, 600 on the right. They both want to occupy the space where the battery sits in the FJ.

But the upside to the RR shocks is they are pretty high quality units. Machined aluminum bodies, quality internals, roughly the same length as the FJ shock and the mounts on each end are the same as the 3CV (bolt on top, clevis on bottom). The RR shocks are also re-buildable, re-valvable, and parts are readily available. They are one of the few OEM shocks that are actually worth rebuilding and tuning.  





Nice stuff in there for a stocker.

They use that stupid tapered spring, but all I have to do is spin out a couple adapters on the lathe and I can use any straight spring I want (more rate choices and more reasonable prices). Re-valving is just re-valving and these shocks offer both adjustable compression and rebound.

Still, that piggy-back reservoir means you can't get it in an FJ. Right?

Well, maybe not:





If nothing else, that will fit in the FJ upper mount now. LOL!

Actually, I had chopped up an RR shock a long time ago for another project. I just never finished it. But now I'm going to revisit it. I'll weld a boss/plate over that hole in both the shock body and the reservoir and use a hose to connect them. I've also got a couple junk F4I shocks with the remote reservoir, but I'm thinking they may only donate the connecting hose. That may affect the adjustments on the reservoir, but only one way to find out.



I also want to kept the remote preload adjuster feature of the FJ. I don't want to be crawling under the bike with a wrench to add preload. In fact, I don't want to have to crawl under the bike to adjust anything. I'm just too old and broken up to want to be doing that any more. A remote reservoir and a remote preload adjuster would certainly fill the bill.

So luckily, I also have an old ZG1400 shock lying around:



Overall, it's nothing really remarkable (typical mass produced stuff) and it's too long to use in the FJ anyways. But; it has a nifty hydraulic collar with remote preload adjuster. It just slides right off the body:



It's juuuuust a hair to small in the ID to fit on the RR shock body at the spring mount collar position. But a pass on the lathe should bore it out to juuuust the right size to fit the RR shock. It will take up space in the spring space, but if it works I can ditch the RR adjuster and gain back that space.

Having my own lathe is going to be the glue that lets me fit all this together properly.

Whether or not it works out the way I think it will once it's on the bike might be a different story......


I've got lots of other projects for the FJ on the go, so this particular one may take a while. But watch this space for more developments. It certainly looks "do-able" at this point.

[Tuned forks]

You certainly are not afraid to modify stuff and take things apart.  I've been watching your wheel thread for advice as I'd like to complete the same this winter.  Now you're disassembling shocks, cutting, adding, who knows what else?  Your threads are entertaining.

Joe

[Pat Conlon]

Boy oh boy,  I would love to have a remote preload adjuster on my Penske shock.
What is the ID needed to slip over the shock body and what diameter spring does the ZG1400 use?

I'm aware Ohlin has a remote preload adjuster for their shocks, but *I think* they use a cable system to turn the adjuster, not a hydraulic like you have.
I'm not sure the Ohlin is compatible with the Penske...I've been meaning to call Traxxion Dynanics and check.
My 8987 has a remote reservoir with high speed and low speed compression adjustment.

[great white]

Boy oh boy,  I would love to have a remote preload adjuster on my Penske shock.
What is the ID needed to slip over the shock body and what diameter spring does the ZG1400 use?

I'm aware Ohlin has a remote preload adjuster for their shocks, but *I think* they use a cable system to turn the adjuster, not a hydraulic like you have.
I'm not sure the Ohlin is compatible with the Penske...I've been meaning to call Traxxion Dynanics and check.
My 8987 has a remote reservoir with high speed and low speed compression adjustment.

Don't remember off the top of my head. I'll try to get some measurements tomorrow.

For me, it doesn't matter. The zg spring is the wrong length, I'll be making custom spring collars and the adjuster will have to be bored/reamed a bit as well.

This coukd all just turn into a pile of junk when I'm done, or it could turn out to be something pretty cool...

[great white]

You certainly are not afraid to modify stuff and take things apart.  I've been watching your wheel thread for advice as I'd like to complete the same this winter.  Now you're disassembling shocks, cutting, adding, who knows what else?  Your threads are entertaining.

Joe

Probably shouldn't mention the Venturecruise system I'm adding to the FJ then:

[ribbert]

Boy oh boy,  I would love to have a remote preload adjuster on my Penske shock.

Wilbers do an electronic adjustable shock conversion, including pre-load adjustment, for $900 (you have to provide an ESA donor shock for the electronics).

Ohlins do a universal electronic version ( I think without pre-load adj ) for $3500!!

Noel

[great white]

Boy oh boy,  I would love to have a remote preload adjuster on my Penske shock.

Wilbers do an electronic adjustable shock conversion, including pre-load adjustment, for $900 (you have to provide an ESA donor shock for the electronics).

Ohlins do a universal electronic version ( I think without pre-load adj ) for $3500!!

Noel

Holy ouch batman! On both counts!

I don't think I have much more than a hundred bucks in all the parts you've seen pictures of in this thread so far.

Maybe another hundred for a proper spring, some aluminum to make the collars and some oil. Then I just have to rework the ports and shim stacks (I have lots of shims in the drawers already).

Now, I my not be a "suspension guru"that can squeeze that last "10/10ths" out of my rig, but I'm good enough to get 8-9/10ths out of it. Which is, quite frankly, above the level I ride at these days anyways.

So glad I have a lathe and a 220V mig with spool gun at my disposal. Was well worth buying them so many years ago. The price tags hurt at the time, but I've used them so many times over the years on everything from office chairs to custom automotive stuff that I'm sure I've gotten my money's worth out of them.

For example, I like to play racing sims games (Forza mostly) when I have some time to waste and wanted a "racing chair". Prices were absolutely foolish for store bought stuff. Anywhere from 500 to 1000 for what was, essentially, an office chair done up to look like a car seat. That was not counting the price of a sim racing wheel or even a built in mount on the chair to hold a wheel. I wasn't spending that much on a "game accessory" that I would use once in a blue moon, so I bought an office chair at the local thrift store that was in decent shape and built this:





Total cost? 20 bucks, not including the wheel and pedals. Those were bought used for 40 bucks. The chair was 12, the steel came from my scrap pile, I had the black spraypiant left over from other projects and the wheels underthe pedals were about 8 bucks. The rest was my own labor on a lazy weekend afternoon. So 60 bucks with the wheel vs 500-1000 for a ready made product.

Saved enough on that one project to pay for 50-75% of the welder alone.

I've always said you can never go wrong buying tools and learning how to do things for yourself. Assuming you actually take the time to learn to do things the right way that is.....

[Pat Conlon]

Thanks Noel, I do recall reading about the Ohlin uber $$$ shock, but not Wilber's.
I'm happy with my Penske. Old school (like me) on the fly I can reach down with my left hand and turn a knob and tighten or loosen up compression.
Setting the shock spring preload...uuugh. A different matter.

If the measurements work out with the ZG1400 collar and my Penske, I'm heading to FleaBay.

[great white]

Looks like 50mm:

[Pat Conlon]

Ok, thanks! Much appreciated.
Thank you for giving me the idea, or at least reminding me how much I dislike getting down on my creaky knees and fussing with that preload collar.
If 50mm will get me over the shock body, making the spring perch for the spring will be easy.
Last question: Approx how much adjustment range does the hydraulic spring collar have?  3/4"?

[great white]

Ok, thanks! Much appreciated.
Thank you for giving me the idea, or at least reminding me how much I dislike getting down on my creaky knees and fussing with that preload collar.
If 50mm will get me over the shock body, making the spring perch for the spring will be easy.
Last question: Approx how much adjustment range does the hydraulic spring collar have?  3/4"?

Couldn't tell ya. It needs to be on the shock and under spring pressure to work properly.

[Pat Conlon]

Ok, thanks again!

[ribbert]

..... but not Wilber's.

It's not a universal unit like Ohlins, it's a replacement for BMW's with ESA suspension. I was looking at the possibility of fitting one to the FJ. The canbus wiring looks like it will be the biggest hurdle.

Noel

[great white]

Not a lot of progress today, but roughed out the adapter for the hose attachment point:





It's literally just a block of aluminum machined to the rough shape right now. Still to do is drill the fluid passage, then thread for the hose fittings and finally, welded to the shock body. There's no real mechanical force there, other than the fluid, so it just needs to be solid and a "fluid tight" weld.

Then it's on to do something similar to the reservoir end and connect the two via hose. The revervoir will be easier, it basically just needs a "block" off plate. The shock body i wanted angled down and away from the frame mount and spring.

Then it's work out the springing and valving.

Yeah....that sounds simple, right?

[great white]

Toying with where to mount the remote reservoir:





I'm leaning towards pic #1.

I could mount it further up and back, but the shape of the "stub" where the valve is puts it (and the connecting hose) right over the rear tire. It's high enough that it will never hit, but adjusting the valve would be difficult and it would be just pelted with road debris, water, etc. Down by the footpeg support it's easier to get to, looks better and I can shield it a bit with a hugger fender or something similar.

The LH side is not really an option, with the chain being right there.

The preload I'm thinking I might put in the FJ location under the side cover. I'd still have to remove the side cover, but that's still must easier than crawling under the bike with a wrench....