Is this just another rumour???

[Ferruz 11702]

26 minutes ago, Willy iine said:

I just used the basic Kyosho grease.  There is some tension (does not free spin like a Hornet open diff when spun by hand).. Kogawa-san recommended ball diffs if going to change the limited slip action and does appear to be a nice upgrade.  I don't drive the car enough so just using the kit diff.  

Thanks so much for the prompt answer! So you mean that you've used the grease that comes with the kit in the diffs? I guess basic grease is not a bad idea.. I don't want to upgrade to ball diffs just yet, am more than happy to start off with gear diffs which I usually prefere anyway. Maybe I will get some diff oil anyway and see how it feels... I'm thinking of trying 7000wt in the front and 5000 in the rear, as it seems that's what @toyolien did to start with in his detailed build.

[Willy iine 18805]

5 minutes ago, Ferruz said:

Thanks so much for the prompt answer! So you mean that you've used the grease that comes with the kit in the diffs? I guess basic grease is not a bad idea.. I don't want to upgrade to ball diffs just yet, am more than happy to start off with gear diffs which I usually prefere anyway. Maybe I will get some diff oil anyway and see how it feels... I'm thinking of trying 7000wt in the front and 5000 in the rear, as it seems that's what @toyolien did to start with in his detailed build.

Yes, I use the green/blue colored grease in the Kyosho white tube.     Car drives great.  

[toyolien 4680]

14 minutes ago, Ferruz said:

Thanks so much for the prompt answer! So you mean that you've used the grease that comes with the kit in the diffs? I guess basic grease is not a bad idea.. I don't want to upgrade to ball diffs just yet, am more than happy to start off with gear diffs which I usually prefere anyway. Maybe I will get some diff oil anyway and see how it feels... I'm thinking of trying 7000wt in the front and 5000 in the rear, as it seems that's what @toyolien did to start with in his detailed build.

I did indeed and it ran superbly on the astro track I raced on. However, I ended up selling it to fund another buggy to enter in the vintage series next year.

[Ferruz 11702]

I'm now deep into the Mid building process, and am enjoying it very much.

As I'm getting closer to building the infamous re-re shocks, I'm starting to have a look at what's going on in that department. As previously brought up by a few others here, I too have noticed that, despite looking the part, they seem to have quite a few possible flaws. For starters, their bottom-filled design might not be the brightest idea ti begin with.

And indeed, much to my amazement, there is absolutely nothing stopping the inner O rings from being pushed up by the rebounding shaft!!  I haven't started building them yet, so maybe I'm missing something, but this looks to be it and it just doesn't feel right 🤔

I've been thinking hard 🤯 and maybe I have an idea, I have to try it out and see if it can possibly solve that issue. These gold shocks look absolutely gorgeous, and I would love them to be a functioning item rather than ending up as some golden junk in my parts bin.

While I try to think this through, I'd be curious to know something @Willy iine: as the proud owner of three Mids, technically you are now dealing with no less than a dozen re-re goldie-shocks  big question is, what are the casualties so far, leaking-wise? I hope none, but I'd love to know.

[toyolien 4680]

1 minute ago, Ferruz said:

And indeed, much to my amazement, there is absolutely nothing stopping the inner O rings from being pushed up by the rebounding shaft!!  I haven't started building them yet, so maybe I'm missing something, but this looks to be it and it just doesn't feel right 🤔

 

I was bemused by this also, and couldn't understand why they'd built them this way. My shocks were great while the buggy was on the shelf (which is where I suspect most Mids will be resigned to), but I raced mine and just couldn't stop them leaking. Well, I did manage to solve it. I fitted some Tamiya Big Bore Dampers, and the issue was gone for good....

 

[Willy iine 18805]

@Ferruz I am happy to report I have no leaks on any of my Kyosho including the red dampers.  Funny how these only use the basic red o-rings and no leak!  

[Ferruz 11702]

2 hours ago, toyolien said:

I was bemused by this also, and couldn't understand why they'd built them this way. My shocks were great while the buggy was on the shelf (which is where I suspect most Mids will be resigned to), but I raced mine and just couldn't stop them leaking. Well, I did manage to solve it. I fitted some Tamiya Big Bore Dampers, and the issue was gone for good....

 

Yeah, I remember that (I was an avid reader of your Mid build thread)... solving the issue by getting different dampers is exactly what I wouldn't want to do, so before going down that route I will certainly try my luck with the goldies. I intend on running the car though (not racing, I wish I could, but there's nothing vintage oriented in my area), so I'm going to need more than just luck.

 

2 hours ago, Willy iine said:

@Ferruz I am happy to report I have no leaks on any of my Kyosho including the red dampers.  Funny how these only use the basic red o-rings and no leak!  

This is great news @Willy iine, happy to hear that 😀👍This gives me hope.

What I have in mind is to come up with something to help retaining those O-rings into place. This tweak will have to be effective, but not invasive. If I'm lucky enough, I might find some washers of the right dimension for this purpose. I would simply cast them into place with a drop of CA glue, which should be strong enough to keep them O-rings from resurfacing.

Anyway, still playing this through over and over in my head for now. If there's any development worth mentioning, I will.

[moffman 5752]

14 hours ago, toyolien said:

I was bemused by this also, and couldn't understand why they'd built them this way. My shocks were great while the buggy was on the shelf (which is where I suspect most Mids will be resigned to), but I raced mine and just couldn't stop them leaking. Well, I did manage to solve it. I fitted some Tamiya Big Bore Dampers, and the issue was gone for good....

 

Mine was exactly the same! Ok sitting on the shelf but the moment it's used "all" the oil just evacuates and makes an absolute mess of front (In my case) of the buggy and it's down to the plastic collar that the shock shaft goes through! The said plastic collar doesn't have a tight fit and just comes away with the shocks shaft when it depresses! Other than buy some more collars and no guarantee they are going to be any better I can't see any other solution if you want to keep the same shocks because when they are working like in my turbo optima they are brilliant!

[Mrowka 494]

18 hours ago, Willy iine said:

@Ferruz I am happy to report I have no leaks on any of my Kyosho including the red dampers.  Funny how these only use the basic red o-rings and no leak!  

Same. I put the dampers together (red or gold), added shock oil, closed up and that was that.

[Ferruz 11702]

6 hours ago, moffman said:

Mine was exactly the same! Ok sitting on the shelf but the moment it's used "all" the oil just evacuates and makes an absolute mess of front (In my case) of the buggy and it's down to the plastic collar that the shock shaft goes through! The said plastic collar doesn't have a tight fit and just comes away with the shocks shaft when it depresses! Other than buy some more collars and no guarantee they are going to be any better I can't see any other solution if you want to keep the same shocks because when they are working like in my turbo optima they are brilliant!

In a scenario where the O-rings would stay where they are supposed to, I think that the plastic collar wouldn't even need to be much of a tight fit...?

O-rings in place means nothing coming away when the shaft depresses, unless again there's something I'm missing. I'll try to work with the idea I was starting to explain above, and see what happens. Time to stop analyzing and enter "hands on" mode anyway.

So Moffman, are you saying that the shocks are exactly the same of the working ones on your Turbo Optima? 🤔 Including the bottom-fill design? If so, it's pretty weird how some work and the others don't! One last question, were they all made in Taiwan or were the Turbo's ones maybe from Japan?

[Tamiyastef 1967]

I haven't build them yet but according to the manual the shocks on the turbo Optima and on the Optima Mid are exactly the same. OTW128-01 and OTW129-01. Strange no one had a problem with these on the turbo 

[Rb4276 803]

1 hour ago, Ferruz said:

In a scenario where the O-rings would stay where they are supposed to, I think that the plastic collar wouldn't even need to be much of a tight fit...?

O-rings in place means nothing coming away when the shaft depresses, unless again there's something I'm missing. I'll try to work with the idea I was starting to explain above, and see what happens. Time to stop analyzing and enter "hands on" mode anyway.

So Moffman, are you saying that the shocks are exactly the same of the working ones on your Turbo Optima? 🤔 Including the bottom-fill design? If so, it's pretty weird how some work and the others don't! One last question, were they all made in Taiwan or were the Turbo's ones maybe from Japan?

I havent built my mid yet but i do have the gold shocks on my re re optima. When i first built them I had no issues for well over a year. I then decided to change the oil weight. Once i did that i had 2 shocks leak. I rebuilt them twice and they still leak. I did nothing different and used the instructions the shocks came with. They are def the same as the mid gold but who knows maybe machined somewhere else. I also had a problem with my red optima shocks, one leaked. O matter what i did. 

[moffman 5752]

5 hours ago, Ferruz said:

In a scenario where the O-rings would stay where they are supposed to, I think that the plastic collar wouldn't even need to be much of a tight fit...?

O-rings in place means nothing coming away when the shaft depresses, unless again there's something I'm missing. I'll try to work with the idea I was starting to explain above, and see what happens. Time to stop analyzing and enter "hands on" mode anyway.

So Moffman, are you saying that the shocks are exactly the same of the working ones on your Turbo Optima? 🤔 Including the bottom-fill design? If so, it's pretty weird how some work and the others don't! One last question, were they all made in Taiwan or were the Turbo's ones maybe from Japan?

Yes mate they are exactly the same shocks but my rear on my mid don't leak just the front shocks and the turbo optima have Never leaked! I tried black o rings from my tamiya parts because they are a tiny bit chunkier but the hole in the middle is exactly the same size and they worked up to a point but I'm finding the moment that plastic collar detaches it pushes the o rings up! I even tried without any springs and you can feel it click then the shock shaft moves all over and the oil comes flooding out! That's just my experience?

[Ferruz 11702]

@moffman Thank you mate for sharing your experience 😊👍I find it very helpful, especially what you said about trying the damper without spring and still feeling the click of the parts moving up.

I did a "dry fit" today and experienced the same: even if I push the shaft up ever so slowly, the inner parts (or at least the upper O-ring) pop out of the hole and go up with it. Imagine this setup under the extreme stress of off-road running!! No kidding it leaks  But then again, many amongst these shocks seem to work fine, so my confusion remains.

I am no engineer -not even close, but it almost seems as if they had a big party at Kyosho while designing the shocks, and then while still hangover they just moved on to the next part without doing the rest of the thinking 😅

Anyway, I started actually building the shocks this afternoon, and I followed through with my idea of adding the extra washer as an O-ring retainer.

Using CA glue inside the shock body to hold the washer into place felt like the most counterintuitive idea of 2023 so far, also it was quite a nightmare because of the patience and precision it required, but it seems to have worked so far. Them O-rings aren't going anywhere, and the washer isn't in the way of either the shaft nor the threaded part of the shock. I shall be done tomorrow and then -if convinced enough by what I've done- I'll post an accurate description with photos, washer measurements and all. 

Well, one of the front shocks is already built, and there are no leaks after manhandling it for a while. But I guess only a proper maiden run will tell if my tweak was actually beneficial.

[moffman 5752]

@Ferruz no problem at all! I'm like you definitely no engineer and my problem with this is when I buy a kit like the optima mid which is an expensive purchase I want it to work properly and is the fault with the shock cylinder or o rings or the plastic collar I personally don't think it's the o rings and I could order a new collar sprue probably the cheaper of the two parts but why should I need to do that when its obviously a manufacturer error I'm going to take them down to my LHS this weekend for a second pair of eyes to look at it!

[Willy iine 18805]

The only general advise I can give that is not in the instruction manual is to oil the damper shaft thread prior to inserting the o-rings and turn the o-rings (as threading them) on to prevent any tear..  but we all know this from assembling Tamiya dampers.  

If anything it was the outer gasket that is a pain to get on without damaging them.  I had that problem on the Javelin which was my first Kyosho..but once I got a fresh one on, no leak.  Not sure if there is any trick.. just be patient and gentle as you force it on.. 

[Ferruz 11702]

4 hours ago, Willy iine said:

The only general advise I can give that is not in the instruction manual is to oil the damper shaft thread prior to inserting the o-rings and turn the o-rings (as threading them) on to prevent any tear..  but we all know this from assembling Tamiya dampers.  

If anything it was the outer gasket that is a pain to get on without damaging them.  I had that problem on the Javelin which was my first Kyosho..but once I got a fresh one on, no leak.  Not sure if there is any trick.. just be patient and gentle as you force it on.. 

Yes for sure, I second all of the above. This time with the gold shocks I chose to avoid the threaded part of the shaft altogether, and inserted the O-rings the other way around instead(where the C-clips go) to further prevent tears. It felt much better, so from now on I'm going to do it this way whenever the shocks construction allows me to.

Yep the outer gasket does require patience and "technique" 😅. Also you don't wanna be shy when tightening it, as that gasket sure feels to be more plasticky than rubbery.

Getting those gold shocks up and bouncing is proving to be tricky, but man they look gorgeous when done... it feels like jewelry. Yesterday, once I completed the first one, I called my wife to show it off and she was also impressed 😁

[Ferruz 11702]

Ok, I am now back to life after pretty much a couple days of full Kyosho shocks OCD (I'm on vacation so whatever, lol).

They are now all built -with my extra hack to keep O-rings+plastic retainer firmly into place- and feel supple and "right". Only a proper run will tell if this actually works and who knows when it will happen (build still w.i.p.), but I can definitely say that I have a good feeling about it.

Here's what I did, in case somebody wants to have a go at fixing their leaking goldies.

I started with looking for the proper washer size, and quickly found the right one in my spares. It had to clear both the shaft and the inner shock thread, while at the same time being beefy enough to retain the O-rings. So,not much tolerance. These are the measurements that worked for my purpose: 8.75mm outer diameter, 4.3mm inner one. 

Once I found the right washers, I chucked them in nail polish remover (with acetone) for a while to help getting rid of oils and grease.

The following photos show where the additional washer is supposed to go

Definitely not much surface for it to stick to... precision and hope needed!

Here you can see the tiny bead of CA glue that I put all around, carefully avoiding both the O-ring and the shock thread. I've used the thinnest CA glue I could find in my stash for this purpose.

Casting the washer on the CA glue was also quite nightmarish, it felt like a one-try-do-or-die type of situation 😅 fortunately no issues there, I was also lucky for sure. Once in the right position, I put another thin layer of CA glue on the outside of the washer to help sealing it in (careful, once again, not to get any glue in the threads).

And finally, the final result ready to go:

A side view, you can still see the washer. As a consequence of this extra piece, my car will now sit 0.7 mm lower. I can totally live with that, if it means no leaking.

Did the same thing for all fours

...and here are the goldilocks, all finished up and ready to be mounted on the car.

As gorgeous as they look, I really hope that they'll work now because:

12 hours ago, moffman said:

when I buy a kit like the optima mid which is an expensive purchase I want it to work properly

Exactly, I couldn't agree more!!

I'll follow up on this when I start running the car (or earlier if I find an oil puddle on the bench, hopefully not!!)

[toyolien 4680]

@Ferruz That's a nice fix. Looks like it'll work a treat. 👍

[Tamiyastef 1967]

Has anyone with leaking shocks already contacted Kyosho about this? I read in a build thread ( I think from @silvertriple ?) of the turbo Optima they were very friendly and send new stabilizer connectors as these broke mounting them on the pivot balls.

Maybe they have some magic trick to keep the o-rings in place they fogot to mention in the manual? 

@Ferruz I think gluing in the top o-ring itself might also work. You keep the whole length of the shock and need no exact washers and such fine motor skills. Just a bead of gel type  CA glue between the outside of the o-ring and the inside of the shock bottom. Or am I missing something? 

[silvertriple 3557]

9 minutes ago, Tamiyastef said:

Has anyone with leaking shocks already contacted Kyosho about this? I read in a build thread ( I think from @silvertriple ?) of the turbo Optima they were very friendly and send new stabilizer connectors as these broke mounting them on the pivot balls.

Maybe they have some magic trick to keep the o-rings in place they fogot to mention in the manual? 

@Ferruz I think gluing in the top o-ring itself might also work. You keep the whole length of the shock and need no exact washers and such fine motor skills. Just a bead of gel type  CA glue between the outside of the o-ring and the inside of the shock bottom. Or am I missing something? 

Never had an issue with Kyosho shocks : I always add sillicon grease on the o-rings before mounting them...

[moffman 5752]

@Ferruzthat is a brilliant idea top Marks for that  I'm definitely going to give that a go but the one thing I can't get my head around (and trust me it's me not you) why do you need to CA glue it wouldn't it just clamp between the shock body and bottom cap? 

[moffman 5752]

@Ferruz ignore that comment above I've just looked at your pictures again and now I know why you need the CA glue (and a very steady hand) 

[BuggyDad 4474]

1 hour ago, Tamiyastef said:

Has anyone with leaking shocks already contacted Kyosho about this? I read in a build thread ( I think from @silvertriple ?) of the turbo Optima they were very friendly and send new stabilizer connectors as these broke mounting them on the pivot balls.

Maybe they have some magic trick to keep the o-rings in place they fogot to mention in the manual? 

@Ferruz

I haven't started building mine yet but this is such an obvious design flaw (or assembly error I guess but I struggle to see how that would be) that it would be entirely reasonable to at least expect some kind of communication out of Kyosho on the matter. Myself, I. Have bought some Yeah Racing shocks to run. In Kyosho's shoes, I'd be embarrassed and looking for a fix to this. 

[Ferruz 11702]

2 hours ago, Tamiyastef said:

 

@Ferruz I think gluing in the top o-ring itself might also work. You keep the whole length of the shock and need no exact washers and such fine motor skills. Just a bead of gel type  CA glue between the outside of the o-ring and the inside of the shock bottom. Or am I missing something? 

I did think about it, but decided not to as I'm not sure it would work in the long run. I'm afraid an O-ring in contact with CA would be an unhappy one, more prone to breaking and becoming brittle with time. Cyanoacrylate does like rubber/silicon, but not vice versa in terms of losing flexibility. I didn't want to take the chance and went for something that felt more solid. We'll see if it works, but it's probably enough done for now, after all it was only a pre-build preventative measure😅