Turbo Optima Build - Stripped Set Screw Receptacle

[sundevil67]

My Turbo Optima re-re assembly was going swimmingly, yet just as I was hitting my stride around step 16, I hit my first real snag. If I address the problem now, I think it’ll mean tearing apart the whole front-end to replace the entire front gearbox housing, essentially sending me back to step #1. When securing the suspension arm, despite using the correct set screw, the threads inside the gearbox housing stripped immediately, leaving no way to firmly tighten the OT233 pin.

In the grand scheme of things, I’m not sure it’d matter a whole lot if I just left it as-is. It’s not going to come apart. On the other hand, I haven’t assembled one of these things in about 30 years, so I’m feeling like a 2nd opinion couldn’t hurt. What do y’all think I ought to do here?

[GoMachV]

I wouldn’t sweat it. Make sure the pin is in all the way and the flat is facing the setscrew and install it as good as you can. That flat against the screw will be plenty to retain it.

[mtbkym01]

You could try some CA glue in the hole, let it set then replace the grub screw. The CA dries hard, and a new thread will be cut when you re install the grub screw

[jwscab]

Agree on the glue, but this way.

Add a drop to the hole and add a drop of oil to the threads of the set screw. Install as normal. The oil will prevent the glue from sticking to the threads but form very tight to the screw and hole. I do this a lot for lower shock ends for rc10 when they are kinda loose.

[sundevil67]

Thanks so much - I'll give this a go after I wrap up the tie-rod step...(also my least favorite step 20 years ago)! I have to really prepare whenever I bust out the CA...the de-bonder must be nearby...I can't remember ever using that stuff without gluing my fingers together. I've been so careful not to over-tighten anything and have really been proceeding with kid gloves...that's why this incident was so annoying at first... For the most part, the fit & finish on this kit has been A+.

Though there is one curiosity .... there's a supplemental instruction sheet that I discovered after I was already through with the belt drive guides. There is no indication why this exists, where it goes exactly, etc. If I knew Japanese, it might make more sense. Not worth another thread (I don't think... of course I may learn the hard way at some point why this change was made)... but anyone else see this?

Agree on the glue, but this way.

Add a drop to the hole and add a drop of oil to the threads of the set screw. Install as normal. The oil will prevent the glue from sticking to the threads but form very tight to the screw and hole. I do this a lot for lower shock ends for rc10 when they are kinda loose.

[XLR8]

I thought this was odd as well. It's a revised upper belt/chain guide. I've studied both the revised guide and the standard one very carefully and I couldn't find a difference.
Anyway, I've gone ahead and installed the revise guide just in case.
Maybe someone else here has been able to find the difference? Perhaps Kyosho has simply changed the plastic for this part?

[sundevil67]

I was looking at them side-by-side last night as well and couldn't see the difference. It might be where the little piece of lexan slides in under the guide & perhaps it eliminates this unsightly space I'm not sure about...though exactly how is still escaping me.

I thought this was odd as well. It's a revised upper belt/chain guide. I've studied both the revised guide and the standard one very carefully and I couldn't find a difference.
Anyway, I've gone ahead and installed the revise guide just in case.
Maybe someone else here has been able to find the difference? Perhaps Kyosho has simply changed the plastic for this part?

[sundevil67]

Forgive me for adding this extra assembly question; I know it's technically off-topic for the post, but since I have a few folks here who've been through this build...

I'm really stopped in my tracks at step #25 (radio plate installation). I don't know what they're called, but part #OT205/4, where you have to somehow get this tiny nut threaded straight while somehow keeping it from falling out. I spent the better part of an hour failing at this last night before I had to give up. I tried greasing it up, which helped keep it sticky for a bit, but I just can't get it threaded straight with no way to secure that nut.

There has to be a tool or technique I'm missing here - no one has small enough fingers to hold that nut in place while tightening the screw. I managed for the front end, but those 2 in the rear are much harder to get to. Anyone willing to share the secret here? I'd considered the possibility of needing help from the LHS on this build considering how long it's been since I've built any kit, but it'd be a real annoyance to have to haul it in for something like this.

[jwscab]

does the nut go into a small hex recess? if so, i'd do the ol crazy glue thing again, add a dab to the hole, add the nut, and the secret.....install the screw with a spacer if necessary to tighten the nut in place. this will keep it square, then once dry, it should stay put. and even if it doesn't have a recess, you could install the part and nut with the screw, then add a dab on the outside of the nut to hold in place.

[Coelacanth]

Forgive me for adding this extra assembly question; I know it's technically off-topic for the post, but since I have a few folks here who've been through this build...

I'm really stopped in my tracks at step #25 (radio plate installation). I don't know what they're called, but part #OT205/4, where you have to somehow get this tiny nut threaded straight while somehow keeping it from falling out. I spent the better part of an hour failing at this last night before I had to give up. I tried greasing it up, which helped keep it sticky for a bit, but I just can't get it threaded straight with no way to secure that nut.

There has to be a tool or technique I'm missing here - no one has small enough fingers to hold that nut in place while tightening the screw. I managed for the front end, but those 2 in the rear are much harder to get to. Anyone willing to share the secret here? I'd considered the possibility of needing help from the LHS on this build considering how long it's been since I've built any kit, but it'd be a real annoyance to have to haul it in for something like this.

rear_hub.jpg

I'm confused. Your drawing excerpt part of the assembly has no nuts. The top plate mounts you've shown are simply assembled with screws. The original Optima didn't have countersunk holes in the aluminum side-plates like the re-re does, but other than that, I never had problems bolting those on. What nuts are we talking about? Maybe a different pic was intended?

EDIT: Wait, I can see a nut pressed inside the inner portions of those top deck mounts. That's definitely different from the original car. But once the nuts are pressed inside, they'd be captured nuts and shouldn't spin or fall out once threaded partially...unless maybe their capture holes have been stripped out, allowing the nuts to rotate?

[winner_evo]

EDIT: Wait, I can see a nut pressed inside the inner portions of those top deck mounts. That's definitely different from the original car. But once the nuts are pressed inside, they'd be captured nuts and shouldn't spin or fall out once threaded partially...unless maybe their capture holes have been stripped out, allowing the nuts to rotate?

That's exactly how the instructions appear to me. If the op posts pictures of said parts it should be clearer.

Edit: They may not be rounded out but may be loose enough for the nut to fall out, in which case, stick a piece of tape over to hold it in while fitting the screw.

[sundevil67]

The tape I'd tried, but while it holds the nut in place, it won't stop it from spinning when I try to tighten it from the other side. This step should have been completed before the chassis was assembled so there'd be room to hold it in place with something. If the receptacle where the nut belongs wasn't hopelessly stripped before, it definitely is now. I noticed these are one of the few option parts offered in aluminum - but they're very hard to find in stock...and even if I could, they are so outrageously priced I could never consider it. I mean, $76.99 for these 2 tiny pieces of metal? Ridiculous. I think my options are to order new plastic ones & take the chassis apart to mount them, or just skip it & move ahead, seeing as how it doesn't look like an essential piece. I'm not sure.

[GoMachV]

Something isn’t right. I’ve built several of the rerelease kits. The proper nut fits firmly into the pocket- I use a screw to pull it into place. There is no reason the nut wouldn’t stay in place long enough for you to install the mount. You also say the area where the nut seats into is hopelessly stripped- I can’t even imagine how that could happen. Since you have not got the nut to tighten, how could it have spun causing the nut to not be held in place? I suspect the part is not being installed correctly or something was misinterpreted. Do you have actual pics of what you are dealing with?

[GoMachV]

I pulled apart my only rere based optima on the shelf to show you how it should look. Notice in my pic the nut is fully seated in the plastic and holding it inverted, smacking it on the table etc would not dislodge it. I can put force against it when tightening the screw and it happily stays in place. Something just isn’t right on yours. Pics would help us figure it out.

Again, ignore the non factory side plates. It’s still an optima and the parts we are discussing are the same as yours

[winner_evo]

Yeah, really need a pic of said parts.

If they are screwed, then new aluminium ones are available cheaper: https://www.ebay.com/itm/Jazrider-Aluminum-Front-Rear-Radio-Post-Set-For-Kyosho-Optima-2016-RC-Buggy/351814559151?hash=item51e9c825af:g:osIAAOSw9NdXttbu