Eman77

So way back in the day, my very first hobby-grade RC kits I got to build and run was an SG Coyote. Bad choice. Anyway, one of my best friends that was also into it got a Losi Jrx2. It was different. It was neat. It was colorful. Most of all, I remember it was fast.

Mind you, this was back when NiCd batteries ruled the day, and brushless wasn't around. So keep that in perspective. This was the late 80s or early 90s.

Anyway, he was running a Trinity Speed Signature Joel "Magic" Johnson motor, and it was cool. Nuff said.

Fast forward to just recently, and he was kind enough to give me his old Jrx2 as-is, for me to restore (since he knows I still mess with this stuff). So I decided to create this restore thread, and post pics as I go.

Here is just a pic or two of what i got - tons of used wheels/tires, a well-broken-in body and wing, and a brand new (in package) body. Included was an old Tekin mospower ESC that I believe was a no-reverse, no turn limit ESC. Plus the "magic" motor, along with another trinity motor (appears to be 17T).

Eman77

I gave it a decent look-over, and found a few things that will need replacement or fixing:

• It is using RC10 shocks, so I might try to acquire some original Jrx2 ones, pending cost
• The screws are a bit of a mis-match, so I will try to go all-hex screws as I rebuilt it (it already has some, but others are phillips)
• The steering servo and ESC are using older plug styles that aren't used today - since I want to put in a 2.4GHz receiver unit, I'll likely replace the ESC and servo. I already have a Losi servo lying around, so will have to figure out the ESC part later
• I will definitely paint up the new body and use that - I will likely stick with the orange, black, and white wheels that it came with, I'll go orange/black on the body, unless another color strikes me.
• Will likely get a new gear cover and wing

Eman77

I started by taking it apart entirely, and started washing every bit using a simple-green and water mix. I started with the front end and chassis, and ended up with this after the cleanup.

In the tear-down, I could not get one of the rear axle pins out of the axle - it was brutal. Almost fused to it (in it?). I ended up using a cutter on a dremel and chopped the axle off so I could pull it out of the rear carrier. I will get a new axle to replace it.

I also ended up ordering bearings for it - the transmission ones were still in excellent shape, but the wheel bearings have had it.

Eman77

Here is the transmission pics before, and after the cleanup.

I still have the shocks to deal with (I'll tear them down and clean, even if I won't use them after all). I was pleased to find that the ball diff was in excellent shape. Guess I'll have to start putting this all together soon - I'll post more when that starts up! In the meantime, I'm waiting on some parts to arrive.

Next on my to-do list is to catalog the screws I'll need, compare to what I have (that are in good shape, and hex heads), and then order what I need.

collector1231

My Feedback: (1)

Pretty! Cant wait to see the results! Did you choose paint colors yet?

collector1231

My Feedback: (1)

Also, have you found any screws yet? http://www.rcscrewz.com/product_info...ts_id/3441?SID

Lunchboxer

Are you gonna put in new electronics?! New servo, ESC, etc.?!

Eman77

Not sure on colors yet, need to put some brainpower towards pondering that.

Eman77

I actually ended up going with TonysScrews, just ordered them today. Will post pics when I get them in.

Eman77

I've decided to use a Losi servo I have lying around, I'll look up the specs when I post a pic. I will also go with an inexpensive new ESC - the only extra I have around is a Castle MM, and that's a bit overkill for this since I'll be using the 17T Trinity brushed motor that came with it.

The plan is to run 2s LiPo batteries (since that's what I have), along with a mild ESC and that 17T motor.

Eman77

So, I finally got around to some some more on this build. In short, all the parts have been stripped down and cleaned, checking for damage. I've placed orders for the following so far:

• Battery end//cup to replace the white one
• New AvidRC bearings all around when needed (the inner transmission bearings were fine, but the outer ones and wheel/carrier bearings needed replacing)
• A rear outdrive axle, since I had to cut one in half to get it out of the carrier - it's a long story, but it involves the pin getting stuck and bent beyond removal, a lot of swearing, and Mr. Dremel tool.
• Front carriers, since one of the ball studs stripped out of the plastic
• New thrust bearings for the differential, since 2 belleville washers were missing
• new steering posts, since one was missing

I've reassembled the ball diff, and here is the pic of it. The interesting part is that I really don't know how far to tighten it down except "by feel". There are no instructions in the manual for that.

Incidentally, I found a PDF manual here: http://vintagelosi.com/Manuals.html

Additionally, I am purchasing parts from SabulaTech.com - I did some googling for Jrx2 parts, and they seemed to have the most parts, and reasonably priced. They also offer some 3D printed parts (like the battery cup I ordered). I found that original eBay parts were horrendously overpriced.

Eman77

I also noticed a snag on one of the diff housings - one of the flathead screws that hold it to the chassis had broke off long ago, and part was still in the housing. It was too recessed into the housing to dremel a slot into it, so I ended up using a regular drill bit, but with increasing size (starting much smaller than the screw itself) until I basically shredded it out. We'll see how well that works when I go to attach it again. :P

No pics on that, as I tore into it straight away without much thinking.

Here's a pic of the left/right housing, after cleaning and installing the lower gears and a few bearings.

Eman77

Another update:

The diff was placed inside of the housing (see pic), along with the brass-colored gear (counter gear?) that is driven by the spur. Screws are driven though the housings to attach to the motor plate, as shown. The hole that juts outward from the transmission housing is for access to the screw that controls the differential tightness/looseness. So that's cool, I can tighten/loosen on the fly quite easily!

I put a little Tamiya ceramic grease on the gears in the transmission as well.

Eman77

The steering servo I'll use is a Losi Losb0819 (pictured). Torque and speed-wise, it's comparable to a Futaba S3010 (their standard nylon geared high-torque servo). Specs are here:
http://www.losi.com/Products/Feature...rodID=LOSB0819

I figure this will do just fine for a 2WD buggy for just tooling around the street and dirt.

Eman77

Question for any readers - what's a good (modern) shock replacement for the Jrx2, assuming I can't find a suitable original front/rear combo? I'm still trying to figure out what I want to do here - I could make the RC10 ones that I have work with it, but it won't match my (likely) orange/black color scheme I'm planning.

collector1231

My Feedback: (1)

Team Associated B4 shocks look like they might fit. Give me the specs from top of cap to the part that screws on the shaft, and I'll measure mine in the morning. Heck, I may even sell my shocks for a good deal if I feel like it!

Eman77

Well, it turns out I got hasty and ordered some rears and pieces for the fronts, so I think I'll be set. I was torn between originality and going less expensive and getting something modern that would be solid, but not look perfect.

Turns out Losi made 3 shock body types back in the day - silver was standard, and black was their hard anodized version. I ordered the blacks, since they will match the colors I want to go for anyway, and will look "period correct".

Also found out that when they first introduced the shocks on the JRx2, they had a single o-ring design that was leaky. They quickly came out with a new double o-ring version that was much, much better. That's what I'm going with.

So thanks for the offer of help collector, but I got hasty and am already set here I think.

collector1231

My Feedback: (1)

Ah, no worries. Good luck! lol

Eman77

Here's a pic of the battery holder I got (3D printed) - after putting it on and trying to put my smallest LiPo battery in (4000 mAh), I see some issues.

This battery end cup is a little forward of the one that came with it - on the good side, that means that my LiPo pack actually fits (barely). The problem is that you can see it starting to cover a hole there. That hole is where one end of the steering servo block will go.

Putting the original cup in there means it's too short for any of my batteries to fit (I even tried a regular old 6 cell NiMh stick pack, and that's too long). I will have to ponder a solution - Mr. Dremel might have to make an appearance. In the meantime, I took it back off.

Eman77

I also noticed that although the holes under the chassis are counter sunk, the flat head screws I'm using don't sit flush at all. This bothers me a little, but maybe not enough to do anything about it.

Eman77

Here's the front end before and after I got the suspension arms on. Scratches are evident of course, but overall it cleaned up pretty well. The new nylon nuts are really shiny compared to the shock mounts. Hmm, maybe I should bleach those.

Eman77

I'm waiting on some parts still, as I snapped a rear outdrive by accident as part of the disassembly (oops). Also need a few e-clips, and some other odds and ends. As a result, I only got one of the rear sides put together. I'll have to wait a little while before I proceed any more.

But for now, check it out - new rubber sealed bearings in the carriers, new hex hardware all around (not just the rear),

I'm fascinated by the way the rear linkage is set up. Very different from what I've seen, and a bit awkward to work on until you get the hang of it. It's interesting how the rear shocks will mount on to the bottom horizontal link, instead of a rear lower arm. You'll see more pics of that once I get to that point!

Eman77

Update on the JRx2:

New outdrives are installed, and I found and put together new front and rear hard anodized (black) shocks that were an option for the JRx2. Got the steering all set up, so thinks are rolling. I'm really just needing some electronics (on the way), shock mounts (what I had fit the RC10 shocks, not the JRx2 ones), and springs (I temporarily put on some stock tamiya springs).

I'll have to take some recent pics and share.

For the body color, I'm going with black, and perhaps a horizontal orange stripe near the bottom on the sides (across the flares on each side), or a wider orange stripe that covers the entire flare side. Not sure how that would look.

Eman77

At last, some more pics!

You'll notice that the front shocks are black, while the rears are more of a dark gray. Both were labelled "hard anodized" (which is supposed to be black), and both were NIP from Losi, so I don't know if they were a bit off in color back then, or the rears aged? Either way, they are nice smooth shocks.

The rears I bought as a set - the fronts I had to get piece by piece - at the time, no front rods were to be found of the standard variety, so I went with the Ti-Nitride upgraded ones for a few $$ more. You'll see the color difference in the front shock rods vs. the rears.

You'll also notice I used nitro fuel tubing as a temp shock mount up top until the real ones arrive, as I couldn't wait to put them on.

Telcoguy

I'm in a unique situation as I am new to the hobby and have recently been given what is essentially a JRx2 chassis that I intend to restore/restomod. I have no shell, bad shocks, bad springs, no motor, an old Novak esc, possibly bad diff, and a futuba servo with a very old radio and receiver. From what I can tell generally everything needs a refreshing or an update, I'll be following your thread closely, Eman.

Any advice as to what I need to be able to run mild brushless setup? I think I have some differential issues as is, I assume normal behavior is to spin one wheel and the other will spin in the opposite direction? I haven't opened the gearbox yet to examine for wear, so everything is speculation and ignorance on my part at this point.