At last, I have a JRX2 to rebuild...

[aggpm09]

Nearly 7 weeks for a beat up JRX2 to be delivered to the UK but it's here, now the fun starts. Once I've striped it down I will know what parts I need however I already know I will need a slipper clutch. The right one seems to be the Hydra clutch but exactly which parts do I need? I assume I'll need a different gear cover too....?

Are there any other parts which are advisable to replace with later produced parts?

I'm sure I'll be asking you guys other questions once I get into the reconstruction.

Thanks

[clm]

Replace the driveshafts with Traxxas bandit shafts for one they are more durable then the 20yr old originals, then if you still have the thin servo saver bellcrank swap it out with a rigid. The slipper shaft is the same one used for single/double/hydro you can also adapt the b4 slipper to it I believe.

Chris

[LosiXXkid]

The Losi part numbers that you will need to run a dual disk slipper or Hydra-Drive are:

A-3120
A-3121

Both of these are available from Wheelspin Modeis in the UK, here:

http://www.wheelspinmodels.co.uk/i/67044/
http://www.wheelspinmodels.co.uk/i/67045/

Hope this helps. :

[aggpm09]

Thanks Chris and LosiXXkid.

LosiXXkid - is it only those two parts I need? Do I need to buy slipper pads, springs etc, spur gear, gear cover separately or will the standard ones fit?

Sorry, whilst I've had a JRX it was 25 years ago and these parts didn't exist, and weren't required for my Twister 17 double motor!

[LosiXXkid]

Thanks Chris and LosiXXkid.

LosiXXkid - is it only those two parts I need? Do I need to buy slipper pads, springs etc, spur gear, gear cover separately or will the standard ones fit?

Sorry, whilst I've had a JRX it was 25 years ago and these parts didn't exist, and weren't required for my Twister 17 double motor!

Once you've got the A-3120 slipper shaft installed - you'll also need a new 22T pinion gear as well, part number A-3022 - you'll need the A-3121 Slipper plate as per photo. Then you can use Losi or AE spur gears and slipper pads, finishing off with Losi part number A-3132 and then some of the parts from A-3124. The newer spur gears and slipper pads are better as they offer much more in the way of contact area.

A-3022 22T Pinion Gear Installed

Losi Jr.2 Update 004.JPG (120.81 KiB) Viewed 2796 times

A-3022 22T Pinion Gear Installed

Losi Jr.2 Update 004.JPG (120.81 KiB) Viewed 2796 times

A-3120 Slipper Shaft Installed

Losi Jr.2 Update 011.JPG (114.14 KiB) Viewed 2796 times

A-3120 Slipper Shaft Installed

Losi Jr.2 Update 011.JPG (114.14 KiB) Viewed 2796 times

A-3121 Slipper Plate (Long boss)

Losi Jr.2 Update 018.JPG (100.81 KiB) Viewed 2796 times

A-3121 Slipper Plate (Long boss)

Losi Jr.2 Update 018.JPG (100.81 KiB) Viewed 2796 times

Here's mine with the Hydra-Drive installed.

Losi Jr.2 Update 025.JPG (107.91 KiB) Viewed 2796 times

Here's mine with the Hydra-Drive installed.

Losi Jr.2 Update 025.JPG (107.91 KiB) Viewed 2796 times

In summary, you'll need the following Losi parts:

A-3120 Slipper Shaft w/ Hardware
A-3022 22T Pinion Gear (required for A-3120)
A-3121 Slipper plate (long boss)
A-3132 Slipper plate (short boss)
A-3124 Hydra-Drive Friction Slipper Springs, Cup, Washer

Plus you'll need the spur gear and slipper pads - this is what the modern RC10 B4 ones look like:

AE Spur Gear

AE Spur.JPG (19.29 KiB) Viewed 2801 times

AE Spur Gear

AE Spur.JPG (19.29 KiB) Viewed 2801 times

AE Pads

As far as the gear cover goes you'll need one of the ones made by RPM suitabel for the Jrx2 with Hydra-Drive, part number #7307. I bought a NIP one recently and it cost me $50.00 plus shipping (plus UK VAT and and an £8 handling fee) ...but I have seen used ones on eBay for less although you may need keep your eyes on eBay for a while as they don't come up that often.

Hope all this helps.

[aggpm09]

Excellent, I owe you a beer!

[LosiXXkid]

No problem, that's what this forum is all about. Post any questions or issues that you have and someone on here will provide the answer.

[DerbyDan]

No problem, that's what this forum is all about. Post any questions or issues that you have and someone on here will provide the answer.

Exactly - any questions/problems along the way, please just share it on here - someone will be able to help out.

The weak point in the LRM gearbox seems to be the diff gear & i'd recommend fitting a slipper clutch no matter what motor you intended to run... a mate of mine gave me a box full of old JRX2 spares from when he raced one back in the late 80s/early 90s - alot of the parts were all cut-up or broken - which included various stripped diff gears, so it was obviously something that broke even with old brushed motors! I went for a double plate slipper using parts from my Losi XXX/CR2 buggy rather than trying to fix up the Hydradrive unit that I have which needs a re-build & new fluid.


BTW its nice to hear of anothe UK member fixing up a JRX2 for running/racing - make sure you keep us updated with pics etc.... I ran mine all this season & its been great fun!

[aggpm09]

Hey LosiXXXkid. I have all the parts for my re-build including all the slipper parts. When I put the gearbox together I have two issues:

1. The replacement internal gearbox pinion gear is a fraction bigger than the standard gear so the gearbox has tight spots. I've done a bit of filing which has helped but not completely removed the problem.

2. The slipper back plate is touching the gearbox casing (on the boss) so that when the slipper is fully assembled and the nut is tightened it's not longer free running. Any ideas?

Thanks

[FasterLouder]

I dispute that the LRM trannys are weak,I've run silly,and I mean silly,brushless power through several,all without slippers,or Hydradrives.
A slipper kinda takes the fun out of a JRX2/T,too.
Nothing like the hair trigger,motor plate scrapin' fun of a slipperless JRX2!
The slipper/hydra does look killer on the LRM,though.
If you're going through the trouble of fitting a slipper,why not just run a rtetrofit XX transmiision?
I have quite a few XX retrofit parts that I'd be willing to donate for free.

How 'bout some photos of the car,man?

[LosiXXkid]

Hey LosiXXXkid. I have all the parts for my re-build including all the slipper parts. When I put the gearbox together I have two issues:

1. The replacement internal gearbox pinion gear is a fraction bigger than the standard gear so the gearbox has tight spots. I've done a bit of filing which has helped but not completely removed the problem.

2. The slipper back plate is touching the gearbox casing (on the boss) so that when the slipper is fully assembled and the nut is tightened it's not longer free running. Any ideas?

Thanks

Can you upload some photo's....? It would really help to see what's going on! You can see my gear box in the previous posts in this thread and I had none of the issue's which you mention and I can't think what might be causing the problem.

[kaiser]

I'm with fasterlouder, I've never run a slipper on an x2/xt. There's a sweet spot with the diff, once you find it and use throttle control so you don't mash the spur they are an absolute blast to drive.

4 years in a row, no diff rebuild. I race it yearly at the vonat's and a couple other races per year.

I almost tore into it before last years vonat's but it still felt great. I talked myself out of it.

[fredswain]

The first time I ran a JRX on a hard packed clay track was a couple of years ago. I had a Trinity 19 turn brushed motor in it and no slipper. I stripped the diff gear. I had never done that in the past. Then again I usedto run 27 turn stock motors, let the diff slip a little, and run on loamy tracks so it was very different. I rebuilt it and installed a slipper and no more problems.

I have a non slipper JRX now but it only has a 25T brushless motor and a metal diff gear so no problems yet.

[aggpm09]

In the UK we tend to run on outdoor AstroTurf tracks, on the rare occasions it's not raining the tracks are very high grip which increases the risk of spur gear issues - that's why I want to run a slipper.

LosiXXXkid - I'll post some photos later, once family duties are done!

[aggpm09]

Photos attached below. I should say I have now filed the boss on the slipper back plate to see if I can stop it touching the gearbox housing. The end result is no different except the backplate is now very close to the motor plate. I am thinking I should order another pinion shaft and backplate to see if that makes any difference. I'm open to other ideas though...