Losi JRX2 restoration/modification with mid motor conversion

[VintageLosi]

I've been away from RC since I was a teenager but the other day I decided to dig out the old Losi JRX2 from the loft. It was certainly worse for wear but after a little googling I decided it might be a worth while project. After reading about other people's projects and looking at what is popular now I decided to modify the car. I was really keen to see how the car would perform utilising the 5 link suspension and a mid motor layout. More to follow.

[VintageLosi]

The car has a lot of RPM upgrades. The front end is RPM as well as the 5 link chassis mounts which have multiple holes for making adjustments. The first thing was to strip the car down and see what I've got. Everything appears to be in good shape apart from the differential.

The gearbox on the JRX2 can be rotated very easily but I had solve the problem of inboard toe and anti-squat. After some consideration I decided to take the rear support for the inner hinge pins, (now the front support) cut it in half, and remove enough material that it can be narrowed sufficiently to give inboard toe. I then made a brace from aluminium which would screw down from the top to hold it together. The second set of holes were slotted so it could be screwed to the chassis with the gearbox In the traditional manor. A couple of spacers gave a little anti-squat.

[VintageLosi]

Titanium turnbuckles on the top link. Don't know what the shock absorbers are from. Had them in my stash. They look good but must be nearly 20 years old. Still thinking about the rear shock location. Amongst the spares I had a set of rear arms that have a row of 4 holes in them which appear to be intended for a shock mount.

[OptimaFan]

Interesting project. I have a jrx2, but it is built for the shelf. Looking forward to updates. Shocks could be Schumacher, but that is just a guess.

[VintageLosi]

The front end is all RPM with a few extra degrees castor. Bearing steering arms and some new RPM rod ends with blue anodised turn buckles. A new old stock Losi bumper too. Waiting for some more parts in the post and I've solved my rear shock location which I will implement this weekend.

[VintageLosi]

Wasn't 100% sure where to mount the rear shocks. The original Losi shocks were knackered and with the rear tower now being aft of the gearbox the standard location on the bottom 5 link was out. I've mounted the bottom of the shocks to the rear bottom arm as close to the outside as possible. I found a set of Schumacher upper shock standoffs that fit perfectly. Just waiting for the turnbuckles and ball joints to make new bottom arms for adjustable toe.

[VintageLosi]

The 5 link on the JRX2 leaves some room for a bit of slop. When it's worn there can be a lot of play. I wanted to get rid of the play and at the same time make the rear toe adjustable. I decided to swap the forward lower arm for a turnbuckle with ball joints. I could only find 3mm ball joints so I had to drill the balls out to 1/8" so they would fit the stock Losi pins.

http://i284.photobucket.com/albums/ll28/danielsx125/ef69c321-bb63-49b5-a255-b92561d34a5d.jpg (http://s284.photobucket.com/user/danielsx125/media/ef69c321-bb63-49b5-a255-b92561d34a5d.jpg.html)
http://i284.photobucket.com/albums/ll28/danielsx125/0b07d1b2-448a-4a5a-a520-91ef57af7c14.jpg (http://s284.photobucket.com/user/danielsx125/media/0b07d1b2-448a-4a5a-a520-91ef57af7c14.jpg.html)

[VintageLosi]

I am using Associated B4 wheels all round. The fronts are on with the small spacer from the rear and Associated thin nyloc nuts. The width at the widest suspension travel is 247mm. The rear wheels use the standard spacer plus a 7mm wide hex adapter. This means the rear wheels clear all of the suspension links and the maximum width is 246mm.
http://i284.photobucket.com/albums/ll28/danielsx125/afb77dbe-3dd8-4cd8-9fab-51920562b021.jpg (http://s284.photobucket.com/user/danielsx125/media/afb77dbe-3dd8-4cd8-9fab-51920562b021.jpg.html)
http://i284.photobucket.com/albums/ll28/danielsx125/acf3acb3-8bf1-48b0-bac4-40d02a145323.jpg (http://s284.photobucket.com/user/danielsx125/media/acf3acb3-8bf1-48b0-bac4-40d02a145323.jpg.html)

[mr. ed]

Starting to look good.
I did the mid conversion long ago myself: trimmed the lower part from the bulkhead and left the bottom part in place. Then drilled the holes of the rear mount out so I could pass some longer screws through, and mounted the upper part of the bulkhead on top of the rear mount.

I also trimmed the motor mount plate and swapped it over to the other side

[VintageLosi]

I've made some progress. I have fitted an A&L power clutch from the states and I have swapped the motor plate over.Tyres are now fitted along with the last of the new turnbuckles and ball joints. I need to sort a set of suitable springs and get some electrical gear in it. The body has yet to arrive from the states.
http://i284.photobucket.com/albums/ll28/danielsx125/AE6CC26C-2AE9-4180-BACE-92D544739433.jpg (http://s284.photobucket.com/user/danielsx125/media/AE6CC26C-2AE9-4180-BACE-92D544739433.jpg.html)
http://i284.photobucket.com/albums/ll28/danielsx125/58757B02-ED13-454A-8C9A-E7958CF93EB8.jpg (http://s284.photobucket.com/user/danielsx125/media/58757B02-ED13-454A-8C9A-E7958CF93EB8.jpg.html)

[wookiee76]

I think those are old kyosho shocks, had some that looked identical on my old loptimazer frankenstein. Is the jrx2 the same diff as the jr2? The diff outdrives drive a pair of gears attached to the driveshafts? If so I have one kicking about in good nick.

[OptimaFan]

I think those are old kyosho shocks, had some that looked identical on my old loptimazer frankenstein. Is the jrx2 the same diff as the jr2? The diff outdrives drive a pair of gears attached to the driveshafts? If so I have one kicking about in good nick.


I don't recall Kyosho shocks having a hex shaped part at the top. These look more like Associated shocks to me.

[KRob]

Looks like the shocks are Traxxas to me - from the TRX3 when they got rid of the blue and made them gun metal.