Help With My Jrx Pro

[Joe P]

Hi Guys, newbie here. This webpage is awesome! I pulled my Jrx Pro out of storage. I had it as a kid back in 1990ish. I would love to get it running again. Im sure I will need alot of help, and will be asking alot of questions on the way. One thing I notice is that the rear end seems to be to close to the ground.. The clearance from the ground to the END of the chassis where the mounting screws connect to the motorplate is only 5/8-3/4 of an inch.
Its been 23 years since I really looked at the car, and at the time I was only a kid so maybe I didnt notice it back then. Can somebody that owns a Pro please measure theirs and let me know if the clearance is correct?
I looked in the old owners guide and the rear shocks and rear suspension rods all appear to be mounted in the correct (suggested) mounting holes.
The front sits pretty high compared to the front. Thats without a battery
or any other added weight on the chassis.

Second question, If you look at the motorplate from the back of the car, where the losi engraving would be- is the plate suppose to be somewhat level? Mine appears that it tilts to the left a little, meaning the top right of
the plate appears to be a little higher than the top left corner. Is this just the natural shape of the plate? I dont remember ever bashing this car. We
didnt have a local track and I basically only used it on a local baseball field because it had great red clay for dirt in the infield and the car handled great! So what Im trying to say is that I dont think the car ever smashed into anything to make something tweek out of line or bend. These are
just things Im noticing now as an adult. I will try to post photos somehow. Im in a new home now and all my computer stuff is packed away. Im typing this on my fiance's little netbook laptop so im limited on things I can do. Thanks ahead of time!

[Joe P]

Oh, one other thing!! Does anybody remember what suggested
oil weight was used for the front and back shocks?? I cant find it in the
owners guide. Im sure it needs to be changed. I found team losi oil in one of my boxes. I believe its 20 wgt, its clear. I cant remember if that is what I used for the shocks or not. I wish I could turn the clocks back!

[DerbyDan]

Hey welcome to the board Joe! You're not the 1st new member on here recently, who has found their old childhood JRX Pro & is looking to get it up & running again!

With regard to ride height - a decent starting point is to adjust the rear ride height (by slackening & adjusting the collers up & down on the shocks that retains the top of the springs) so that the chassis is just below the height that would make the driveshafts level - then adjust the front so its slightly higher.

Your Losi shock oil has probably 'gone-off' now - I got a whole bag of the old coloured Losi oils given to me (the colour indicated the weight), but the colour dyes had fallen to the bottom of the bottles - the oil itself had seemed to have lost its viscocity, so its probably best if you buy yourself some fresh oil - I assume you are not going to race your Pro so ultimate tuning is probably necessary? Your 20wt probably sounds about right - although I think i'd go for 30wt - for some reason that always seems to be a good starting point (I'm guessing you have the kit pistons fitted inside the shocks?)

Would be good to see some pics of your Pro & keep us updated with your progress - The Pro one of my favourite 2wd buggies from that era - just love the sleek bodyshell especially when painted up like the car on the box!

[Joe P]

Derbydan, Thank you for the reply! You pointed something out that I
can see is wrong with the car. The drive shafts are not level. The tire sides of the drive shaft is higher than the transmission side. Not by alot, but
its just enough that if i adjust it, it will gain some height in the rear end.
I loosened the shock springs but the tire wont drop. I believe the tire
is held in place by the rear turnbuckles? The strange thing is, in the manual there is a photo of the turnbuckle to use for reference of length.
My turnbuckles are almost exact length of the one in the photo. So how else can I get the driveshafts level? Hmmmm....

I actually just looked in the back of the manual and there is a few pages of "tune ups". It says that they usually run there cars with the drive shafts pointing upward slightly. So with that said, Maybe the car sits good as it is? It just seems like it wouldnt take much for it to bottom out. If I just pick up the rear end about 10 inches off the floor and let it go, the chassis hits the floor. That doesnt sound right to me.

Thanks again!

[Joe P]

After reading the Tune ups again im wondering which way they are saying the drive shafts should be pointing upward? If they mean they should be pointing upward towards the transmission meaning that the tire side should be lower than the transmission side- that would make sense. That would raise it up a bunch. If thats the case, I just cant figure out what I did wrong during the set up. Everything appears to be mounted or screwed in the correct holes...? Does anyone have a picture of the rear end of their Jrx pro so I can see which way your drive shafts angle? Any help on this is greatly appreciated.

[Joe P]

Im getting closer!! I disconnected the rear shock from the top shock
mount and the tire did drop perfectly, so its not held into place by the turnbuckle (its been a long time so bare with me ) So that tells me
that something needs to change with the shocks to get more ground clearance... but what? The top shock mount is where it should be- its in the top inside hole of the tower. And the bottom mount is in the correct middle hole (second from bottom). As it sits, the shock appears to be fully expanded (word?). Its almost like the rear shocks are to small? Or it wont open enough to get to both shocks mounts with them mounted in
the suggested spots. This wont beat me!!

[Joe P]

Problem fixed I think. I think I had the front shocks in the rear and the rear shocks in the front. The JRX Pro comes with two different sized shocks. I had the longer shock bodies (just the silver part) in the front and the shorter ones in the back. I swapped them and now the car is sitting pretty! Am I right by doing what I did? Can any Pro owners tell me if I made the right move? Are your longer shock bodies in the back and shorter in the front? When I was a kid I was probably in a rush putting it back together after cleaning it and screwed up by putting the wrong shocks in the wrong spots. Any input guys??

[Joe P]

Derbydan, if what I did is right, thank you for bringing the angle of the driveshafts to my attention. If you didnt mention it i wouldnt of noticed it and wouldnt of tried to figure out a way to correct it. Good job!

[DerbyDan]

Derbydan, if what I did is right, thank you for bringing the angle of the driveshafts to my attention. If you didnt mention it i wouldnt of noticed it and wouldnt of tried to figure out a way to correct it. Good job!

Haha no worries - sounds like you are having 'fun' with it already.

One suggestion - perhaps it might be worth stripping your car into its individual parts & then re-building it exactly to the manual... Adult's eyes & experience may spot errors that you made when you originally built it (sounds like you already have).... I know that my attention to detail now is much more than it was when I was younger when I was just too excited to get it built!

Your description of the chassis hitting the ground when dropped from 10" sounds to me like the shocks are not offering the damping that they should - either your oil has leaked out or it has gone thin - new oil should solve this. You may also want to consider some new shock seal cartridges (part # LOA5015) as these may have deteriated over the years (& maybe the reason for the leaked oil?) Check also the shock shafts - if these have been scoured with pliers for example then this will allow oil to pass by the seals & also damage them!

[kfeldt]

One suggestion - perhaps it might be worth stripping your car into its individual parts & then re-building it exactly to the manual... Adult's eyes & experience may spot errors that you made when you originally built it (sounds like you already have).... I know that my attention to detail now is much more than it was when I was younger when I was just too excited to get it built!

This is a good suggestion. I did the same with my JrxPro when I pulled it out of mothballs last year, and I did find a few "surprises".

Keith

[Joe P]

Thanks for the input guys. Ive been going through the car. So far so good. I have made some minor adjustments but nothing major. I wish the old car action links were still working on the scans forum. I would love to look back and look at the old paint jobs I saw in those magazines back in 89-92. Im not talking about pro paint jobs. Im talking about the paint jobs done by the owners. There would be race photos of buggy and stadium races and some of the colorful paint jobs were great. I really liked the old school style with the dripping paint look. Classic.

[kaiser]

Hey welcome to the board Joe! You're not the 1st new member on here recently, who has found their old childhood JRX Pro & is looking to get it up & running again!

With regard to ride height - a decent starting point is to adjust the rear ride height (by slackening & adjusting the collers up & down on the shocks that retains the top of the springs) so that the chassis is just below the height that would make the driveshafts level - then adjust the front so its slightly higher.

Your Losi shock oil has probably 'gone-off' now - I got a whole bag of the old coloured Losi oils given to me (the colour indicated the weight), but the colour dyes had fallen to the bottom of the bottles - the oil itself had seemed to have lost its viscocity, so its probably best if you buy yourself some fresh oil - I assume you are not going to race your Pro so ultimate tuning is probably necessary? Your 20wt probably sounds about right - although I think i'd go for 30wt - for some reason that always seems to be a good starting point (I'm guessing you have the kit pistons fitted inside the shocks?)

Would be good to see some pics of your Pro & keep us updated with your progress - The Pro one of my favourite 2wd buggies from that era - just love the sleek bodyshell especially when painted up like the car on the box!

30wt is a great starting point. my jrx2 with stock pistons is just about perfect with 30wt all around (5link).