Rupp Roadster 2 Suspension

[Special.k]

I'm slowly refurbishing my Rupp Roadster 2 and I was wondering how the characteristics of the front and rear suspension should feel. I rear shocks have been cleaned up and reinstalled as well as the front. I found that the rear suspension is rather springy versus a nice cushioning give. Does this sound correct?
I am looking for some opinions on what a healthy rupp roadster suspension should feel like so I can determine if mine is off.

Thanks

 

[Lindy]

I just redid a Roadster 2 and took the back shocks apart and replaced all the bushings, washers and roll pins. The thing to remember with the original shocks is they're really just springs, not a modern pneumatic shock.

If you're off the bike and can lift (stretch) the springs, you may need to replace the washers and roll pin. These stop the rods from exiting the bushings, limiting the upward movement, which may be the reason for the bouncing you're experiencing.

Just a thought.

 

[Special.k]

Thanks for the input. I cannot further extend the shocks when I am off the bike. It seems like my shocks don't have any oil in them or to light of weight oil. Also the shocks on my roadster don't look the same as the original ones. Could they be aftermarket or something?

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[Lindy]

I'm not familiar with those shocks or how they'll perform on the Roadster. The Rupp I worked on was my first mini bike. So I'm only familiar with those original ones.

The other guys on the site will know what type of shocks those are.

 

[Havasu Dave]

Thanks for the input. I cannot further extend the shocks when I am off the bike. It seems like my shocks don't have any oil in them or to light of weight oil. Also the shocks on my roadster don't look the same as the original ones. Could they be aftermarket or something?

Sent from my Nexus 4 using Tapatalk 4

They can be aftermarket. I'm no Rupp expert, but I have received all kinds of different shocks on bikes than what was original.

A good question might be to ask what the original Rupp eye to eye length is supposed to be. Very few of the minibike shocks were oil filled. Just friction with a spring and a piece of rubber for a bumper stop. All of the Rupp Roadster photos I see show a shock with a shorter spring that what you're showing.

 

[Special.k]

I know that these are oil filled shocks because when I removed the springs from them I could feel the viscosity of the oil when I pushed them shock in and out. Unfortunately I was unable to open the shocks up because the cap was screwed on so tight it was impossible to open.

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[Rupp 72]

i have found oil filled shocks to be unnecessary on a minibike because there is not enough weight to create a noticeable amount of oscillation.

your shocks do look like they have a really long spring length, you could get a stiffer spring, or get shocks with less draw.

if u do want to open up you shock, heat up around the eye, works every time for me.

 

[markus]

Thanks for the input. I cannot further extend the shocks when I am off the bike. It seems like my shocks don't have any oil in them or to light of weight oil. Also the shocks on my roadster don't look the same as the original ones. Could they be aftermarket or something?

Sent from my Nexus 4 using Tapatalk 4

yes those are aftermarket, and because of the length probably a heavier spring rate compared to the original Betor shocks that Rupp used. With that said, the original shocks are crap, they bend easy and they compress past what they should so you see a bunch of rupp with seatpans that are bent up a little farther than they should and cracked fenders. The ride on the street is nothing to get excited about either, sloppy and bouncy.

 

[Lindy]

I totally agree the Betor's comment, they may be original but that doesn't make them better than what's available today. As I start to work on this second 72 Roadster, I plan on putting some update shocks on.

Any suggestions on a good but also economical pair?

 

[jrzmac]

pretty sure the originals were 13" eye to eye. kinda tough to find that size nowadays. most are between 12 and 12 3/4". they must work o.k. because I see them a lot of rebuilt Rupps.

I think these are the type that were used for the rebuilds but not positive, Shock Mini Bike GO Kart Mechanical Absorber 12" 3 8" | eBay haha, check these bad boys out.. Rupp Mini Bike Roadster Enduro Scrambler Black Widow NOS Rear Shocks | eBay they will work!!! :smile:

 

[Special.k]

Thanks everyone. I have a better idea of what the suspension should feel like.

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[sludgeboy]

Those shocks are more than what I paid for my whole entire running 72' Roadster2. I bet they go on the Pawn Star Rupp.

 

[ridesolo]

I know this is an old thread but I'm hoping someone can offer some advice. I'm doing a rebuild/semi-restoration on a '70 Rupp Roadster that has these Betor shocks. From this thread I understand how these come apart but after messing and messing it seems that there is no way I'm going to get them apart w/o destroying the plastic bushing. I'd like to be able to just take them apart, clean, paint, and replace what parts I can. How do you get that thing out of there w/ no damage? If I can get it out is there a source for new bushings? I've found lots and lots of Rupp parts out there but I haven't seen those.

If I have to destroy the bushings to get things apart, I've got a piece of bronze I can put into the Unimat and turn into new bushings, but my skills are a little rusty (and so is the Unimat)!

 

[capguncowboy]

You can get the bushings from BlackWidowMotorsports.net

#15212A REAR SHOCK BUSHINGS, 1970-75

They're not cheap, but they are an exact replica


That being said, I used a pair of large snap ring pliers to hold the bushing on mine. I still marred them up a little, but once they were reassembled and on the bike, no one would ever know without sticking their head underneath them.

 

[Ajf]

Use a large caulk gun to compress the spring cups together then you can unscrew the plastic nut. I've used this method half a dozen times with nothing but great results. The caulk gun is under $5 at Home Depot.

 

[ridesolo]

Use a large caulk gun to compress the spring cups together then you can unscrew the plastic nut. I've used this method half a dozen times with nothing but great results. The caulk gun is under $5 at Home Depot.

I appreciate that. Good idea on the calk gun. I made a spring compressor so that part of the problem isn't the issue... just getting them apart, getting the thing to unscrew, is the problem.

 

[ridesolo]

You can get the bushings from BlackWidowMotorsports.net

They're not cheap, but they are an exact replica


That being said, I used a pair of large snap ring pliers to hold the bushing on mine. I still marred them up a little, but once they were reassembled and on the bike, no one would ever know without sticking their head underneath them.

Thank you. Hmmm, usually we're pretty good at internet searches and have even been to blackwidow, can't believe we missed that.

I've got a hinged spanner, the right tool for that kind of thing, and they just don't turn. Have been considering letting the thngs sit in a 200 degree oven for a while to see if that frees them up.

 

[capguncowboy]

Try tapping on the downtube where it overlays the threads of the bushing using a small ball hammer. Just slowly roll it as you go until you've gone around it 2 or 3 times. If that doesn't work, the oven trip would be my next attempt

 

[ridesolo]

Thanks for all the help! I wanted to report back about what's happening with this. Tried the hammer tactic with no success. I finally gave up and just used a torch. The plastic/nylon melted pretty quickly! :glare: Not the best method, but they are apart now. Of course, the second shock came apart relatively easily using the spanner wrench just like it was suppose to. (Go figure!) New bushings ordered from the folks at Black Widow Motorsports. I contemplated turning them out of bronze, but got lazy. Again, thanks for all the help and suggestions!

Now off to the hardware for new mount bushings!

 

[GustoGuy]

I totally agree the Betor's comment, they may be original but that doesn't make them better than what's available today. As I start to work on this second 72 Roadster, I plan on putting some update shocks on.

Any suggestions on a good but also economical pair?

I agree. The original shocks are nothing more than a rod running through a nylon bushing supported by springs. After a while the rod eggs out the bushing and the shock gets even more sloppy. I put on a real set of hydraulic small motorcycle shocks 13 1/4 inches long on my resto-mod Rupp with a stage 3 un-governed Predator 212cc with ARC Billet rod and Billet fly wheel with a 22mm Chikuni and 22lb valve springs and it is a night and day difference. i used the original bushing from my Betor shocks and the fit exactly inside the metal grommet inside the hydraulic shocks. The Motorcycle shocks I bought are at least twice as heavy and when you grab them on the bike they are solid and allow no lateral movement on the top unlike the Betor Rupp Shocks dislocating shock top. Plus they are oil dampened and when you sit down hard on the seat they do not bounce either and you can actually feel the dampening of the oil in the shocks. Much better than the stock shocks especially if your going to be riding on bumpy terrain.