Do it cheap - Do it Street legal?

first off, my bike isn't a "thumper." But I had a guy from my GS forum tell me this was the place to go for supermotord intormation. :-) I tend to trust my GS friends, so here I am.

Here's the plan.

Pick up spare wheels. Preferably from a newer RM than I have. (my bike is "mostly modern" it's a 1983 rm250, so it has a flatslide carb, water cooling, long travel suspention, but the seat doesnt' go up over the tank, and it has drums, and now powervalve)

I live somewhere that ridable dirt... well... is next to imposable to find. So the next idea other than just riding the living daylights out of hte bike, was to get it out on the street.

The tires I use on my streetbike are available in sizes that will fit the RM. I use Bridgestone BT45's on my streetbike. And RM wheels in stock sizes are cheap and pleantiful. (read $30 shipped on ebay)

At least that's the cheapest way I can concieve of getting "good" road tires on the bike. And using a newer RM wheel would get me a disk brake. I happen to have brake master cylinders and calipers I can use on said disk as well.

Are the front disk mounts universal? I know that at least the whole of the suzuki sportbikes use the same 5 bolt disk mounting pattern. or am I going to need to get creative with adapter plates?

now there's a final problem. Lights. In illinois you need a headlight, taillight, and brake lights. Great, that means the switch setup is simpler. HOWEVER, this is a pure dirtbike. And it doesn't have a "normal" stator setup. Instead of having a magnet swinging around the stator. It has a magnet swinging INSIDE the stator. it also has two coils, so there's really no room to try and suck more power out of that electrical system. Basicly, I need to leave the ignition system intact.

The other option is to run a battery. Again, we have this whole chicago-flatlander problem. It's a coupple hour drive to get anywhere worth riding. or a 40 mile drive to get downtown. so this pretty much eliminates the idea of running a total loss electrical system.

Also, it gets dark fast in the countryside, so I want a good headlight. drawing 10 amps of headlight is a very quick wayt o kill a battery.

*sighs* This means finding some way of generating electrical power. And I think my roomie and I have found a solution. There's a ready made alternator that most geeks have. Stepper motors. Coupple that with two phases of your average, run of the mill regulator rectifier and you have a darned good power source. :-) (testing with a nema 23 size stepper provided 98vac at 1200rpm, this worked out to about 200 watts of electrical power) So for all intents and purposes the electrical system problem is solved.

So.. For this lowcost supermoto...

$170 for tires

$15 for the stepper motor

$0 for the R/R (this is a part I have in stock in the house)

$40 for the lights

$60 for wheels (I would like to keep a set of dirt wheels as well)

Registering the bike may be a problem. only "may" becuase I think I can sneak it through under "custom construction" seeing that the bike never was titled in the first place.

Has anyone else taken a motocross bike and made it into a street legal supermoto style bike? How have they dealt with the challenges?

Honestly it could be a bit harder getting disc brakes on your RM because at some point all the RMs went to a different axle size. I don't have all the specifics but a more modern RM is a very universal bike from like at least 96 and up. I mean total part compatibility from wheels to front ends, brakes, swingarms whatever.

I don't know what your budget is but for all the trouble (especially the electrical and brakes) why don't you just try to find a used RMX and slap some street oriented tires on it. Its a 2 smoke, Has lights already, fairly cheap. It would be a huge upgrade.

Still.... mixing gas sucks and you better make sure you can even register it first.

Pretty much most of the guys here have taken a motocross or offroad bike and made it into a supermoto bike. But 99% of them are bikes that are less than 10 years old and are easy to get SM parts and items for.

After all its Thumpertalk and the big Thumper MX boom is post 99 and the SM boom is even newer. So..... most everyones bikes are fairly new with the exception of a few.

Most of my riding is done in a "flowing" aera, so brakes that can stop me faster than hitting a brick wall aren't even close to necessary. The stock brakes are dual leaking shoe drums which actaully have respectable braking power.

the bike cost $250. And runs exceedingly well. I couldn't justify the $2500-3000 for a newer bike, and all the supermoto parts.

I have NEVER seen an RMX in my aera.

Back in 88 or 89 I plated an RM250 in Illinois. I just had to add all the street requirements headligh, brakelight, working turnsignals, horn. Yes Illinois does require a bike going through inspection to have turnsignals even though once it is registered they aren't needed. I also had a title for the bike and had to get it corrected from Off Road only to On Road title. The title correction fee was $130 the last time I did it.

I think the wheels will be your biggest problem. The forks are going to have to be modded, if the newer wheels with discs fit, you will still need a something to mount the caliper to.

Al E


If you live close to St. Louis there is a motorcycle salvage company called Archway International Motorcycle Salvage.

It's on Martin Luther King in StL.

Down in the basement of Archway are a ton of old Suzuki, Honda, Yamaha and Kaw motorcycles (3000+).

I was in the basement looking for 17 inch rims and I came across a bunch of disked rims with calipers and all the goodies need to set up a motard on the cheeeep.

Take a good flash light and bring your axil along and you sould have no problem find everything you need.

Feel free to email me if you need any info on AIM

I have a RMX that im getting plated next year for NJ and wish i could find some motard tires & rims cause that bike would be awsome on the streets except for the fact that i have to mix my gas so im limmited as to where i will go

I have a RMX that im getting plated next year for NJ and wish i could find some motard tires & rims cause that bike would be awsome on the streets except for the fact that i have to mix my gas so im limmited as to where i will go

All you'd have to do is figure out exactly how much oil per your tank of gas and then carry a small container or two to mix at any gas supply.

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