Building a soap box dune racer -- need ideas

[FatBoy Racing]

It's time to build something fun! I'm working with a friend to build a soap-box type car for shooting hills in the dunes. I'm in search of a street bike motor to power this thing and was hoping some of you could offer some insight on selecting a 'donor' motor. We will be using junker quad parts for axle and front suspension, and a home-brew frame so we can adapt for whatever junkyard parts we end up using. The 'body' will be wood, and I'm hoping to keep it looking as non-threatening as possible, so it looks like a toy, until you start it. Steering may even be with ropes for authenticity, but might be kinda scary once it gets moving. I was thinking of using an air-cooled motor and venting the box, but I'm thinking that may not allow for enough air flow in the heat of the dunes, so a liquid cooled motor may be better, I suppose I have room for a radiator anyways, but I want to keep the front as light as I can.

Anyhows, this will probably be a year long project and we're just throwing some ideas around for now, but I suppose our power plant is the first consideration, then we'll build around that. I initially though about using a KZ1000 motor since there are so many out there from police bikes . . . what do you think?

[MY450R]

all i know is i wouldnt want to ride that thing
id do a lot less power for your engine you get hurt with that 1000 in there

[FatBoy Racing]

safety is not a factor! :devil: Besides, I'm welding up the frame myself, so I can make it as strong as it needs to be.

I don't know what the dunes are like in Mass., but here they eat up power like crazy -- the whole point of building this is it will be a 'sleeper' beast -- besides, I seized my 450r 2 days ago, so now I've got all this free time on my hands for this project.

I was toying with the idea last night of using a motor with an auto clutch to eliminate the need for that pedal. I think there was a street bike called that used the term 'hondamatic' or something similar? I think it was in the late 70's, but I'm not sure. Anybody savvy?

[SHOCKER]

hey, thats sounds like a very fun project, a streetbike motor is a very good motor to use for a little 1 or even small 2 seater, is it going to be a 1 or 2 seater? i recomend keeping the front light but not super super light, i think an auto would be great but there is nothing wrong with shifting, if i were you o wouldnt use wood, use some aluminum, or dont even put on any siding, you can buy some really cheap fiberglass bucket seats from a buggy mag. they are ussually around $40-60 for a decent seat with the cover, they arent very comfortable though, um for the seatbelts i surely wouldnt skip out on them, get some nice 4or 5 point seat belts, by the way ya got a PM :D

[MY450R]

if you dont want to shift then use a snowmobile clutch
btw there are no dunes here in mass at all
how did your 450 sieze up?

[AndreS]

i suggest a snowmobile motor.... find a wrecked donor & you're set. use the whole powertrain, a track from a snowmobile hooks up really well in sand, just gotta put a seat & front end on it .

[TheFontMaster]

Originally posted by AndreS
i suggest a snowmobile motor.... find a wrecked donor & you're set. use the whole powertrain, a track from a snowmobile hooks up really well in sand, just gotta put a seat & front end on it .

I wouldn't sugest using the snowmobile track though. Stuff on part of the track would start to melt after a little while. The snow keeps it cold, and keeps it from melting. The sand would also add to this problem.

[FatBoy Racing]

this will be a 1-seater and wood sides are a must for the look we are trying to achieve. I will probably be making the seat out of wood as well, but after the initial run, if it's too scary, I may elect to swap out to a regular seat. Here again, I'm trying to keep an authentic a look as possible.

Snowmobile motor is a pretty neat idea too, but I would worry about cooling out there, temps hit 110+ real easy, and with no snow to cool, could get hairy. The track is a neat thought too -- maybe something more for the future tracked-recliner project?

As far as the 450r seizing up, I don't know why yet as I have not torn it down yet (scared). I'll pull it apart this weekend and see. I'm bummed, but at the same time I don't feel too bad as this is the first time I've locked up a motor, so I guess I'm about due (trying to stay positive here). I was only 15 mins away my property (as the quad flies) and I noticed sort of a 'dieseling' sound coming from the top of the motor, so I checked oil (which was fine), and started heading back, that's when it went. I was idling at the time it locked up. No temp light warning and no lack of oil, so I'm assuming there was some trouble pumping it. Anyways, that 15 min ride out was a 1-1/2 hour trek back home to get the truck, but I got it out.

Thanks!

[TheFontMaster]

Originally posted by FatBoy Racing
Snowmobile motor is a pretty neat idea too, but I would worry about cooling out there, temps hit 110+ real easy, and with no snow to cool, could get hairy. The track is a neat thought too -- maybe something more for the future tracked-recliner project?

I doubt the snomobile engine would over heat, most of them are licquid cooled. Like I said before what you have to worry about overheating is the track.

[FatBoy Racing]

I'm no snowmobile guy, what are those tracks made of? Is it something I may be able to fab from a different material that would be more appropriate for the sand?

[TheFontMaster]

I'm not much of a smowmobile guy ether, but i want to say that the slider things, those are what would melt I belive, are made of eurathane:confused: Or some kind of hard plastic thing. IMO gettin a track to work properly and reliably in sand would take too much time and money to make it worth your while. Although you should check out mat-tracks. thats the company name. They make tracks for utility 4-wheelers, and trucks. Now a street bike motor powered mini sand rait with mat-tracks would be something uneque to try.

[TheFontMaster]

heres what they look like
http://www.litefootatv.com/assets/images/105split1smblk.jpg

[TheFontMaster]

And heres some pics of mat tracks in action. Also the webiste for them is www.litefootatv.com

http://www.litefootatv.com/assets/images/action_hill.jpg
http://www.litefootatv.com/assets/images/action_snow1a.jpg
http://www.litefootatv.com/assets/images/action_rocks.jpg

EDIT: And Dirt Wheeles, or ATV Action magazine did a test of these probably like 4 or 5 months ago.

[FatBoy Racing]

oh HELL yes! That/those would be perfect for the dune recliner! Though that's a future project, they would be perfect for that, I'll keep that info -- thanks!

[TheFontMaster]

your welcome :cool:

And if you do some project with the mat tracks make shure you make a post about it. I'm surprised I haven't seen them on sport 4-wheelers for the dunes:confused:

[FatBoy Racing]

will do -- I'm gonna have to get me some new skills before I tackle the 'tracked dune recliner' project, but I'd like that one to steer like a tank, with control sticks on either armrest - - - like I said, I'll need some new skills :cool:

[TheFontMaster]

That would be awsome having it steer like a tank, but do you think it would be stable at speed?

[FatBoy Racing]

Probably wont be very stable, but how fast does a recliner really need to go? At best it will go about golf cart speed or less. It'll be more of a novelty anyways (ie: 'drunk vehicle'). I'm thinking maybe a pair of smallish 2-stroke motors (50's?) so it at least sounds like its hauling butt.

:confused:

[TheFontMaster]

I think a blaster motor would be better. I doubt know if a 50cc motor would be able to move the tracks. Those wiegh probably a good 70 pounds for one track. If a 50cc motor could turn them you would only be looking at mabey 10mph, and say good by to hill climbing. I like the twin motor idea. But I'd say that you would need bigger motors.

[FatBoy Racing]

i wont be shooting hills with that vehicle, just playing around camp really. I would like to use two small motors so that each stick runs it own motor, otherwise I'll have to do something really wierd in the rear end to be able to operate each track independently. Even with twin 50's I can gear it low as hell since it won't have to go very fast. Though it would be funny as hell to hit woops with it reclined, unexpectedly dropping the foot rest and going for a tumble :D

Maybe twin 80's, but that's starting to get pretty fast. Anyways, I think twin blaster motors would be pretty frikkin hairy on a recliner!

:devil:

[TheFontMaster]

They 80's sound better. I know you don't want it fast but I think it would just be really underpowered with the 50's. Cause like I said those tracks have got to wiegh like 70 pounds a pice, and I really dont think a 50 could turn those.