| Author | Message | ||
     Barrick09 |
I am fellow bueller (99 x1) who is about to graduate with a bachelors in Industrial Design. For my graduate project i have choose to develop a full blown dirt bike as a proposal for an extension of EBR's line, keep in mind this is all concept. However i am a product design and by no means an engineer and need some help with question someone here may be able to answer. Engine - What are the effects of an engine being dropped from the height that dirt bike commonly see (25 - 50+ feet) In reference to that question, can a v-twin stand up to the abuse that 4 cylinder dirt bikes manage. (high revs) I know know Aprilia just launched their v-twin but would still like your thoughts. Chassis - Some manufacturers choose to run a tube frame and others a box frame. This applies to dirt bikes as well, at first i thought anything over 450 was going to run a box frame but soon found out this wasn't true. Whether a company chooses to run a box frame or tube frame seems to be based on something i cant find out. Pros and cons of tube frames/box frame and a companies choice to go with one over the other? Suspension - Duo lever suspension on a dirt bike. No one does it and to me it just makes sense, is there something I am missing. The dynamic of this suspension, though made for street bikes, seems to benefit dirt bike dynamics as thought it was made for it. also any reference to other project/buell dirt bikes that have been done that you may know of feel free to post a pic or link. Anything that i should consider etc. Anywhere else i should post on here to get this thread attention, may the knowledge vault, not sure. Thanks. (Message edited by barrick09 on May 30, 2012) | ||
| Fahren |
I'm going to bet you will get a lot more, and more varied, replies if you were to post these questions on the Quick Board. Not that you won't get help here, just suggesting you go for a wider cross-section. | ||
| Barrick09 |
Thanks Fahren, i looked at some threads but didn't see anywhere it fit exactly so i posted here being this is my home ground. | ||
| Fahren |
You are probably aware of it, but there have been hints and tales of a Buell dirt bike from the Buell (pre-EBR) days. I have no idea about any details of it, however. | ||
| Kilroy |
Doubt you will ever see a 4 cylinder dirt bike. Most are likely single cylinder (someone correct me please). Good suspension should protect any engine from loads that would destroy it. | ||
| Reepicheep |
Weight and packaging is everything on a dirt bike, with max HP being secondary, so a single is the way to go. A 50 HP street bike is on the edge of dull. A 50 HP dirt bike is pretty much terrifying (in a good way). If it is over 250 pounds, it is already too heavy. | ||
| Azrael_cervale |
You should consider using a Buell Blast. They are plentiful and cheap. Not to mention much lighter and with a smaller engine would be easier to get into a decent frame. | ||
| Court |
There is a very detailed thread somewhere on the internet by a couple of the project folks who worked on the dirt bike at Buell. It has drawings and lots of information. | ||
| Imaposer2 |
Not meant as a negative comment, but I can tell from your questions that you really don't have a background in the world of dirt bikes. If you're making this a graduate project I would suggest that you start some heavy duty research into the world of off-road riding. There are a lot of forums devoted to the off-road discipline and spending some time on them would give you a much better understanding of what it is that you're hoping to accomplish and which direction to take in your design "proposal". Yes, a Buell engine can take the "abuse" but it isn't really suited to a true "dirt bike", IMO. A true dirt bike really doesn't need 100 hp and 100 ft/lbs of torque, but it does need to be light, compact and narrow, none of which the Buell engine really is. The current top tier singles already have more than adequate power while being much lighter than the Sportster based powerplants of the Buell twins. Suspension and chassis layout are very important to the handling requirements of a dirt bike and packaging that around the long overall length of the Buell powerplant, while maintaining adequate swingarm length and room for 10+ inches of front wheel travel, would probably be hard to do. The decision to use a box section frame vs. tubular is a complex one, balancing cost of production, weight, stiffness, service access of other components, as well as a ton of other factors. Each has it's advantages and disadvantages. I'm not sure what you mean by "duo lever" suspension, but the largest advances of dirt bikes over the last 40 years or so has been in suspension and it's that more than anything else that allows modern bikes to do the amazing things they can. The current overall layout and design is fairly standard in the industry because it works. Now if you were to move a bit away from a true dirt bike and more into the realm of a hardcore adventure bike, then you may be onto something with teeth. Something more along the lines of this:  You can find the build thread over on advrider.com here: http://advrider.com/forums/showthread.php?t=657449 &highlight=Sportster+conversion There are other threads on similar conversions but this one is one of the best IMO. Looks like a ball to me!  Of course a bike like this, as cool as it is, still has a very limited market. But anyway, you could spend years on advrider learning about things with a more off-road bent to it, as well as various conversions and ideas. Good luck with your project.  | ||
| Barrick09 |
imaposr no negativity taken, i don't have much background in dirt bikes. I also do not plan on actually building this bike! The final will be a 1/6th scale tangible clay model (aesthetics) the suspension components, as wells as the frame will be solidworks modeled and 3D printed. This is all concept im looking for a radical idea for a buell dirt bike, not necessarily something that could be really build, like i said concept, with some hints of reality. so any technology or feature not normally used will be considered. i want to make this bike different that what industry standard is. and by duo lever suspension i mean the one BMW uses on their street bikes.  | ||
| Imaposer2 |
Well, you know the goals of your project far better than I ever will. Perhaps I understand your goal a bit better now. I guess I just have more of an engineer's mindset and look to the practical application side of the equation rather than the purely fanciful. Ah ha, I thought perhaps you were referring to the BMW designs. I love the telelever on my GS and while they do offer some advantages that could possible transfer to a dirt bike environment, the trade-off in added weight wouldn't be acceptable. Even BMW doesn't use it on the smaller, more dirt oriented 850GS or even the bigger Mega Moto. In fact, even with it's advantages, a lot of people criticize it's weight for street use and it isn't used on the super sporty 1000RR. Also, one of the main things it does is separate suspension action from braking action by eliminating, or at least controlling front end dive on braking. This has advantages, but in dirt riding, this weight transfer can actually be used to your advantage, so I'm not so sure you would want to eliminate it. Anyway, good luck on your project and maybe you could still do some prowling around over on advrider for some ideas. There are a lot of people that step outside the box and build "different" things over there. In fact they have a whole subforum devoted to "projects", called "Some Assembly Required" http://advrider.com/forums/forumdisplay.php?s=&day sprune=&f=83 Some of those guys are pretty imaginative. | ||
| Hugie03flhr |
I was always afraid of the rubber mounts ripping under the abuse so I found a basket case sportster to make into a dirt bike. Anyone who rode dirt in the 70s and 80s will see a similar feel of a vintage dirt bike .i283.photobucket.com/albums/kk314/hugie82/Dirtste r/IMG313.jpg | ||
| Hugie03flhr |
http://i283.photobucket.com/albums/kk314/hugie82/D irtster/IMG313.jpg A buell engine would be a welcome addition because the evo is 30 lighter than my old iron head. Shaved flywheels, aluminum cyl and aluminum heads would be awesome! Fuel injection will let you get crazy not to mention double the power. I would gear it down for slow crawling and a big ass oil cooler with fans if you're running hot! (Message edited by hugie03flhr on May 31, 2012) | ||
| Imaposer2 |
 Fixed it for ya... |
