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Discussion Starter · #1 ·
OK you guys here's a question,you guys know i had a bayou 300 sold it and now i have a Mojave 250 with some engine issues:) i had a brain fart of maybe putting 600 or 750 engine out of a bike on this ,i can get a hole engine and all the goodies to make her run for 450$ or i can rebuild the 250 that needs cams piston rockers timing chain and new clutches for 400,

i know it'll need a little mod work to mount in the engine but imagine the looks on peoples faces if i were to pull into the trails and or make it street legal,its up in the air still what do you guys think of my brain fart -corey-
 

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I just parted out a honda CBR600 engine on Ebay that I had bought off of craigslist to mount on a sport bike frame. I decided I already had too many projects but I had done an awful lot of thinking and planning before deciding to scrap it so I may be able to help your project out with some of my thoughts.

Street bike engines can be put onto sport quad frames but there are some special considerations to be made-

#1 Liquid cooling- Street bikes are designed to be driven at speeds in a range from 0-150 mph but mostly around 50mph while under a normal engine load (cruising down the highway) Sport quads are designed to be operated from 0-50 mph but mostly around 20mph while under a normal engine load. The cooling capacity of the respective engines are designed accordingly. Air cooled multi-cylinder engine banks are designed too close together and with too little thermal mass to be operated under heavy load at low air flow.

#2 Induction- Most modern street bikes (crotch rockets) are designed very specific induction systems. Most use ram air from the front of the bike to increase HP at high speed. Almost all have a large airbox directly above the engine bank and down draft induction directly into the intake tract. Whether carburetored or fuel injected, the airflow relies on the very specific design of the airbox for maximum horse power output. You have to accomodate for the airbox in your design. Most of the modern sport quad frames are wide enough to allow for the airbox but most of them also use the space where the airbox is going to need to be for fuel storage. Basically the gastank is in the way...

#3 Drivetrain- Most of the Japanese design bikes use o-ring chain on the left side of the crankcase. Some have driveshaft output and some have the chain on the rightside. All of designs could be used on a quad swingarm with enough ingenuity but obviously left side chain drive is preferrable.

#4 Swingarm- Even high output sport quads put out less than 50 hp. A 600 cc sport bike isn't competitive at less than 100 hp. A compromise between trail ability, turning radius, overall traction, and the ability to keep the front tire on the ground is going to have to be made. Without some sort of extension, it will be a wheelie machine even when you don't want it to be. With an extension long enough to keep the front tires on the ground all of the time, you will need an acre field to turn around in.

#4 Reverse- bikes don't back-up... Want all the power? Gotta give up something

#5 Gussetting- You're going to have to chop a lot of the original frame out of the way to shoe-horn that engine in. Make sure that the result is strong enough to hold together without weighing as much as a sherman tank. Reinforce the frame with gussets to make sure one good bump doesn't turn into your last.
 

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Discussion Starter · #3 ·
did you say wheelies i love em wheels not touchin lol the ground.
i thought about that id have to extend the rear arm alot to keep it down unless i use wieghts "lead" bars i used for gocart raceing back in the day.

as for turning i thought about that with no reverse i thought id just dump the clutch and spin that sucker around lol. but i see your point on the air box they have like about 2 cubic foot of box so id have to engineer a box with the same cubes as oe in a different place and thats with tubeing to go to the carbs/injectors so i can put the tank back on .

but i really dont want to cut the frame or add gussets for just incase i want to put the oe engine back in. this is a hard decision to call.but it would be cool i guess to do this project being i paid little for the machine.

its goin to be up to momma which way i go i guess . if she will let me spend 50 dollars more than rebuild the engine.plus all the time to mod this fit ,and the fab work i will have to go to a old fab shop so i can use there tig welder and machines to fab brackets/mounts gussets ,hmmmm i love brain farts lol -corey-
 

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If you have good health insurance go for it!

I built a Honda 200X three wheeler into an 1000 cc Kawasaki powered rig a bunch of years back. Other than a few weeks in traction as a stupidity tax for failing to avoid an ornery tree that jumped in front of me, it was a great deal of fun! Not only that, the metal implants I have today make for real interesting times getting through airport security.

Do not worry about the air box, just use the oil type foam filters made for direct carb mount, one to each carb. Simple and effective.

One thing about it, if you do not have hair now, you certainly will after you ride one of these creations. The only problem is that it will not be on your head!
 

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Discussion Starter · #5 ·
hair is thinning now from pullin on it so much fixin these things lol,

1000 cc man that had to be a wicked ride, and i to hate them trees that just jump in your line at 50 mph ,iv hit one slideing sideways down a hill lucky i didnt break nothing i should have jumped for it but my luck is the bike would have landed on me :(it was a steep hill -corey-
 
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