crf 450 in a 400 frame

[jasoncarr25]

who makes the kit to make this work? do i need a different airbox? i have a aluminum one now. around how much for just the kit if i do all the welding.

[jasoncarr25]

i need to know soon any body know

[exatak199]

it's called the http://www.exriders.com/forums/images/new/search.gif button;)

thats some major burnage. :eek2:

[exatak199]

here takes like 1 min to find.:eek:

http://www.exriders.com/vbb/showthread.php?threadid=90605&perpage=10&highlight=how%20to%20crf450%20conversion&pagenumber=1

[quad_quazy]

I just got done doing that conversion. East Coast ATV sells a kit for $450 that includes all the mounts-upper frame, lower cross, fwd aluminum, swingarm bolt bushing, CDI mounts, coil mounts, radiator mounts (250R), shroud mounts (250R), kick starter extension, and descentlly comprehensive instructions. Next take your time, set it in right get it all tacked up and pay to have a good welder do it right. Of course you also need to buy your own radiator ($200-500), shrouds, upper engine mounts (from the bike), yamaha 450 kick starter ($100), water pump cover that angles forward ($100). You have to get your left swingarm spacer machined down a little (find a good machine shop for this). For exhaust I found a stock TRX450R header pipe and modified a silencer to fit to it, the TRX header pipe is a little on the small diameter side but you don't have to bend it plus I was running a 7in long by 4in diameter muffler can and needed the smaller headpipe for some backpressure (better torque). The intake is a little tricky, I took the engine in the frame up to the local auto parts place and asked if I could scrounge throught their radiator hoses and found one that had about a 45 degree bend to go between the carb and engine. I've been told that there is a John Deere tractor hose that is absolutelly perfect but I didn't feel like driving 100mi to the nearest one. You can use your 400ex airbox but you have to move it fwd about 3/4in. Also you have to cut a section out of the subframe fwd cross brace so the air tube will angle corectly. The thread above showed a good way of doing the rear crossmember of the frame, wish I would have done that. On the carb you have to shorten up the choke lever if you want to use it (trust me you do). The thread also mentioned using a YZF throttle cable, you might try that one. I used a Honda Foreman 400 cable and had to cut down the barrel 3/8in on the bar end. I also used the Magura clutch lever and it pulls so nice. Some other possibilities you might consider is a flywheel weight ( I put a 9oz on an 03 motor because of stalling in the corners). For gearing I am running a 13 front and a 38 rear but I run a lot of tight tracks and 18in rear tires. For big outdoor/baha you might try a 36 rear. Other than that hold on and let er rip. I have raced in 3 races since and haven't had a bit of problems getting a holeshots against YFZ's, Banshee's, 250R's, or even my freinds 250 dirt bikes. Good luck, hope I helped, it took me 3 weeks to convert it but I got everything in before I started. If you have anymore questions email me at quad_quazy@yahoo.com and I can try and get you some pictures. The guys at ECATV are pretty helpfull and I'm passing on all I can think of that I had to ask them. There was a thread on here not to long ago about another "budget" way of doing it and it looked pretty nice

[quad_quazy]

Holly crapamole I didn't realize that was such a long post. Maybe ya'll can vote for me for the longest thread, HA HA. I also forgot to mention, they give you gussets for the front end and rear frame for carb clearance.

[brandonpeake]

yeah BURN
but there is ***** loasds of threads and 416exmx even did it with pics , no way he did a search