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View Full Version : YZ250f motor in YFZ450R chassis



rf928
08-19-2010, 09:13 PM
Hey guys, I was just wondering if it is possible to put a 250f motor into a 450R frame? I race in the 250 class, and found out how much HP the 250f motor puts out and it got me thinking. Instead of spending a heap of money on a raptor 250, why not just put a different engine in the 450 chassis. I was wondering if anyone has done this, or is looking to do this.

Thanx

mx Eli
08-19-2010, 10:21 PM
you could do it but it would take some fab and you could only race it in local series becuase it would be considered a hybrid or non-production

rf928
08-20-2010, 10:16 AM
what kind of fab? would it be less work to just build a whole frame?

mx Eli
08-20-2010, 11:22 AM
I'm not sure but a conversion usually has some work with where the swinger attaches the the motor and frame and then bottom and front motor mounts. chain alignment would probably be off but that can be adjusted with offsetting the motor to one side or the other. then all the rad hoses would have to be figured out. and the kick start would most likely need a extension to clear the frame.

If I were going to do this I would look on here for a 250r with all the fixings (suspension mainly) and use that to put the motor in. becuase then you dont have to deal with the fuel pump in the tank and it would probably cost a lot less if you found the right 250r

rf928
08-20-2010, 11:51 AM
thanks. And 250r i am assuming is the honda 250 two-stroke. Is that quad built to handle as well as even a stock raptor 250? I don't want to spend a load of money on suspension or a arms. Thats why I chose the YFZ450R

tayyo789
08-20-2010, 11:57 AM
You can probably even find a 250r with a 250f already in it, with top of the line parts on here. All hybrids are for sale, you just have to name a good price. Except for mine :devil:

tayyo789
08-20-2010, 12:01 PM
I have no idea if he still has it, but I was talking about one like mamafite's:

http://www.exriders.com/vbb/showthread.php?s=&threadid=253252&perpage=10&pagenumber=28

sno-x139
08-20-2010, 08:33 PM
or buy my national built raptor 250 for $6000.

rf928
08-21-2010, 11:00 AM
No, I don't want a modded raptor, because the more you mod it the less reliable it is, and I do more than race. Is there any other quad frame that the 250f motor would fit in?

mx Eli
08-21-2010, 12:05 PM
it isn't just going to drop in a frame. and you must not know a lot about the 250r because it will run circles around a little raptor 250. and do you understand I ment get a 250r with all aftermarket suspension then put a 250f motor in it. and it would most likely still cost less then a yfz450r and it would perform better also

IRISH-RACER-14
08-21-2010, 03:04 PM
put a crf250 motor into a 450r. those are similar motors!

sno-x139
08-21-2010, 03:38 PM
It isnt unreliable. It is also much faster than you would think. It is faster than a stock YFZ or TRX, and I can holeshot mildly built 450s at local races all day long. I have over 15k in this bike. So $6000 for a super nimble bike with similar power to a stock 450 doesnt seem to bad to me. Also if you ever went to an AMA National race you couldnt race the 250 bike powered quad in any class other than Open.

mildtowildracin
08-31-2010, 05:13 PM
ya a blaster ;)

mildtowildracin
08-31-2010, 05:15 PM
and contemplating on selling it 2! Bike rips, the 2 championships that its won should explain that :devil:

700xxmaniac
10-16-2010, 11:18 PM
Originally posted by sno-x139
It isnt unreliable. It is also much faster than you would think. It is faster than a stock YFZ or TRX, and I can holeshot mildly built 450s at local races all day long. I have over 15k in this bike. So $6000 for a super nimble bike with similar power to a stock 450 doesnt seem to bad to me. Also if you ever went to an AMA National race you couldnt race the 250 bike powered quad in any class other than Open.

id just get a 300ex and put a built crf250r efi motor in it.... or build the 300ex.... my ferind traded his 99 300ex for a new 08 raptor 250 and he bent 2 frames already... now hes lookin for a 450r

SRH
10-17-2010, 10:10 PM
why couldnt u sleeve down a 450 ? and run it in a production class???? i think they did this back in the day

trx90luke
10-19-2010, 07:40 PM
that blaster 250f looks way sicker than that raptor 250 posted up. and its prolly faster

mildtowildracin
10-20-2010, 08:54 PM
yaa, the blaster runs with stock 450's, i ran mid B class times on it

m0t0xk1d
10-29-2010, 12:38 PM
Are you kidding me dude? a national 300ex can have up to about 40hp. thats what rage has in brent sellers national 300ex. thats more then a stock 450r. so that is incorrect. obviously its faster


Originally posted by rpfeifer11
If you can make a raptor 250 run half as good as a 450 then you are doing something right. Every race I have been to the 300ex was on top and a national 300ex doesnt have **** on a bone stock 450r.

blaster12s
10-29-2010, 02:42 PM
Originally posted by m0t0xk1d
Are you kidding me dude? a national 300ex can have up to about 40hp. thats what rage has in brent sellers national 300ex. thats more then a stock 450r. so that is incorrect. obviously its faster true..

sno-x139
10-30-2010, 04:27 PM
Yeah, I was told directly by rage that he got 40hp out of that 300. The 300ex is 70lbs heavier than the raptor, so that makes the raptor almost 90lbs lighter than a 450. The power to weight ratio of my raptors is enough to easily beat stock 450s. They are also extremely nimble and super fun to do huge whips on(and bring them back). So dont run your mouth if you dont know what you are talking about. I mean yeah, 450s are way more powerful WHEN built, but a stock 450 is more than enough for a novice rider. And dont tell me I dont know what fast is, cause I have 2 Harold Goodman race bikes sitting in my garage.

Ryko racing
10-30-2010, 06:34 PM
Just about every race district that i know of runs the 300 class as a production class.( must have matching oem frame and engine cases, frame mods can only be done for strength not to improve geometry)

As far as snox 139 raptor, this thing flys, he has it done 100 percent right ( no hack jobs) thus the 15 grand price tag.

AS far as reliability , i dont know but we had a stock one just for practice for 2 seasons ( we run 30 min practice motos and never cracked the frame or even broke a bolt and only changed the oil 1 time per season so i am sold on the Raptor for quality.
My son is a top national rider in 90 mod and Supermini so he beats his practice bike hard..

Jake, if Ryan gets cleared to race next year by his doctor i may be intrested in the Raptor. I will know the end of december.

Sno x is definitely out this year as Ryan is still recovering from a head injury. He is really bummed as he likes Sno x more than atv racing and was looking forward to getting back on a sled. I think he would have given them a good race. Oh well.