CR250 motor in a 300ex frame..

[Pvt. Maggot]

First thing you think when someone asks about putting a non counter balanced 2 stroke motor into a quad frame....CRACKS!...well...I beg to differ...I'm looking at a CR250 motor...if I buy it...heres my plans...Rubber mount all the motormounts...buy anti vibe bar inserts...and my crazy idea to maybe fill the frame with anti vibe foam...lol...but my friend welds...so i'm going to guesset the frame good...and even if it cracks the frame...i have a welder to fix it...what do you guys think...if you think its stupid or whatever just don't post...but if you have some positive info your more then welcome to post...I think it would be one fast mofo :devil: thanks!

[Diedrich]

go for it man..try it..i used to be told to put silicon in your frame to cut down on vibration..put go ahead and try it out bro

[NikNacs67]

Tell and show us how you're gonna mount it.

[RIDER11X]

I know what you mean about everyone saying it will crack.......But there has to be a way it can be done. You may need to do some cutting-turning and rewelding on the pipe to squeeze the expansion chamber in there, but it should be no big deal.

Also, a rear hinge on the rear plastic will be helpful for the rear kicker to clear, or a generous cut out on the right side.

Post pics as you work on it. I'm intrested to see it! :cool:

[brandonpeake]

it was another forum and like two years ago but iheard a guy say he put the foam in his frame and it helped
i dont even remeber for sure what his conversion was but
i think you are on the right track

[UglyMotha™]

better yet how bout if you just do it already instead of making a new post every month for the past year telling us WHAT your goin to do :huh

[Chanman420q]

Originally posted by UglyMotha™
better yet how bout if you just do it already instead of making a new post every month for the past year telling us WHAT your goin to do :huh

wasnt the last one like an XR500 engine in a 300ex frame with a 250r sub frame and 400ex pipes...:eek2:

[UglyMotha™]

EH, got me he talks about some new crap every month :rolleyes:

[Out_Sider]

dont rag on him dude...he is just wanting to make the right decision. Even tho i still think the KLX 300 motor would be kool... but the cr250 would rule!

[nacs400ex]

If your going to make a project quad use a 400ex or 250r chassis, why would you do it to a 300ex:huh

[ny300exrider]

probly because he already has a 300ex to work with

[Tommy 17]

Originally posted by Chanman420q
wasnt the last one like an XR500 engine in a 300ex frame with a 250r sub frame and 400ex pipes...:eek2:


thats 2 simple for some of the ideas this kid thinks up...

[Pvt. Maggot]

i can't help it i get some crazy ideas lol...but you know...when you get ideas...they usually turn into good things...so stop the bashing..i'm just going through all my options...and i'm not using the 400 or 250r chassie...1 because i like to be different. and 2 i already have all the 300 parts so why buy new stuff? but yeah i need a little more money then i'm going to buy the motor...so i'll keep you people who really care updated..

[RIDER11X]

It would be cool to see it come together. Granted the 250r or 400ex chassis would probably be a better platform, but I assume he is a little short on cash flow or he would probably be asking when his new 450r is coming and where the best price is on a HRC kit.

Good luck to ya, we all start someplace and if nothing else you will learn alot of valuable experience from the project, plus have something not many people have. Take it easy on him guys, he's givin' it what he got. :cool:

[NikNacs67]

I am kinda like him guys. I was gonna put a yz426f in my 400ex frame... changed to a 400ex engine and now im going to put a 250r motor in it.....

[X-SLaYeR]

... you mean kinda like this?

http://www.servicehonda.com/trx250r.html

[Kawboyz beware]

KLX 300 motor would be kool. I have personally seen one and that thing was fast. he also had some other goodies on the 300ex. I think he said the motor was lighter than the stock 300ex motor. I also seen a 250r motor in a 300ex I have a pic of it. I own a 350x /300ex bike

[RIDER11X]

I know a member on here with a 350x motor for sale that has beed prepped to fit a 300ex chassis if anyone is looking for one.

PM me for info.

[ewalker302]

I think the best way to do it would be to concentrate more on frame strengthening rather than the vibration. Really gusset the frame twice as much as normal.

Im sure anti-vibe mounts would be needed.

:bandit:

[RIDER11X]

Originally posted by ewalker302
I think the best way to do it would be to concentrate more on frame strengthening rather than the vibration. Really gusset the frame twice as much as normal.

Im sure anti-vibe mounts would be needed.

:bandit:

Gusseting can be a two way street though. Too much and the frame can become so rigid that your tubing stresses and fails.:eek: I believe moderation is key in gusseting.

[UglyMotha™]

Originally posted by RIDER11X
Gusseting can be a two way street though. Too much and the frame can become so rigid that your tubing stresses and fails.:eek: I believe moderation is key in gusseting.



yup, there is a such thing as over gusseting you can actually gusset your frame to the point that it would have been more rigid to have just left it stock

[Pvt. Maggot]

bumping to the top :devil:

[400in300]

I am in the process of taking my 96cr250 motor and putting it in my 300. The 300 locked up Sunday. My dirtbike works perfect i just have way more fun on the quad so i amgoing to put the 250 in there. it will go good with the works shocks 250r a arms.

i dont care...as long as im still faster then u guys are :blah: ...have fun doing this...ur gonna run into a lot of problems trust me

[knight rider]

HEY leave the guy alone, thats an awsome idea i might evin do that with my 300ex but a diffrent motor so thanks for a good i dea and star on what i should do:p

[400in300]

Like what kind of problems .I have took my quads apart so many times i really can't count. A 250 engine is smaller, lighter, and of course faster. Of course you gusset the frame and maybe some exaust and kick start modifications but, I don't understand why you all think this is a big deal. And i think it will smoke a 400,probably not my old 416 but, hey it was reallllll fast.

[hondafox440]

Originally posted by XxHonda_RacerxX
i dont care...as long as im still faster then u guys are :blah: ...have fun doing this...ur gonna run into a lot of problems trust me

Yea dude, can it. You're just some cocky punk with little knowledge of quads and a big mouth and signature. Get over yourself.

[toby400ex]

Does servicehonda.com's 250r use a counterbalancer?

[400in300]

I dont no if it has one, but gussets and rubber mounts should be enough I hope.

[ewalker302]

OK so just make sure to reinforce the frame, mainly in places that absorb impact from jumps. I still think this will be more important than engine vibration.

DO NOT put foam in the frame
it will get eventually, 1-5 years depending on use & storage start to rust from the inside out. The foam will begin to break down & collect pockets of water.

Be sure not to overdo it (on the reinforcemant) blech!!

& why not do the swap???

I think it's a cool idea & will probably draw some attention.

:bandit:

[YZEATER]

Originally posted by toby400ex
Does servicehonda.com's 250r use a counterbalancer?

no.. it is a cr250 engine from a cr250 dirt bike.

[400in300]

Originally posted by YZEATER
no.. it is a cr250 engine from a cr250 dirt bike.

They dont have a counterbalancer. I think it is better than putting a 400 motor in there, even though I already had a 400 motor sitting in the 300. Dont you all agree that this going to be a really good quad, giving that it is done right with 250r a arms extended rear durablue works shocks renthals. I CAN NOT JUMP ALOT BECAUSE I HAVE A BROKEN BONE IN MY LEFT WRIST AND I WHERE A BRACE WHEN I RIDE . IJUST HAUL *** THROUGH TIGHT SECTIONS ,HILLCLIMBS, DUNES, AND SET UP JUMPS ECT .....Therfore the bike will have less stress. I could understand where the question would come up '' whats the point of doing it to a 300?'', If its your only bike matbe not, but i've already got a 416 and few R's including a couple torn apart banshees. And ive nevewr seen one before but i am sure someone has done it..........im doin it regardless what you cooks say:devil: :blah: