Who has put a 4-banger in a R'

[grude73]

I was wondering if anyone here has sucessfully grafted a 4 stroke engine into their R'....

Ive found a few posts and seen some attempts that have failed miserably.....

Im thinking a 4 stroke with electric start would be sweet, reverse would rock....

and to answer the question that most might ask, Im not buying a 450r for 2 reasons, I have too much invested in my R that I can never get back and I love the R.

If you have done it, some pics & details would be sweet..


Thanks guys.

[racerx573]

I have.

[deathman53]

if you want to use the stock r frame, its proably not gonna work, the 4 stroke motors are too tall. I would get a aftermarket chassis built for the motor and uses all 250r parts, that way you can sell your frame and motor, then buy a 4 stroke motor and frame for it and you can use all your r parts. Too many frames have been destoryed for the use of dirtbike motors, 350x motors, street bike motors you name it. Some say a yz426/450 fits right in no problems, I know a great deal of frame mods had to be done to fit them.

[grude73]

That thing looks sweet, I see from your site you used a yz426 motor, how is it compared to the old 250, and any details on what you did would be great.

I know a lot of people want to do this type of thing, and if I do it I intend to take step by step photo's & document the process.

I have several years of fabricating experience, and have the tools needed so if I can decide on what motor to use, then find one, I will start.

G

[racerx573]

A lot needed to be done in order to get the engine to fit correctly.

It can work in any frame, and work well if done right.

The lower rails were cut out (the smaller ones that have the lower engine tabs.

On the CR500 link frame, we raised the lower linkage mount, due to relocating the pivot mount, in order to have the pivot bolt go through the engine (like on the dirt bike). Also we used an '89 style swingarm, and machined out the inside so we could put it around the engine as well.

Also the Laeger's CR link frame has additional gussets, which we removed and relocated by welding them to a headstay we made. It is very important to have all of the engine mounts with these engines, if you want the frame to last. The gussets needed to be moved for the engine/carb to fit right.

The 426 engine runs a lot like a 2-stroke, as far as how hard it hits once you are on the gas, which is primarily why I chose that engine. And since my 250R is a powervalve, it bridges the performance gap even better and so I did not have too much transition to get used to.


Here is one pic showing the lower rails..

[racerx573]

Also as you can see, we removed the lower engine tabs in the back, and you can see where we added the headstay & moved the gussets; the pivot bolt relocation is also shown.

[racerx573]

Here is the original frame. The pic is crappy, but the differences are obvious.

[grude73]

Thanks for the pic, anyone else got anything to add???

[TampaBoy813]

2001 426 Motor in a 400ex Frame
http://img256.imageshack.us/img256/2552/tampaboy0037aa.jpg

[hollywood250r]

Originally posted by TampaBoy813
2001 426 Motor in a 400ex Frame
http://img256.imageshack.us/img256/2552/tampaboy0037aa.jpg

That is not a 4-stroke in an R frame!

[TampaBoy813]

yes I know....it is a hybrid must the less...and was a pain in the Ars...

[Slinky]

the frame for my 350RX was pretty well chopped...i'd have to say if your going to do it. find someone with a frame thats allready chopped or bent or something...dont chop up a good frame...if i hadnt bought mine allready done i would never do this!

[wicked265R]

im buying a yz450f motor to put into my 86' R frame. If anyone has a layout of how to do this in steps, it would realllly help me. Thanks guys.

BTW, you can put any motor into any frame if you have the tools and knowledge ;) and a "4-banger is the term used for a 4 cylinder engine, not a 4-stroke motor. I thought i was gunna come in here looking at an R with a street bike motor in it :blah:

[grude73]

LOL i wondered if anyone would notice.... :-)

How about a 4-smoke ???

[mullet250r]

how about a z400 motor in an r frame i know gust ran this for awine idont know was frame he was runing

[xrxmxcx]

Originally posted by wicked265R
im buying a yz450f motor to put into my 86' R frame. If anyone has a layout of how to do this in steps, it would realllly help me. Thanks guys.

BTW, you can put any motor into any frame if you have the tools and knowledge ;) and a "4-banger is the term used for a 4 cylinder engine, not a 4-stroke motor. I thought i was gunna come in here looking at an R with a street bike motor in it :blah:

im with you on that one:p haha

the best bet is to get an aftermarket chassis, the stock R frames arent worth the hassle, there not as strong and are harder to fit them into, etc, etc...

[kicker696]

you are gonna hve some MAJOR problems putting the yz motor into a stock R frame! you will run into clearance problems, along with strength problems. Plain and simple the stock R frame CAN NOT handle a 4-stroke, it was never meant to!

[250R_4_ever]

here some other pic of a hybrids some with R frame some Not

http://i22.photobucket.com/albums/b332/volks_r_us/hybride.jpg

http://i22.photobucket.com/albums/b332/volks_r_us/hybride1.jpg

http://i17.photobucket.com/albums/b60/stivi/DSC024501.jpg

KTM 525
http://img.photobucket.com/albums/v216/shee_04/picture144.jpg


This one his made with a PRP frame
http://i39.photobucket.com/albums/e157/250rbleu/PRPCRF450002.jpg

http://i39.photobucket.com/albums/e157/250rbleu/PRPCRF450003.jpg

http://i39.photobucket.com/albums/e157/250rbleu/PRPCRF450001.jpg

[McKinney]

if u decide to do it since the stocl frame wont work cause the 4 stroke engine is to tall email me and i would like to buy the rolling chassis everything on it except the motor
Nick_McKinney