Hybrid Project help

[wicked265R]

Hey guys, I sold the motor out of my R and will be purchasing a yz450f motor to put in. i have a stock framed 86' R fully gussetted and PC'd black. I really don't know where to start on putting this motor in. I am going to fab up motor mounts and all that myself, I have all the tools neccessary to do this job (mig welder, torch, plasma cutter, ect.) so it shouldn't be to difficult. i just need some sort of directions or layout of how to start. Thanks guys, I really appreciate this. Yes, I know i'll be molesting a stock R frame but it's mine, isn't it? :rolleyes: I've always wanted a hybrid and now I have my chance, so I'm gunna run with it.

Pictures would help a lot too!

[Pro1200]

Haven't a lot of people say the stock R frame isn't strong enough for a hybrid motor. If I were you I'd buy a nice aftermarket one. That what I'm doing after I finish my R. But your choice anyways good luck. Also don't think many people do this conversion in stock frame, too weak.

[Tom TRX250R]

I'm sure RacerX573 could have something to chime in to this project.

[TheIceMan]

I know the bottom frame rails will need to be lowered aprox an inch and a half or so,for added motor height and sprocket/pivot alignment.Good luck, show pics of the project!!!

[mullet250r]

i read about the yz in250r frame you said you have to modify the frame but what about a z400 motor do you still haveto chang the frame or canyou tilt themotor farther forward or will that afect the oiling system

[wicked265R]

I've read around that the stock frame isn't strong enough, but to me thats a bunch of bullsh**. my frame is fully gussetted and I will go over the frame when i'm done fabricating motor mounts and weld gussetts in places i think could use them. An aftermarket frame is a rip off. I'm not getting a good amount of info so i'm just gunna go by the seat of my pants on this one and see what needs to be done myself. It can't be that hard to figure out.

[Mean250r]

i dont think it will be that hard to figure out as well, but as for the frame, i agree the new frames are rip offs but the 250r frame has a hard enough time staying together with the 250r engine, let alont the torque of a 4 stroke, i really cant help ya out cuz i never did it before, good luck tho!

[kicker696]

take it from me, i own my own a welding company, THE STOCK FRAME WILL NOT HOLD UP!!!! just buy a used aftermarket frame, they go on ebay all the time for under 1k

[wicked265R]

i dont need any more input about the frame not holding up. I dont have any more money to spend on this project and dont want an aftermarket frame. I will be putting this motor in my frame and just need to know how to do it.

[kicker696]

your going to need to cut the bottom frame rails out and drop them about an inch, tach everything in, then test fit the motor to make sure that its in the right spot. you will also need to make new motor mounts, thats basic, just make them out of cardboard first as a template. make sure to pay very close attention to the angle of the chain and that it lines up nicely. Are you going to be using the stock radiator? If so i would highly recommend getting an aftermarket one in the near future, its not a must, but you will have problems with overheating when you aren't moving with the stock one. Another thing to watch for is the carb boot and the airbox, your def. gonna have to make your own boot. I don't know how much you know about welding and what not, but i am going to assume that you know the general basics about welding. With that said get yourself a couple of scrap pieces of metal before you do start to weld up the frame, and run a couple beads across them, make sure you are at the right settings, with that motor in there, being off by even a little bit could be a disaster!

[racerx573]

You don't need to drop the rails, that would weaken the frame a lot more..

If you can get precise measurements, relocate the pivot bolt.. and then machine the swingarm so it will fit around the engine.

The key in these projects is alignment/weight distribution

You will need to cut off the lower rails and replace them with a cross member with engine tabs, this compensates for lowering the rails.

I HIGHLY recommend a chassis skid plate if you do it that way.. the engine will then sit a bit higher in the frame so you will need to remove the bolts from your mounts on your tank.. use longer bolts and 1/4" spacers to allow for other clearances (carb, cables, hoses, etc)

The stock R frame may need to have the engine move forward more than we did on mine because of the lower rear shock mount.. (allows room for the carb)

[racerx573]

It's not hard to relocate the pivot either you can see that in the previous pic as well..

Here is a pic of an '89 style swinger machined out...(still uses stock R bearings)

You may also need to make custom bushings for the engine if you decide to go this route..

[racerx573]

Here is a pic with the engine in..

[racerx573]

If you want any close up pics of any particular parts, hit me up. I have the bike ripped apart right now.

[racerx573]

Also as far as an airboot.. an LT500 boot works great. I dont have one... but I have heard good things about them, also Walsh makes a boot.. but it is $$$

[wicked265R]

wow, racerX this project is for you man :p That is a good amount of information that i needed. Could you take pictures of the chain side just to see how it is angled to the sprocket on the swingarm. Thanks

[racerx573]

Yeah I will get some pics tonight when I come home from work. One thing I did have to use was some washers on my rear sprocket. Between the hub & the sprocket, to move it over a tad for the right clearances; so it didn't get out of alignment... With something like this.. the slightest bit of being off will cause the chain to throw..

[wicked265R]

get around to taking those pictures? Thanks

[matt250r21]

I have worked with a YZ 426 motor in a modified Laegers 350RX frame with stock 250R shock linkage. This frame was made for a ATC 350X engine and the lower frame rails were 1 inch lower than the 250R frame. The YZ 426 motor still fit crappy in it and this is with an extra inch that you dont have with your stock R frame. The stock link rear upper shock mount was totally in the way of the carb and intake boot. The only way to get it to work was to cut half of it off and then brace it. It did work, but I wouldnt take it on an MX track. Frames with CR 500 shock linkage take the YZ motor a lot nicer. Whatever you do make sure your pivot bolt gose through the YZ motor, this will set your chain up right.

[wicked265R]

i'm going to take whatever advice racerX is giving to me on this project. His turned out gorgous and thats exactly how I want mine to turn out. I just got my motor today and found out that its a yz426 and not a yz450. No difference in installation so i'm not mad. It came with a full white bro's exhaust, hot start lever and cable, clutch and cable, full twist throttle assembly, carb, all electrical, and other misc. parts. I hope this installation goes smoothly.

RacerX, are you running the twist throttle or a thumb? The carb has a 2 cable set-up, which i think is called a "double pumper" (not sure). I think i'm just going to run the twist throttle to avoid any more complications. Let me know

[hontrx265r]

racerx's is on the right track I would definetly listen to him. I put one in a stock geo arens frame, The rear shock mount is a *****, but you can work around it. However its a pain in the ***. I decided to cut mine out after a year and build a no link here is a pic.

[matt250r21]

Stock top shock mount is really in the way, to make it work right raise it up for a long travel no link or do a CR 500 link. Stock link sucks anyway.

[250-R-250]

I dont know if this is any help but I thought it might resemble what your trying to do.

http://cgi.ebay.com/ebaymotors/TRX250R-with-CRF450-Motor-450R-250R-250R-hybrid_W0QQcmdZViewItemQQcategoryZ6724QQitemZ46154 79139QQrdZ1

[wicked265R]

well, i think i figured out a way to avoid the shock mount situation. Instead of putting the bolt through the back of the motor and the swingarm, i make a spacer out of metal that is connects through the original swingarm bolt, and then it goes through the back of the motor. in simple terms, it pushed the motor forward instead of being so far back so i dont have to move the top shock mount. i think it will work very well. Since it will be more forward, it will put the shifter in a better place and it wont be so cramped up against the footpeg. I'll still have to cut the bottom engine mounts out and make a cross member, but that is pretty simple. Thanks for all the help guys its coming along good for now. I'll post up some pics soon.

BTW, i'm looking for a 400ex oil tank to put on this thing so if anyone has one, hit me up. Thanks

[250-R-250]

Look for the ebay item number 4615479139

[matt250r21]

I hate to keep bringing you down but Im just trying to help out with some of my past experinces. It is best to put the swingarm pivot bolt thru the motor for stength and correct chain torque. Putting the countershaft sprocket farther away from the pivot bolt wrecks havok on your rear suspension when it gose thru its travel.

[wicked265R]

actually, if you do it my way, it will put the countershaft almost in the same spot the R's was. So tension wont be to bad. I'm just moving it forward to clear the shock mount. nothing more. I appreciate any advice, so dont worry about it.

[the_hulkamaniac]

Is the pivot bolt the same size between Honda & Yamaha?