I’ve read several posts about putting a 250R engine in a 400EX and I was just curious what the weight difference would be between a normal 250R setup and a 400EX with 250R engine?

 

I have lifted a 400ex engine and would estimate a complete engine at about about 80-85 lbs. It seems about 50 lbs would be in the ballpark for the 250r engine. Anyone have a better answer for the weight of the 250r engine?

 

If my memory servers me right, I believe a 250R motor weighs 57 pounds. Dave

 

Actually I was wondering the weight difference between the entire ATV including frame etc… Someone said why not just use a 250R frame so I was wondering if you could cut some weight by using the EX setup w/ the R engine. If you where to do the same mods to both i.e. a-arms, shocks, swing arm, axle, etc… the only difference would be the frame. So does an EX frame weigh less than a R frame?

 

I have lifted both to a work bench . The 250 is easily 15 pounds ligher . I will scale both next time .

 

i weighed my 400ex engine and it weighed 85lbs

 

BOTH QUADS USE BASICALLY THE SAME FRAME AND EQUIPMENT(EXCEPT SQUARE FRAME COMPARED TO ROUND TUBING FRAME)TOTALL WEIGHT DIFFERENCE IS ABOUT 30LBS(DONT FORGET ABOUT THE WEIGHT OF THE RADS,COOLANT ETC OFFSETS THE MOTOR WEIGHT SAVINGS.400EX=375LBS(MOTOR=91LBS) 250R=340LBS- DRY WEIGHT FROM HONDA MANUALS SO WET WOULD BE AROUND 30LBS DIFFERENCE.

 

Let me see if I got this right:

EX = 375(stock) – 91(EX-engine) + 57(R-engine) = 341 lbs.

That is the same as a stock 250R give or take. If this holds true then you could buy a 400EX sell the engine, buy a 250R engine and have a new EX250R for around $6,000. Or am I missing something here? That would definitely be a lot cheaper than building one from scratch with an aftermarket frame.

 

This conversion is probably more expensive and time consuming than you think. While it may be easy to put the 250R engine into the 400ex frame, the other stuff that you need won't be so easy to mount. You need to mount a radiator somewhere where it can get plenty of airflow and still be out of the way of the pipe which will probably have to be a custom pipe because of the way 250R pipes mount. You have to mount the silencer as well. Then you have to look at the airbox situation and make sure that the carb and boot will reach the intake manifold. I don't think that this could be achieved without making some kind of custom intake boot. So now you have spent all that money when you could have just bought an aftermarket 250R frame.

 

Yeah, I would rather have the aftermarket R frame anyway. They are still lighter than the EX frame and better designed as well. Also made for the 250r motor's vibration (not that much, but more than a 400ex), a radiator and whatever else. Much easier if you ask me.
You can buy an Arens chassis for like 1200, so why spend the money on a 400ex chassis?