How much HP does a ESR 310 have?

[speedfreek]

I have an ESR 310 with the 9 port work (mid to top end) and an 11 pipe (hi-rev) with a 38mm mikuni carb on it.

I have the chance to get a yfz or yzf 426 engine and all electrical parts from a dirtbike. Just wondering which would be the better engine?

I'm thinking about swapping out my ESR engine for the 426. What do yall think?

[deathman53]

you are talking apples and oranges here, even with the esr310(really 293) compared to a lrd, led, sparks, ct or duncan. To start with Esr has really cookie cutter porting and it isn't good at all. The yz426 will fit in the stock 250r frame, but you will have to lower the bottom frame rails and modify more of the frame. Its essentially destroying a 250r frame. 4 stroke and 2 stroke power is very different. Now if you got a GOOD ported motor and setup right 310(293) its right with the yz426 in terms of power. The difference is the yz426 will be easier to ride faster and less tiring= more consistent and faster moto's.

You have to consider, it will cost you close to $1500 to get a yz426 in a 250r CORRECTLY. Now factor in the cost of the motor, carb and electronics. It would be better to take off your top end, send it to c-leigh, get a 38 a/s carb and other stuff that he recommends. I'm not saying this because it will destroy a 250r frame, it makes more financial sense. If you want a 250r hybrid, buy one already built, you can probably get one in mint shape for under 3g's. Or even just the hybrid frame, swingarm and rear suspension, bolt the rest of the 250r parts that fit it and sell the rest of the 250r. With all the 250r hybrids out there being parted out, it doesn't make sense to create a new one.

[speedfreek]

Thank you for your reply. Yea, I don't want to destroy my 250r frame.

I also have a 400ex that I could put this engine on.

I have all the electrical stuff for the 426. I could sell the 400ex motor and get enough $$ to buy the 426 then put it on this frame.

What do you think about this?

[deathman53]

there is a member of this site that sells(used to) bolt-on engine mounts for a yz-f or crf into a 400ex, minimal work involved.

[speedfreek]

Originally posted by deathman53
there is a member of this site that sells(used to) bolt-on engine mounts for a yz-f or crf into a 400ex, minimal work involved. Thank you. I will probably do this swap soon.