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I am thinking of doing some crazy stuff (dry sump questions...)

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I am new here and it seems like there are a lot of knowledgable people here who could help me out. I am an avid (and slow) karter and an engineer. I am in the preliminary stages of designing and building a 250f powered shifter kart. I would really appreciate it if someone could tell me which of the current 250f's have dry sump lubrication systems and which engines are known to have oiling problems (especially starvation).

Also, do any of you know of someone who has done this. I hope to start this project in a couple weeks and am trying to figure out what i should use as my powerplant. I appreciate any help.

mike major

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i am pretty sure the yzf is dry sump. it would probably be the best motor for your application. a little more reliable than other 250f motors.

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Only the YZ250F has a true dry sump engine. The KXF/RMZ have a "semi-dry sump", where the transmission is used as the reservoir.

The CRF can have lubrication issues because of the very small volume of engine oil.

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Why doesnt the YZ250F have tranny oil?
Unlike the other 250Fs, all of the YZ250Fs oil is pumped out of the crankcases and into the external reservoir. The CRF is a wet sump engine, and the KXF/RMZ is a semi-dry-sump that stores the engine oil in the transmission cavity.

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How long has the current Yamaha engine been in production? Are the mounting points different between the 03, 04, 05, 06 etc? How long has the Yamaha been a dry sump (as of which model year?) Is the yamaha still a wet clutch?

I appreciate all of your help now in the hopes that my project will go much smoother when I get it underway.

Mike

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Is the external reservoir incorporated into the frame on the Yamaha?
Only on the steel-framed bikes. When they went to aluminum for '06, they built a reservoir that attaches to the front of the engine.
How long has the current Yamaha engine been in production?
Since '01.
Are the mounting points different between the 03, 04, 05, 06 etc?
They are the same for '01 to '05 for sure. I don't know if any mounting points were changed when it went to the aluminum frame for '06.
How long has the Yamaha been a dry sump (as of which model year?)
Since it's conception.
Is the yamaha still a wet clutch?
Yes.

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WOW, you guys rock! So I am getting more and more encouraged here, especially since yamaha went to an external reservoir. I want to be able to use as many OEM pieces as possible (I was a development engineer for some aftermarket automotive applications and the quality/integration differences are astounding). I will have to go to the yamaha store this week, but as i am sure you all know the dealer usually knows very little.

Are the engine and oiling system the same on the WR 250F also? I ask because I would make it an electric start TAG setup if possible.

Thanks again for the help, and i hope to have a result to show everyone.

Mike

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WOW, you guys rock! So I am getting more and more encouraged here, especially since yamaha went to an external reservoir.
The nice thing about the new reservoir on the '06 is that it eliminated the vulnerable external oil lines.
Are the engine and oiling system the same on the WR 250F also? I ask because I would make it an electric start TAG setup if possible.
The only difference between the YZ-F engine and the WR-F engine is the exhaust cam is retarded by one tooth on the WR, and the WR has "the magic button".
Thanks again for the help, and i hope to have a result to show everyone.

Mike

When do we get to take it for a spin?

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I am getting a lot of great correspondance, and I was wondering if anyone can elaborate on the engine changes through the years (from 01 to present) and the mounting hole locations. would an older engine work with the new oiling system. does anyone have any pictures (like i said, i have to check it all out at a dealership this week.).

I have a feeling I will be in the market for a YZ/WR engine in the near future...

mike

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The WR is not a race engine as some one said before you'll have to change the cams but the elec start is well worth that

as far as a oil tank the 01-05 is in the frame the 06 is a seperate tank either way youll have to fabricate one for a kart

At www.cycleranchmx.com they are building a kart track and super moto as we speak

The motors are different but not much just been fine tuned

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You will have to fabricate a resivour which is nice because you can add oil capacity to add to reliability. The 06 motors have the oil resiour built into the front of the crank case. I would go and make a custom oil box. The WR also has a lighting coil so you can run any electronic gadgets you might require.

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From what you have written, it seems that

a) the 01-05 engines are the same while the 06 engine has an integral sump.

Q: ARE THE CASES AND MOUNTING HOLE LOCATIONS THE SAME?

:thumbsup: the WR has the *EXACT SAME* cases as the YZ, but with different camshafts

Q: CAN THE STARTER MOTOR OFF THE WR BE ADAPTED TO FIT THE YZ?

c) someone else is already working on this same project

Q: ARE THERE ANY PICTURES OF IT ONLINE?

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