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wr250f 2010 with yz250f cams- bike not run well

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hey, i got wr250f 2010. after i bought the bike i replace the muffler with yz250f muffler (i connect it to the wr250f header) and replace the main jet from 172 to 175 and the bike run good. after that i bought yz250f cams and put them on the bike but to bike not run well. the engine start with no problem but when i ride it, its not got power in the low and mid range, in top range it run like a turbo engine! what should i do to make the bike run smooth?

another question, what oil you use? full synthetic? 

thanks!

cheers from israel!

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Maybe those 2010 YZ-250FZ cams aren't a good choice for your bike, especially with how you want the power characteristics to be.

Sounds like you simply traded away your low-end for a big wallop up top - like you could use on a motocross track with a motocross bike.

 

Myself, I'd try putting the stock WR-250F cams back in the engine, but retard the exhaust cam by a tooth.

This mimics the YZ-250F (from 2006) cam timing and will give you a considerable increase in midrange and top end power at the expense of some low-end power and torque.

Hopefully, you will end-up somewhere in between your stock WR power characteristics and what your bike runs like now as far as having some usable low-end and a stronger mid-range and top end.

 

I tried this, myself, and found the power characteristics suited to terrain where you can actually unleash the increased power often.

I found it does not make sense on tighter trails in the woods.

Judging by your picture, I think you have suitable terrain for the YZ exhaust cam timing.

 

One step you need to take when retarding the stock WR exhaust cam is to grind 1 millimeter off the decompressor pin that sticks out of the camshaft.

Search on this subject to read more about it.

 

You only need to use full synthetic if you need that in order to make yourself feel better.

Most guys are easily impressed by the flashy label and the high price tag, and lots of guys will buy what some just-out-of-high school parts guy will tell them to buy while shopping for oil.

These are the same youngsters who will recommend $100 custom graphics for your bike.

Personally, I've never met an engine oil expert.

Plain ol' Yamaha, Honda, Suzuki, or any other brand of MOTORCYCLE oil in 10/40 will do just fine and dandy for your bike, something I've proven to myself over 33 years and counting.

The thing is to change that oil on a regular basis, as ANY dirt bike requires.

 

Servicing the air filter often is the other biggie.

Edited by YZEtc

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thanks for the answer! :thumbsup:

i change it back to wr cams, the bike run good now.

if i put again the yz cams do i need to rejet the carb? if i do the 1mm grind with the yz timing do i need to rejet?

 

i will buy 15\50 semi synthetic motorex oil.

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I would:

 

Use the stock WR cams with the exhaust cam retarded one tooth.

Decomp pin on that exhaust cam ground down one millimeter.

 

Done as far as the cams go.

 

Carb jetting depends on what Israeli bike come with.

In the United States over here in North America, the WR-250F comes with carb jetting that allows the bike to be EPA-compliant, but not let the bike run strongly (or even correctly).

So, everybody that has half a clue rejets their carbs with one of the available jets kits for their bike.

 

On the 2009 WR-250F that I now wish I did not sell two years ago, I used Yamaha's own (in the United States, remember) GYT-R AIS Removal Kit which comes with it's very own jet kit - the real reason for the kit, actually.

 

On the 2002 WR-250F that I now own, I used the stock carb needle from the 2002 YZ-250F and a main jet a couple of sizes smaller (yes, smaller, due to the YZ needle passing more fuel).

The bike runs well like this.

 

You can read about loads of other guys' jetting specs on the jetting thread on this forum, as well as use the SEARCH bar.

Edited by YZEtc

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Why would you put yz parts in a wr ?! Yz is a mx bike ridden at high RPMs, a wr is a trail bike ridden for bottom to mid range

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The usual:

 

MORE POWER!

 

But, losing a lot of low-end can be a problem, too.

You need a balance.

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