Jump to content
Sign in to follow this  

yz250f falls flat at hi rmp what are you doing Yamaha?

Recommended Posts

Why does yamaha keep building the same engine that doesnt rev? year after year

I rode my buddies 07 that was a broc tickle race bike (its pretty sick, not sure what has been left on or in the bike from those days)but it falls flat on its face. The lack of over rev off jumps is almost dangerous. What can be done to make it rev?

I owned a 06 4 years ago and hate it too. Low end is nice but come on yamaha. I bought a newer yz125 and sold the 06. It was the worst bike I ever owned. Slow, heavy,and handled bad.

And I have had Yz's all my life starting with a 1983 yz80 in 83 when I was 11.So I'm not a Yamaha hater.

Do they not see the light or what?

Also seems like there is not much out there as far as engine builders for these bikes. Its all crf. Is this due to the 1 cam and 4 valves vs 5 valves and 2 cams?

Share this post


Link to post
Share on other sites

Not a lot of people are buying new bikes these days so Yamaha isn't going to spend a lot of money in research and development. People buy Yamaha for their reliability. Last I checked Honda has a reliability issue amongst other things.

Share this post


Link to post
Share on other sites
Not a lot of people are buying new bikes these days so Yamaha isn't going to spend a lot of money in research and development. People buy Yamaha for their reliability. Last I checked Honda has a reliability issue amongst other things.

I bought a 06 crf450r new in 06 heard about the valve thing but have had no problems at all even racing the bike put a new top end in it at 60 hr and still no problems.

Yamaha spend money ? What they just redesigned the 450 complete. That was a bunch of money.

Share this post


Link to post
Share on other sites

Actually the new 2012 yamaha is supposed to have all top end. The problem with top end is that it makes you feel like you are going fast when your actually going slower lol. In turns you should be grateful for that bottom end.

But if you want your 250f to rev faster and have more top end then get it ported, put a 2012 piston in it, and remove the counter balancer(less rotating mass) and it should be pretty good

Share this post


Link to post
Share on other sites

take the stock cdi and skip it into a pond.

call jesse at williamsmotorworks and tell him you want his MSD cdi.

and jet it right. you are not jetted right.

on the dyno i gained almost 2hp in overrev with the correct jetting

Share this post


Link to post
Share on other sites
take the stock cdi and skip it into a pond.

call jesse at williamsmotorworks and tell him you want his MSD cdi.

and jet it right. you are not jetted right.

on the dyno i gained almost 2hp in overrev with the correct jetting

Agreed, the stock CDI holds the top end back. I switched to a vortex ignition and mine now pulls all the way to the rev limiter.

Share this post


Link to post
Share on other sites

Check out jd jet kits and or look for the right jet size or needle notch setting, and air fuel screw setting for your elevation. Check it out before you dump money into it.

Share this post


Link to post
Share on other sites
maybe its the rider. wanna sell it? got a gooood honda i will trade ya.

yeah I'm sure he would trade want to bring it to San Diego.

by the way the ride is slow. But he has $$ to spend to make it run right.

Share this post


Link to post
Share on other sites

after 08 honda turned to shit. yamaha isnt the highest performing bike and every one knows that. and every one knows they last the longest.

Share this post


Link to post
Share on other sites

i HAD the same problem. i dissected my bike and found a small amount of sand in my gas tank blocking the flow of gas through the petcock. also had a very dirty carb and float level was incorrect. i also backed out the fuel/air mix screw .4 of a turn and it runs great now! no bog at all. as soon as you slam the throttle it hits the rev limiter! good luck.

Share this post


Link to post
Share on other sites

JD jet kit recommends a 185 main jet for 06-09 at sea level! :thumbsup::ride:

Using his needle (blue @ fifth clip), 55 leak jet, and that fat main (along with O-ring mod which comes w/ kit), ought to make it rev better for ya.

Share this post


Link to post
Share on other sites
after 08 honda turned to shit. yamaha isnt the highest performing bike and every one knows that. and every one knows they last the longest.

yeah so does a xr those dont rev or have the hp either

Kinda the point of a race bike.

Don't care how long the top end last cause you change them any way.

Share this post


Link to post
Share on other sites
yeah so does a xr those dont rev or have the hp either

Kinda the point of a race bike.

Don't care how long the top end last cause you change them any way.

You'll care when the cranks or the pistons go out and trash your head all the time...they cost a pretty penny I'll tell you that. Ill stick with my reliability for a 1-2hp loss...

Share this post


Link to post
Share on other sites

Yeah here in so cal in the motocross Capitol there are 20 times red over blue

I'm just not seeing the issues everyone talks about.

Yes a guy rides a bike 100 hours does nothing to the bike and has a problem.

Bought a 06 crf450 new don't rude it much has 100 hrs on it no valve problems

Buddies have crfs no problems either

Have owned both yz250fs and crf250 and the Honda is a better bike by far

I found a very clean crf250 with no hrs on it for 1800 bucks if it blows up I'll throw it in the trash

Share this post


Link to post
Share on other sites
Yeah here in so cal in the motocross Capitol there are 20 times red over blue

I'm just not seeing the issues everyone talks about.

Yes a guy rides a bike 100 hours does nothing to the bike and has a problem.

Bought a 06 crf450 new don't rude it much has 100 hrs on it no valve problems

Buddies have crfs no problems either

Have owned both yz250fs and crf250 and the Honda is a better bike by far

I found a very clean crf250 with no hrs on it for 1800 bucks if it blows up I'll throw it in the trash

You could at least part it out or add a smoker motor to it. :thumbsup:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×