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woodsguy

woodsguy

Ride Red
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Rob
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Yamaha 250 4 stroke offroad bike!
 

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18" rear, 6-speed, side stand, and e-start! Otherwise it's a m/xer!!!! About time
 
So a KTM 250xc but blue? :D


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Nice! It's about freaking time someone else decided to play in this segment. Come on honda, update yours!!
 
Click on the OP's thumbnail, you can see the rearward slant of the engine. You don't see that everyday.

"The revolutionary, rearward slanted, high-performance liquid-cooled, 4-stroke, 4-valve, fuel-injected engine has been tuned to challenge for race victories in the very competitive GNCC and Hare Scrambles race series.

"The position of the engine moves the rotational mass of the cams towards the center of the bike which allows for a straight shot, down draft intake and straight exhaust port for ultimate performance. This keeps air box up high, out of dust and mud/water."
 
Rman of 237 said:
Click on the OP's thumbnail, you can see the rearward slant of the engine. You don't see that everyday.

"The revolutionary, rearward slanted, high-performance liquid-cooled, 4-stroke, 4-valve, fuel-injected engine has been tuned to challenge for race victories in the very competitive GNCC and Hare Scrambles race series.

"The position of the engine moves the rotational mass of the cams towards the center of the bike which allows for a straight shot, down draft intake and straight exhaust port for ultimate performance. This keeps air box up high, out of dust and mud/water."
Click to expand...

Yamaha has had the slanted-back engine to improve mass centralization since 2010 on their YZ 450F and since 2014 on their YZ 250F.

Should be a good bike. Plenty of competitive YZ 250F's out there racing off road, so this one should good too.

As far as a two stroke version, I doubt that would ever happen. It is so easy to take a two stroke YZ and make it rip on the trail that I don't know what the point would be. When Yamaha did have a two stroke off road bike (WR 250), it was a slow heavy pig of a bike that no one bought and Yamaha's own off road race team wouldn't even ride.
 
I too wish for a YZ 250X two stroke. Not really excited about the expensive maintainaince of four strokes.
 
Johnf3 said:
Myth. Yamaha four stokes are pretty much bullet proof.
Click to expand...

woodsguy said:
Agreed!
Click to expand...


Good to know. Not a major bone to pick but do they tend to go through the stock Titanium valves fairly quickly like the Hondas do? However once they go I know you can replace with the stainless valves for not much money and then basically forget about them.

_
 
SilverBullet said:
Good to know. Not a major bone to pick but do they tend to go through the stock Titanium valves fairly quickly like the Hondas do? However once they go I know you can replace with the stainless valves for not much money and then basically forget about them.

_
Click to expand...

Yamaha does not have head or valve issues on their four strokes anymore. Their early five valve heads had some issues but that was a long time ago.

The best thing about Yamaha is their Kayaba SSS forks. They have resisted jumping on the air fork wagon even though Suzuki, Kawasaki, and Honda have changed (KTM MX bikes are rumored to change to air in 2016).

The SSS forks, set up properly, are the best out there. Every time I ride a newer Yamaha I wish that my Husaberg and KTMs had that set up.

This Yamaha 250 will be good right out of the box I bet. Glad to see something new from the Japanese makers.
 
What he said. I've got a friend just bought a KTM. He likes as long as he doesn't ride somebody's yamaha. Lol
 
SilverBullet said:
Good to know. Not a major bone to pick but do they tend to go through the stock Titanium valves fairly quickly like the Hondas do? However once they go I know you can replace with the stainless valves for not much money and then basically forget about them.
Click to expand...

Bike with stainless valves are slower.
 
Is this also the design with the intake on the front of the head and the exhaust on the back with a wrap around header?
 
My old CRF went from 54 RWHP at 10,500 to 52 RWHP at 10,300 when the ti valves had to be replaced with SS. I couldn't tell the difference. Heck that little difference could be explained from one dyno run to the next by any number of variables.
 
ed29 said:
My old CRF went from 54 RWHP at 10,500 to 52 RWHP at 10,300 when the ti valves had to be replaced with SS. I couldn't tell the difference. Heck that little difference could be explained from one dyno run to the next by any number of variables.
Click to expand...

The difference between winning and loosing. :rofl:

My understanding is that after switching to SS valves, the RPM limit should be lowered to prevent valve floating. So, if you're going to be pinning the throttle wide open alot, that might be an issue. (Like sand riding)

I agree most woods riders don't stress their engine enough to worry about it. But what about people riding in more wide open places (like CA), alot of wide open pinned throttle ?
 
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