Hi, I recently bought a used 2014 Yz250f (efi bike) and i have been having a problem with it. So i bought the bike from a guy who raced motocross, he kept the bike in tip top shape. When i got the bike, it had a fresh top-end with a high compression piston, and stage two hotcams and a aftermarket exhaust systems. I race a mix of woods and moto races so i figured i could just add a few things for the woods and it would be set to go. When i was riding the bike before buying it, the seller mentioned that the bike almost "hesitates" when going from low to high rpms, he said that this had something to do with the new sprockets but to just stay on the gas. i bought the bike not thinking much about that because it was all around a really nice bike but now i cannot for the life of me figure out what is a causing that bog. On a moto track you hardly notice it because your always riding in the top end of the rpm range, however in the tight woods it makes the bike difficult the ride. It almost feels like there is a gap inbetween the bottom and top end powerwise, and you have to roll on the throttle real smooth in order for it to not sputter. If your going slow and then try and grab throttle quickly (to get over a log for example), it sputters out and there is no power. I tried giving the bike more bottom end power by adding a bigger sprocket, which gave more bottom end but didnt make the bog go away. Then i bought a GYTR Power Tuner, thinking i could retard the Ignition timing and move the power to the bottom end. I haven't gotten to test it a ton yet, but so far maps have helped take away the bog. Aside from that the bike runs perfectly, i have looked online and found no one else who seems to have had this problem which is why i am posting this. Any ideas would be greatly appreciated, as i have no clue what to do next, Thanks.
So the first look Yamaha YZ450F/YZ250F. I dont see a big update at here.
YAMAHA FACTORY RACING TEAM “factory machine developed with an eye to acquiring championships in all Japan Nationals and acquisition of advanced technology. For metal spring front forks and intake / exhaust system layout, we follow the market YZ, adopt electric starter etc, and incorporate factory exclusive parts in each part.
“YAMAHA FACTORY RACING TEAM” will compete in IA 1 and IA 2. The team is organized by professionals from various fields centered on Yamaha engineers. With a strong team structure I will fight the mission to acquire IA 1, double title of IA 2, and advanced technology aimed at feedback to commercial vehicles.
Rider participates in IA 1, Hirata Yu who is one of the domestic top riders and is a part of the champion candidate. The 2016 season returned for the first time in a season from the injury of the year before last, the ranking became the fifth place, but it is a presence that does not feel blank and it exerts its presence. This season we aim for the challenge of the wish of the factory machine “YZ 450 FM”.
It is Yusuke Watanabe who drives “YZ 250 FM” at IA 2. Last season, I participated in a youth team that aims to train young people, jumped up from 6th place in ranking to 3rd place in 2015, achieved great growth as the team concept, and this year was promoted to a factory rider. For the 2017 season, we are training to Doug Dubac who flew off to America and played an active role in AMA, and this season we aim to win the IA 2 championship.
More at : MOTOCROSSTIME
I have a 2006 yz250. It was fully rebuilt top to bottom last winter before racing started
rode all year and it was fine
the problem I am having after winter start up is
starts no problem, run decent, when I turn the throttle smoke and. Lack oil spray out of the silencer like if I put a glove on there's a nice layer of oil
also the part of the carb that comes out of the tps and sits on the throttle slide. To me seems loose as in I can lift it to a point and it doesn't spring back. Is it suppose to stay tight to the top of the slide
it feels like it doesn't any force down till about 3/4 throttle when I hold it up with my finger
also when I lean my bike over the idle picks up a lot
2009 Husky WR 300.
New top and bottom end.
New brake pads and they were just bled.
Hyde skid plate.
FMF Gnarly pipe and FMF Q-Stealth silencer.
JD Jet kit.
Comes with extra cylinder, head and piston.
Comes with lighter springs for the suspension.
Pulls like a mule.
This is an awesome trail bike. If you ride Georgetown, Foresthill, Elkins Flat or Chalk Bluff this bike will not let you down.