3 posts in this topic
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.
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.
By Steve Sutton
Apologies for the long post, but I’m including as much info as possible.
I have a 2-Stroke Yamaha TDR250 1KT, same motor as the TZR250 apparently.
I just completed a top-end rebuild. I only replaced the left piston as the right one look good. Probably should have replaced both, but anyway…
My problem is the right cylinder/exhaust gets very hot very quickly and smokes a lot. The exhaust is hot only after 30 seconds of idling. The left remains room temperature and does not smoke.
I don’t want to ride it too much in case it causes irreparable damage. But when I did try to ride her, I can only get a few hundred meters before she cuts out. I have to start again and can not get into 2nd gear before it stalls again. I’d have to limp home at a bicycle’s pace as anything above idle revs kills the engine.
Not sure if the poor running is related to the hot exhaust, or another problem entirely.
I’ve done the following troubleshooting:
- swapped around plugs – no difference
- swapped around plug leads – no difference
- swapped around Carburetors (but not the Jet Needles) – This then made the left cylinder smoke and the right smoked a little, but not as much as previously. The carbs are back on their original sides as they are specifically left and right.
- sprayed carb cleaner onto the carb boots to test for air leaks and that had no effect.
- Raised the Jet Needle in the right carb for a richer mixture – It appears to smoke less (could be my imagination), but it still gets hot quickly.
- Checked the plugs again and the troublesome cylinder’s plug looks to be running very rich (all dirty), so I lowered the needle this time for a leaner mixture. Still no difference.
I removed the exhaust and wiped my finger in the cylinder’s exhaust port. Looks like black paint!
Has anyone ever experienced this and what was the solution?