I bought a 2001 YZ250F this spring to mostly trail ride with my kids. Although not ideal for this type of riding, I've been having a ball on this bike (a little too old to start serious motocrossing, but getting a little air has been fun!). I've been having problems with it overheating, though, even when only idling for a couple of minutes while warming it up. Today, I let my older stepson, who hasn't ridden at all, ride the bike for about 15 minutes, and he was riding pretty slow most of the time. When he came back, the exhaust pipe was glowing redhot out of the engine, something I never noticed before. I let it cool off for a few minutes, then rode for about 20 minutes much faster, but the pipe was glowing again when I stopped. I didn't notice anything unusual about how it was running, but am wondering if the red pipe is unusual or hazardous for the bike, or if I just never looked before. After it cooled off I added a few ounces of antifreeze/water mix, but nothing more than in the past. Any ideas?
YZ250F Red Hot Pipe
- Thread starter NuMtrHd
- Start date
Your bike is not overheating! You are burning fuel in the pipe. Either the valves are out of spec, shot or just running rich on the carb. With the choke on at night I bet it turns yellow! I have tried to melt the ti and it is impossible!
Same thing happened to my 03 YZ250F.
I noticed it while night racing. After being warmed up for about 5 minutes waiting at the line, the pipe is glowing bright orange all the way to subframe. I ran the race, nothing happened, and at the end of the race it wasn't glowing as much, but still glowing.
Due to a leaky radiator, I have switched to Engine-Ice, and noticed my valves were a bit tight, so I re-shimmed. Also read the spark plug, but it was running a good air/fuel mixture.
After reshimming, I havn't ridden at night, which was the only time I noticed it glowing.
I noticed it while night racing. After being warmed up for about 5 minutes waiting at the line, the pipe is glowing bright orange all the way to subframe. I ran the race, nothing happened, and at the end of the race it wasn't glowing as much, but still glowing.
Due to a leaky radiator, I have switched to Engine-Ice, and noticed my valves were a bit tight, so I re-shimmed. Also read the spark plug, but it was running a good air/fuel mixture.
After reshimming, I havn't ridden at night, which was the only time I noticed it glowing.
BadgerMan
Mi. Trail Riders
- Jan 1, 2001
- 2,479
- 10
It's normal for the headpipe to glow when the bike idles for a few minutes. My 2001 YZ250F did the same thing when it was new. Mine stopped glowing when you started riding or when you reved the engine.
Unless you know that it has been recently serviced, it is a good idea to check the valve clearances on a bike that old.
Unless you know that it has been recently serviced, it is a good idea to check the valve clearances on a bike that old.
- Nov 25, 1999
- 7,926
- 43
Normal. These titanium exhausts heat rapidly and without airflow across them they will glow red. As stated, check your valve clearances and do it regularly after that. On a side note, Scorpa is using a variant of this engine in their SY250F. Trials bikes have much smaller radiators and it has been a problem. Even using a fan on the radiators, the SY250F runs hot.
I'm not suggesting that your 250F is running hot but it IS a racing engine and designed to be run hard, keeping the air moving over the head pipe and radiators. When riding this bike in slow conditions I would advise you to keep an eye on your coolant level. Use proper care when checking but don't be overly concerned if it pukes out the overflow now and again, just get some air moving across the radiators or shut the bike off for a while.
I'm not suggesting that your 250F is running hot but it IS a racing engine and designed to be run hard, keeping the air moving over the head pipe and radiators. When riding this bike in slow conditions I would advise you to keep an eye on your coolant level. Use proper care when checking but don't be overly concerned if it pukes out the overflow now and again, just get some air moving across the radiators or shut the bike off for a while.
- Thread starter
- #6
Thanks for the information. After reading some other threads as well, I'm planning on flushing the radiator system, refilling with water wetter and new antifreeze, and adjusting the valves. I just hope to get some time to do it soon so we can ride a few more times before the snow flies here in New York!
