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Only $10 for all 2024 SX, MX, and SMX series (regularly $30).
His sponsor helps with the parts and he does the work. He helps us out TREMENDOUSLY but I still pay him. Our local factory dealer is at $90 bucks an hour. So I'm appreciative of every bit of help.
I feel like people make these bikes out to be less reliable than they actually are.
A 250f is as reliable as the rider on it, if you sit on the rev limiter around the track your gonna need To maintaine it more often. I've heard tons of stores about well ridden 250f's not touching the valves for 100hours and still being in spec.
The Shop
Have a '14 YZ250F, staying off the rev limiter (upshift & use torque). Change oil very 3 hours (Rotella T), air filter as needed, running ethanol free gas (90 octane w/ stabilizer).
Is it recommended to do top end every 50 hours - or can you go longer?
Saw this one on TT, where he had 110 hours on the bike before new top end:
http://www.thumpertalk.com/topic/1106704-2014-valves-long-term-reliabil…
I think people recommend 50 hours for top ends. Depends how you ride the bike.
They say 20-25 hours to check valves, some people say every 50 hours for valves.
Just watch a few "How to" videos on Youtube and you should get a pretty good understanding of what's involved fairly quickly.
https://www.youtube.com/results?search_query=check+valves+YZ250F
The only real specialty tool you'll need is a set of feeler gauges. I use these:
https://www.rockymountainatvmc.com/p/989/20116/Bike-Master-Dual-Reading…
I have seen many connecting rod failures that destroy most of the motor. I have one in my shop right now with 70 hours on it from a novice rider that is mostly a total loss.
Luc from C4MX can confirm this. He has been working on several of them as well. It sucks that you have to rebuild an engine right out of the box but it is very dangerous and super expensive if it lets go.
My mechanic is checking the valves tomorrow night. We will be at 90hrs. I will post what we find out. At this point, if the valves are in spec I am going to let it go until 120 and decide if I am going to freshen it up or sale and it and buy a new one....
Pit Row
Great bikes for reliability.
I am the same on maintenance, all though I have started looking at the air filter. Some days my son rides by himself here at the track. I use the little red FLO prefilters and sometimes the filter have hardly any dirt on them. So I may go 2 rides on that, on these days we do a 3-4 lap warm up. Then 2 or 3 7 lap moto's. Oil is changed every other ride or 2 hours max and then the oil filter every other oil change.
Derek Harris built the motor in this one (its a full mod 276) and says he wants it back the first time at 20 hours. Also change the oil every other ride. I use the Yamalube in the silver bottle. A fresh top end wont put weird loads on the crank from clearances letting the piston move in ways the crank wont. High comp pistons are what is hard on the 14 and 15 cranks. The 16 is revised and stronger. In fact if you buy a GYTR high comp piston for a 14 or 15 it comes with an oil jet that cools the underside of the piston.
I know guys that ride off road that do top ends every 50 hours with no problems, but they are not running wide open much of the time like on a moto track.
Just my thoughts and experience. $100 for piston and ring kit and $18 for a timing chain is awful cheap insurance.
i almost bit the bullet and sent it out for all that this winter to c4mx. that would be a sweet motor but $.
These bikes are pretty tough, I didn't properly tighten the drain bolt and it fell out on the track. Bike shut off in a turn thankfully! Put oil back and kicked it over a few times and she fired right up. Changed the oil after running a few times to make sure no metal particles. She has 15 plus hours since and still runs good. Don't want to push it any further. Since installing a new rod the crank will be inspected for damage as well!
A local pro was practicing at our track awhile back and lost the tip of the spark plug on his YZ250f. Said it's the second time it happened. I suggested maybe popping head and seeing if any damage? Saw him a couple weeks later and he had just threw another plug in and rode it. Those YZ's must be almost bulletproof.......
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