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This is no different than a modern day car compared to an older car with a carburated small block. Times are changing and the manufacturers and dealerships will be lining their pockets from service parts and labor.
As for the TP sensor on these YZF250's, don't all EFI bike basically use the same TP sensor? Matter of fact, the same sensor is used on lots of EFI street bikes and even cars. Seems the problem would not be unique tot he YZ250F.
The Shop
If you feel its still electrical and you've changed everything out, try adding a handmade grounding harness between ALL the major electrical/electronic components. Depending on chassis grounds can sometimes lead to issues. If there's no external "metal" or grd tab on the component, splice it into the designated grd wire itself.
Longshots, but desperate times calls for desperate measures!
Yamaha is of no help at all. Very dissatisfied with their poor customer care and company ethics/product backing.
Their rep for our area continually will not answer my calls, and will not return my missed calls or voicemails. When I call Yamaha I get put on hold for 30+ minutes just to be told to "Leave a message and info and we will get back to you". Sometimes not even that the line just hangs up.
After not hearing anything all week from Yamaha or the rep about my bike I call them today. A 40 minute phone call and about 2 minutes was actually conversation. The person I talked to earlier this week was the one I was trying to talk to, They were "unavailable and told me to take a message, we need to make a call to RT about your bike issues one more time to confirm some things, we will call you within the next 2 hours before we close". It's 6 hours later and nothing... sadly I expected that.
So my bike is currently sitting in my garage, will not start, no support or contact from Yamaha, and I will be missing another weekend of being on my bike. Looks like if I want this thing fixed anytime soon I'm gonna have to invest my own money into finding out Yamaha's mistake and fixing it.
I love my bike (when it runs) but Yamaha is frustrating me to no end. Anyone else struggling with them?
Assuming everything else checks out:
Crankshaft position sensor. The thing about the CPS is that it might be generating a signal and look good based on resistance, but if the timing is off both the FI and ignition will be all screwed up. The manual doesn't show exactly how the sensor is triggered but typically it's either a small magnet on the flywheel/rotor or a series of teeth around the flywheel with a couple of teeth missing. When the magnet (or missing teeth) pass the sensor the sensor produces a pulse telling the ignition and FI where the piston is relative to TDC. For example, maybe the rotor key sheared off and the flywheel moved? You'd think the dealer would have seen a problem when checking ignition timing but you never know. Sometimes the timing teeth is simply a ring pressed over the flywheel and can come loose and spin when hot. Maybe the gap between the sensor and flywheel is out of spec? If it's magnet based, maybe the magnet got "demagnetized" just enough to prevent a clean pulse.
Injector. On multi-cylinder engines this is a bit easier to diagnose. However, it wouldn't hurt to take your injector to a local FI specialty shop and have them test it. We back flush them and run a series of flow/volume tests.
Other weird stuff, maybe you have a tight valve or your decompression mechanism is stuck or otherwise holding a valve open? A stuck cam chain tensioner can change valve timing a bit as well. Check your cam timing after you verify that the flywheel is properly keyed to the crank, maybe a cam to cam gear issue?
Have the dealer "reflash" your ECU.
Mark.
Got the call from the dealer late Friday afternoon to come try it. They went and rode a trail with my son for 20+ mins! Bike is running PERFECT! Brought it home put about 20 mins, usual time to get it to act up, and is still running great! Carried it to the track yesterday and bike is SOLID! Really hoping this is the problem!
Here is my quarrel with Yamaha. IMO, they must know of this problem. I have spent thousands of dollars in sensors, lost count of labor bills, and hundreds in fuel hauling this bike around.
The shop that repaired it really hated to give me the bill, I didn't buy the bike from them. It was $500 with the part, part was sold at cost.
In total I feel pretty sure I have $2000-$3000 in chasing a problem I feel they knew about.... That is BS IMO....
I have already spoken for a new 16 for my son, I plan to document with video any and every issue we may have. I hope we get a good next time, we love the bikes.....
To confirm, only a new TPS (Throttle Position Sensor?) was installed that corrected the problem? Do you know the part #? Can anyone swap it out, or is something else involved (calibration) that the shop had to do? Does it affect only 2015, or 2014 too? Thanks
Chucky
What's weird is I asked about the TPS after I saw what you said... Yamaha denied it saying there isn't one. The dealership said there was no bulletin message telling of a new TPS or recall on them either as of a few days ago. Although mine hasn't shown any symptoms like yours, it's obviously an issue if they issued a new one and I definitely want the new one.
I don't know.. the lack of communication and concern from Yamaha is really shady. The fact JGR and Star Yamaha DIDN'T wash there bikes all weekend long this past weekend, says to me there is an obvious issue that they are keeping quiet about.
Dealer has my bike this week is trying to find the issue, I will update if I find any answers.
replaces part #
1SL-85885-00-00 is the one that came on the bike!
We have had endless shit until we replaced both the stator and flywheel and we made up custom bolts to hold the stator in place. (Side note - both the 250 and 450 run the same stator)
On one occasion we diagnosed that the flywheel was rubbing on the three bolts that hold the stator on. What happened was the bolts got so hot due to friction that the loctite broke down. The direction that the flywheel spins slowly unscrewed the bolts and at the same time ground the bolts shorter and shorter until the stator came lose. In otherwords the torque bolt heads were ground away until the stator was just floating on the headless bolts until they were ground away enough (and short enough) forr the stator to come lose and rotate with the flywheel ripping the two wires.
Let us know once you have diagnosed your problem.
Thanks and good luck
Second guessing now big time.
Pit Row
I simply do not want to deal with air forks.
It's still the best 250f out there IMO... I know a kid that is on his way to the ranch that has tons of hours on his and has had zero issues. I got a bad one. I understand it happens. I just wish Yamaha was more forth coming about the problem. To many people chasing a problem they know exist!
My 2014 YZ250F has not had issues (changed shift shaft stopper & impeller for the new updated parts), but engine is not cutting out.
Should the TPS sensor be replaced anyway? What do you all think? $129 will not break the bank for a peace of mind.
sgrimmxdad, sorry for all your trouble - truly hope for you it is fixed now once and for all.
Chucky
2014 yz250f, no issues. 26hours
I'm assuming the old sensor just isn't sealed well enough to keep moisture out of it? Anybody have a picture of the two side by side?
Post a reply to: 2015 YZ250F PROBLEMS!