Hello all,
I am a brand new dirt biker.
I used to ride ATC 250R's back in the day, so i know a little.
I just purchased this 2019 YZ250 used with 17 hours on it.
I have a little property, and a home track i made for my 5 year old to ride is PW50 on. The second ride, about 1 minute in, the engine quit running, a new plug was installed and all good.
Yesterday i took it to a local track. The 1st ride of around 30 min went well. The 2nd ride.... About 2 minutes from my truck, and the track, the bike just died.
I forgot to bring a spare plug....
Got the thing home, put a new plug in it and it fired right up. When i pull the plug, its a little wet and dark.
After the 2nd plug in a little over 2 hours i decided to take this thing out on the street and open it up a bit. It runs great. I just noticed that many times i could not get the thing into 4th or 5th gear....
I am running what i believe to be stock jetting, Amsoil Dominator at 50:1 and non ethanol premium 92 pump gas.
I changed the oil after i bought it with Maxima MTL 80WT XMSN lube.
It is thought that the bike sat for 2 years or so prior to the sale to me. I am the 3rd owner.
Spark plugs are NGK BRES8
Help please
I forgot to mention that with the bike running, clutch in, I can shift through all the gears positively.
I might need to try this again to verify
YZs are known for a variety of transmission issues. How many hours are on the bike?
Sounds like it's running rich and loading up and fouling plugs. Switch to 32:1 or 40:1 and you also may need to lean the jetting just a hair.
If the bike sat, a basic carb cleaning may also help a little.
Make sure the bike does not have an aftermarket oil drain plug. Some of them are too long and interfere with shifting.
99% of the time a plug fouls is from idling too long without revving the bike and cleaning it out. Or just putting around at low revs without revving it occasionally to keep it from loading up. Backing out the air will help a little bit.
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As told to me.
45p/175m jets. Oh, and a 40 power jet. N3CW needle w/clip @3. AS out bout 1.5.
Thank you to all!
I have been riding the thing for a bit more without problems. I moved the shifter so it sits a bit higher. Seems to be going through all the gears consistently now.
I am going to order the the jets etc to have on hand
YZ250's don't usually foul plugs, make sure to check your jetting (start at stock) and adjust the airscrew. Pick up a service manual if you don't have one already.
Since you fouled a few plugs already you might want to take off the pipe and clean the power valve. Sometimes it can get gummed up if the plug does foul.
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