Hey my name is Daniel and this is my first post on the forums. I recently bought a used 2009 KLX250S.
Been having some issues with it (I'll save the details for a new thread) so I've decided to start off with some basics before taking it into a shop.
Currently draining the gas and will be filling it up with 94 octane, ethanol-free gasoline. Thinking I might do a Seafoam treatment as well.
I also washed the air filter in mineral spirits followed by several more washes in warm soapy water. It's currently on the clothes line drying off.
My manual says to saturate it in engine oil and squeeze out the excess. My question is, does it matter what type of engine oil I use?
I have some 5w20 synthetic oil left over from a car I sold that I no longer need. Would this be a good oil to use or should I not use synthetic oil on the air filter? Does it even matter?
Once I get the bike all sorted out, I'll replace the air filter with a twin air or uni filter at which point I'll probably also look into more specific foam-filter oils. I heard No-Toil is good??

Edit: So if I'm reading this article correctly, it sounds like synthetic oil would actually be better to use.

 

Most any oil will work on the filter, I use chainsaw oil. I would not run 94 octane nor would I seafood the engine. After fresh fluids and filters, just ride!

 

Thanks for the reply. I would just change fluids and ride but my bike likes to leave me stranded on the side of the road far too often. So I can't just ride...
When I am riding in 6th gear at wide open throttle, the bike eventually dies on me and will not start up unless I wait a good 3-5 minutes or so.
I think I've narrowed it down to a problem with the carburetor. When I was draining the old gas from the tank and carburetor, I noticed the flow out was very weak (I even made sure the drain screw was backed way out).
I was watching a video of someone draining their KLX250S and the flow was about twice as fast going out.
I'm suspecting the carburetor bowl is not filling up fast enough so when I am WOT in 6th gear, it eventually runs out of gas and dies on me.
This problem doesn't happen when riding on the trails and staying in 1st, 2nd, or 3rd gear. If the trail straightens out for a bit I might be WOT for a few seconds but not long enough to have a problem.
I'm going to check the fuel lines and I think there is a fuel filter somewhere on the bike that I will check out as well. Start with the simple things first.
If that doesn't solve it, I feel I am left with either doing a Seafoam treatment or removing the carb and cleaning it out manually (something I've never done before).
Why don't you recommend the Seafoam? I've heard it's worth trying out before disassembling the carb.

 

I think you're correct, it's the bowl, given the symptom you describe. With the carb still installed, remove the bowl, spray carb cleaner or brake cleaner into the needle area, clean bowl and replace. Give it a try.

Drain the tank, blow compressed air through the lines, petcock, etc. Reconnect, fill with fuel and give it a try. No need for high octane fuel, always just follow the owner's manual.

Seafood is very rarely needed, in spite of how often we hear of it. I'm sure your combustion chamber is just fine, no need to dump chemicals in there, risking gasket leaks and such. After you put a few miles on the bike, and heat cycles it will run better and better. Most often than not, clean fluids and filters, and maybe a new spark plug takes care of everything.

​​​​​​​Report back!

 

dan,
That running in 6th WOT and dying is a symptom I don't recall ever hearing of before, but I think you're on the right track with the fuel system.
There's a tiny little fuel filter at the carb inlet, I believe. I tossed mine and installed a proper in-line fuel filter. Find that filter and see if it's fouled.
High octane does nothing for cleaning the fuel system. It's only cleaning your wallet.
I've used seafoam with success before and wouldn't have an issue with giving it a try.

 

I believe the only fuel filter is the "sock" connected to the petcock, tank internal. No need for another, just clean it out when you drain the tank.

 

^yup, that's the one I'm talking about.
Didn't like it so picked up an in-line from my local dirt bike shop.

 

The reason I am using higher grade octane fuel is to avoid the ethanol. The only gas in my area that is free of ethanol is either 91 octane from Shell or 94 octane from Chveron. I checked the manual and it says the minimum octane recommended is 87 but higher octane fuel can also be used. It even says to use higher octane if experiencing engine knocking or pinging.

According to the parts diagrams, there are actually three fuel filters on the bike. Two in the gas tank (one for ON, other for RES), and another at the carburetor. I'm guessing the two in the tank are more like screens and the one at the carb appears to be a paper filter (nope, it's a screen). Considering the OEM filter at the carb is almost the same price as a larger aftermarket filter (and is a silly little screen), I can see why you tossed it and got an in-line filter. I might do the same thing and will also try removing the two tank filters to see if I can clean them out. Haven't had a good day to work on it yet. Did you go with an paper or bronze in-line filter? My understanding it the paper will most likely filter better but require replacing/cleaning more often as it can clog up easier.


UPDATE: I've done several things and the problem seems to have cleared up. I didn't bother testing between each thing so I'm not exactly sure which one fixed her up. I did the following:
- I removed the smog stuff including the CA canister and separator that are specific to California bikes
- I cleaned the gas tank, the two internal filters in the tank, and the tank's breath hose and drain hose
- I cleaned the carburetor and the little screen filter at the carburetor fuel inlet (haven't bothered with installing the inline filter yet)
- I adjusted the float level as it was a little low when testing with the "clear drain hose" method

Since the cleaning/adjustment, I haven't had the bike stop on me yet. I think adjusting the float level and cleaning out the pilot jet probably helped the most. I also had a lot of gas tank pressure before I removed the California smog stuff so that may have helped a fair bit as well. If the canister or separator get fouled up, it can apparently cause problems and the service manual recommends replacing them. The CA canister is not cheap though so I went with the removal option.

I still have a few problems to work out but the bike is at least in an enjoyable state now and no longer leaves me on the side of the road.