Dear sir; my 250xr 1995 is hard staring on an daily basis.the carb has been cieaned and checked all jets are stock.ihave tryed different pilot jets with no results; just get plip on opening up gas? pete.
An expert who has achieved level 3 by getting 1000 points
An expert that got 20 achievements.
An expert that got 10 achievements.
An expert that got 5 achievements.
Re: hard starting;has stock jets.
Install a new stock spark plug after getting the compression checked and the valve clearances checked. Assuming good compression, use the choke when cold starting but don't flood the engine. Clean the air filter? If, when running, the bike dies when the throttle is turned, remove the jet needle from the throat of the carb and move the clip on the needle down one, possibly two, notches. This will richen the low end mix.
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
Black smoke indicates a too rich fuel mixture. Be sure the air cleaner is clean. Install a new spark plug. Check what size the main jet is. The prior owner may have installed a larger than stock main jet. There will be a number stamped on the side of the jet. Call the dealer and ask what the stock jet number is for your bike and then tell them what you have. Go back to stock.
Install a new cylinder and re-jet the carb back to stock. If the ported cylinder has been bored you will need new piston and rings also. I would re-jet the carb first and see if that change will suffice in the fuel economy area. Changing out the cylinder etc., is costly. Check the front and rear sprockets. If they are not the stock sprockets, ( 14 tooth and 48 tooth ), replace with stock. Please rate my answer.
You need to re-jet your carburetors to compensate for the increased air flow. The bike is starving for fuel because the carburetors are jetted for the air box. Typically you would need to change the pilot jet and adjust the a/f mixture on the carbs. You didn't specify if your carbs were stock or modified so I am including a link for you that can guide you through the process. In the meantime, if your bike is a daily rider, put the stock air boxback on until you can re-jet the carburetor. Here is the link: http://www.dynoman.net/carb/pdf/mikRS-access.pdf
did you try the fuel petcock on the bottom of the tank? If not, pull it out and check the fuel filter on the top of it. If it won't start because of no fuel, that maybe the problem or it could just be a vaccum leak. Check the tubes for leaks or just replace them, they are cheap. If it isn't starting because it floods out from to much fuel, then it might just need a new petcock. How did the diaphrams on the top end of the carb look?
Usually this indicates a lean fuel/ait mixture. Remove the main jet and note the number stamped on it. Go to your dealer and give him the VIN from the frame. From that number he can tell you exactly what year, model and engine size you have. Now ask them to check the stock main jet number. If different than what is in the bike then get the stock jet. Check the manifold between the carb and cylinder. If any rubber seals or hoses are hard, then replace them. This will eliminate air leaks on the intake leaning the mix. The image below is for a 1995 model. On the carb main jet and nozzle (in red), make sure they are very clean inside and out.
Scatter gun approach > thoughts to check out > > >
Clean and dry the air filter? Go back to a stock main jet, at least to check things out? Are "O" ring seals on the main jet going bad?Partial internal collapse in exhaust (remove exhaust pipe & do a quick run down the alley), Install a new stock NGK spark plug, Be sure battery connections are clean and tight, Be sure intake manifold and carb are good and tight.
Personally, I would go back to the stock jets, stock air cleaner and stock exhaust then get the carbs balanced and synchronized. Aftermarket stuff is usually flashy and sounds like a good thing.. Sometimes it is but sometimes it ain't. Sometimes one add-on interferes with another. Put some faith in the guys who designed the engine in the first place. Go back to stock equipment and settings and see if the problem disappears.
Keep the cool aftermarket product stickers on the bike. No one will ever know.
Please rate my solution a " FixYa " if all goes well. Thanks!