20 Most Recent 2007 Yamaha yZ 250 F - Page 4 Questions & Answers

It sounds to me like a part is missing in the clutch assembly. Bear in mind that the first plate installed in the clutch assembly is a cork friction plate, then metal, cork, metal, ect.. You should end up with a cork friction plate. There should be 6 metal plates and 7 cork friction plates. The diagram below is a tri-z 250. Please rate my answer. Thanks!

Its not common with YZ but is very common with not starting the bike for long time - you need to take out the pilot jet and replace it with new, You could clean them but why bother they about $5 each?
If I were you whilst you have the carbi off I would change all the jets to new ones especially as been sitting for a while (not essential but worth while as off already?)

running only with choke on and backfire are classic symptoms of blocked pilot jet or incorrect size pilot jet so chuck new one in and you should be good to go
The pilot jet is the jet closest to the engine when carbi was installed (it has perforated holes on the side)
good luck regards Jamie

Check the diagram below to be sure all parts are present. The nut should be tightened to 43 foot pounds torque. Be sure the lock washer tab holds the nut in place.

Generally these bikes take 1.2 litres which is about a quart of oil

as in any vehicle there will be metal in the oil that you remove from it. how ever it is very small and you don't see it unless you really look for it . if it is an excessive amount the you will most likely be needing some major work on either the upper end (i.e. ring job) or clutch plates. get some militec 1 and add to the gas and crank case to try and slow down the ware. have it checked out by a reputable bike mechanic before you do some really expensive damage.

Is this a us machine, american machines have mixture screws, hidden beneath a metal cap where you would. Normaly find a mixture screw.check you have no air leaks in the exhaust system, air entering the exhaust while shutting off would cause this. Also check if any diaprahms are fitted to the carburettor, most bikes of this nature use a diaphram exhaust fuel valve to stop this type of behaviour, good luck paul

just above the gas tank on the frame.....and fyi it takes 1.2 liters of oil.

Has the clutch cable been re-routed lately? If so, it may be stretched around something and causing the problem. Have you put synthetic or "Special" lubricants in the gearbox? They can cause the clutch to slip. New fiber friction plates would need to be installed. Readjust the cable adjuster at the handlebar. Turn it inward. Has the bike been ridden hard for several years? The friction plates may be just plain worn out. Below is a generic diagram. Not all bikes have an adjuster built into the cable. Please rate my answer. Thanks.

suppose to be .1 to .15 for intake and .17 to .22

Checking valve clearances:
http://www.thumpertalk.com/forum/showthread.php?t=394312

Adjusting valve clearances:
http://www.thumpertalk.com/forum/showthread.php?t=394342

good luck.

If the oil is coming from behind the sprocket,then your seal needs replacing.

Good you should ask, the "coolant" for a motorcycle is not the same as and automotive anti-freeze use the correct coolant for your Yamaha Motorcycle made specifically for motorcycles. If you used automotive type it will quickly destroy the circulating system of your bike

Ihave the 2009, and I believe they are the same...I use amsoil synthetic 10w-40 and replace the filter every three hours. (Race conditions) Yamaha also sells a good semi-synthetic that is good.
With filter, I measure 1160cc's of engine oil to fill it.

do yourself a favor and get a manual, mark all bolts and brackets you remove and place them in order, good luck

300-400 labor plus parts, machining.

Take your carburetor off , disassemble , and shoot carburetor cleaner through the jet and body passageways.

check all fuid levels , hold clutch handle in before cranking, always start in neutral, sit on bike
pull ckoke if it is cold outside all the way out until you here it start or backfire . If it backfires
push choke half way in, leave it there until bike is running well. As it warms up push choke all
the way in before riding , Always make sure your battery, and fuel are full charge and plenty
of gas , and chevron is one of the better fuel for your bike . It has techron in the fuel , and this
keeps system very clean . I hope I have helped ?????????

fork oil 10w

on a xs 850 its left corner of sump you forget to mention the bike model ???

Very easy. You just need the correct size spark plug wrench to undo the plug, turning in a anti - clockwise direction. Remove the plug, and using a wire brush, just give it a light scrub. It is more recomended to replace the spark plug rather than clean it. A new plug should last about 15,000 miles.

I would say no, I have one, and know of two friends of mine that race them also, no clutch issues with ours.