Newbies Forum

i weigh 150 and im 5'8"  

ya thats my friends height...i think you should go with the 07 unless you are the type that has to have the newest of everything which i cant say i blame u cuz im the same way but either way u are getting a brand new bike. if i were u since u already have all the gear i would by the 07 and put a pipe and header on it and get it rejetted wtih the extra 1000 u hav  

i was thinking about buying the fmf powerbomb or 4.1 (not sure which one yet) but do you need to re-jet the bike when you get a new pipe? how do you know what to jet it to?  

When I added the FMF PowerCore 4.1 slip on to my 2007 YZ250F, all it took was an adjustment to the fuel screw - no other jetting changes, and it runs like a peach!  
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how often do you have to check/tighten the valves on your 07? Is it difficult?  

I checked my valves after break-in (one hour on the motor) and they were fine.  I plan to check them again at the 15 hour mark, but I don't have that many hours on this bike yet. I'm going to check mine every 15 hours, but if you run the engine hard, you may want to check them more frequently than that.  Checking them isn't hard, and we have a sticky on this forum about how to do it (with pics even!) - do a search and you will find it.  
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I saw the thread about doing valves. It looks complicated though. How hard is it compaired to replacing the top end in a 2 stroke?  

That, my friend, is the whole argument many of us are making about why we ride and prefer 2-strokes.

I can rebuild a 2-stroke topend with 3 sockets, a torque wrench, 1 beer, a feeler guage, a bucket, a funnel, $100 in parts, and about an hour of my time.

Checking the valves is not necessarily hard, it's just time consuming.  It takes me about 3 hours to do it right.  You need the same tools, except I would recommend a whole 6-pack, and possiby a cam-chain tensioner holder, some zip-ties, and don't even think about tryining it without a Service Manual. Then, once you have it apart, you need to measure with a feeler guage and do the math to figure out what shims you need to buy. If you are lucky, everyting is in spec - if not, then the process get's even longer.. agian, not really hard, just time consuming.

Also - do your bike a favor.. once you've changed by 3 shim sizes, have your valves replaced and seats recut.  Also, replace your cam chain every 40 hours - they are prone to stretching, and a chain failure is NOT a good thing to have happen.  
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What tools do you need to check and adjust the valves? i know you need feeler and shims but how do you use them to find out if they need to be tightened?  

you use a feeler guage to measure the clearance.  If it's tight, you install different sized shims to bring the clearance back into spec.  So for tools, you need a torque wrench, a set of socket wrenches, a feeler guage set, and whatever shims you determine from measuring your existing clearance. These are not 'adjustable' valves - you have to replace the shims (using the different sizes available from your dealer) to bring the clearances up to spec.  Does that help?  
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ya a little. so you use the feeler gauge to see how much clearance there is. then if the clearance isnt in spec you have to use different shims to make it the correct clearance? in the thread that shows the valve replacment does it show the shims and how to put them in/use them?  

You got it right on!

I'm not sure if there is a pic in that thread showing the shims, but it's in your owners manual - complete with pics and instructions.  If you don't have a manual, you will need to get one before even trying to do a valve job - you really can't do it right without one.  
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well im buying it from a dealership so im assuming ill get the manual. how does the feeler gauge show how much clearance there is...you just stick it in there and it reads the distance?  

the guages come in different thicknesses, and they are marked with their sizes.  You try different ones (they come in a set) until you find one that just barely fits.  DON'T FORCE IT!! It should slip in the space, but not require effort to do so. To check, use the next bigger size guage - it should fit easily.. once you find the one that fits right (guage, that is), just read the number printed on it - that will be the measurement.  
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skipkh:
That, my friend, is the whole argument many of us are making about why we ride and prefer 2-strokes.

I can rebuild a 2-stroke topend with 3 sockets, a torque wrench, 1 beer, a feeler guage, a bucket, a funnel, $100 in parts, and about an hour of my time.

Checking the valves is not necessarily hard, it's just time consuming.  It takes me about 3 hours to do it right.  You need the same tools, except I would recommend a whole 6-pack, and possiby a cam-chain tensioner holder, some zip-ties, and don't even think about tryining it without a Service Manual. Then, once you have it apart, you need to measure with a feeler guage and do the math to figure out what shims you need to buy. If you are lucky, everyting is in spec - if not, then the process get's even longer.. agian, not really hard, just time consuming.

Also - do your bike a favor.. once you've changed by 3 shim sizes, have your valves replaced and seats recut.  Also, replace your cam chain every 40 hours - they are prone to stretching, and a chain failure is NOT a good thing to have happen.

For an hours work I would require 2 beers at least.  

Bill H. 2000 CR250R