XR250 Valve Adjustment...I can't figure it out!!!

[Studboy]

I am trying to help my buddy adjust the valves on his 2002 XR250.  We have tried NUMEROUS (8+) times to adjust the valves, every time that we fire up the bike now the valves click like crazy!!! (It sounds like they're loose.)

Here is the procedure:

Turn the crank so the mark on the flywheel "T" lines up with the alignment mark on the cover. (Per Manual instructions.)

Make sure that there is slack in decompressor cable.  (I even unhooked the cable after the 5th try just to make sure.)

Loosen valve adjuster locknut.

Adjust valves to .012 clearance exh. and .010 clearance intake using feeler gauges. (per man. instructions.)   I am measuring the clearance between the sub-rocker arm and the adjusting tappet. 

I even tryed adjusting the valve clearance a little tight to see what it would do, and it didn't help.  :whiner:


The bikes valves were silent before we messed with them, and they had never been adjusted (and the bike probably has 40+ hours on it.)

I am REALLY stumped on this one!

 

[Studboy]

Anybody?!?!? We need to go riding!!!

 

[cr25096er]

are you sure its .012 and .010? sounds loose. Also how tight were thye before you messed w/ it? if they are at what the manual says then ride it.

 

[Studboy]

I'm sure. The exhaust was very tight (about 3 turns on the adjuster before loose.) and the intake was slightly tight.

No way in this world am I going to tell my friend to ride his bike like that... it is clattering like a freight train.

 

[maco]

Stud boy-I don't know the 250 but know the 200.Just letting you kow this is all guess work here.Are you adjusting in mm. or in. ???Don't get confused because the manual will give both measurments.Your sure your at TDC on the COMPRESSION stroke?Gotta adjust stone cold on the valves.My intakeadjustment,on the 200, is 0.002in. or 0.05mm.NOt that this means anything in reference to your 250 but that's a big jump according to your specs.Hope you figure it out and post your findings.Good Luck

 

[70 marlin]

Just make sure both valves are closed and your @ TDC. And use the correct specs! Just one thing to remember goes toward the looser side when adjusting! On my bike it goes tighter as the miles rack up! And yes my XR has a slight rattle sound.

 

[kelseybrent]

.010 and .012 sounds way high. Check the owners manual again. My 2000 XR400 valve stem clearance specs are .005 in. for the exhaust and .004 in. for the intake, and I believe the XR250 is the same.

www.4strokes.com/honda/forums is a good sight for searchable info on the XR line

 

[Gman]

Studboy,

Sounds like you were 180 degrees off when you lined up the "T" mark on the flywheel. You have to be at TDC compression. The "T" could be lined up and the piston is at TDC, but your TDC on the exhaust stroke. Just make sure when the "T" is lined up that the cam lobes are pointing down away from the rockers. This must be the problem especially if you had to loosen the exhaust rocker 3 turns to get play.

 

[Highbeam]

I think the inches vs. metric is the problem. Seems the spec is easily switched.

On my XR400 I had to search hard to find a gauge that thin. You are looking for a paper thin feeler gauge.

Also remember to only turn the crank counterclockwise while lining up the T.

A loose valve is a happy valve but cripes. Mine is a little noisy too. Shouldn't be silent.

 

[Studboy]

OK, thanks you guys. I think that I was measuring wrong, and maybe I was on the exhaust stroke??? I was lining up the "T". What does the "F" mark (right next to the T) mean??? I figured that was the exhaust stroke TDC mark. It only mentions the T in the manual.
We finally got it to work, but I know that they can't be adjusted right because we didn't even use the feeler gauge that time we were just experimenting to see if we could get anything to stop rattling the bike. I am really scared to take it apart again, but, unfortunately I think that it is necessary.

 

[Studboy]

Excuse my extremely long sentence! :)

 

[maco]

Studboy-It sounds like your using the owners manual and don't have the service manual.Get the service manual.The "f" mark is used for engine timing.Adjusting the valves is no big thing when done right.Adjust stone cold.Before you've ridden .pull fo the plugs on the left side of the engine.You can use a socket and an extension to turn the flywheel counter clockwise till the "t" lines up withe the notch.Now your right on or will have to go all the way around again to hit TDC.To know which one is right feel the rocker arm at the valves they should be loose.If you've over done it and there loose now all the time pull your spark plug and have someone put there finger over the plug hole.You'll feel a push of air as the piston comes to the top and the valves are closed, that's TDC.Now adjust with the feeler gauge.You'll have to bend it to slide it between the rocker arm and valve stem.It's a pain but not bad once you do it.Once you have it so the gauge has a little tensin on sliding it ,tighen nut while holding screw with screwdriver so the adjuster doesn't turn too.To check slide in the next higher feeler gauge It shouldn't slide in.It might take a couple of tries till you get it

 

[Studboy]

Thanks maco!
We do have the service manual. ($55!)

 

[maco]

worth every cent.Is it all greasy yet?

 

[Draybob]

Just did the valves on my '01 XR250. Should be .004" for intake and .005" for exhaust.

 

[Studboy]

Thanks guys, I appreciate it. :thumb:

It is greasy, but the manual for my YZ is even better! :)

 

[TexKDX]

I set mine this way:

- Clean bike really well
- pull tank and seat
- clean bike again!
- remove rocker access plugs
- pull the left side access plugs (to see TDC marks and turn crank with I think a 14mm socket)
- find TDC
- verify on compression stroke
- loosen nuts on adjuster
- tighten the inner part with a screwdriver to full contact but not loading up the valve spring
- for the intakes, back off 1/4 turn
- for the exhausts back off 1/3 turn
- tighten up nuts
- button it all back together

Guess what - my valve train clatters, especially when cold. This is with all new valves and springs BTW. I have about 400-500 miles on it since the last valve job and adjustment, so there should be some tightening taking place. I'd rather live with a little clatter than have them get tight and burn.

If you choose to use feelers, then the Motion Pro ones are the way to go for the XR RFVC head design.

If you have the adjustments totally hozed up and are not sure if you are on compression TDC, you can always pull the whole valve cover and check the position of the cam. The cover uses a reusable steel gasket, so you can just slap it back on. Be sure and follow the torque specs in the book for it though because the valve cover is more than just a valve cover on the RFVC engine. It holds the rockers as well.

Leo.

 

[ACGUY]

I thought the clearances were .002 and .003 for XR250s?? I think the clearances you mentioned are excessive. Double check them from the local dealer. I know what the book says, but I do mine red hot, and I take almost all of the gap out of them. That never fails to keep them quiet.

 

[Fastbelly]

I have exactly the same problem on my XR250, it was a little noisey so i did the adjustmnt, now i am sure I had TDC on the exhaust stroke. Inlets were spot on. The left exhaust valve was a little tight, so I did that one. The righ exhaust valve was tight. I had to back it out over three turns to get a feeter in there. So I set that and now it sounds like a massey fergason! It's just that one valve that is making the noise. If it were three turns too tight I cant see how it would have had compression let alone run, and it did run fine before the adjustment. Very strange. I have the road version with the electric start so I donr think it had a decompressor to mess with my adjustments. Any ideas?

Fastbelly

PS I used .1mm and .12mm as per the hand book.

 

[wr_guy]

There are 2 TDC's because it is a 4 stroke.
You have to make sure you are on the compression stroke or you will be adjusting opne valves which is not good.

On the other hand your rockers may be worn and making noise. Wiggle them aroung and see how they feel.

Did the noise get louder after you "adjusted" the valves?

 

[zacatac]

Exhaust Valve adjustment

The XR250R has an automatic decompressor that activates when a dead motor is rotated backwards. If you roll past the "T" mark and come back to it. You will lift the left exhaust valve open about .030. If you adjust it there it will rattle like a baby toy. It took me a while to actually read the directions to figure this out. :bang: Good Luck Zac