Clymer specs on valve adjustment??

[lstewart]

I am about to do a valve adjustment on a '95 xr250 so I've been searching the forums for tips. I keep finding the valve clearences suggested on the forums are .004in. intake and .005in. exhaust, but the Clymer manual I have lists the specs at .002in. intake and .003in. exhaust. But, the supplement in the back of the book lists .001in. - .003in. intake and .002in. - .004in. exhaust. I'm thoroughly confused! I have found some "typos" in the Clymer manual. So, I'm wondering if the specs are wrong or if everyone just seems to find a looser adjustment better. Loose can't hurt but the motor does chatter a bit as is. Can anyone tell me what the service manual says, and would the clearences for a '95 xr250r be different from the '96 since that's when some changes were made. A buddy has the service manual for his '96xr250r and they were different but I don't remember what they were.

My smallest feeler is a .004in - .006in, so I'm hoping .004in. for the intake is accurate.

[HonMudDog]

Stewart,

I used to have a 90 XR250r and I'm looking at owners manual right now (don't ask why I still have this filed away,probably for just this question) it states what I remember adjusting them to,

intake .05mm or .002in

exhaust .08mm or .003in .

Me thinks that in ? 96 ? they increased this clearance to .004 or .005 in . My 97 650L calls for 4 & 5 , same as 01 xr400 is.

I paid honda shop to adjust valves for me once on my 250 after I got approx.500 miles on it. They(tech)seemed to prefer/set a looser clearance, (I opened it back up and checked when I got it home to see what they set/did) I believe this is because the valves always tend to tighten up as time on engine & progressive valve seat wear/use allows the valve stem to rise slightly as seat/valve surfaces wear.

I adjust my 650 and 400 valves to the point that I can barely get/shove a .006 gauge under an exhaust that calls for .005 , and can barely cram the .005 under the intake that needs to be .004 . So I just use/need three feeler gauges when I do an adjustment/check.

I had this xr250 get really noisy after going thru a stock piston re-ring and then later a bore and new piston, because timing chain and sprockets wear stretched/worn beyond service limits. Just as a drive chain stretches and sprocket teeth wear/curve & start to puddle the metal(rear sprkt). It started clattering/making distinct noise like the valves were loose/needing tightening. The timing chain,cam and engine sprockets, need to be replaced after a good run/time on the motor. Usually recommended w/every rebuild/re-ring or enough time accumulated.

adjust them too tight, you slightly advance valve timing(valve opens too soon)

leave too loose you retard valve timing(valve is late on opening)

Hope this helps you out, ?

JP

[lstewart]

I guess the Clymer supplement is right at .003in. intake and .004in. exhaust erring on the loose side then.

I just bought the bike and my guess is the valves haven't been done in a while. So if they tighten up over time, but they are chattering now, they must still be loose, or...the timing chain and engine sprockets need to be replaced. Sounds like I may just need to ride it as is the rest of the season and do a complete re-build this winter.

Thanks for the help!