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Hard starting 02 WR250f, loose intake valves

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I'm helping a friend with an 02 WR250F that has a whole bunch of problems, but the biggest one has is it's been a real pain to start.

It's currently only starting with the choke on.  Once started and the choke is removed, it will idle just fine.  Doesn't matter if it's hot or cold.  And even with the choke, it takes lots of kicks to get it going.

So, I measured the valves yesterday.  The exhaust valves were around .20mm, (spec's .17mm to .23mm).  But the intake valves were all loose.  All were above .15mm, one was even above .18mm (spec is .10mm to .15mm).

I always thought as valves wore, they got tighter as the valve seat and valve face wear.  Is it normal for valves to get looser too?

PS. In case someone asks, jetting is 178 main, 45 pilot, 72 starter, 2 turns on the pilot screw, OBELQ-4 needle, 60 leak jet, 200 main air, 75 pilot jet, with an O-ring on the AP linkage.  We've had a decent amount of success with this configuration.  Temps typically 50-80F, altitude is 0-3500 feet.

Edited by jamesm113

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Sounds like something is plugged up in the carburetor or maybe old gas. I have an 07 wr and it has gotten hard to warm up. It take way longer to get it warmed up so it will run without the choke on than it use to. Runs great once fully warmed up.

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For sure, loose valves is a bit odd.  The simplest thing would be to get the valves back into spec and go from there.  

Just made double sure you are using the same measurement standard.  i.e. imperial vs metric.  There was a thread on here the other day where a guy mixed up the two.  The book spec will always be in mm but there are loads of feeler gauge sets out there in inches.  

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50 minutes ago, DarrellH3 said:

Sounds like something is plugged up in the carburetor or maybe old gas. I have an 07 wr and it has gotten hard to warm up. It take way longer to get it warmed up so it will run without the choke on than it use to. Runs great once fully warmed up.

We will be an hour or two into our ride, and he'll kill the engine for a few minutes, and can't start it back up without the choke.  It'll be ~60F out, so it's not like the engine is suddenly too cold to idle properly.

41 minutes ago, CDNSXV said:

For sure, loose valves is a bit odd.  The simplest thing would be to get the valves back into spec and go from there.  

For sure, that's my plan.  He's had the bike a few years, and we've never checked the valves, so I figured it was time. I've fixed the carb plenty of times, and that's next on my list of things to mess with after I ensured the valves were in spec.

47 minutes ago, CDNSXV said:

Just made double sure you are using the same measurement standard.  i.e. imperial vs metric.  There was a thread on here the other day where a guy mixed up the two.  The book spec will always be in mm but there are loads of feeler gauge sets out there in inches.  

Yup - I got the bikemaster feeler gauges.  They're not perfect, as they jump from .10mm to .13mm to .15mm to .18mm to .20mm to .23mm to .25mm, but they do have both metric and imperial markings.

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Well, the main jet was a #125.  I think it got mixed up with a CRF230 jet when trying to jet for altitude (should have been a #175) 🤦‍♂️.  Explains the bog it's been experiencing.

Didn't have time to clean the carb, but I have a feeling it's hard starting problems are going to be solved once that's done.

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