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XR200R Valve seals?

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Hey Guys This is my first post on ThumperTalk!

I have a 1990 XR200R that has been difficult to start for a while, generally smokes pretty bad while it warms up, and idles all over the place.  It also burns oil pretty solidly.  I have suspected for awhile that the compression is low so I picked up a compression tester from harbor freight and tested it.  The compression i got when the bike was warmed up was like 80 and then after I put a cap full of oil in the cylinder I got around 90psi.  So my question is whether or not you guys think i should just jump into a valve seal/cylinder rings rebuild? Or Whether or not something else could be wrong.  Also I am a little unsure of how to find a rebuild kit that will work with this bike.  I appreciate your guys's opinions and am excited to hear what you have to say!

 

Thank You!

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Was the compression test with wide open throttle?

Spec compression is 190psiso so 80-90psi is very low.

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With the symptoms you are telling... complete top end, including cam chain and guide. Rebuild 'kits' are easy to find as these bikes were/are so prolific. Might need a bore or not...can't tell till you pull the cyl. Check ring end gap at that time. Might do a little valve grind while apart. If it is smoking as bad as you say...then someone ran the crap out of it. These little motors are tuff and it takes a lot of hard runnin' to do them in.

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On ‎1‎/‎7‎/‎2018 at 9:25 PM, Saggyoldman7 said:

Hey Guys This is my first post on ThumperTalk!

I have a 1990 XR200R that has been difficult to start for a while, generally smokes pretty bad while it warms up, and idles all over the place.  It also burns oil pretty solidly.  I have suspected for awhile that the compression is low so I picked up a compression tester from harbor freight and tested it.  The compression i got when the bike was warmed up was like 80 and then after I put a cap full of oil in the cylinder I got around 90psi.  So my question is whether or not you guys think i should just jump into a valve seal/cylinder rings rebuild? Or Whether or not something else could be wrong.  Also I am a little unsure of how to find a rebuild kit that will work with this bike.  I appreciate your guys's opinions and am excited to hear what you have to say!

 

Thank You!

I've had many XR200R's in my time, very solid platform. You won't go wrong throwing some money at it...do the whole top end and she'll likely run for another 20 years.

Keep in mind that it's 28 years old and will never perform (idle, etc.) like the newer bikes with newer technologies. I always found that a carb upgrade (new one) makes a world of difference on those old XR's. Enjoy!

BTW...welcome aboard TT !

Mossy:ride:

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I Redid the compression test and still got 90 psi with the throttle wide open.  I havent really had time to dive into it further.

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2 hours ago, Saggyoldman7 said:

I Redid the compression test and still got 90 psi with the throttle wide open.  I havent really had time to dive into it further.

 

Have you by chance checked the valve lash to make sure you don't have a tight valve................?

Old School Al

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12 hours ago, Saggyoldman7 said:

I dont even know what a valve lash is old school al. What does that do?

 

It is the clearance between the tappet on the rocker arm and the end of the valve stem.  Not enough clearance holds the valve open a tad causing low compression............common on all these small engines.   Wear of the valve seat and valve face causes this clearance do decrease...........(even faster with dirt getting by air filter).  Adjusting the valves is when you check and set lash to specified clearance.  Before you do anything you need to spend some time reading a shop manual cover to cover and study up a bit!:thumbsup:

Old School Al

Edited by Old School Al
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