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Boy named sue

Xrl puffin blue on deaccelaration

27 posts in this topic

Just wondering if anybody else has experinced this I have an 02 xrl with with 13,000 km on it I drive it hard but change the oil and clean the air filter often it has all of dave's mods done to it and to the best of my knowledge the valves have never been more than half a thou out .It is trailing blue smoke out of the exhaust on deaccelaration no smoke on start up or under hard accelaration If thinking rings but not sure it did however take in a little muddy water at the biggining of this season 8 oil changes later she was sparkly clean inside.Also thinking of putting a hot cam in if I have to tear it down anyways.Any thoughts.

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My friends have honda quads and when they let of the gas they puff out blue smoke and one of them is brand new. So I think your fine. Also the quads are a recon and a rancher, both 4 strokes.

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typically during decel its a high vacuum situation. if there is play in your valve guides or worn seals the vacuum will pull oil into the combustion chamber.

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Does it smoke when you first start it? Let it sit overnight and start it up. Give it some gas to get the revs up. If it smokes then the issue is valve seals. Not usually a must fix item. If you do replace the cam, put some new valve seals on.

Smoke on decel could also be worn valve guides.

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I will have to disagree. The OEM guides are prone to wear if driven hard or at extended higher RPM's (highway speeds). This was also verfied by my dealer (who knows he was not going to get the parts sale or the service work) when I had a similar problem with my 94'. If you were going to do some head work I would recommend Kibble White guides and valves. While you are in there clean up the ports on both sides but don't take too much out as it will hurt the lowend on the "L". Also the tighter guides will extend the service time for adjusting valves.

RH

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I will have to disagree. The OEM guides are prone to wear if driven hard or at extended higher RPM's (highway speeds). This was also verfied by my dealer (who knows he was not going to get the parts sale or the service work) when I had a similar problem with my 94'. If you were going to do some head work I would recommend Kibble White guides and valves. While you are in there clean up the ports on both sides but don't take too much out as it will hurt the lowend on the "L". Also the tighter guides will extend the service time for adjusting valves.

RH

+1

:confused:

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I disagree and agree LOL ... I have yet to change a valve guide one on my 30 plus year old XL's, only seals. Maybe the new ones ain't made as good.

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mine puffs like that too, with the headers off I could see oil residue on the valve stems. 50,000km. I'll replace the guides when its apart regardless.

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mine puffs like that too, with the headers off I could see oil residue on the valve stems. 50,000km. I'll replace the guides when its apart regardless.

At 50,000 kms the valve guides are allowed to be worn out. You might want to replace the valves and get the seats cut at the same time. A complete rebuild. I had to replace the valves in my XR600 and I don't think it had even close to 50,000 kms on it. My guides were fine though.

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I bought mine second hand and it had been ridden hard and put up wet before I got it. I was not surprised to find this when I tore it down. I replaced the cam and rockers because i did not like the wear pattern. The shop said they were within limits, I told him yea not but what happens in a year or 2. I spent the extra $175 on a cam and rockers just for the insurance.

RH

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I bought mine second hand and it had been ridden hard and put up wet before I got it. I was not surprised to find this when I tore it down. I replaced the cam and rockers because i did not like the wear pattern. The shop said they were within limits, I told him yea not but what happens in a year or 2. I spent the extra $175 on a cam and rockers just for the insurance.

RH

you go with stock cam/rockers, or aft. mkt.?

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Ive stripped a fair few XR/XL engines and never had a problem with guides. I find the exhaust valves wear, the valves faces wear but overlal cam wear and rocker wear usually the limiting thing.

Fitting Kibblewhite guides/valves should make no difference to service intervals, you will still need to check valve pocketing and cam wear no matter how good the parts are.

I find my race motors smoke quite bit on start up but settles down once run upto temperature. Think its prob'ly the fairly generous side clearances on the 102.4mm wiseco.

Worth bearing mind that you can get oil pumping down the valve guides on high lift cams, but not generally a problem until you go to the extreme 12mm+ lift cams that megacycle do.

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Could it be oil ring problems. It was stated in the orginal post that there is NO smoke on startup. That would tell me that oil in not leaking into cyclinder overnight....

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Oh great .... worry -worry - I just lapped the valves on my XL250 head (1972) and now worry that they guides are worn - yet the valves slipped in nice and snug. Guess I will find out when I fire it up, oddly though...this same head had little to no wear evident in the cam (aluminum) head bushings. Must have had alot of good oil in it.

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