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Riddle me this: Intake valves way out of spec

Old 02-26-2013, 08:09 PM
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The ended up bein just over .25mm out... so around a whole .01" out of the center of spec.
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Old 02-26-2013, 08:27 PM
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Emissions tests....and I thought CA was bad.

You won't just destroy parts but I would keep an eye on things and keep track of the valve lash to see if it continues to change.
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Old 02-27-2013, 04:06 AM
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Yeah gotta support the home team Maricopa County, Arizona; the only county in the U.S. who is defending us from the dangers of motorcycle pollution!

I'll check often. It's not hard to pop a valve cover off, and I'm almost certain that just shimming won't actually "fix" the problem, just the symptoms. If I pull a head again, though, I'm going to want to upgrade something, and I'll need some expendable cash that I don't have budgeted at the moment.
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Old 02-27-2013, 12:58 PM
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It's pretty much guranteed it's just the valve faces wearing for what ever reason. I can gurantee it's not a cam. If it was something galling you'd hear it and it'd lock the cams up and you'd have a lot more damage and runability problems.

Yes shimming is a bandaid but it gets you back on the road for now. If it continues to wear and need adjustments then you'll know you'll need to be pulling the head and replace the valves. And it gives you time to prepare yourself for the cost, labor of doing the job.

I'd give your mechanic a call right away to let him know and see what the likelyhood of him warranting it is.
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Old 02-27-2013, 04:49 PM
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While some can guarantee that specific parts can no way be damaged without seeing them, I find that hard to do but I guess I'm just old school.

When asked what possible could cause the problem, I'll give you a list of things that could cause what you have experienced.

To eliminate components, without checking them for no other reason then to rule it out as part of the diagnostic process is poor troubleshooting.

So yeah it is probably the valves recessing into the head but as this is not the only possibility, I would check all the possible causes before checking things that require engine dis-assembly.

Carry on and argue among yourselves if you feel the need.
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Old 02-27-2013, 05:24 PM
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If there's one thing this bike has demonstrated to me, it's to not rule out anything until I've checked it at least twice... It started it's life as a craigslist gem and I look forward to idly checking cam specs only to find out I've got ones meant for the Varadero for some weird reason, lol!
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Old 02-28-2013, 07:53 PM
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Checked cams, they were right in spec. Bolted it together, compression is right back up in the 150 range. She purrsssss.

So it was the valves all along. Now to throw some 45 pilots in and run to emissions. Then I'll have to figure out what to do about these wearing valves. It's not over but it's good to know at least the general vicinity of what's wrong.

Moral of the story is to check compression way sooner in the diagnosis.
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Old 03-01-2013, 08:14 AM
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Very strange. I cant quite picture how it got so badly F'd that the valves would sink themselves into the seats that fast, unless they were reground through the hardfacing.

I have a set of stock '00 VTR cams that I took out of my engine when I built it. They have ~5k total miles on them. They've been stored in a Moriwaki cam box on the shelf since 2003.
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Old 03-01-2013, 08:45 AM
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So what was the solution for now? you just reshimmed the valves and it's good? until it continues to wear and you're back to square one?
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Old 03-01-2013, 08:54 AM
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Originally Posted by 98VTRrider View Post
So what was the solution for now? you just reshimmed the valves and it's good? until it continues to wear and you're back to square one?
Exactly. With the exception of two things: 1) I now know generally what is happening. Not why yet, but what. 2) I can get the bike emission tested which is due this month and not have to deal with more DMV crap than necessary with registration. At least while it's running. I'll pull the covers in a month or so and re-asses my plan of action.
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Old 03-01-2013, 04:06 PM
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Glad to hear you got it running well again. At least for now. Though you know you still have some work ahead of you in getting the problem actually fixed. But you've given yourself some time to get it fixed.

Originally Posted by 8541Hawk View Post
While some can guarantee that specific parts can no way be damaged without seeing them, I find that hard to do but I guess I'm just old school.

To eliminate components, without checking them for no other reason then to rule it out as part of the diagnostic process is poor troubleshooting.
It's not poor troubleshooting, it's about listening to the symptoms and having the experience and knowledge of how all the components work to make an accurate diognosis.
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