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Valve Adjustment Question

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Quick question on valve adjustment...

I am familiar with how to shim the valves, have a copy of the Excel calculator that someone put together etc...

I have no problem making the necessary adjustments when there is actually a measurable clearance. However, does anyone have any tips on where to start when you can't get a feeler gauge under the cam lobe? I'd like to avoid the trial & error approach and assembling/disassembling the valve train 15 times to get it dialed in...

Thanks!

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What size shim is in there now?

It really doesn't matter, you won't get but a few hours, if that, after you shim. Its valve time if they zeroed

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Guessing a tight intake valve? No clearance is due to the valve seats are worn and the valve is cupping.... common problem on hondas. Its time for you to remove the head and have the seats cut and installl some stainless valves

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What I would do is: lets say there's a 2.05 shim in there. Drop down to a 1.85 which should give you some clearance. May even have more than what you need, but at least it's measurable. Just understand that the valve is shot and there's no bandade for it. Once the valve starts to move, your pretty much done. There's a protective coating on the valve the wears off over time and eventually the valve starts to mushroom where the valve hits the seat. Unfortunately, the valve seats also suffer when this occures so you need to have the seats cut of the new valves will not seal correctly. If you re-shim the valves, don't be surprised if you only get a few hrs max before the bike won't start.

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Thanks guys. It's the right intake valve...as usual.

Anyone know WHY the Honda's have right intake valve problems? Why do they wear unevenly?

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Thanks guys. It's the right intake valve...as usual.

Anyone know WHY the Honda's have right intake valve problems? Why do they wear unevenly?

most will say improper air filter maintenance or a poorly sealed air box, im not too sure about this, but one theory that i tend to lean toward is that the unicam design has more modes of resonant frequency (vibration) then a typical OHC. this is primarily due to the added reciprocation and impact of the cam follower that opens your exhaust valves. the amplitude of these vibrations are higher around the right intake valve. again its just a theory but i can see the logic in it.

i have also heard that honda has remedied this problem in 2010 and on...

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There's some logic to what you are saying, but think about all the Honda's that are out there with this issue. After re-sealig the air box right eliminates about 75% of them. I gave a set of intake valves to a friend that was desparate to ride and had no money. The valves had 116 hrs on them when I pulled them out of my kids 08. They were perfect and never adjusted them before I took them out. I stuck them in his head and he's put another 80 hrs on them and they haven't moved. When his valves zero's out, we re-sealed the air box. Because he didn't have the money to have the seats cut, I used an old SS valve and just lapped the seats with it. This was totally against everything I believe in, but the guy was a friend and it was a long shot. The vavles sealed. I dumped rubbing alcohol down the intake ports and nothing leaked past. He's still riding it. Your theory has a lot of merit to it, but I think that the air box may have more to it than what you might think.

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There's some logic to what you are saying, but think about all the Honda's that are out there with this issue. After re-sealig the air box right eliminates about 75% of them. I gave a set of intake valves to a friend that was desparate to ride and had no money. The valves had 116 hrs on them when I pulled them out of my kids 08. They were perfect and never adjusted them before I took them out. I stuck them in his head and he's put another 80 hrs on them and they haven't moved. When his valves zero's out, we re-sealed the air box. Because he didn't have the money to have the seats cut, I used an old SS valve and just lapped the seats with it. This was totally against everything I believe in, but the guy was a friend and it was a long shot. The vavles sealed. I dumped rubbing alcohol down the intake ports and nothing leaked past. He's still riding it. Your theory has a lot of merit to it, but I think that the air box may have more to it than what you might think.

thanks, but its not my theory, i read it on crfsonly a while back and it explains why the right intake always seems to tighten up first. my own theory using your explanation would be this: the intake boot is slightly angle toward the right intake, so i would imagine that any dirt would have more of a tendency to enter the right hand valve cavity, deteriorating it well before the left hand side. this would be my theory, but like all theories its just a guess. 116hrs? that's unbelievable! the most i got out of my crfs was about 20 hrs before having to re-shim (even after the airboot reseal... guess i didnt do it right).

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yea my right intake zeroed out too so i reshimmed the valves made sure it started well and now it sits forsale waiting for the next poor sucker to buy it. I am done with four strokes!!!!

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yea my right intake zeroed out too so i reshimmed the valves made sure it started well and now it sits forsale waiting for the next poor sucker to buy it. I am done with four strokes!!!!

Your great guy!

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i got scammed by a guy like you! ended up having to do a full engine rebuild, top and bottom end. haha

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thanks, but its not my theory, i read it on crfsonly a while back and it explains why the right intake always seems to tighten up first. my own theory using your explanation would be this: the intake boot is slightly angle toward the right intake, so i would imagine that any dirt would have more of a tendency to enter the right hand valve cavity, deteriorating it well before the left hand side. this would be my theory, but like all theories its just a guess. 116hrs? that's unbelievable! the most i got out of my crfs was about 20 hrs before having to re-shim (even after the airboot reseal... guess i didnt do it right).

Well I'm also on that site once in a while along with another and everyone is entitled to their opinion, I read them all the time. I've found mainly where the filter sits on the cage inside the air box, where that plastic sits in the air box is where the dirt is getting in. It does have to do with the air boot and head flow like William said. I wouldn't BS you about the 116 hrs. The only reason I pulled them was beacuse I was doing the 3rd crank replacement and felt they had been in there long enough. Put stainless valves in there and the problem is solved for the most part. I haven't had one in here that had a stainless valve zero out. But then wait, the exhaust guides will eventually go, but that's another issue these bikes have. I've said it a ton of times, these are not the old xr's, so take it for what it's worth. I'm certainly not just feeding you shit, I'm not that guy! I love to read all the theories that come around, I can just go by what I see. I have 2 in here right now that I'm working on so I can only speak from experience and what I see. Go figure, I have 1 with a right intake valve issue. Has close to 100 hrs on it. Air box was never done. Some were sealed good, some weren't! Roll the dice!

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Well I'm also on that site once in a while along with another and everyone is entitled to their opinion, I read them all the time. I've found mainly where the filter sits on the cage inside the air box, where that plastic sits in the air box is where the dirt is getting in. It does have to do with the air boot and head flow like William said. I wouldn't BS you about the 116 hrs. The only reason I pulled them was beacuse I was doing the 3rd crank replacement and felt they had been in there long enough. Put stainless valves in there and the problem is solved for the most part. I haven't had one in here that had a stainless valve zero out. But then wait, the exhaust guides will eventually go, but that's another issue these bikes have. I've said it a ton of times, these are not the old xr's, so take it for what it's worth. I'm certainly not just feeding you shit, I'm not that guy! I love to read all the theories that come around, I can just go by what I see. I have 2 in here right now that I'm working on so I can only speak from experience and what I see. Go figure, I have 1 with a right intake valve issue. Has close to 100 hrs on it. Air box was never done. Some were sealed good, some weren't! Roll the dice!

whoaa wait a minute, im not trying to call you out on anything. like i said these are theories that are out there and i like to speculate myself. i personally tried these mods and i got a lot less time then you did on oem Ti valves (also speaking from experience). that doesn't mean that it cant be remedied. the SS valves IMO are the way to go, and my 08 lasted twice as long as my 04, but the valve life was still below par compared to other bikes. the point is that honda has apparently gotten better life in the valve-train with newer models

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yeah i understand thats sucks man... my clutch basket is pretty much pooched too lol i just filed the notches down and shes good as new lol

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whoaa wait a minute, im not trying to call you out on anything. like i said these are theories that are out there and i like to speculate myself. i personally tried these mods and i got a lot less time then you did on oem Ti valves (also speaking from experience). that doesn't mean that it cant be remedied. the SS valves IMO are the way to go, and my 08 lasted twice as long as my 04, but the valve life was still below par compared to other bikes. the point is that honda has apparently gotten better life in the valve-train with newer models

No issues my friend! All the information we throw back and forth usually gets more folks involved and more theories. Someone has to right eventually! I like the SS valves also, but when you take a high level rider and swap the valves from Ti to SS, they complain that the bike doesn't rev quick enough. Most never know the difference, but the guy working on it does!

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No issues my friend! All the information we throw back and forth usually gets more folks involved and more theories. Someone has to right eventually! I like the SS valves also, but when you take a high level rider and swap the valves from Ti to SS, they complain that the bike doesn't rev quick enough. Most never know the difference, but the guy working on it does!

yes, ive heard about that too, i really couldn't feel any difference :lol: but at the time when i still had the bike, my level of riding didn't use the full potential of the motor. maybe if i tried it now id notice... and i do agree that discussions on the forum can provide good information to riders, its just sometimes people get out of hand on the net

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yes, ive heard about that too, i really couldn't feel any difference :lol: but at the time when i still had the bike, my level of riding didn't use the full potential of the motor. maybe if i tried it now id notice... and i do agree that discussions on the forum can provide good information to riders, its just sometimes people get out of hand on the net

Check out the CRF450r threads. People just waiting to bash each other.

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