600RR 07 - camshaft deffect - 600RR.net
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post #1 of 10 (permalink) Old 02-26-2018, 10:20 AM Thread Starter
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600RR 07 - camshaft deffect

Hello guys!
A several months ago I bought 600rr (~25 000 km), and now I decided to check valve clearance on it.
When I opened valve cover, I found some deffects on the input camshaft.
It looks like tiny pits on top of the cam. It is very hard to catch it on camera, I made a photo and higlited it here.
What do you think guys? Can I go on this camshaft, or it is necessary to change it?
There are too much different info in the internet. Some people says, that it is critical, another - there is nothing criminal and bike can go.
Please tell me, if you also met such problem.
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post #2 of 10 (permalink) Old 02-26-2018, 03:30 PM
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How smooth is it? Is the pits deep enough to catch a dental pick or probe? Or is just discoloration?

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post #3 of 10 (permalink) Old 02-26-2018, 05:43 PM
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So, two ways to look at this: the bucket that rides against it is very smooth, no edges to catch. Reality is you can continue to ride as is, although it will get worse over time most likely. Then there is the way I look at it, and the way the factory would: its failing, and needs to be replaced. If you need a couple months to save up, keep riding. If not, replace now while its all apart.

'06 F4i- Yoshimura RS-3C, Racetech springs and valves, Ohlin's rear shock, steel brake lines, 520 conversion. 87k miles and counting.....
'08 600RR- Stripped trackbike. CRG shorty brake lever, goodridge front brake lines
'15 1000RR- weekend toy
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post #4 of 10 (permalink) Old 02-26-2018, 06:58 PM
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If money is not an issue I would replace them. I would only use new cams and I would coat them in moly and change the oil right after break in.

06 CBR 600 RR
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post #5 of 10 (permalink) Old 02-26-2018, 07:49 PM
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I was unaware of any break in on these style camshafts, care to elaborate?

'06 F4i- Yoshimura RS-3C, Racetech springs and valves, Ohlin's rear shock, steel brake lines, 520 conversion. 87k miles and counting.....
'08 600RR- Stripped trackbike. CRG shorty brake lever, goodridge front brake lines
'15 1000RR- weekend toy
------Disclaimer: I can't spell------
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post #6 of 10 (permalink) Old 02-26-2018, 07:55 PM
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Look up camshaft break-in on google. You'll find thousands of results and videos for this procedure. Every manufacturer has one from GM to Honda to Lada. Failure to break the camshaft in properly will result in decreased camshaft life and less lift - either is bad. The higher the valve spring rate, the more critical camshaft break-in becomes although, even a smogger 350 from the late '70's, with no real lift or valve spring pressure, will fail if not broken in correctly.

Point being, when your engine is designed to run to 15,000 RPM (like the bike) then you know the effective valve spring pressure has to be high, really high. The higher the spring pressure, the more critical camshaft break-in becomes, although not limited to that criteria (see smogger example above) it's essential or else your precious lift will decrease very quickly.

This comes back to metallurgy, case hardening techniques etc etc etc. Either way, the majority of camshaft wear will occur on initial start of a new engine, hence the thousands (if not tens of thousands) of articles from various camshaft manufacturers and OE vehicle builders such as GM, Ford, Chrysler et al.

Back in the day (and even today) if you do not break in a camshaft correctly it will likely fail prematurely. In the automotive trade this is very common. I'm sure that modern manufacturing processes reduce the effect (such as billet roller cams) but you will always see the manufacturer proving a very precise break-in procedure that you HAVE to follow on initial engine start. I personally have seen many camshaft failures just on the trade side that were caused by not following the break-in procedure. No kidding, I've seen it first hand probably 10 times or more.

With my last bike I was looking into have custom camshafts made for the market (ie, for sales world-wide). So I researched and spoke directly with camshaft manufacturers for GM, Saab, etc. The mating surface is also very important. In the case of rocker arms, consider this, if your rocker arm is made of steel that is harder then the camshaft - which will wear faster? Even more, which will cause more wear on the other? If you consider this, if you have a harder rocker arm then the camshaft then the rocker arm itself will wear out the camshaft - and quickly. So there is a lot to it. You can be sure that the 'buckets', which are really lifters, on our engine will be manufactured with a very precise hardness that 'matches' or 'mates' to the hardness of the OE camshaft. Typically, the rocker arm or bucket will be a little softer so that they wear (as opposed to the camshaft). After all, you want to maintain the most lift possible and it's easier to change the rocker or bucket.

My guess is that every engine designer/engineer will have their own special recipe for hardness of material between the camshaft and whatever they are using as the rocker or bucket. I doubt anyone will ever find out what the OE recipe is for various manufacturers. When I lashed my valves on the 600 I spec'ed the cams and they were worn at 40k. As I recall, they were close to the OE limit. This can be caused by all sorts of things including low oil or crappy oil. If any or the previous owners did not use synthetic oil then the wear would easily be attributed to that. In my case, I once ran regular motorcycle oil. The engine would use .5 litre in an hour or two. This was a mistake on my part but the point was clear, and I knew this, not running a very good synthetic oil is stupid and causes wear. Only a synthetic can stand up to the shear in induced by the transmission gears or the pressure/temperature between the bucket and the cam at 15,000 RPM.

Sorry about the long-winded reply but most of this is stuff I forgot long ago and it came back to my memory as I thought about this post.

Oh here we go, even more is coming back to me after posting. Because the camshafts and buckets wear in together they 'mate' each other. This is why the OE Honda service manual (or any manual for that matter) will always tell you to keep them together when you strip the engine so that they can go back into the same locations - because they have worn in together. This begs the question, if you want to replace the camshafts do you need to replace anything else? Ask ANY camshaft manufacturer in the world, or an OE company such as GM, and they will always tell you (and in fact insist) that you MUST replace the lifters when you replace the camshaft. This is accurate and it is essential. So in the case of our bikes, if you replace the camshafts you must replace the buckets. This way you have two new surfaces wearing in together as a set. When you do this the majority of the wear will happen in the first 20k which is why Honda says to lash the valves at around that time. Once it's been done it will usually wear less then during the initial 20k as that is where most of the wear occurs - during initial break-in. So if you replace the cams and buckets you will need to re-set the valve clearance during the job and then again at 20k or so. After that, they are broken in, together, as a unit. I would expect longer service intervals after that.

This, of course, begs the question, what about the valve springs? The fact is that as you run around at 15,000 RPM the springs sag. That is to say, the amount of pressure they put on the bucket will decrease. As the pressure decreases the bucket follows less precisely and valve timing gets more slack. Generally this means less RPM, or more precisely, less accurate valve control at higher RPM. So.....if you are replacing your camshafts for some reason, and you are replacing your buckets (for obvious reasons due to camshaft replacement) then it would behoove you to replace the springs at the same time so that you maintain that higher spring pressure that is required to make the bucket follow the cam at higher RPM's.

This is why EVERY camshaft manufacturer will tell you that if your replace the cam you MUST replace the lifters at the same time. If you think about it, you might as well replace the springs. You now have a camshaft with maximum (new) lift and you have buckets with zero wear (again, maximum lift) and yet, pairing that with used springs means increased chances of valvetrain float. That float will damage camshafts and buckets and ultimately reduce your effective lift.

I have experienced this many times when working with one-off camshafts when I was researching different designs for the market. Another place where you can experience this first-hand, and very easily, is with the clutch. When you replace the clutch, replace the springs. Why? Because when they are heat cycled they tend to sag. In my previous business I designed new clutch springs for one particular bike and marketed them world-wide. After designing them I researched the manufacturing process so that I could determine which factory was going to make them for me. The winner was the one that (among other things) heat-cycled the springs and took into account spring sag. So when I ordered up several thousand springs with x rate the springs really did have that rate because when they manufactured them they took into account the sag that occurs during heat-cycling an usage. So if I wanted, let's say, 100 pounds of seat pressure, they manufactured them with, let's say, 110 pounds of seat pressure and then heat-treated them knowing they would loose 10 pounds of pressure due to heat cycling.

At any rate, it's all very simple when you think about the big picture. For max performance, you want maximum designed lift. This means the camshaft must not have excessive wear. Any wear, no matter how small, reduces lift. So wear is the enemy. This brings about the need to break in the camshaft/buckets with the least amount of wear. How do you do that? With really slippery Molybdenum oil. That slippery oil causes the clutch to slip. How do you avoid that? Break the cams and buckets in at higher RPM using that slippery additive. Once done, you replace the engine oil with normal synthetic oil. Why the new springs at the same time? Because they sag over time and will not follow the cam as accurately resulting in less valvetrain control at higher RPM's.

06 CBR 600 RR

Last edited by Arjay67; 02-26-2018 at 09:23 PM.
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post #7 of 10 (permalink) Old 02-26-2018, 09:24 PM
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Hopefully, this will be my last edit. Hopefully no other experience will come to mind after posting. But I'm a weird rider. I can tell right away if the clutch springs are worn when I shift and I can tell after several high-rpm runs if the springs are enabling the buckets to follow the cam. The reason is that I have experience with weak and strong springs and proper or lower lift on the camshaft. It's worth noting that last year was wearing out clutch springs after 1,500 miles. This may seem excessive but it comes back to how Honda engineers spring rates. It was not until I spoke with two crew chiefs from very famous teams (that shall remain anonymous) that they smiled and told me, that's why they replace the clutch springs every second racing weekend or 1,000 miles - whichever comes first. This is what caused me to design new clutch springs for my other bike and then market them world-wide. I designed a spring (and later a clutch assembly) that lasted 15,000 miles under racing conditions. So I'm sensitive to these things and have experience with all of them.

For the record, I went from replacing the clutch roughly 15 times in my 600 down to ONE clutch per year after sourcing the correct spring and then shimming the piss out of it to increase the clamping pressure (I did not want to design a new spring and do a manufacturing run for the CBR 600 RR as I did with the other bike). In any event, clutch spring or valve spring - they are all the same - a spring - and to get accurate performance from that spring, it has to be up to designed rate. The higher the rate, the more wear on the valvetrain but I will stop now....

To the original poster's issue (pitting on the lobes) I cannot say definitively with respect to camshafts but I have seen lots of automotive rotors where pitting occurs in the steel. I learned (the hard way) that pitting gets only worse. It's in the steel. Once you see it, it only gets worse. |Perhaps camshafts, with all their oil, will do better, but I know what happened when I machined pitted rotors during a break job for a customer. I machined out all the pits, and it came back one month later....with more pits (a lot more) and no pads left (due to the pits) and I learned something important that became policy. Whenever a break job came in, and there were pits in the rotor, the policy was (and is) new rotors and new pads. That way, they never come back!

06 CBR 600 RR
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post #8 of 10 (permalink) Old 02-27-2018, 02:14 AM Thread Starter
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Oo looks like this issue is gonna be serious.

Quote:
How smooth is it? Is the pits deep enough to catch a dental pick or probe? Or is just discoloration?

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I can feel it with my finger, so I think it is not discloration
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post #9 of 10 (permalink) Old 02-27-2018, 02:35 AM
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Quote:
Originally Posted by AlexTR2N View Post
Oo looks like this issue is gonna be serious.



I can feel it with my finger, so I think it is not discloration
It's definitely pitting but it also looks very minor. The lobe is still holding it's shape just fine which is what really matters. What you have is not ideal but I don't think it's worth replacing either.

Rather, run it for 10k miles or so (using a heavy duty oil such as Rotella T4) and check it to see if it's gotten worse.

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- Renthal Sprockets (15/45) - DID 520ERV3
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post #10 of 10 (permalink) Old 03-07-2018, 01:58 AM Thread Starter
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Thank you guys! Bought another camshaft,a used one, but in newer conditions and without defects.
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