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Valve problem

Old 07-14-2006, 07:03 PM
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Angry Valve problem

I had one of my CCTs go bad last week and in the process one of my exhaust valves was bent. What exactly do I need to replace now?? Is this something that a weekend gearhead could replace himself or do I need to bring it to a specialty shop and have them put it all back together? Any help would be amazing links pictures whatever you have send them my way. Thanks in advance!!!
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Old 07-14-2006, 07:25 PM
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It depends on how far you've gone with motors before. If you're asking, you probably do not want to.

Have you done a compression test on that cylinder? If you bent a valve, the valve guide could be messed up as well. Either way, you have to take off the head and replace the valve and probably the valve stem seal at least. Replacing the valve guide is also a possibility, not to mention the valve seat could be damaged. Seems like a lot to worry about.

Do you have a service manual? That will tell you all the tools you'd need. I don't have a Chilton, so I don't know if there are cheap substitutes; but if you don't have any of the nine tools they list, it's going to be expensive just to get all the tools.

Have you ever done a valve adjustment before? That is a baseline you may want to go by. If you've done that in one night and thought it was a piece of cake, then maybe you can get this job done in a weekend. If it would be a first for getting your hands dirty underneath a valve cover, it would probably be best that you send it out. I like to think of myself as handy and capable, but if I didn't have almost every one of the tools at my disposal, I wouldn't bother.

Then again, if you have another bike that's a hoot to ride, this would sure be a great learning experience. I recommend enlisting a mechanically inclined buddy as help should you decide to go for it. Whatever happens, good luck!
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Old 07-14-2006, 07:31 PM
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Well I already have the head off and I can see where the valve is bent I know that with the right ammount of time that I could do it but I think that I am just gonna take the advice and send it to a repair shop here by my house. His prices are right and it will work the first time.
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Old 07-15-2006, 09:36 AM
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If one exhaust valve is bent they are for sure both bent. To replace just the valves is a nightmare because one you get eveything setup and the seats machined you'll have to deal with clearances and there won't be enough. You'll have to machine the top of the valve stem until you are close enough with shims.

If you plan to tackle this yourself find a good low mileage head that doesn't need a valve adjustment. The hardest thing to tackle then is timing the cams but if you're pacient you should be able to get it.
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Old 07-15-2006, 11:08 AM
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I have already timed the cam chain and cams that is how I found out the valves were bent.
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Old 07-15-2006, 12:28 PM
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Originally Posted by Speed_Demon
If one exhaust valve is bent they are for sure both bent. To replace just the valves is a nightmare because one you get eveything setup and the seats machined you'll have to deal with clearances and there won't be enough. You'll have to machine the top of the valve stem until you are close enough with shims.

If you plan to tackle this yourself find a good low mileage head that doesn't need a valve adjustment. The hardest thing to tackle then is timing the cams but if you're pacient you should be able to get it.
It's not a lawn mower. Replacing the valves (et al) doesn't require machining the top of the stem.
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Old 07-15-2006, 09:22 PM
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Originally Posted by jschmidt
It's not a lawn mower. Replacing the valves (et al) doesn't require machining the top of the stem.
Have you ever rebuilt an DOHC head? To replace a valve right you need to cut the valve seats and the valve if its used. You will not have enough clearance between the cam and bucket even if you install the smallest shim. Trust me I've been there. Whatever you take off the valve seat and or valve face in machining has to come off the valve stem for proper clearances. I mean you could try doing it and then hoping the really small shims will work but I doubt it and even if it did remember you'll need a place to go for future valve adjustments.
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Old 07-15-2006, 09:32 PM
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Originally Posted by cb21983
I have already timed the cam chain and cams that is how I found out the valves were bent.
Do it yourself then. You can easily spot the bent vlaves by checking the valve clearances. They will be like 1cm when they should be around .02mm. Look on ebay, get yourself a good head and a new gasket and put it back together. Its not recommended but if you're really cheap you could use the tensioner off the replacement head. Remember the front and rear head are different. They look identical but I believe the tensioner is on the wrong side if you pick the wrong head. Good luck!
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Old 07-28-2006, 09:28 PM
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valve replacement

Originally Posted by Speed_Demon
Have you ever rebuilt an DOHC head? To replace a valve right you need to cut the valve seats and the valve if its used. You will not have enough clearance between the cam and bucket even if you install the smallest shim. Trust me I've been there. Whatever you take off the valve seat and or valve face in machining has to come off the valve stem for proper clearances. I mean you could try doing it and then hoping the really small shims will work but I doubt it and even if it did remember you'll need a place to go for future valve adjustments.
have you ever replaced valves in a superhawk before you do not need to cut the stems just lap the new valves in I replaced my rear exhaust valves some time ago on the rear head after my cct broke loose I just lapped the new valves in my clearances were perfect check compression and the bike runs great. know on a high mileage and I mean high and highly abused engines you MAY need to cut the stems but only if you cant get your clearances. Bikes are not all the same as cars and their is no wrong way to replace your valves as long as you have your clearances when you get it all torqued and the valve has a good seal on the seat. dude cutting the seats and stems is a last resort, and if it comes to that the right way is to buy a new head!!
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Old 07-28-2006, 11:47 PM
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what is a CCT and how do i know if it has gone bad??
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Old 07-29-2006, 03:03 AM
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Originally Posted by miken996
have you ever replaced valves in a superhawk before you do not need to cut the stems just lap the new valves in I replaced my rear exhaust valves some time ago on the rear head after my cct broke loose I just lapped the new valves in my clearances were perfect check compression and the bike runs great. know on a high mileage and I mean high and highly abused engines you MAY need to cut the stems but only if you cant get your clearances. Bikes are not all the same as cars and their is no wrong way to replace your valves as long as you have your clearances when you get it all torqued and the valve has a good seal on the seat. dude cutting the seats and stems is a last resort, and if it comes to that the right way is to buy a new head!!
I would say lapping valves into a used and possibly damaged seat is cutting a corner. Are we talking about getting it running as cheaply as possible or doing it right? If your going to spend your precious time tearing the bike apart and spend money on head gasket you may as well do a repair that will yield the longest service life possible. Especially when you are talking about the valvetrain in a motor with a 9.5k redline.

That being said. If you have the time and you want to save money, lapping new valves will probably work and be reliable. In this case a low mileage eBay head seems to be the best bet though.
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Old 07-29-2006, 04:20 AM
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Just because the valves were bent does not mean that valve seats are damaged as well. In my case the valves were bent because when replacing my CCT I released the pressure on the cam chain and allowed the CAMS to come out of time. I turned the motor over with the starter maybe 5 revolutions before I knew exactly what I had done. The valves were tweaked but the seats were unharmed. My local bike shop even said there was no need to machine the seats after they looked at the head. New valves, valve seals and a little bit of $$ for labor and my bike is back together and running great.
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Old 07-29-2006, 10:38 AM
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Haha! You bent your valves while you were replacing your tensioner. Now thats ironic.

I think honda wants $50 per valve and for sure will want $40 - $60 an hour for labor. Get yourself a low milage head from ebay, check the clearances and throw it in. On of my buddies found 4k heads and the guy threw anything in the motor he wanted for $100 (98 Superhawk). All that guy wanted was the case covers to sell. If you need to do any adjustments I would suggest a 9.48mm hot cams shim kit (over 100 shims, 3 of each size 120 to 350, .05mm incriments). You can find them on ebay for $75 with shipping rather than spending $5+ per shim at honda. Good luck.
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Old 07-29-2006, 07:21 PM
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valve damage

Originally Posted by Speed_Demon
I would say lapping valves into a used and possibly damaged seat is cutting a corner. Are we talking about getting it running as cheaply as possible or doing it right? If your going to spend your precious time tearing the bike apart and spend money on head gasket you may as well do a repair that will yield the longest service life possible. Especially when you are talking about the valvetrain in a motor with a 9.5k redline.

That being said. If you have the time and you want to save money, lapping new valves will probably work and be reliable. In this case a low mileage eBay head seems to be the best bet though.
I totally agree with you if the seats are damaged but I would venture to say 99% of the time the seats are not damaged and you should leave them alone they are the hardest part of the head and takes alot of force to damage them. another option would be to have the damaged seat cut out and a new seat installed and cut to specs but finding someone competent to do that I believe would be difficult.
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