Hey guys. I've got a '99 F4, and at idle i get a low pitched rythmic thud coming from somewhere in the engine. I can't hear it at speed, but even if it was happening at speed, I don't think I could hear anything but the pipe anyway.

Also, if I understand the other threads properly, this noise doesn't necessarily mean that the CCT has to be replaced, but it's just an annoying sound. Is this correct? What would I look for as a sign that the CCT is bad? Just the bike running like crap or not at all? If the CCT goes out in the middle of a ride, am I going to end up in a hospital bed or worse?

Thanks

 

on my F2, my CCT was starting to go bad. it only made a loudish sound when first started up (cold) then it would go away..i dont really remember hearing it at speeds tho..

 

i just had mine adjusted.(i have the APE manual CCT) and it rattled when first started up then once warmed up it was noticeable around 5k, and on deccel..

 

yep, CCT lifter makes noise around 5K - higher, and sounds like a spring unraveling inside the engine.

 

i dont think there has ever been a case where a noisy cct has damaged an engine. its just a poor design from honda, not something breaking. the tip just vibrates. people ride on their stock, rattling ccts for years with no problems, but they just put up with the noise. you can get a manual cct or a new stock one to hopefully fix it for a while. both options have their pros and cons, so you have to decide which route you want to take. but dont worry, nothing bad will happen if you ride around with a noisy cct.
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The cct keeps your timing chain in place. In theory if it got very loose you could jump timing, or even spin the chain. If you are at any kind of rpm's when this happens you could have valves hit pistons, mess up a camshaft, maybe even ruin a head.Honda and all the other major bike makers put a hydrolic or adjustable tensioner on the bike for a reason. Too tight a chain causes problems, and too loose a chain can cause problems. Although i would not worry, as long as you "dont think" anything has ever happened.

 

The reason for the hydraulic tensioners being put on from the factory are because while labled a, "superbike," it's intended use is on the streets. In other words, not a racing application.

You're not going to find many CCT's going bad on a bike that's been *****-footed. To understand it, understand how it works.

At higher RPM's, the CCT (OEM style), backs off the cam chain as the chain becomes more and more tensile. This allows for higher engine revs without damaging the chain. As you back off the throttle, the tensioner is supposed to come back to the chain and add more tension. This whole process essentially keeps the chainat atheoretically consistent tensile strength.

The problem comes when the rider backs off the throttle rapidly at high RPM's (not vehicle speed). When this happens, the OEM CCT simply lacks the design to "snap back" into place as quickly as the engine speed is decellerating. The result is a brief moment or two where the cam chain does not have the required tension and therefore wobbles around inside strongly resembling the sound of a couple of marbles bouncing aroundinside your engine.

This whole process suggests there is a significant amount of freedom of movement inside the engine when really we're talking centimeters. Those precious centimeters are what causes the sound. Potentially, you could break teeth, destroy the chain all kinds of good stuff. However most people that can hear themselves fart will quickly recognize something is amiss and investigate the sound.

I have written up a short how-to before but I'm too lazy to ifnd it. It's a very simple process to swap out the OEM for a manual. One in which it is important to remember we're only talking centimeters here. No big movements. Kinda like backing up a truck with a trailer. Small movements.

And no, the manual CCT isn'tbad at all. Kinda read like someone suggested it above by saying the hydraulic ones were on there for a reason. Like I said, yeah there's a reason... and it's because these aren't racing bikes. However I would say a good amount of the population would be guilty of treating them as such and as a result, they should be installing manual CCT's.

Ask Dick Mann about the OEM style CCT, haha. That was over 30 years ago!!!

 

from what i understand from the research i have done, the noise is caused from the tip of the shaft vibrating in place. i dont think it really gets looser the more you ride on it. if you have an old cct in your hand, you can wiggle the tip of it and see what i mean. its because of the poor 2 piece design that honda uses. yes, i agree that if youre bike was to jump timing then it would mess your motor up pretty bad, but i dont think the rattling tip will cause any skipping.

source of my info: http://cbrworld.net/forums/thread/261176.aspx
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f4 and F4i and newer bikes don't have a hydraulic cctl. it's spring loaded. it doesn't back out, only gets tighter when detects a certain amount of slack. therefore it only gets tighter.

yes the cctl design sucks, too may parts, etc...wear and tear on the hard parts lead to excessive play and a noisy cctl. if the part was known to fail, timing would jump, bike would run like crap, and definitely unsafe to ride...so why no safety recalls? because cctl is still doing it's job, it's just noisy. why no one has yet to report a noisy cctl leading to a catastrophic failure?

i know of 1 instance when APE was too tight, melting chain guides, etc. and plugging up oil passages, starving the motor of oil.
i know of 1 instance when cctl (OEM) failed and bike was just fubard....RC-51.
i know of 1 instance when an F4i, about 500 miles had major engine problems...the person didn't know now what was wrong with the bike or anything, just that dealer "said" cctl caused it all...i really question the dealer on that one.

even if you do the flare mod to the stock cctl, the noise may still come because there's no way of reducing the tolerance where the shaft meets the cctl body once that part is worn out...maybe replace that piece...but that's about it.

 

Sorry if i came out too strong on my previous statement. I certainly didnt mean that if you let it go something will happen, but i thought it was fair to say that something could happen, even though its not common.