Hi! I am new to this forum, and also fairly new to motorcycles in general, although I have worked on cars all my life. I have a 1990 CBR600F1, which I bought used with about 23000 miles. About 500 miles or so after I bought it, the bike developed a rattling noise on cold start from about 2500-3000RPM. Below 2500 it is quiet. Above 3500....quiet again! At first i thought it was an exhaust bracket loose or something....but i cannot find anything loose! After reading about all the timing chain tensioner issues on these bikes, I am wondering whether that could be my noise! When the bike warms up...the noise goes away....so I have just been trying to make sure I warm it up a little more before I take off! If it is the hydraulic tensioner that malfunctions to cause this noise, then why does warming it up help? Thinner oil? Does the oil thin out and flow better when it warms up? In theory, this would cause LESS oil pressure! Should I change oil and use THINNER oil....or THICKER oil? 10w-40, 15w50, 5w-40??? I would like to do the oil change, to see if i get the "symptoms" to change....just to make sure it is the CCT before I go ahead and change it! Anyone else ever have a CCT with these symptoms?

 

Camchain - the Hurricanes are famous for it.

 

I have an 89 model, replaced oil at different weight, change cam chain tensioner O. E. part, adjust valve, still making rattle or ticking noise at cold starts at 2 to 3 thousand rpm. When warm no rattle or ticking sound.. My suggestion, if it is running good at normal operating temp. Enjoy it open up the throttle at your favorite twisty roads. These are Carburator Engines not Fuel Injection. Carb. Engine run best at normal operating temp.

 

id say definitly the cam chain tensioner. oem are junk get a manual one. just did mine so nice having a quiet running bike again!! its located on rear of engine in the middle kinda a pain to get to but not too bad. just two bolts and a gasket. tighten the manual one finger tight as far as it will let you and back it off 1/4 turn or so and your set for the rest of the bikes life! oh yea they are on ebay for 45 bucks

 

The oem tensioner is not junk, the real problem is that the cam chain stretches with age as Shadow mentioned previously. Once the chain stretches far enough the oem tensioner cannot take up all the slack in the chain since it is maxed out and you get a rattle, even with a brand new oe tensioner. The reason the manual tensioner gets rid of the rattle is because it can be adjusted tighter. Basically a band-aid covering up the real problem which is a worn out cam chain.

It is a pretty big job to replace the cam chain, so if you're only interested in getting rid of the noise the manual tensioner might be for you. Just be aware that it's not fixing the real issue which is probably the cam chain itself.

 

Is this only true with older hurricanes? I see many comments on here, (and across the internet) of people who have replaced their tensioners with another OEM tensioner...and that silenced their noise! If the OEM tensioner was unable to tension far enough to silence a stretched chain....then how would ANOTHER OEM tensioner fix the problem? Is the chain stretch problem mostly on pre-1991 bikes, or is that still a problem on newer models? Also, is the CCT problem worse on certain years than others?

 

I replaced my tensioner with an OEM part and it's almost silent except for about around 2000-2500 rpm when cold. I was referring to the aftermarket manual tensioner mentioned above that's basically a screw not a hydraulic tensioner like the OE one. With the aftermarket piece you can screw it in farther than the OE tensioner is able to compensate for, which is why it makes the rattle stop on badly stretched chains. I prefer the OE hydraulic unit over the manual one though, it is a better design.

I have 50,000 miles on the original cam chain on my bike, but have replaced the tensioner 2x. The chain is probably not in need of replacement, but they do commonly become a bit noisy on the Hurricanes for whatever reason. I would try replacing the tensioner and changing the oil & see what happens from there. I use 10w40 in mine.