Sounds like a rattling camchain

[Crosbie]

Afternoon boys and girls.

Have hit a problem with the CBR 600 (had to happen sooner or later).The last 3 times ive ridden the bike its started to make a very disconcerting noise when i am backed off the throttle and slowing down. Each time it has happened about 15 minutes into being ridden, lasted about 15miles (while riding home) and then stopped and sounded fine. From what i have been able to find on the net the CBR600s have always had an issue with canchain tensioners sticking - so have replaced with a new one hoping this was the solution. Turns out it wasnt as once fitted the bike made the same noise 15 mins into the ride but only lasted for 2 miles and was fine again.

As i said above, the noise occures once the bike is warmed up approx 15 mins and goes after a random time/mileage. The noise sounds as though its coming from the right side of the engine and can only be described as mechanical - something rotating and either rubbing or hitting resistance for a second resulting in a "wering" noise whilest backed off the throttle between 1500 and 4000 revs. The performance does not appear to have been affeted.

Does this sound like a slack cam chain/ knackered guide or something unrelated? Id like to have a bit more of an idea before giving up and taking it to a garage.


Many thanks.
Anthony

[Mitch9128]

If you take the new tensioner out, is it extended past it's service limits? If not, it doesn't sound like the chain, does sound like a fubarred guide from your description. RHS indicates it's not the final drive, if you put it on stands, in gear, does it do it, what happens when you pull in the clutch?

[Crosbie]

When installing the new tensioner there was resistance ie the tensioner retracted into its self i assume after coming into contact with the tension plate against the chain, which like you say would indicate the chain is not overly slack and probably ok. I havent tryed it in gear on the centre stand due to it taking a combination of 15 miles or 15 mins to warm up and start making the noise (plus i need the missus to help get the sodding thing on the centre stand unless there is a slight slope to hand lol) The noise remains regardless of the clutch being in or out. Ill give it a ride at lunch and see if it is more prominent when the bike is leant and if keeping it upright reduces the noise. How would the guide become fubared if the chain is tensioned?

The other puzzle is the fact that each time its has done this the noise has dissapeared between 5 and 20 miles later? :-?

[Mitch9128]

Guides can become brittle and break, i've had it do it in a car. If the noise disappears when warm, suggests timing chain related still. Head off time me thinks.

[Crosbie]

Dam it. ::) I havent got the time to be tinkering myself so a ride to the garage at lunch (and hopefully a noise from the engine for the mechanic to listen to) will result in a booking and likely an unwanted bill by the weekend. :(

[Crosbie]

ooooooooooh. :( New cam chain, guide and tensioner plate plus over 300 squidoolies and she should be working by Friday as long as the parts turn up on time at the garage.
Well at least Ill be riding again although if it stays as cold as it was thismorning i think i may give it a miss. BRRRRRRRR ::)

[Mitch9128]

£300 isn't a bad price tbh.

[Crosbie]

£300 isn't a bad price tbh.


Thats what i thought. If i was doing it my self the parts alone would have come to a little over £160. I was just hoping it would be one item needing replacement. Though if they are all done at the same time its one less thing to worry about for the future! ::)

[Mitch9128]

get the clearances done whilst the head is off.

[Jon_W]

The clearances will have to be done when the head is re-fitted.

[Crosbie]

Sorry, your talking to a newbie here. By clearances are you refering to the pistons :-?

I am very much straped for cash currently being the new year and all, if the garage havent allowed for doing the 'the clearances' what could the cost of this be while the bike is already apart? Could i potentially knacker the pistons/valves if i dont get it done right now?

Thanks.

[Crosbie]

VALVES!!! Just done a bit of reading - was looking at this in the haynes the other night funnily enough. Fortunatelly for me the garage have included for this in their price of £316. Most definatley a good price and saves me a job in the summer.

Fingers crossed she will be running butterysmooth. Just the leaky rad to swap over when the weather starts to warm up a bit and i have some spare time.

Jon W, you were right about the CBR being "challenged". lol

[Jon_W]

If the garage is taking the cylinder head off then it will have to be done as a part of re-fitting the head as a new head gasket will be used and this will be a slightly different thickness to the old one.

If they are not taking the head off you can ask them to check, but it will cost you the time it takes them to do so. I'd just ask for an estimate of the cost.

;D That Honda is "challenged".... there can't be too much more to go wrong on it!!! (Touch wood)

[Scotty]

Jon, once fitted and torqued down a new head gasket will be the same thickness as the previous one. On engines with overhead cams the valve clearances are unaffected by head gasket thickness - no pushrods! ;)

Is this "challenged" Honda Emlyn's old heap? :-? I suppose that some unfortunate soul had to be stitched up for it, and as Emlyn's probably left the country he isn't concerned if the new owner is local... ::)

[Crosbie]

Is this "challenged" Honda Emlyn's old heap? :-? I suppose that some unfortunate soul had to be stitched up for it, and as Emlyn's probably left the country he isn't concerned if the new owner is local... ::)

Indeed... lol. Long story but after some tinkering and basic maintenance that somehow Emlyn had managed to miss but informed the buyer it had all been done the bike has been running ok since August/Last 4k miles. The radiator will be replaced with a better condition one once the warmer weekends come. Again, there has been a clear problem with it for some time but Emlyns answer to leaky things seemed to be silicone sealant.... :-/

Oh he also didn’t divulge the bike was an import and had in fact never been registered in the UK. In fact was almost the complete opposite to what he said when selling....

[Jon_W]

Jon, once fitted and torqued down a new head gasket will be the same thickness as the previous one. On engines with overhead cams the valve clearances are unaffected by head gasket thickness - no pushrods! ;)

True. I should bring myself out of the 60's. Last two engines I did were an A series and the Cub.....

I'd be careful assuming that the head gasket is exactly the same thickness even when torqued down. I've never seen two that are. Your not talking much mind.

[Crosbie]

Right, After having the camchain replaced complete with new guides etc the bike rode fine for the following 3 weeks with no noise. One of the noises is now back (minus the noise of the knackered cam chain), the noise being a wurring noise at low revs either when accelerating gently or backing off the throttle. Typlically between 2-4k revs.

Managed to get some kind of recording this time which is here - https://www.youtube.com/embed/tPEndjWjikI
Any ideas what is going on?
Thanks.

[Crosbie]

After hours of watching utube videos over many days i have found one other video that has the same noise!!!! This video has the noise a bit clearer than mine.

http://www.youtube.com/watch?v=kIME1Epiq5g

[GingerWizard86]

what a pain..

I know a VERY skilled motorbike mechanic in Trowbridge.

He balanced my carbs for me this weekend, made the world of difference to Harriett.

Think he is £45 P/H including parts (dependant on the issue)

Let me know if you what me to put you in contact.

I know its all money but if anyone can tell you what it is, he is the man.