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strange noises from motor!!!

14 posts · Started by yorks phil · 30 Jul 2011

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can anyone throw any light on a noise coming from me 990?

it only does it under load, any gear, around 3.5 to 4000 as soon as its over 4k it stops..... it gets quieter too the nearer 4k it gets to... seems like left side of motor, nearly had a do with a hedge while trying to locate the noise!!!

it sounds almost like that grounchy clicky only half a gear smashing teeth off noise when a gear is missed. or could be described as that noise when it grates going into first when it don't go straight in......???

it's an SM 990 (6000miles)

and i've checked the front sprocket which was finger tight!!! only tab washer keeping it on.sorted that, still got same noise.
been out on SD and it pulls real clean from right down at 2000 with none of this noise or anything remotely similar.
read loads of posts and can't find anything remotely similar anywhere, so now at a loss. hydraulic cam chain tensioner???
any ideas folks?
I could hear something similar, chain slack and no oil in it, every time you open the throttle on low revs and high gears.
After servicing the chain it got better.
cian27.......


drive chain slack or cam chain? and it has just been serviced , or should i say book stamped and receipt for oil etc.......!!!

Sorry for tha mate...they're both chains...

I'm talking about the drive chain...that if it's been serviced by a dealer you shoud consider retightening and spraying some chainwax.
It's not common if you have only around 6000miles, but maybe you have a tight spot on your chain.
Lift the rear wheel and check for the tightest spot, tight it to 7mm.

Cam chain on the rear cyl is on the right side, front cyl to the left side, so if you could locate where the noise comes from...

If it's been serviced recently, take it back and explain the situation!
Chain tension fine, no tight spots.

had front hydraulic cam tensioner out and it's fine... similar sort of noise on start up till the little thing filled with oil...
only thing i can think of on the left is altenator, anyone know of any issues with em coming loose????

I had a CBR with similar issues, most CBRs had a faulty CCT .
It only gave me problems when engine was cold, when revd up to 3,5k sounded like ratchet...so I let it warm up first.
It had no longer warranty...so I didn't bother in changeing it, and dealer convinced me that a new OEM CCT will bring the same problem.
Once the odo got to 45K...the cam chain started to sound just like you say, on heavy load you could hear a whistle...it was hard to hear where it came from, confussed with wind...secondary chain...untill I heard it clearly from the rght side.
Changed CCT and sounded like a new bike...there's no vsual wear, just the spring looses strainght, and you can't see that.
A 'slappy' sounding front cylinder cam chain at circa 4k rpm caused by a partially blocked oil jet was the first symptom/sign of my water pump seal/bearing failure.
hmmm the old water pump business....

generator is all ok, just checked. might just do water pump job for peace of mind!!

as for CCT's both feel the same tension wise on their springs....
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The usual small gradual loss of coolant was the only other obvious initial symptom - oil colour etc seemed OK.
Hello again guys, been out for quite a while and have recently started riding the bike again...
As yorks phil explains, mine does exactly the same noise. I try not to ride it under 4000k.
It's not getting worse...but I'm starting to get worried, a part from that, oil consumption is massive and I'm afraid that it might have something to do with it.
Yorks Phil, did you get yours sorted???

Cheers guys!!
If you think its the cam chain tensioners then measure them. Its all explained in the Workshop manual. Very easy to do.
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I guess you could do it to be extra safe but just removing the cam chain tensioner should be fine without the cylinder locked off. I can't see the chain jumping teeth while you check the measurement. Always best to follow workshop manuel though.
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