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Whining noise from engine

920 Views 44 Replies 8 Participants Last post by  Paulcbr
Hi to everyone, am a newbie, I own a 98 bird with 38000 miles on the clock , over the winter I replaced chain and sprockets and new wheel bearings d.i.d chain JT sprockets, and Toyo wheel bearings have done about 150 miles since work and everything was fine but today I noticed a whining noise from engine which appears in each gear when underload if I dethrottle or pull the clutch in the noise goes , it sounds a bit like a race box running straight cut gears. Everything works as it should and gear change is smooth. I would appreciate any help or any ideas before I go balls deep and strip the engine down , the chain is not overtight and I have no play in bearings and bike handles really well I also get vibration through the bars but not excessive
Regards Paul
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1. Worn cam chain tensioner? Sounds like a bucket of bolts at 3000rpm. Unlikely, but check it anyway.
2. Defective chain/sprocket(s)/wheel bearings?
3. Chain out of adjustment. Bike on sidestand, push middle of chain up. Should be 1 1/4" or a little more.
4. Axle nut tight?
5. Front sprocket must be free to move axially on splines 1-2mm or 1/8". Pull cover to check. During installation of sprocket, the splines must be coated with appropriate moly grease or anti seize compound.
6. Check oil level also check for fuel in oil.
7. Gearbox/engine trouble. Lets not go there yet.
Cam chain tensioner is fine engine sounds great , revs freely without any issue and sounds great , wheel bearings are all new and good quality ones, chain and sprockets are new , it is a little on the slack side but is a did chain vxm type , I have ordered a tru tension chain adjuster and laser alignment setter to set the tension and ensure rear sprocket is aligned with front ., Axle nut is tight , front sprocket as just a slight amount of side play and is a JT rubberised one to dampen vibration
Oil level is ok and oil is a nice light brown colour and correct level , so not sure where to go now , have noticed when running in first gear on centre stand that the chain as a slight jump at rear at about 2000 rpm just where it engages with rear sprocket but only does it in gear with engine running with wheel in air , does not do it if manually spun the whine only happens under engine load in any gear and does not change , is the same noise in all gears at any revs above 2000
I have removed sprocket casing on engine and cannot feel any play in final drive bearing I will try to tighten chain a bit then run bikeup to 50 mph with back wheel in air and sprocket casing off to see if I can hear it
You might need the sprocket casing casing on to operate the clutch.
A tight chain is more likely to cause a whine than a slack one.
The engine won't be put under load if the rear wheel is off the ground.
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Thanks for your reply but I cannot think of a way of producing the noise without riding it and when riding the noise appears to come from wherever I stick my head down beside the bike , so how do I chase the sound down to a specific problem
hello welcome.
how long have you owned the bike for?
As Punts put, usualy its a to tight chain that can cause whine, I dont want to come across as saying how to suck eggs,, but when you check chain slack,
1, do it in the tightest spot of the chain bottom run.
2, when you push the chian up on the bottom run of chain, keep an eye on the top run of chain, and as soon as it starts to lift up because you are pushing the bottom on the chain up, stop, its easy to over tighen a chain if you push up on the botom run of chain and not notice the top run lift at the same time, if you did it this way your chain would be to tight if you had also set it to the minimum free play.
oh and 1 last thing, do you have a spacer on your rear shock, to jack it up a bit?
did you check your rear sprocket carrier bearing when you had the back wheel off?
Thanks for replying , the chain is definitely on the loose side and not the tight side , it as no tight spots as only done 200 mile tops , I have been riding bikes for some 43 years and have never come across this noise before but it whines like straight cut gears on a car race transmission any
Ps the carrier bearing is new and the rear as a new yss shock which I adjusted 12mm longer

2 pics of front sprocket as far as I can see it came off with the JT writing on outer edge and are those indentation marks around the rubber part normal as it seems to have the chain resting on it and causing the marks
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Is the chain compatible with the rubber rimmed front sprocket? Most are I think, but not all. The link between pins must be concave enough not to gouge out the rubber part. If this part is too straight then the rubber will be damaged in a few hundred miles causing a strange noise? Maybe.
I have been trying and checking everything to do with rear wheel and chain and sprockets, have just noticed that my rear sprocket carrier as slight lateral movement when rear wheel is tightened up not loose as such but if I grab the rear sprocket I can force it to have lateral movement by using my hand can feel any play but definitely moves about a milimeter or two is this normal
OK, Second look at sprocket pic, I see dents line up with pins. Checked my bike, same dents (bike is apart in big pieces).
Also checked rear carrier. Under hand pressure, couldn't move it in any direction relative to wheel.
Thank you very much fizzy, so at least I have something to look at now , am in middle of changing oil at mo , oil looks clean and nothing on magnetic drain plug so all good there, thanks for checking for me I will remove wheel and check carrier , once again thanks
your rear carrier is mounted in cush rubbers so that explains very slight movement.
I know your chain is new, and there shouldnt be any tight spots yet, but because the sprocket carrier is mounted in cush rubbers, you can still infact have a slighlty tighter bottom chain run when spun.
the other thing is, if you have extended the rear shock past oem length hight, you need to also give more free play in your chain, you probably already know that but i just thought i would type it just incase.

I think if you had the jaws 6mm spacer, jaws states something like 45mm free play, which is more than stock free play, so if your 12mm over in shock length, you need more free play than standerd.
I have done about 5mm on mine with my nitron shock and i settle for 35-45mm free play.
every thing i have put is just in the hope that you can sort this out with out going in to the engine.
I just checked your front sprocket numbers on the jt sprocket site, and it is the right one.
Thanks bikerian , I will set my free play to 45mm I am going to use the tru tension device and a laser to ensure everything is in line and correct play, what I did notice today is even though my chain at present is quite slack I only need to move it about 30 mm before the top run starts to lift
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You might need the sprocket casing casing on to operate the clutch.
A tight chain is more likely to cause a whine than a slack one.
The engine won't be put under load if the rear wheel is off the ground.
For the last point I just put the bike on centerstand & apply rear brake to load it up a bit.
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I will do that , thanks for your reply Banshee
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