Help with strange whining sound (MT125)
2015 Yamaha MT-125
After passing my CBT earlier this year, I recently bought a new (to me) bike. I have only been riding for a little over 2 months on it, and have always had my earplugs in for every ride that I've done.
On Friday, I forgot my earplugs at work but decided to ride home anyway. Thanks to this error however, I noticed my MT125 making a strange whining sound which is not audible with my plugs in. It sounds like it could be coming from the right hand side of the bike, and I was wondering if anyone knew what this could be?
I've watched a few other YT videos of the MT125, but they mostly all have aftermarket exhausts on so I can't tell if they have the same sound. It's almost like the sound a car makes when it goes too fast in reverse.
A picture paints a thousand words, but a video tells the whole story - so I've done a quick edit of my ride back so you can hear it.
A few things to note:
- Speed/accel appear to be unaffected.
- It sometimes struggles to downshift from 3rd to 2nd, but only 1/20 times.
- The whine is related to engine speed, not road speed.
- Chain does not have any tight spots, and has 30mm play (within OEM spec).
- Bike had been serviced before I bought it and had plenty of oil. I did an oil change last night as a precaution and the oil was still golden with no flakes/metal in it. Whine was still present after oil change.
- The whine is loudest at 1:14 when the bike noise is bouncing off the other cars.
- At 0:40, I tried to give it extra revs to see if the whine would come into play earlier (it didn't) but I tried again on a hill start at 1:23 and it did.
- It does not whine when revving at idle, or when the bike is on F+R stands and in gear. It only seems to happen when there is a load on the engine.
Any help would be greatly appreciated.
u/AuricomFazr — 23 days ago