The first generation (2016-) Yamaha MT-10 (also known as FZ-10) has a common failure that is not very well documented unless you search online for the specific issue.
My discovery of this issue started when I would come to a stop at the traffic lights and smell a metallic burning smell. I thought my clutch was burning up but no matter how much I adjusted my lever and smelled inside the oil filler hole the smell did not go away, but the smell also did not come from inside the cover itself. Asking on owners forums, many people said it would be my brakes, which turned out not to be the case. The smell appeared to be coming from around the brake side air vent, near my radiator… It wasn’t until I smelt my coolant I realised that the smell was the same. First thing I learned was that the blue coolant in my bike smelt metallic and the green coolant most vehicles run has a much sweeter smell that you’d associate with burning coolant. Now, instead of searching for “MT-10 burning clutch smell” on google I started looking for “MT-10 burning coolant smell” and it was then I came across various forum posts about an oring that fails on the MT-10 and causes coolant to leak!
Many owners DIY the fix but some go as far as removing the front wheel, the radiator, oil cooler and exhaust system off the bike. I am here to tell you that just dropping the oil cooler alone is enough. I did the entire job with my wheels, radiator and exhaust on the bike and did not struggle to access the pipe to replace the oring.
The steps are quite simple and the hardest part of this job is removing the actual oring. If your oring was destroyed anywhere as bad as mine, it’ll be well-baked into the coolant pipe and you need some sort of pick to remove it. I ended up removing my oring by using a long strip of aluminium about 200mm long and 5mm wide. I used the sharp corner of the strip to pick at the oring until it release from the groove and came out.
You can see the coolant pipe you need to remove as below, the black plastic pipe behind the headers that is held on by 3 (2 visible) bolts. First picture credit .
Below, you can see what the oring and pipe looks like if you did remove the pipe. Picture originally from here.
- Drop the oil cooler – very simple.
- Remove the 3 bolts holding the coolant pipe, lots of coolant will come out, so have a drain pan ready. You need about 1.5L of coolant to refill the system after this job.
- Pick out the old oring. Take care not to bend the black pipe too far back while doing this job. I found it easiest entering behind the headers from the clutch lever side of the bike.
- Put the new oring in place. Might require some finesse but if you get the right size oring, it’ll fall right into place and hold itself there nicely. I found the best way is to create a gap between the head and coolant pipe slightly larger than the oring, slide the oring into place the wiggle the coolant pipe to catch the oring and locate it into the groove. Then a final push against head, pull back the pipe to check and you will see it is seated nicely.
I suspect the factory oring may be NBR (Nitrile Rubber) oring as they are only resistant to 120 degrees celsius. Thus the oring burns and hardens to a crisp, thus failing to seal in coolant correctly. It is recommended you either replace the oring with a genuine Yamaha part 93210-27778-00 (this supersedes the old oring) or you can get an HNBR (High Temp Nitrile), FKM or Silicon Oring. In my case I got a silicon oring. The part itself is less than a couple of dollars! The oring that comes out of the bike is roughly 32mm OD, 28mm ID and 2.5mm cross section. In the case of my silicon oring, the only sizes available are in imperial (inches), the shop matched my old oring as close as possible with a 32mm OD 2.5mm cross section oring, it fit perfectly into place and seals nicely. Whatever you do, ensure your new oring is resistant to ethylene glycol (coolant) and can handle temperatures of over 150 degrees celcius.
I dropped the oil cooler and let it sit there for the whole job, just ensure the metal mounting brakes on the bike don’t damage the oil cooler fins.