How long has the power drop happened? Many ks or just a couple of full tanks of petrol?

 

Thank you very much for your reply. The power loss has been happening for around 800–1,000 km. I’m sorry I can’t give you the exact number, but my riding is sometimes light and doesn’t push the bike to 6th gear or high speeds. That means the issue may have been happening for longer before I actually noticed it. However, the bike still runs normally, except for not being able to reach higher speeds.

 

For 37 years I've owned BMW motorcycles that tracked servicing by on-board computer. The only computer-induced performance throttling I've seen was limiting rpms during the break-in period. Removing those limits requires a BMW service computer, but that's not applicable to you because you are long past your break-in period.

How long after you had the 10K service performed did the problem begin?

Performance and rpms are normal in gears 1 through 5?

 

Thank you very much for your reply. After the maintenance with my mechanic (outside BMW) at 9,800 km, the bike was running fine. Later, I noticed the issue around 12,000 km. At that point, I went back to my mechanic to check what was going on. He changed the coolant, air filter, cleaned the spark plug, and checked the fuel system. Everything came out fine. After that, I tested the bike again and it improved in some ways, but now the temperature sensor gets triggered when riding at high rpm and high speeds (6th gear).

Regarding your second question, yes, gears 1 through 5 work fine, it keeps the power and in 5th gear it reaches normal speeds (around 125 km/h), maybe with a bit more effort. But as soon as I shift into 6th gear, the speed and rpm gradually drop. For example: in 5th gear I can reach 122 km/h at over 7,000 rpm, but when shifting into 6th gear the speed gradually decreases to around 115 km/h or less, and the rpm drop to about 6,000 rpm.

I’ll try to make a video to show this more clearly. Thanks again for your reply.

 

RPM and power loss only in 6th gear, though you also say 5th is normal...with a bit more effort.
Did your mechanic take the bike for a test ride? Did he experience what you are describing?

 

Yes, exactly as you mentioned. My reference point is that in the past the bike felt more powerful, both in rpm and in top speed.


As for the test ride by my mechanic, he did take the bike out and noticed the same issue, but he hasn’t been able to identify the cause. He has already disassembled parts of the bike — we thought it might be the air filter, low coolant, or the radiator. We adjusted all of that, and we also cleaned the sensors in case there was any problem with communication to the computer. Everything seems to be in good condition.

 

Sorry, but I think you've checked everything accessible to a non-BMW shop and it's time to get it to a BMW dealer. Without that, we're just guessing.

 

I think you’re right, I’ve already gone through all the possibilities that can be handled outside of BMW. I’ll go to another city where BMW service is available. If I get any updates on this, I’ll share what happened in case it can help someone else.

Thank you for taking the time to answer my questions, your replies have been really valuable. Greetings from Colombia.