Triumph Rat Motorcycle Forums banner
  • Hey everyone! Enter your ride HERE to be a part of this month's Bike of the Month Challenge!
1 - 10 of 10 Posts

·
Registered
Joined
·
311 Posts
Discussion Starter · #1 ·
When I turn the ignition key on my Thruxton before pressing the starter the bike does its little prep routine, then there is a constant light whirring noise from somewhere in the engine.

I don't recall this on my previous Triumphs. I guess it is normal but thought I would check. Thanks
 

·
Registered
Joined
·
3,470 Posts
Don't know for certain but I'll bet it's either the radiator fan or the fuel pump.
 

·
Registered
Joined
·
5 Posts
That noise come from the electric system that control butterfly valve. the noise will change when you twist throttle and you could hear valve moving inside engine carb.
 

·
Registered
Joined
·
1,882 Posts
I don't recall this on my previous Triumphs. I guess it is normal but thought I would check. Thanks
Wow. You're right. That sound did not happen on my '14 or '98 Triumphs - sure, they made sounds resetting the stepper motor and priming the fuel pump but then it stopped once done.

I noticed this new bike keeps making the whirring sound like you said, as long as the key is on. I was a little concerned the first time I heard it, but chocked it up to 'these darn kids... what will they think of next' ; -) After reading this thread, I went to the garage to see if it did change sound with the throttle position and - it does. You can make the darn thing sound like R2-D2 !

I'm pretty sure it's suppose to do that, but I really wonder why. What exactly is going on there?
 

·
Premium Member
Joined
·
20,740 Posts
It could be something to do with a phenomenon called stiction, the static friction present in the sort of moving parts associated with electronic throttles, suspension systems, fluid valves, etc.

An electrical signal, independent of the proper control one (I think it's called an oscillating or "dithering" signal) coming from the twistgrip is constantly injected into the DC motor that controls the butterfly valve and keeps it "exercised" as it were.

As an example we have a machine at work that injects sticky chemicals to be mixed together to produce a packing foam and even at rest there's a constant humming coming from the mixing valves as they're moved to and fro by a tiny amount.
 

·
Premium Member
Joined
·
2,880 Posts
Yep, that's the sound. My XE does the same. Managed to fix the noise by putting on my earplugs and helmet before turning on the ignition :D
 
1 - 10 of 10 Posts
Top