Exhaust turns red hot on my Triumph Boneville: Reasons?

There was no white /black smoke, no misfiring, everything else was normal except this overheating of the exhausts on both cylinders.

BHPian argchoff recently shared this with other enthusiasts.

Its been 10 years owning this wonderful bike. However post covid i have had very little chance to ride as frequently as before due to nature of my profession and being more into cars than bike due to owning two lovely pets that like to travel.

Last 3 years i have only used the bike to go to and from the service center and regularly serviced the bike at authorised Triumph service centre in Pune. Main problem i have faced is having to change the battery. I am on my 4th battery now.

The day I have to leave home for joining ship, i start both my bikes (Triumph Bonneville and RE classic 500) for 5 mins whilst parked and rev the engine to about 4000rpm to charge the battery then disconnect the battery, put insulation tape on the terminal and store till i come back to India. I have been doing this for all these years without any issues. However today when I revved the Bonneville for just 5 minutes both the exhaust pipes just after the exhaust manifold turned red hot.

There was no white /black smoke, no misfiring, everything else was normal except this overheating of the exhausts on both cylinders.

What could have possibly gone wrong??? Is it safe to ride the bike??

Here's what BHPian GTE had to say on the matter:

I wonder if your mufflers are choked with something.

Here's what BHPian Nilesh5417 had to say on the matter:

Bike is running too rich is what i think. A bit of googling says that it could also be coupled with a valve issue causing the unburnt / partially burnt fuel escaping and burning in the exhaust.

To me, it is absolutely unsafe to ride the bike - you could get hurt accidently touching those bend pipes on your legs. For the bike, at the least, it could seize the engine and worst could blow it off! Rebuilds are a pain and darn expensive so please get this looked at some competent FNG or A.S.S.

Read BHPian comments for more insights and information.