Moto GP Racer
Join Date: Feb 2012
Thanked 396 Times in 376 Posts
Feedback Score: 0 reviews
First off, never warm up sport/supersport bikes that way. 3 minutes at most before beginning to ride because the engine, made from aluminum, will develop hot spots and things like the cylinder head can potentially warp; the exhaust headers face the front so the forward motion (ideally) distributes the heat evenly throughout.
Now on to the issue...to be clear, this is occurring where the collectors are correct?
I'd like to know what other mods the bike has, as well as what service has been done and by whom, but I'm guessing the PAIR delete hasn't...something I recommend not doing but that's a separate topic.
I suppose valves not seating properly could possibly be the culprit, especially if the PAIR delete hasn't been done, but that'll also likely cause compression loss and unless it's nearly even across all cylinders you'll probably notice it and would be posting about that instead lol (a leakdown test may be a good idea anyways on a bike of this age)
I'm leaning towards the fuel map needing adjustment and my advice is to have the bike pro-tuned...they'll use a wideband O2 sensor so if the AFR on your initial run is super high, then that's what's causing your EGT's to get hot enough to cause the melting and a proper tune should do the trick.