Running Rich

[Highc5555]

intake air temp sensor

[JagLite]

Well that's a rotten deal. I'm sorry I don't have an answer for you since I haven't heard of that before.
I would suggest figuring out what the previous owner changed when he added the straight through exhaust.
Usually when reducing the exhaust restriction an engine will run a bit lean so a small increase in fuel will be  beneficial and sometimes very necessary to not overheat the engine.
Usually that is.

The Drifter 1500 is limited by the very restrictive intake design so changing or modifying the exhaust doesn't require adding fuel. If we modify the intake by installing a filter on the right side where the dummy air cleaner cover hides the sensors for the fuel injection system the bike may require modifying the fuel flow. This is done by adding a Power Commander or similar electronic fuel mapping device, OR, by modifying the stock temperature sensor to trick the FI system into adding fuel.

Your engine may have been been modified one way or the other.
Other members who are a lot smarter than I am will hopefully offer more/better help.

Of course it could be that one of the FI sensors has gone bad and needs replacing,
The shop manual should have instructions on how to test the sensors (air temp, air flow, etc.) to see if they are all in spec.

I hope you are able to get it figured out quickly, or if you take it to a shop, they can figure it out quickly.

[therathouse]

Hi folks, thanks for the letting me in. I have had an 800 previously and now own a 99 1500 with straight through fishtails. Apologies if this has been raised before, I looked but may have missed it.  The issue I have
is the bike running really rich, black soot on the I side of my fishtails and eventually fouls the plugs on its own. Both pipes are affected so I don't suspect an injector issue, no power commander fitted and (as far as I know) everything else stock. The bike sat for about two years prior to my picking it up.
Does anyone have any experience of this issue, or have a cure, or an inning of what the issue might be?
Advice or assistance gratefully received