My friend has the evil 98 RK with FI that he, actually, has had zero problems...till now.

Over winter he decided to get the motor redone: new stock cam, bearings, gaskets, rings, lifters...you name it. The only change he made was he had the heads swapped with some Screaming Eagle heads he was given. Not sure why he installed those as I doubt it would make much of an improvement (save for easier breathing) without a race tuner, diffrent cam and so on.

Ran fine till a longer trip it started "burping" and flashing a code. When he would twist to accelerate it would burp (looked like too much fuel) and then go. It also ran thru a tank in under 100 miles (normally good for 160 how he drives).

Switched out an O2 sensor and worked fine...for a month. Did it again the other night and has a new code flashing (last time the code was for something unrelated).

To give all the info I can: installed stage 1 (air filter and thunderheader 2 into 1 exaust) and then hand the cpu flashed.

The "mechanic" who worked on his bike on the side said he didn't need to reflash the cpu, change the cams/pistons or basicly anything with the new heads. But, with all the odd goings on, I keep coming back to them being at the heart of the problem.

Any thoughts or recomdations?

JC

PS Oh, he also painted the bike black with green metal flake. Personally, I think the green is the issue here !!

 

Yes, I'd take 80 grit to it then paint it any other color... with a brush...

Seriously, I am totally clueless about anything to do with fuel infection. (intentional typo) But you might glance thru this thread: https://www.hdforums.com/forum/evo-c...injection.html
There was a lot of good info posted. Maybe something in there would be of some benefit...

 

If the mechanic meant that there was no need to install a further flash beyond the one that had been installed, he was probably correct--at least to some degree. btw, why did you put quotes around "mechanic"? I assume that means you think he doesn't know what he's doing.

If what you said about pistons was accurate, those heads will simply up the compression ratio to about 9.5:1. They will make that engine more apt to ping when hot. If these heads were actually SE heads, then adjustable pushrods were also installed, or you'd be hearing bent pushrods by now. 9.5:1 is probably a little too much compression for a stock cam, but it should still run okay--sorta.

Can't think of any reason off the top of my head why anything you've told us would cause a "burp"--unless you are describing a lean sneeze because there is no EFI tuning device installed. Should have at least installed a Power Commander or similar, if he hasn't. If not, get the damn thing to someone who knows something and get one quickly before it burns a valve, melts a piston, scores a cylinder, whatever. MM bikes are much more sensitive to pipes, air cleaner changes, etc., than are later Delphi bikes. And what the hell was the code?

Based on what you've told us so far, it's more likely to that it'd be pinging, hard to start when hot, etc. But--it all depends on what flash and if there's a tuning device or not.

And what's the deal on the O2 sensor? Did you forget to tell us something--like maybe there's some sort of FI auto-tuner with an O2 sensor installed? Or did he change out something else thinking it was an O2 sensor? 1998 bikes did not have an O2 sensor. If there is a self-tuner, that's a whole 'nother problem...possibly having to do with which base map was chosen. Or we could have an install(er) problem...

I assume that "hand the cpu flashed" is a typo, and you meant "had the cpu flashed". What flash? Stock? Stage I? Stage II? It makes a real difference in this case.

Why would someone do all this and then install a stock cam? Hmmm.

 

I was going to ask the same thing, there is no O2 sensor on a 98 Roadking. Could be any number of things. As a burp I take it you mean an intake backfire? If so it is lean. Maybe a TPS gone bad? Maybe a vaccum leak?

 

The front head has a engine temp sensor in it and if I remember the SE heads do not. Without that sensor the ECU will think the bike is colder than it actually is and therefore run way too rich. This would cause the burping at low throttle and the 100 miles to a tank.

 

Cylinder head temp sensor will make it idle fast and cause it to pop especially just off idle. Been there done that and got the t-shirt....

 

Yes, there is a temp sensor in EVO SE heads. No O2 sensors. I agree, there is a lot of bad info here. A flash is not a substitute for a fuel mgmt. device.

And there is nothing evil about a '98 with FI, unless all you see is the tail light.