Okay, John, you've just gone way past my knowledge base. Can you explain what a high VE engine is and roughly how one is achieved? I can tell you, if your looking at it, it's obvious, someone put a lot of money into this bike and the motor may have been proffesionaly built. It has a brutal, thunderous sound to it; an "on purpose" sound if you get my meaning. Far more than just your average loud or straight pipes...I just don't know the history.

That being said, I don't want to grenade the motor because I have it set too lean. But, as I said, if I richen up the main, it falls on it's face; yet, at the same time drop even one size in jets and it starts showing signs of obvious starvation.

It feels like I'm missing something. I can't wrap my head around it, no matter what was done to that engine, there's no way I would need an intermediate that big is there? If I go back and check again for vacume leaks, other than spraying, what do you suggest?

 

IMO no you wouldn't need an intermediate that big. My 80" wasn't a monster but with head work ( ported/shaved ) CCR around 9:1 , and Andrews EV57. My E was jetted at 73 main 31 inter. Have you pulled and read the plugs at all?

Edit* Has there been an external air bleed installed? Do you have the S&S backing plate with no blockage to the air circuit?

 

But have you checked to see if someone else has messed with it...it should be .040. Also what pipes are you running, reading on s&s website they make it sound like having 2" drag pipes on an EVO would pretty much make the carb impossible to tune.

 

I haven't checked the air bleed Tom. I just assumed it was correct. Again, the bike acts and runs like it finally has the correct jetting, but everything I think I know tells me something's off and that seems to be the general opinion on this forum too. The question is, where to look? Could the VOES somehow be causing the vacuum leak John was talking abut?

I think the pipes are the old V&H stagered shots. They look just like the ones I had back in '88. There looks to be some sort of restricter way up by the bend and they exhibit no signs of being straight drag pipes, no decel poping, none of the dirty tinniness in the sound, just a nice clean, thump-thump-boom. They should be making plenty of pressure to tune the carb.

 

Go back to close to what it should be for a starting point? specially Air bleed .040
interm .295, and 72 main. If that don't get ya close there is probably other problems.

 

Yeah, I can't run .295 a .31 is the smallest I can run and still maintain some kind of drivability and even then, it's a little too lean. With a 72 I'll foul the plugs. I've been chasing this issue for a year, believe me, I've been over it and over it.

 

FWIW I just found out that the brass bar that supports the butterfly is a wear item and you can get an air leak were it comes through the carb body.

I forget the name of the bar though.

 

Bushings in the carb body to support the butterfly shaft are a wear item in all carbs and even throttle bodies, I suppose, although one does not hear of issues with them as much.

It's sounding like there's something else wrong with that carb. I think a PHONE CALL to S&S tech support is in order. Nobody answers email. Too much spam.

 

This is probably the problem...too much cam for the engine...most common mistake of engine building...may have to peek at the cam and see what you have.

 

So where does that leave me? There could an issue with the carb somewhere and Tom makes a good point too. Could the cam be too radical? I guess I have to start with a phone call to S&S. I'll let you all know what they say. Then after I have a conversation with S&S, maybe I'll pull that cam and have a look at it, or maybe I should do that first...

The most imediate question is do y'all think I have enough fuel to prevent it from destroying itself? The supply from the main jet builds ontop of the intermediate. So, with 34 and 66 is there enough fuel to safely ride in the interim? The plug color looks right on. What do y'all think?