I'm about 500 miles into a SE113 build and having some issues with it.

1. The bike sputters at low RPM.
2. It also "lurches" as I ride down the road....at all speeds...in all gears.
3. I'm getting 25 mpg despite the fact that others have reported 35+ with a similar build (I could care less about MPG, but if it's a sign of something wrong, I'm concerned with it). Steve at GMR thought I should be getting much higher, as well.
4. Black residue from the pipes is building up on my swingarm and on the front side of my chrome suspension cover. This hadn't occurred before.

Steps I've taken:
1. I've checked the map on my Thundermax and confirmed my AFR by calling the Thundermax tech support. Got 13.5ish. Every 100 miles or so I've written my learned fuel adjustments to the base map.
2. I've also done my 500 oil change with synthetic.
3. Ordered T-Man 625 cams and roller rockers at GMR's recommendation. This ought to bring the power band down to mid-range and might fix the sputtering at low RPMs? The SE266E cams don't kick in till like 3500 RPMs or so. Would cams designed to work at full throttle perform poorly and cause sputtering at 2000-3500 RPM?

 

Have you pulled the plugs and checked them? Black soot usually means running very rich. The lurching and sputtering could mean it's getting too much gas, like trying to flood out. But, you don't have a carb.

 

Here are the plugs.

 

My NT displayed some of your characteristics (lurching, pore mileage and NO bottom end power) when I was running V+H BSS with BCT baffles, ran like a POS actually.......swapped out to SE header pipes and mufflers and ran a LOT better.....I would suggest a different exhaust (might be a long shot).

 

This could all be caused by not enough back pressure/wrong pipes?

 

Doubtful.

 

How do the plugs look?

 

I sure hope your troubles fade away.

 

Man that sucks........The cams may not be the problem but they sure would amplify it.

 

Not firmiliar with t-max but 13.5 afr at what throttle position? That afr should be WOT.
I'm running a TTS and any tp less than 70% is in the 14.2 - 14.6 range. Plugs show its running fat and sputtering is a symptom of that! Is the CR where the cam likes it?