08 FLHT. Bought the bike with stock pipes from an 09 RK and an SE intake. Seemed to have had a stage 1 dealer tune on it, fuel mileage is mid to upper 30's typically. Otherwise the engine seems stock.

Fast forward to today. I mounted up a set of V&H slip ons and it suddenly runs pretty cruddy. I haven't yet swapped the old pipes to confirm, but I did just ride it a week ago with no issues. Here's my description of symptoms...

- Idles a bit funny, varies RPM more now than it did before.
- Low RPM is poor quality, have to keep revs around 2k when setting off. Sometimes bucks or pops.
- As soon as I get to 2k and down on decel, it sounds as if only running on 1 jug.
- At exactly 4k and light throttle it misses pretty bad. Go WOT and it clears instantly.

I pulled the plugs and they looks just fine. White ceramic, light gray ground electrodes.

Had an hour or so to kill at a stop during our ride today and had a knee jerk reaction to order a set of ViED's from KnightRider. Will this help?

Any input is welcome, I like to absorb all the info I can from forums.

 

It definitely sounds lean. I don't think anything else is wrong if you didn't change the head pipe in any way at the same time. I think you will be a lot happier in the long run with a real tuner with downloadable maps. Contact Fuelmoto. And you should be getting better mileage than that with only a stage one.

 

I thought I should be getting better mileage as well.

I've cancelled the vied order and have an fp3 on order now. I'll see how that works when I get it, but is it possible to tweak the maps or do you only get to input your parts and get a canned tune?

 

You will like the FP3 if the canned map isn't what you like you can always call v&h they are great. But give it one tank of fuel and if your not happy try a couple of auto tune I did that and it trimmed the map out perfectly. What I did after the first tank was to check the codes on my phone(how cool) and kept gunning auto tune until there was no more codes. My codes were rich front and rear I am running stock 02's

 

Also, have you checked the header/pipe joints for leaks? It only takes one small leak to cause problems...

 

Agree with above, I would also add some Seafoam with fresh tank of good gas, here I use 93 octane. My 2 cents

 

I haven't checked for leaks, never really gave it a thought. I suppose I should get some copper rtv stuff and re do the install.

As for gas, it was fresh already and I got another full tank while we were out. Always 93 around here.

Is there a way to tell if I have a stage 1 dealer tune?

 

Lean or vacume leak. Also make sure the O2 sensors are not reversed. VIED's are not going to help this issue, yet.