Just got my FXFBS tuned (TMan 124"...complete top end) with a PowerVision & Target Tune. Tuner is saying when coasting to stop, clutch pulled or in neutral, bike revs approx 2000 rpms (fluctuates between 2000, 1800, 1500, etc., sporadically). It will idle down once it comes to a complete stop. Bike is not throwing any codes. I've searched on here and this subject leads to either, wrapped, cracked, or leaking manifold, bad clutch switch, or a bad twist grip sensor.

My tuner contacted Dynojet and their response is they know about the issue but do not have a fix yet. WTF?! The rep said something about the adjustments for this is "somewhere in the background" of the tune and they "do not yet have access to". The rep further stated "when/if" they get access, "it will probably be changed in MOST" of the tunes they provide...as "MANY folks" have contacted them about this same issue.

I'm picking up the bike today. It is 3.5 hrs away. Once I get it home, I will check those things listed above. Not sure how to determine a bad twist grip sensor...any ideas?

Also, anyone else dealing with this? Just pisses me off...I got a sh*tload of money in this bike and because of my health I have to sell. This will make it difficult!!!!!

 

This issue just reared it's ugly head out of nowhere since taking the bike out this season......2018 Fat Bob 114. I purchased my PV from FuelMoto and contacted Jamie about this same issue. He emailed me a new tune to try out yesterday. Will know more this weekend.

I replaced my levers with Oberon adjustable units. I will be reinstalling my OEM levers before riding again. Something tells me this might be my issue.

 

Did you guys swap out your throttle bodies? Stock is known to crack or melt since the moco decided to go with a plastic backing

 

Funny, I have Oberon levers too...I'll have to check the clutch lever out.

I just got back last night with the bike...will be heading out to the garage after my coffee. Please let me know if that new tune works...but according to Dynojet gurus, there is no fix yet.

 

Thanks for the input, I'll check my throttle body, but what I researched on here was the plastic manifolds warping. I have the SE 64mm throttle body and aluminum (polished) manifold.

 

I asked Jamie the same thing. Jamie's response was this: I changed some tables related to idle in the background. We are a primary source of technical support for Power Vision and of the thousands of M8 bikes we have in the field I have only seen a few M8 bikes do this, and in each case it's simply a tuning fix.

 

Well damn! Good thing I bought my PV&TT from Fuel Moto! I'll be hitting Jaime up after I check and eliminate any other possible issues. Thanks for the info.

Also, if it does fix it...Jamie might want to hit up the gurus at Dynoject because they do not know or have the fix yet.

 

Pretty sure my issue is the substantial intake leak the tuner/shop grossly missed and I just found. I'll let you know how it goes.

Thanks for the info

 

My bike does this as well but only jumps to about 1300 as I'm coming to a stop and settles back down once I'm fully stopped. It has always done it so I didn't think much of it. Seems to do it more now though. Can you possibly share how you went about finding the intake leak? Sorry if this is a dumb question, I still have a lot to learn on diagnosis of issues.

 

I'm always willing to help...not a dumb question at all. I'm not a guru mechanic...I learn as I go too. But, I'll try and help.

First...do you have a stock throttle body and manifold? If you do, one of the biggest complaints I seen/heard is the plastic manifold warps from engine heat...could crack or just not seat right. Harley now sells an aluminum stock size replacement manifold for M8's. Also, I read about a couple stock throttle bodies cracking, but not positive on how...probably over tightening. Some have used a soaping water solution or a non chlorinated cleaner to spray around the seals of the manifold and such to search for leaks...if you do this, use it "lightly".

In my case...I just got a flashlight and started looking at all the seals to make sure things were seated correctly. I found that my front breather bolt was not tight and left an 1/8" gap between backplate and TB. Then I noticed that the manifold did not look seated completely...and sure enough, I could wiggle the TB and manifold. Thats were I stopped...pissed that the shop didn't find this very basic leak.

The leak might be the issue...but might not. There is a known "background idle issue"...Dynojet does not know a fix, but Jamie does know how to fix it. True story. Very few bikes are affected...9 times out of 10 it's a different issue causing the erratic idle.