Ok, so here's the deal. This will be a long post, bear with me but feel free to flame!

Over the father's day weekend, I happened to get in some '11 Wide Glide bars that I bought off a forum member (thanks aplineman!) and I needed to do my 20,000 mile service. I also wanted to adjust my fork stem bearings due to slop and the Fat Bob shuddering that is so famous.

Anyway, in the course of pulling everything off, I find out that my throttle cable adjusters are seized. Ok, I free up the idle cable no problem but the throttle cable stripped out. Now I have to replace them, which worked out because I needed the longer ones anyway (I kept the 6" pull back risers too). So, I go out and buy some Barnett black vinyl throttle/idle cables of stock '10-11 FXDWG length. When I reassemble everything, I of course put some graphite on the bar for the throttle sleeve, and I go to adjust my cables.

Now, I've been adjusting throttle and idle cables for a lot of years, and I don't remember the last time I actually read the book on the procedures. Here's what I did, the same thing I always do. Spin the grip to wide open and adjust the throttle cable until the throttle on the manifold just hits the stop. Release the grip and tighten the jamnut. Then I adjusted the idle cable until the metal hit the spring in the retainer on the manifold. Pretty standard stuff. Tighten the jamnut. Afterwards, roll the throttle a few times and make sure it isn't binding, it goes through full rotation, hitting both idle and WOT stops but doesn't have an excessive amount of motion left before the throttle sleeve bottoms out in the hand control housing. Everything checked out great.

Finished up what I needed to do and went out for a test spin. On the test ride, I thought to myself "Wow, this thing seems a little more responsive and a little quicker." But then I figured, nah, I only changed bars and cables. I didn't do any mods to the motor, it's still stock.

Next morning I ride to work on the highway. I-4 in Central Florida, 80MPH in spots. Let me tell you, off the line starts are amazingly fast, no sluggishness. Rolling on the throttle at speed doesn't result in pinging like it used too, even now when it's hotter than a bull's ***** outside!

Now get this, 6th gear is actually usable! It doesn't bog down below 70, heck this morning just to test I rolled on from 60 to 80 with no problems in 6th. I'm sure if I had just banged it to WOT I could have made it ping, but rolling the throttle on gradually, the bike worked like a carbed EVO.

So I started to wonder what could account for the change in riding performance. Beforehand, I was like everyone else. I wanted to do a 30 tooth pulley because of the off the line performance. 6th speed was useless below about 75 and the bike would ping anytime I rolled on the throttle in traffic trying to make quick lane changes, acceleration moves, etc...

I pulled out my manual and my wife's EVO manual and guess what? There is a difference in the procedures, and here is where my theory comes in to play. The new procedures for EFI bikes add a last step to the throttle cable adjustment. Once you hit the stop on the manifold, it tells you to release the grip then tighten the cable 1/2 to 1 turn more. This step does not exist on a carb bike, once you hit the stop, you're good. So why do it on EFI? Let's think about it...

 

On an EFI bike, you're not making mechanical changes to a fuel delivery system. You're changing resistance on, essentially, a rheostat which sends an electrical signal to the ECM. The ECM then determines the amount of fuel to send to the cylinders, based on throttle position.

However, by tightening the cable that extra 1/2 to 1 turn, I believe we're not sending the proper signal to the ECM and I think the MoCo is doing it on purpose to make the bikes run lean. Think about it, we're making the cable shorter, so the rheostat spins faster, but not as far and will never actually hit full throttle.

Now, I have no way of testing my theory. But my seat of the pants result is that my bike's off the line performance is vastly improved. I have no sluggishness in 1st, 2nd or 3rd during acceleration and the only time my bike has pinged over the last week has been when I've intentionally banged it to WOT at extremely low RPM to induce it, just to make sure it still would.

 

Oh yeah, it should be noted that my Fat Bob is basically stock. I am running XIEDs, stock exhaust and stock air cleaner. I did punch a hole in the exhaust disc for better sound, but that's the only mod and doesn't really affect performance (Plus that was done almost on day one since bringing it home in '09).

The only mods I've done have been for rider comfort to this point, since I commute on this bike more than anything else.

 

And your point is what?

 

1/2 turn to 1 turn should not have a significant effect in the throttle/idle cable adjustments one way or the other ... perhaps there was something in either the graphite lubrication of the grip or maybe something to do with the throttle position sensor (was something gummed up) ...? Could it be psychosomatic ... feels different, huh ...?

No real way of knowing, it seems ...

... but, I don't see what could have realistically made a noticeable difference ....

If you figure it out, bottle it and sell it ...!

R/
'Chop

 

My basic point is just that if the throttle position sensor (rheostat) is turning more degrees than it should for a given amount of actual throttle input at the grip, then the ECM is constantly trying to play catch up. Which is what some of us have concluded is the cause of the pinging. It's a result of the bike momentarily running too lean while the ECM tries to catch up to the throttle input and supply enough gas to the chambers.

Now, if you actually synchronize grip input to sensor input, it's possible that the ECM actually has the capability in stock form of keeping up. But for whatever reason, the MoCo seems to have us deliberately throwing the sensor out of whack by a small amount. Believe me, 1/2 to 1 turn on the adjust doesn't sound like much on a cable, but when you're talking angles of rotation that it represents to the sensor it could be making an impact.

Is there anyone else out there with a stock trim bike who wants to try and duplicate my results? All it takes is adjusting the throttle and idle cables according to carb spec and not adding that last 1/2 to 1 turn at the end on the throttle side. I'm just curious if anyone else will see the same results.

Believe me, it's not that it feels different and I'm not imagining things. The bike is performing different. Granted, there's always the chance that in removing and reinstalling the air cleaner assembly I eliminated an air leak that I didn't know I had, but I didn't replace any of the gaskets. Also, if I did have an air leak previously and now it is fixed, I'd expect to see a difference in fuel mileage. It's still the same.

 

Changed my mind. I'll just sit back and see where the theory goes on this thread.

 

I thought I was the only guy who knew this. Did it on my Lowrider last year accidentally. Major noticable difference. I don't know why and don't care. The bike runs way better and it feels like my hand is connected to the fuel injectors. No lag, no slop.

 

Thank You! So I'm not the only one at least. Now, if I remember correctly the 06 Dynas came with the six speed tranny, but they had the primary gearing of the EVOs and 5 speed Twin Cams. Is that right?

Can anyone with an 07 and later confirm my sanity as well?

 

The primary gearing is the same on '06 and '07. The final drive is lower on the '06, smaller back pulley.