Unsafe Throttle Problem
 

I have a 08 Super Dyna Glide Custom. The bike is still stock with 7,000 miles.

My problem is the throttle. The bike runs great with power on, but when I let off the throttle a little bit it's like a shutting the fuel off, though the engine doesn't die. A little throttle on the bike wants to peak out.

I have to use the throttle lock to prevent any unexpected throttle change.

If you can picture going through corners trying to power on and power off, it can be scary. I've almost fell twice because backing off even a little was like putting the brake on unexpectantly.

Now picture what it's like in a higher speed curves when trying to power on and off to control the lean. Yelp! I'm all over the road.

I've taken it to the dealer on several occasions. They say it's normal, but can I test drive any their EFI bikes and I don't have the same problem.

If the road is a little damp and I have to negotiate painted lines in the curve the quick throttle on has caused the back end to come around almost dumping the bike.

If I were riding with a passenger, we'd be bumping helmets constantly. Even at lower speeds it wants to hurky-jerky. I know I will read in some of your post that the 96c.i. is higher RPM engine, but I can't go through corners at 25 miles hour. This problem exist at any speed in any gear - highway speed, turns or curves.

Needless to say bike had had this problem since bought it in 2009 with 6,000 miles.

One of service reps told me I needed to open the exhaust and air breath then dyno tune the bike. Why would Harley put out an unsafe bike? This would be an expensive iffy if it didn't fix it.

The bike is not a fun bike to ride. I'm hoping someone here at the forum can help me.

Take it somewhere else other than a HD dealer.

Might try cleaning the throttle bodies, just be sure to use NOX sensor safe cleaner. Are you feeling any catches while using the throttle? Has the cables been lubed? Of course I would think the dealers would have already done theses.

I don't know much about 'chinery but going to Stage 1 sounds like a ploy to make even more money off you and still not fix the real or imagined problem. Time to go to a reputable independent shop. 1000 miles in 4 years indicates pretty low usage and you sound convinced it is not operator related because you do fine on other injected Harleys (probably frustrating dealer that you did not solve the problem by buying another bike from them). Since it has been looked at I can only assume all the usual possible solutions have been tried...or overlooked. Hence recommending a good Indy shop, they know about 'chinery.

I was on the phone with Pro Vision today. I sent them an email with a description of the problem I was having. I was inquiring if their product would fix this if I did a stage 1 upgrade. The tech's responds was to have the he bike running like it's suppose to be stock then do the stage 1. He thinks remapping the controller with the factory mapping might help, especially if there are any updates to the codes.

If the Harley shop doesn't want to do it, there's an Throttle Speciality shop near me with a dyno tuner.

I'll try to keep everyone posted on this.

Thanks to everyone who responded with their solution.

The first thing I would do is check for an air leak at the throttle body. Just idle the warm bike and spray WD40 at the seals. Listen for any change in RPM. if there is any change you have found your problem. if not I would have it tuned by a reputable shop..It should not run that way!

I took the Dyna back into the dealer in Tacoma and explained to the service rep that we do not know what the previous owner did to the bike i.e. failed Stage 1 install and tried returning it back to stock. The service rep agreed that this could be the problem. When the tech connected my bike to his laptop to remap it, he found out the version I had for the mapping was "Version D". The latest version now is "Version H". It only took the tech about 10 mins to remap it to the latest version with all the updates. Unfortunately, it was raining buckets when I road the bike home, but it did seem to be running like it should. It's definitely not running like it was. I can speed up and slow down with the throttle in any gear with more variable throttling without it been like an on/off switch.

I want to thank everyone who responded from the forum for their experiences on what to try to fix this discrepancy. :-)

Here's the answer everyone been await to read. I know this is a long delay in responding, but that's how my riding summer went this year.

I did put the Dyna-Glide through an extensive test ride with solo rides, long and short, and group rides.

Wow! It was a totally different bike. I can now cruise through parking lots at low speeds without constantly double clutching. I can smoothly accelerate and decelerate from any speed. Acceleration is very strong and fast. I don't have to down shift as much now because it has very good pull when accelerating from a lower RPM. It now rides like a Sportster on steroids.

Another good news is my mileage went from 40 mpg to 52 mpg on the highway. That's a 25% gain.

Any inputs on air filter and exhaust pipes for a Stage 1?

I hope this helps someone who is having the same problem with there throttle response.

This fuel injection on a Harley Irks me a little. I mean, my bikes are carbureted and ther require periodic maintenance, but being in a position where you "Have" to go to the dealer for a map upgrade etc. that leave you a slave to the dealer indefinately. Hopefully the aftermarket will offer a tuner where you can "Map it yourself " and ne done. I suppose they will. It took a few years to get car engines converted to injection. The only downside is that a modern day auto mecganic cant rebuild and tune a carb. I wonder why NASCAR still run carburetors? Also, most american cars top speed is "Computer limited" I think American cars are limited at about 140 or 150 MPH. European Porches can do 200 MPH plus on the autobahn. The EPA just one more way "the man" is keeping us under control...

NASCAR doesn't use carburetors in the Cup series. American cars are not speed limited by the Gov. And you don't have to go the dealer for a map upgrade. I've done mine 3x, it's never been to a dealer for any fuel injection mapping. TTS, SEPST and the DynoJet line doesn't need any trip to the dealer for anything.