Crummy idle NOS DT300i

[CROSSBOLT]

A little over a thousand miles, idle jumps to 2500 rpm. Did the initialize drill waiting at a stoplight and all was well. Noticed the idle was creeping up the last few rides and was wondering when it was going to be crazy. This was a repeating drill on the old 2013 DT although did not have to do it for several months before it was stolen.

Karl

[moparkid]

Yo Karl....do you think the quality of gas has anything to do with it. I find when I buy gas at non affiliated gas stations ( 7-11, Quik Trip, etc,etc) my bike idles more rough than when I get gas Shell or Chevron....what say you?

[Stig / Major Tom]

Hello Karl,
Burgman guys say to make certain the scoot's brain has booted up (instrument needles have made their sweeps ) before hitting the start button.
But I doubt you are not already doing this. You know how to start your scooters.

One guy said he fixed his coursing idle by spraying  a little WD40 on top of the throttle body area that controls the idle. Something was 'sticking' he thought.

Another had the "ECU values reset" by dealer with "diagnostic tool".....to cure this in his Burgman 400.

It does sound like an EFI/ECU control issue. My LIKE200i fluctuates by some 200-300 rpm's, but that is all.... and mostly only when first started.

On a car I'd be looking for a vacuum leak.

Stig
Bummer.



 

[CROSSBOLT]

Have not got a slug of water or mystery fluid out of a gas station in years. Some brands I won't touch unless no option but other than that no problems with fuel. This is a trait of the Downtown judging from the last one and probably is of any system with three sensors: TPS, ISC and MAP. I know the Yager and the People GTI300 are made like this. I had periodic problems with the Yager idle and fixed it with initialization. The wife's People still runs like a sewing machine. She'll tell me if it goes nuts! I do think it is either the TPS resistance changes or the ECU gets corrupted that causes this. But since the initialize mumbo-jumbo fixes it I am clam-happy. Yeah, the start rocedure is let it finish its dance then light the fire!

Karl

PS: One of the two mechanical guru's Zombie or Bettin' & Losin' said early Honda cars with ECU had this same type of problem and the fix was to either initialize or reset the computer.

[Stig / Major Tom]

Since the Burgman guy said he cured this issue with a squirt of oil on the throttle body. ...IS there a moving part on there that could be hanging up periodically?  A pivot point, or some such?
Can you observe the underseat area while the problem is occurring?
(Helmet cam on neighbor kid's pet gerbil. Tape him under seat..)
Stig

[CROSSBOLT]

The only thing that has any movement is the TPS and that is internal. Meaning there is no exposed movement. Clever, elegant thing the TPS: turned by opening the throttle; turns back following the throttle by a very small coiled tension spring; zero backlash. sealed up with an o-ring so even WD-40 sprayed on the outside cannot get to it. Now, the mechanical throttle is exposed with its substantial spring and pull-pull cables (pull open, pull close). This has no electrical/electronics function; TPS is on the other end. Sorry for the Burg-man! His is probably made the same way.

Karl

[agilebda]

A little over a thousand miles, idle jumps to 2500 rpm. Did the initialize drill waiting at a stoplight and all was well. Noticed the idle was creeping up the last few rides and was wondering when it was going to be crazy. This was a repeating drill on the old 2013 DT although did not have to do it for several months before it was stolen.

Karl

Karl, it could be something as simple as restricted air flow. Pop your airbox cover off and check the element. Starving for air, that probably why the idle increases. More fuel than air. Also chck your plug to see if she running rich or lean!

Regards,
Toni

[CROSSBOLT]

Thanks, Toni but was through all that with the old DT300i with negative results. The initialize procedure produces immediate results after what you suggested had been done.

Karl

[CROSSBOLT]

Just had to bump this one to remove all doubt: venting the gas cap FIXED THIS!

Karl

[mousejunks]

My idle kept dropping to 1000rpm and felt like stalling, so I removed the ISC (idle speed controller) on the throttle body and cleaned it out with carby cleaner. Plenty of black stuff came out and fixed it.

[CROSSBOLT]

Sorry I took so long, Mouse but that is GREAT information! Dint think of that but thanks to you I do now!

Karl

[mousejunks]

The air box has a clear tube hanging off the bottom to drain oil mist from the crankcase vent tube. This clear tube can break off where it joins the air box, allowing air to leak behind the air filter and contaminate the ISC and MAF sensor.