V-Twin Forum banner

1 - 3 of 3 Posts

·
Premium Member
Joined
·
73 Posts
Discussion Starter #1
2001 Magneti-Marelli Road King. Bike has suddenly started bogging down and missing/popping at partial throttle. I can open the throttle and it smooths out, but my cruising throttle position is where the problem is. I checked the engine codes via the on-off ignition method and no codes. Don't have access to a scanalyzer, other than an indie or dealer.

Bike runs fine when cold, seems to overly richen the engine after it reaches operating temp, which leads me to suspect one of the EFI sensors.

Anyone else have this problem? What are the most likely failures to cause these symptoms? I have no problem taking it to a shop, but I can replace some sensors for what I would pay just to have it diagnosed, so if it's a common and easy fix, I'd just rather do it myself.

Thanks
 

·
Registered
Joined
·
25 Posts
This is just a WAG but cheap to try. I had a problem with the stator on my 2000 RK with the MM EFI. Prior to the stator failing, I had symptoms where it would not maintain an idle but ran fine at higher RPM's. It was also backfiring more then what I've become accustomed to. Anyway, I brought the bike to an indie's house to repair the stator. Apparently, he makes it a habit of giving the bike a once over before he gives it back. Among a couple of other smaller things, he found some bolts by the air cleaner loose. They are apparently hollow and allow (IIRC) crancase venting to the air filter housing. Apparently they also allow enough air in to lean out the mixture causing the problem because it went away after they were tightened. It idles fine and the engine decel backfiring is back to a "normal" level. Checking this is cheap and easy.
 

·
Registered
Joined
·
2 Posts
Another Shot in the dark, but when attempting to diag EFI, I find plugs to be a great place to get a bearing on if it's lean or rich. (Darker is richer)

On rich issues, I always start with air intake related issues. This goes along with your observation of running well cold when it is running richer.

It could also be related to the engine temperature sensor. This helps the cpu know when to lean out the mixture.

Rather than run ragged thru the sensors, take it to someone with a scanalyzer or digital tech, and have them peek at what's reported. Then you can scoop the parts and fix it directly yourself. Much better than "part swapping" unless you have really deep pockets and most Dealers will not mind spending the 10 mins to do it for you unless they're jammed for time :)
 
1 - 3 of 3 Posts
Top