| Author | Message | |||
     Moto619 |
Looking for help diagnosing this problem. I had this same hesitation / misfire problem in the past. The bike runs ok until about 4000 RPM it then hesitates misfires and then runs ok above 5000 RPM. I bought a race ECU (used) which took care of the problem for a few weeks then the problem returned. There are no error codes. I changed the head temp sensor no effect. Any ideas where to look next? | |||
| Harleyelf |
Cam Position Sensor. Take the timing cover off and smell it. | |||
| Alfau |
DDFI learns. It could be the way you ride the bike. learn how here.
(Message edited by alfau on June 16, 2017) | |||
| Alfau |
 this bit. Note:- The bike misses, hiccups during transition from open loop to closed loop. Might not be what your on about but worth knowing anyway. | |||
| Moto619 |
I rode it a little bit and took the timing cover off and no smell. I noticed that you bought a drag specialties CPS would you recommend that and do they still make them for that bike? | |||
| Steveford |
Drag Specialties stuff is garbage from China. What's the O2 sensor doing when the bike is hot? The voltage should be jumping around like crazy: high/low, high/low, etc. | |||
| Hootowl |
Measure the voltage from the TPS, or disconnect the leads and measure resistance, as you roll on the throttle. Watch for areas that are not linear. | |||
| Harleyelf |
I use the Sportster CPS because I put a carburetor on my bike. Can't speak to the quality of the Drag Specialties DDFI sensor. | |||
| Williamscottrobertson |
I just put my DS cam sensor on. It's about 3 inches shorter than the original. Required some creative re-routing. I think it would have been nearly impossible to get it back under the starter as before anyway. It barely came out. My stock one fell apart on removal. Corroded at the terminals. I marked the lines on the stock one to the timing cup and lines of the DS version. Put the new one in the same spot and it fired right up. I pulled the spark plugs and put my finger over the hole waiting for compression. Then found the timing mark in the window. I tried with the switch and kill on and couldn't hear the fuel pump, even if I moved the rear wheel back and forth. I guess I'll try to figure the breakout box thing to make sure it's timed  | |||
| Natexlh1000 |
Can't you just use a timing light like the old days? Or are these newfangled things only static timed? | |||
| Harleyelf |
Timing light will work but will also spew oil all over unless you get a lucite plug for the hole. | |||
| Williamscottrobertson |
Yeah I may buy a view plug and do a running check just for my piece of mind. | |||
| Zac4mac |
Most of the ignitions I've seen start with a static time. I tried a lucite plug on my ironhead 30 years ago and only saw oil when running. marks? timing? really? I always static-timed then ran it to dial in the advance to just below detonation clatter. Z | |||
| Alfau |
Thgat makes sense, to a galoot! | |||
| Harleyelf |
If the lucite plug gets covered in oil, don't screw it in quite so far. I've set mine without the plug - the trick is to get it done quickly - then clean up the oil from the timing light and your face. | |||
| Williamscottrobertson |
Bought a drag specialties timing plug for $5 from the local HD dealer. The timing mark was almost out of view to the rear of the bike (I think that's the advanced direction). Ran it about 100 miles like that, it would hesitate and ran warmer it seemed, would surge at idle when really hot. The idle smoothed out when I got the mark centered. Hopefully this fixes the surging and hesitations that weren't there before. Hard starts seem to be gone and random misses seem to be gone also. (Message edited by Williamscottrobertson on June 30, 2017) |
