Engine sputtering and backfiring

[Evil Mitch]

I did that on #s 2 and 3, but I couldn't get to the connectors on #1...on the ones I could check everything looked good.

Im putting my money on one of your leads being faulty . I had almost identical symptoms to you a while back .
I checked everything else mentioned here and nothing . Mine seemed to idle fine but backfired and hesitated under load it was a real problem . Eventually i started the bike and pulled each lead one by one . First couple i pulled the idle dropped and ran rough so i knew it wasnt them then the third one i pulled didnt effect the idle at all so bingo i had the culprit . i removed the lead and inspected it and found a small crack and discoloration on the plug where it mounts to the coil .Once i replaced the lead it ran like brand spanking new i couldn't believe the difference from running like a pig to flawless. Oh yeah this was after a dealership checked my leads while being serviced and stated there was nothing wrong with them hence why i do all my own work these days.

best of luck hope you get it sorted

 

[grampi]

Im putting my money on one of your leads being faulty . I had almost identical symptoms to you a while back .
I checked everything else mentioned here and nothing . Mine seemed to idle fine but backfired and hesitated under load it was a real problem . Eventually i started the bike and pulled each lead one by one . First couple i pulled the idle dropped and ran rough so i knew it wasnt them then the third one i pulled didnt effect the idle at all so bingo i had the culprit . i removed the lead and inspected it and found a small crack and discoloration on the plug where it mounts to the coil .Once i replaced the lead it ran like brand spanking new i couldn't believe the difference from running like a pig to flawless. Oh yeah this was after a dealership checked my leads while being serviced and stated there was nothing wrong with them hence why i do all my own work these days.

best of luck hope you get it sorted

Was yours running bad at just one specific throttle setting?

 

[grampi]

I would say that it is a good chance that one of the hoses is off because when the engine backfires there is a lot of pressure on those hoses its not uncommon for them to pop off.
(on cars that backfire)
i am not familiar with the 6 hoses it only takes one off to cause a problem. somewhere at the end of those hoses is the map sensor thats all i know.

Like I said, none of the vacuum lines are disconnected. I looked at them all myself.

 

[warp9.9]

Like I said, none of the vacuum lines are disconnected. I looked at them all myself.

When mine went bad (after it was a couple years old) it took me a while to chase it down as all the vac lines looked good along with the plug caps. It was not until I started to pull one of the caps off that it stretched enough for me to see the dry rot cracks. So I changed the lines and caps and the problem was solved. Same with the low tension leads. the may feel tight but need to be pulled cleaned (both male and female connectors) and re-crimp so they were tighter and the vibration that was shaking the connection so it was loosing contact every now and then. When we looked at you Map sensor reading the number three was out the most by 20 points but every now and then it went 30 points.

Now as for the front coil your right a PITA to get at. but still has to be done. there is two bolts going thru the plated on top of the coil thru the coil and to the frame. This plate besides being in the way of reaching the coil with ease is there so Triumph could anchor the harness connectors to it. I removed mine and just ran the bolts thru the coil and to the frame. Left the wire connector laying up there. It does not mess thing up and besides being able to reach number one coil it is also easier to check plug connectors.

Anyway since you changed to the 2780's If your not going back and are not using the pig tail extension for the temp sensor that used to fit in the ram air. I would like to buy it from you????

Also considering someone else has been under the tank removing the air ducts I would not hesitate to check the high tension leads from the coils to the plugs in case one got accidentally damaged during the mods. Especially since the ducting has been removed. I believe your extra vac lines that us early rocktes do not have are probably emissions and possible ABS stuff. (not sure as I do not have a roadster manual)

 

[idk]

It sounds like TPS settings are wrong to me.

 

[warp9.9]

It sounds like TPS settings are wrong to me.

It could be or his TPS is starting to give up the ghost.

 

[Loonitick]

I believe your extra vac lines that us early rocktes do not have are probably emissions and possible ABS stuff. (not sure as I do not have a roadster manual)

Cannot see why the ABS would need vacuum lines, unless bike ABS is very different to car ABS (doubtful).

Have a lot of cases at work of misfiring under load caused by bad HT lines, so agree with Warp that checking condition and fitting would be a good idea. Also, for the coil connectors, if possible, unplug them and check that there is no moisture or burnt pins.

 

[warp9.9]

Cannot see why the ABS would need vacuum lines, unless bike ABS is very different to car ABS (doubtful).

Have a lot of cases at work of misfiring under load caused by bad HT lines, so agree with Warp that checking condition and fitting would be a good idea. Also, for the coil connectors, if possible, unplug them and check that there is no moisture or burnt pins.

YA I was not sure just guessing why all the extra hoses are on and other then Emission crap like every bike is built for California now. The only different thing I could come up with was the ABS crap. Most likely it is just emission stuff.

 

[idk]

CA emissions stuff makes sense. There should be vacuum hoses going to the charcoal vapour cannister.

 

[warp9.9]

CA emissions stuff makes sense. There should be vacuum hoses going to the charcoal vapour cannister.

Thank God for older Rockets !!!!!!!!!!!
Not so much filtercarb on them