Engine Miss Fires at 5000rpm

[ScottG]

Update - so I have changed out the Pick Up's in the clutch cover. The problem still exists. I have then swapped out both coils today and YIP the problem still exists!

Any views as to whether the Throttle Sensor could cause this symptom?

That and the water temp sensors are the only other electrical components that connect to the ICM!

Some suggested that the cluster / clocks could a have some rev limiter function connected to the Rpm gauge. I have ran the bike with the cluster / clocks disconnected and the problem still exists!

Symptom is exactly like a rev limiter kicking in......

With the front end accident that caused this, the ignition was broken open - could a direct short possibly have screwed up the ICM?

Does any one know anyone that had this same type of problem and got it fixed? Really getting frustrated now

[tony.mon]

To eliminate a tps problem, simply disconnect it.
The bike will run ok without it connected, but not as well as it will with it connected, as the ignition doesn't advance as revs rise.
If it then revs out, or conversely refused to run at lower revs, there's your problem.

[VTR Phoenix]

Have you revved it up in neutral and seen if it revs past 5000, have you checked the carbs are seated correctly as they could have dislodged slightly, have you checked your lines and filters and that the.vacuum tubes and such are all firmly attached.and in the right position. If you have bungs or pipes on the syncing holes for the carbs have you checked they are still plugged. I still believe it's something to do.with air/fuel when under load. Start simple.rather than chucking money at it. Can't be too complicated if it was running fine before the drop.

[VTR Phoenix]

You don't need to swap the tps, you can test it to see if it's faulty with a multi meter.

[MacV2]

It's feked I'll give you a £10 & take it off your hands...

Check the petcock diaphragm for splits or pinholes if thats ok check the carb diaphramgs...

Vanstub had an issue with the bike cutting out on him useally on the M way at 70 + so not good...

We swapped, ecu, coils he bought a new fuel fillter...whilst the petcock was off we checked the diaphragm...

[ScottG]

Have you revved it up in neutral and seen if it revs past 5000, have you checked the carbs are seated correctly as they could have dislodged slightly, have you checked your lines and filters and that the.vacuum tubes and such are all firmly attached.and in the right position. If you have bungs or pipes on the syncing holes for the carbs have you checked they are still plugged. I still believe it's something to do.with air/fuel when under load. Start simple.rather than chucking money at it. Can't be too complicated if it was running fine before the drop.

Hi, yes the same symptom still persists when the bike is standing still under rev's. Carbs have been off and on twice, all cleaned and seating 100%. All fuel / air pipes are connected correctly with no split ends.I will test the Throttle Sensor this morning to eliminate that as a possibility.

Than You.

[ScottG]

Update: So as you may have read so far I have changed out the Coil Ecu Unit, I have changed out the Pick Up's, I have changed out the actual coils and HT leads. I have cleaned out the carbs, crossed checked all the suggestions from the threads and there was still no joy in fixing this problem.

I then ordered in a 2nd hand Ecu main unit from a breaker in UK and it arrived this afternoon, Yip we have fitted this and guess what....


That was the problem all along, with the new 2nd hand Ecu unit the scoot started 1st time after warm up she revved with ease straight passed 5000 rpm with no splutter at all. Clean revs all the way through to 8500 / 8750 with no hic ups - we are really chuffed now as the bike was about to become an ornament in our pub

Speaking about pubs, it is off for a or three.

Guys, really appreciate all the inputs and suggestions that have been offered. They got me thinking and cross checking many other aspects. As I had mentioned my gut feel all along was the main Ecu but chose to try all the cheaper electronic elements 1st.

Thank You.

For Sale: 1 set pick ups, 1 set coils, 1 primary Ecu

[AMCQ46]

great work getting to a solution, and thanks for posting the results so others can shortcut their investigations

Fabio, this can go on the list for your bike that wont go past 5000rpm too

[fabiostar]

yeah iv been reading this with interest..

[fabiostar]

Update: So as you may have read so far I have changed out the Coil Ecu Unit, I have changed out the Pick Up's, I have changed out the actual coils and HT leads. I have cleaned out the carbs, crossed checked all the suggestions from the threads and there was still no joy in fixing this problem.

I then ordered in a 2nd hand Ecu main unit from a breaker in UK and it arrived this afternoon, Yip we have fitted this and guess what....


That was the problem all along, with the new 2nd hand Ecu unit the scoot started 1st time after warm up she revved with ease straight passed 5000 rpm with no splutter at all. Clean revs all the way through to 8500 / 8750 with no hic ups - we are really chuffed now as the bike was about to become an ornament in our pub

Speaking about pubs, it is off for a or three.

Guys, really appreciate all the inputs and suggestions that have been offered. They got me thinking and cross checking many other aspects. As I had mentioned my gut feel all along was the main Ecu but chose to try all the cheaper electronic elements 1st.

Thank You.

For Sale: 1 set pick ups, 1 set coils, 1 primary Ecu

which one was it? the larger of the two boxes i take it?

[sirch345]

Good to hear the outcome, always helpful for others further down the line when they come across this thread trying to sort a similar problem as AMcQ says.

Well done in fixing the issue

Chris.

[VTR Phoenix]

Looks like hawk was right.again, be will.be missed

[fabiostar]

how strange that two storms had the same problem in one week

[VTRDark]

Looks like hawk was right.again, be will.be missed

No that was pulse generator not the ECU but your right he will be missed.

Hawk was right about it being rare for an ECU to fail. These generally only fail when there has been a charging system overload (spike) ie failed R/R. It would be worth giving the charging system a once over to make sure it's all good.