Engine wont rev pass 1300 rpm cuts out

[VINTAGEFEETUP]

Hi 1982 XS650 stock latest problem the engine starts and idles a little rough but when throttle applied gets to 1300 rpm and just cuts out completely reaaly feels electrical . I tried another electronic ignition unit and different coils exactly the same both times . I am thinking the pulse pickup may be going bad but I thought it works or it doesn't? Any ideas as to what else it could be . I did replace the rotor about 4 weeks before this started as it wasn't charging.
Thanks

 

[rybeatty]

could be carb related. I'd clean them out just to be sure and rule it out

 

[Uhlaf]

My bet is 100% ignition related. I had the same problem 2 months ago, swapped out the TCI for PAMCO

Thread here

http://www.xs650.com/forum/showthread.php?t=41142

 

[retiredgentleman]

Hi 1982 XS650 stock latest problem the engine starts and idles a little rough but when throttle applied gets to 1300 rpm and just cuts out completely reaaly feels electrical . I tried another electronic ignition unit and different coils exactly the same both times . I am thinking the pulse pickup may be going bad but I thought it works or it doesn't? Any ideas as to what else it could be . I did replace the rotor about 4 weeks before this started as it wasn't charging.
Thanks

Unplug the rec/reg unit and then run the engine and see if it will rev up normally. If it revs OK then you need to buy a small magnet to glue onto the alternator rotor.

The replacement rotor, was it new or an old used one? The existing small magnet that is embedded into the rotor, may have become weak over the years.

 

[XSLeo]

On my 81 I had low voltage problems. Partly dirty connections along the power path from the battery to the TCI and coil as well as poor charging.
It would idle fine with a fully charged battery but as you rode it and the charging system couldn't keep up the battery slowly drained. Once it hit about 12.5 volts or there abouts it would idle but not take throttle.
Check your battery voltage as it runs.
Leo

 

[VINTAGEFEETUP]

OK today I disconnected the Alternator/stator connector and put the chock on and the bike runs at about 3000rpm as expected and it does rev well sort of, but take the chock off and the bike dies . Seems to feel like idle line blocked but when I reconnect the stator it will start and idles and does not rev pass 1300rpm as before. The rotor was new from eurosports so I am hoping that isn't the cause but maybe its a duffer.Any thoughs?

 

[VINTAGEFEETUP]

OK Update
After 2 more beers the mind cleared and then I remembered I forgot to connect the vacumn line for the petcock put that puppy on it reved perfectly with the alternator / stator disconnected.
So where do I put this magnet on the rotor or maybe the stator is buggered. I have infinity resistance to ground so I assume thats correct and little resistance between phases What should it be ?
Thanks for all your input very helpful

 

[retiredgentleman]

Use the Google Custom Search the upper left corner. Type in something like...............
"rare earth magnet". The second post down talks about the Radio Shack magnets.
That should solve your problem.

 

[VINTAGEFEETUP]

I did all the Curly's tests and this is the results
Magnetic slap tested OK
Output from the stator and its 10.5AC volts at idle the rotor is new and the resistance test was good at 5.5 ohms between tracks and there is infinity to ground which is correct. The stator has 0.8 ohms between phases and infinity to ground with yellow wire disconnected connected its 25 ohms.

Now the rectifier seems to be correct according to the test it reads equal values one way and nothing in reversed.

The interesting part is if I disconnect the 12v dc coming from the rectifier the bike runs great with a slight flat spot around 1500rpm but I am running on the battery now if I reconnect the 12v dc wire in the rectifier the bike idles but when I rev it then runs badly like misfire or timing is off and will just quit if I continue. The battery appears to increase in dc volts as I try to rev the bike checked with the voltmeter went to 13 volts DC . So everything seems to be working OK electric charge wise but the bike is unridable.

I am a little stumpped as to what is going on any thoughts

 

[retiredgentleman]

I did all the Curly's tests and this is the results
Magnetic slap tested OK
Output from the stator and its 10.5AC volts at idle the rotor is new and the resistance test was good at 5.5 ohms between tracks and there is infinity to ground which is correct. The stator has 0.8 ohms between phases and infinity to ground with yellow wire disconnected connected its 25 ohms.

Now the rectifier seems to be correct according to the test it reads equal values one way and nothing in reversed.

The interesting part is if I disconnect the 12v dc coming from the rectifier the bike runs great with a slight flat spot around 1500rpm but I am running on the battery now if I reconnect the 12v dc wire in the rectifier the bike idles but when I rev it then runs badly like misfire or timing is off and will just quit if I continue. The battery appears to increase in dc volts as I try to rev the bike checked with the voltmeter went to 13 volts DC . So everything seems to be working OK electric charge wise but the bike is unridable.

I am a little stumpped as to what is going on any thoughts

13 volts DC is not high enough. You should be able to get to 14 volts DC (Actually 14.1 to 14.2 is ideal) I assume you have confirmed that the brushes are 3/8" or longer.

You said you had an extra TCI Black Box available. Perhaps you should try using it again.

 

[VINTAGEFEETUP]

Problem resolved Bad Rotor the magnet that signals the pulse pickup had lost its magnatisum manufacturer replaced the rotor as it was only a few months old Thanks for all the input .

 

[retiredgentleman]

Problem resolved Bad Rotor the magnet that signals the pulse pickup had lost its magnatisum manufacturer replaced the rotor as it was only a few months old Thanks for all the input .

Glad to hear you got things sorted out Sadly, so called "new" components from aftermarket sellers, does not mean they work properly.