running like crap - 2000-3000 RPM - a bit stumped and not sure where to go

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joe czech said:
THANKS FOR ALL THE RESPONSES - plenty of things to check out. my gut feeling is centering around the podtronic unit - plan is to install my original (lucas) rectifier and Zener, and give all wiring connections a good look over. been thinking about replacing the podtronics anyway, so this may be a good time for an upgrade. again, thanks....
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Trying out the old Zener and rectifier or another reg/rec box sounds like a sensible test.
 
concours said:
In that case, use a jumper wire from the battery to supply the TriSpark. I fixed one of those on the side of the road too.
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Ya know, that actually makes sense. If the OP has witnessed his problem at the same RPM in any gear, the root cause could be vibration at some frequency affecting an electrical connection.
 
My procedure
joe czech said:
i've been fighting this issue, on and off for a couple months now. seems like i have an engine problem between 2000 and 3000 RPM. happens with any gear - above 3K, seems to smooth out and appears to be running normal.
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1. Rare but sometimes mechanical i.e, oil contamination, broken cracked hose, leaking carb or manifold is possible but low
2. Poor carburation (rich) infecting the plugs therefore manifesting as ignition problem/symptom.

Torontonian said:
Put in new plugs. Run. Ride. Pull plugs and give us a photo with sustained problem R.P.M.'s. Drop out quicklly then pull plugs to photo show us.
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This is where you put in screaming hot champion N11Y plugs. Riding around low/medium throttle mainly to test cutaway mixture.
2a. If it now runs clean without misfiring then carbs need work, Do not run at sustained WOT. The hot plugs will respond if your cool/rich combustion temperature and try to stay clean.

3 no change? then I suspect an electronic ignition or interfering electronic controlled charging system.
3a, test by removing or disconnecting the interfering electronic controlled charging system. ride to test mostly on cutaway not WOT varying the load/throttle.

4. Bad retarded ignition curves ALSO cause cool running at throttle cutaway running loads which makes the plugs foul and then misfire

Try to notice if besides the RPM range.....is the misfire aggravated in a particlular throttle opening, therefore "load"= cylinder pressure which affects the spark voltage requirement to ignite.

works for me;)
 
joe czech said:
THANKS FOR ALL THE RESPONSES - plenty of things to check out. my gut feeling is centering around the podtronic unit - plan is to install my original (lucas) rectifier and Zener, and give all wiring connections a good look over. been thinking about replacing the podtronics anyway, so this may be a good time for an upgrade. again, thanks....
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It may not be the POD reg/rect considering you basically took it out of the electrical loop when you tested with the alternator disconnected as suggested by Tri-Spark. However, it's never a bad time to upgrade. Do the POD test outlined previously so you know if the POD is actually good. No sense throwing it out if you upgrade and it is still good.

I don't know anything about the Tri-Spark EI unit, but I would think if it were going out, it wouldn't clear up over 3000 RPM. Been wrong a few hundred times before though. A lot of things fuel and electrical related can cause the symptoms you are experiencing. You are definitely at a point where going over the entire wiring harness and all the grounds is a good step. Tedious to say the least, but worth it.

A failing coil will act like fuel starvation (bucking and so on) and recover a few times, right up until it dies and leaves you stranded on the side of the road. I've never had it happen with a Norton, but I have with old automobiles.

Good luck finding the solution
 
kommando said:
Why not disconnect the alternator, reg/rect and go for a ride just using the battery. That will give you a clue where to start looking.
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did that - no difference. i was planning on upgrading the rectifier/regulator to a newer mosfet unit anyway, so this looks like a good time for it. in the mean time, i'll keep plugging along.
 
joe czech said:
did that - no difference. i was planning on upgrading the rectifier/regulator to a newer mosfet unit anyway, so this looks like a good time for it. in the mean time, i'll keep plugging along.
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Like Schwany says, test it first. Good backup if it is still good.
 
If you had podtronic unit out of loop and there was no change in miss at same rpm ... would that Not eliminate the Pod as culprit, or should I read this thread again , or turn my brain on ..... also you mention not sure if it one side or both , why not pull plug lead off one side while running and see if you get the miss at the problem rpm , then try same on other side , easy tests to answer one unknown ....
 
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Sounds like the charging system is not causing the problem in any way since you ran the bike without the charging system connected.

When you are out on the bike, if you are at idle in gear and you open the throttle to a fairly large opening, does the bike misfire as it accelerates through the "bad" RPM range or does it just misfire in that range if you hold the throttle at whatever opening it takes to maintain that RPM?
 
Check that the rivets on your coils are tight. I had a missing problem on an old Jowett Javelin many years ago. Drove over the Haast Pass in pissing rain and it stared missing over certain revs. Fitted new plugs. no different . Worked out is was to do with speed, and sometimes direction in which the wind was blowing. That sorted out where the problem was. Loose coil terminal. To do a temp fix, I revolved the coil round a bit to put tension on the coil terminals.

Dereck
 
I chased mine around the world several time searching out one of these gremlins which in the end vanished when I replaced the battery..... Which BTW had checked out as being okay. In general these issues are in obvious places we miss due to going down rabbit holes. I've chased many of the furry critters causing endless frustration too.
I hope you find the cure quickly Joe.
 
jbruney said:
I chased mine around the world several time searching out one of these gremlins which in the end vanished when I replaced the battery..... Which BTW had checked out as being okay. In general these issues are in obvious places we miss due to going down rabbit holes. I've chased many of the furry critters causing endless frustration too.
I hope you find the cure quickly Joe.
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The battery is the heart of your electrical system. Learned that from friends many years back.
 
Based on the supplied info, it sounds to me like "weird electrical" as opposed to "normal electrical" issues. ;)

Weird electrical is, for example, a connection that is affected by vibration so that it becomes intermittent with a certain level of vibration and returns to normal when that vibration is absent. Ignition coils are also famous for very odd behavior when they are faulty. As I have said here before, I had one in a car that cut out out with aggressive left turns; worked correctly at all other times.

One of the first suspects for weird electrical problems is grounds. Do you have a good, solid (additional) ground to the engine itself, as opposed to the normal harness ground that terminates at the head steady? Admittedly, ignition problems usually show up first as a problem under load, they do not typically occur at low RPM and then disappear at higher RPM/load. That's why I'd tend toward some sort of vibration-related thing.

Per my earlier post, does it occur under load (in gear) as the engine passes through the rev range? Does it occur if you hold the RPM steady in that range? Does it occur when the bike is in neutral as you move the throttle through that range?
 
Also had an internally corroded wire at fuse holder cause intermittent missing and cut-outs in mid to high RPM which took seemingly forever to locate..... Had easy start ups, low end was okay, but as soon as it got rolling along the alternate elusive miss began. Don't recall why I tugged the holder judiciously but out came 3"-4" of rotten green copper. Spliced in new holder and all went away. I know I know I ramble.
 
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