Misfire/stuttering at low RPM - Triumph Forum: Triumph Rat Motorcycle Forums
Trophy Trophy 3 & 4 - for all 900 and 1200cc models 1991- 2004

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post #1 of 10 (permalink) Old 02-07-2009, 12:04 AM Thread Starter
Grand Prix 250
Join Date: Feb 2009
Location: Dallas, Tx
Posts: 47
Angry Misfire/stuttering at low RPM

My 1996 Trophy 1200 has had a problem with stuttering when you roll on the throttle. First dealer diagnosed sticking carbs - had carbs cleaned and synched for $500 and no change. Problem goes away with half choke on ALL the time (not good gas mileage). Second dealer diagnosed bad coils and pick-up sensor. Just replaced both coils with NOLOGY Pro-Fire and a brand new TRIUMPH Pick-up sensor. Bolted everything back together and I still have a misfire (can be heard at idle - sounds like a slight "ping" out of the tailpipe).
The next thing is a bad ignitor, but that didn't come up on either diagnosis.

Help!! Any ideas are greatly appreciated.
Bike has brand new airfilter, sparkplugs, and runs on 93 octane gas (no ethanol).

Thanks in advance

1995 1200 Sprint Quattro Nightshade
1996 1200 Trophy Merlot
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post #2 of 10 (permalink) Old 02-07-2009, 05:16 AM
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When you replaced the coils, I take it all the HT leads were replaced ?
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post #3 of 10 (permalink) Old 02-07-2009, 07:05 AM
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Location: Cleveland, Ohio, USA
Posts: 348
why 93 octane? My 900 runs fine on 87. If it's not the igniter, she sounds fuel starved. check all the rubber lines and filters, gas cap and tank vent, fuel petcock may not be opening fully at low rpms, check vacuum lines.

These are the cheap fixes.
Good luck.

"The Glory of God is man fully alive."
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post #4 of 10 (permalink) Old 02-08-2009, 02:35 PM
Grand Prix 250
Join Date: Jan 2009
Posts: 51
Don't head down the slippery slope

When I had a 95 Trophy I had the same problem. Check your battery and charging system as if that isn't in good shape the symptoms you describe can appear.

More importantly though, I'd suggest stop paying a lot of money for experimentation. Motorcycle mechanics and electrics is a science, not an art. All too often we visit the dealer and the dealer tries this and that with no good result. After trying a lot of thises and thats, they stumble upong the problem and fix it. By then you've paid lots of money and the $300 reasonable service fee has become nearly a thousand. That is unacceptable. Here is what I did after having had enough of this type of service (not my current dealer-they are great).

Pay for a diagnosis only. For a lot less than trial and error the service fee should isolate the problem. Replacing parts on and on hoping to fix it is not service, a monkey can do that.

When you get the results of the diagnosis, get a quote for the repair and with a statement that this is the solution and if not, no charge.

If the dealer isn't willing to do this, find another dealer, you have found someone incompetent or worse, a rip off artist. I know I'm sounding harsh here but for too long, dealers have just replaced part after part and eventually anyone can fix anything that way. Why do you need them?

Triumphs aren't any harder to work on than anything else. Try to have electrics on a Honda CX Turbo or mid 80s Sabre fixed.

Once I started asking for a diagnosis only and paying for that, things changed. Things went from parts replacements to figuring out what the problem was and fast, reasonably priced solutions.

If new coils didn't fix the problem, the dealer owes you $500 period. I wouldn't give him another penny.

Find yourself a good dealer and talk to them. I delaer shopped when I recently bought my 2000 Trophy. They treat me like Gold. I spend my money there in reasonable amounts for high quality service. When they say the bike will be done, it is done. No surprises on the price because I know ahead of time what it will cost. No fix, no money.

Sorry for the rant but just because it is a Triumph doen't mean it has to costs thousands to maintain and every problem isn't rocket science.
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post #5 of 10 (permalink) Old 02-08-2009, 02:43 PM
Grand Prix 250
Join Date: Jan 2009
Posts: 51
Now for some help

Something to check. Are you using a K&N air filter? If so, make sure it isn't gooped up with too much filter oil. One way to check is to remove the filter, clean out of the box and run the bike. A minute or so isn't going to hurt anything unless you do this during a dust storm. If it runs better, it is a fuel/air problem and start there.

One more thing, if it seems to load up (more throttle than necessary then cleaner up top) check the plugs as they may have fouled up. Happened to me in conjunction with one bad coil.

Water in your tank (part of the fuel air thing)? Can happen easy and water bing lighter will stay in the tank a long time. Since you know the coils and igniters are good, fuel/air is likely the culprit. Check your grounds while you're at it. With bad charging/battery good coils and igniters can't save you. Battery check is in order.
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post #6 of 10 (permalink) Old 02-08-2009, 07:52 PM Thread Starter
Grand Prix 250
Join Date: Feb 2009
Location: Dallas, Tx
Posts: 47
Okay, I did shop around for competant dealers (that is why I went from Dealer #1 to Dealer #2 - only one more dealer left in town).
I did get diagnosis from both, albeit different diagnosis. I know the following are good:
  • coils
  • pick-up sensor
  • sparkplugs
  • air filter
  • battery
  • alternator
  • fuel

I have read up in the archives regarding similar problems, and it seems to be there are many possibilites. I will be looking at the petcock tomorrow.
The Bike has 28,000 miles and has been dealer maintained.

Will keep everyone posted, and if someone can think of anything else, it would be greatly appreciated.

Thanks in advance

1995 1200 Sprint Quattro Nightshade
1996 1200 Trophy Merlot
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post #7 of 10 (permalink) Old 02-08-2009, 08:17 PM
Grand Prix 250
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Posts: 51
Sounds good

Take me with a grain of salt, when it comes to paying extra just because a dealers say the bike is a Triumph I cringe.

Had same thing happen to my V-Strom. 4 dealers before one of them picked up the phone, verified there was a recall on the ECM and replaced it under warranty. Everyone else wanted to sell me power commanders, coils, air filters, tune-ups because it stuffered.

If the petcock is okay, you can also check to see if each carb is pulling air. That requires removing the airbox but after that it is pretty easy to tell. No steady air pull=unsteady running.
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post #8 of 10 (permalink) Old 02-15-2009, 12:17 AM Thread Starter
Grand Prix 250
Join Date: Feb 2009
Location: Dallas, Tx
Posts: 47

After looking at just about everything the following has been definately determined:
  • faulty coil
  • faulty fuel petcock
  • faulty pick-up sensor

  • both coils with NOLOGY Pro-Fire
  • fuel petcock
  • pick-up sensor
  • vacuum line
  • sparkplugs
  • air filter

also while I was there, I added an airhorn for good measure (seems like people like to overlook the motorcycles here in Dallas...)

1995 1200 Sprint Quattro Nightshade
1996 1200 Trophy Merlot

Last edited by TxGr8WHite; 02-15-2009 at 12:21 AM.
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post #9 of 10 (permalink) Old 02-17-2009, 02:47 PM
Supersport 400
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low tension connections

check the low tension connections to the coils. they need to be TIGHT, not just tight.
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post #10 of 10 (permalink) Old 02-23-2009, 07:06 AM
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I was having exactly the same problem your stating and after many hours of head scratching and swapping parts from one of my triumphs to another then it turned out to be the carbs a fault and after investigation then it was the pilot jets that were blocked but they looked ok without using a magnifying glass.

Now i know that people say to clean them with thin wire and check for any glazing with a magnifying glass but to be honest i couldn`t be bothered and for the price of £7 or about $10 for each new pilot jet then i decided to buy new.

After fitting them then the bike pulled great without any stuttering at all
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