Triumph Rat Motorcycle Forums banner

1 - 18 of 18 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I'm looking for some help. I've got a 2,000 T-Bird with about 18,000 miles. It has been a GREAT bike. It's always run great, without a single problem. It's entirely stock.

I have not been riding it much this last year. From July through November, I probably rode only 3-4 times. I keep the battery on a trickle charger, and idle it for 15-20 minutes every week or two if I can't ride, but that's it.

I rode some in December, and it ran fine. It always has started fine.

About 3 weeks ago, I noticed it start to run a little rough in mid-gears at fairly low rpms (around 3-3500 rpm). This bike has always been happy at about 3-3500 rpm. It's always run very smooth in that range, so the roughness was noticiable, even though not severe.

I've been riding 2-4 times a week since then, and the problem has gotten worse. It starts up fine, and runs ok at idle speed. When the engine speed is between 2500-3500, it misses and sputters a lot. At steady speed in this engine speed range, it runs ok, but will sometimes sputter a little. When I accelerate from this range, it's VERY rough and misses quite a bit. I can see the tach jumping around, going up and down 2-400 rpm at a time.

Once the engine speed is up above about 4,000 rpm, the problem is gone. Below 2,500 rpm, I'm not sure. At idle, it's ok, but there's no load on it. In 1st gear, it seems ok as I start from a stop. Other than that, I'm never really spending time below 2-2500 rpm, so I'm not certain there is a lower end to the engine speed range in which this problem occurs.

I've read a lot of posts, and I'm about ready to try replacing the coils. The spikey tach sympton is what first made me suspect an electrical problem, rather than fuel. Plus, the problem is isolated to only a range of engine speed, and it seems like a fuel problem wouldn't do that. I'm no mechanic, but that is what I was thinking.

What do you think? I would really appreciate any suggestions. If I replace the coils, should I replace the plugs, too? Would a bad plug do this? I understand why bad coils might act this way, but I can't see how a bad plug could cause this. But as I said, I'm no mechanic, just a guy who loves his T-Bird and wants to get her running smooth again.

BTW, there aren't any Triumph mechanics anywhere near here, so I'm hoping to take care of this myself. If I should replace coils and/or plugs, what replacement parts should I use?

Thanks.
 

·
Premium Member
Joined
·
9,798 Posts
Have a look at this thread.

http://www.triumphrat.net/hinckley-classic-triples/77415-tbs-sport-running-rough.html

If the bike runs rough under 3500 rpm it is usually a sure sign of the pilot jets being clogged, which they probably are after sitting for so long.

You could pull the carbs and clean them out or try what I have done a few times with success and run some fuel system cleaner in the gas and go for a long ride.

It may take a couple of tanks of gas with a half bottle of cleaner in each tank, but it is easier than pulling the carbs.
 

·
Banned
Joined
·
2,731 Posts
Both Tbirds I've had suffered from jumpy tach's. I don't worry about it. My current Tbird has 70,000km on it and still the original coils, with no rough running episodes. Try new plugs, and fuel cleaner.
BTW my bike is stock witht heexception of a K&N filter element. No rejetting or other nonesense.
 

·
Premium Member
Joined
·
2,626 Posts
Try running the bike at absolute minimum throttle in first gear and accelerate gradually keeping throttle to a minimum.

If it starts bucking and misfiring as the rpm increases and is worse when cold, your pilot jets are gummed up and need cleaning.

A rough transition between small throttle and large throttle can also point to dirty pilot jets.

Weak ignition coils usually show up at low rpms as a misfire and clear up as the rpms hit 3000-3500 where the alternator kicks in and takes over from the battery.

Jim
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Follow up

Thanks for the responses.

The problem is NOT worse when it's cold. It is about the same or maybe a little bit better when it's cold. It does NOT go away or improve as it warms up. If anything, it gets worse the longer it runs.

I have tried accelerating with minimum throttle. In 1st gear, about the lowest I can get is around 1500 rpm. If I accelerate very slowly from there, she runs fine. The same is true in 2nd, though I've only tried that down to about 2,000 rpm.

But if I'm at about 2500-3000 rpm in 2nd and gun it, all Hell breaks loose until it's above about 4,000 rpm. Now that only takes about a second, but it's a wild and shaky second.

My tach is only jumpy when the engine is missing and sputtering in this rpm range. It has never jumped around before, or at least I never noticed it.

I also suspected a fuel problem, given the long time without much engine use. But the odd thing is that the first real ride I made after the long time off the bike was about a 250 mile ride over 2 days. It ran fine then. If it was a fuel issue, wouldn't it be at it's worst just after the long sit-up?? I may be totally wrong about that, but that is what I was thinking.
 

·
Premium Member
Joined
·
2,626 Posts
I have tried accelerating with minimum throttle. In 1st gear, about the lowest I can get is around 1500 rpm. If I accelerate very slowly from there, she runs fine. The same is true in 2nd, though I've only tried that down to about 2,000 rpm.
Sounds like the pilot jets are ok...

But if I'm at about 2500-3000 rpm in 2nd and gun it, all Hell breaks loose until it's above about 4,000 rpm. Now that only takes about a second, but it's a wild and shaky second.
That could be a carb needle stuck/sticking (due to a bad or cocked retainer with Keihins)or possibly a broken carb slide spring.

Both of those problems are quite uncommon

My tach is only jumpy when the engine is missing and sputtering in this rpm range. It has never jumped around before, or at least I never noticed it.
Tacho jumping suggests a problem with the ignition coils or igniter. The tacho output is picked off one of the ignition coil primaries (I think #1) so if that coil isn't firing the the tacho will bounce.

Also, the 2500-3000 rpm range is where the alternator takes over for the battery, so that can indicate low battery voltage, bad grounding or dirty/corroded battery terminals. It can also indicate a weak battery since the ignition load increases a bit with rpm.

I'd suggest hanging a spare sparkplug from the plug wires and cranking the engine. If you get a fat blue spark the coil is probably OK but if it's thin and yellow then there's a problem.

If at least one spark is good then you've got a bad coil or two. If all three sparks are weak then check the battery and terminals first but it's entirely possible to have three bad coils -- you won't notice until they deteriorate to the point of affecting rideability.

There are other places to look for a weak spark, but check the spark first and get back to us.

Jim
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
Thanks for all the input. I'm going to replace the coils. It's a job I know I can do, and my gut tells me that's what it is (after reading of so many folks with failed coils and similar symptoms). I will post again after that and let you know if it solved the problem.

I don't think its the battery. It's a Yusa battery, just over 1 year old. I use a battery tender on it when I am not riding at least every few days.

I don't think it's fuel. Plus, I'm not going to mess with the carbs myself. I would only cause more harm. If the coils don't solve the problem, I will run some cleaner through the carbs. Beyond that, I will have to find someone to take over the job.

Another question: Would high humidity tend to make a weak coil worse? Would the humidity possibly lead to a coil going bad? I keep the bike in my garage, but for about a year, I've had a BIG problem with the garage flooding when it rains hard. The bike, and everything else in the garage, sits there in 1-2" of water for a day or so as it slowly dries out. It's pretty humid here (south La.) anyway, but this is even more extreme. Could this have contributed to the problem??:confused:
 

·
Premium Member
Joined
·
2,626 Posts
Another question: Would high humidity tend to make a weak coil worse? Would the humidity possibly lead to a coil going bad? I keep the bike in my garage, but for about a year, I've had a BIG problem with the garage flooding when it rains hard. The bike, and everything else in the garage, sits there in 1-2" of water for a day or so as it slowly dries out. It's pretty humid here (south La.) anyway, but this is even more extreme. Could this have contributed to the problem??:confused:
Take a very close look at the terminals in the ignition system! Corroded terminals will cause the same effects as bad ignition coils.

Jim
 

·
Banned
Joined
·
2,731 Posts
I never use a battery tender, and I have heard that they may actually shorten your battery life.
Of course, the real reason I don't have is that I am too cheap to buy one.
 

·
Premium Member
Joined
·
14,085 Posts
I suggest you do what Jimmy advised, check the spark in the plugs and the ignition terminals before you change the coils, coils are very expensive and changing all 3 is a small fortune. If you've have a nice blue spark on all three it's not the coils.


----------------
Ride on ! :)
 

·
Registered
Joined
·
350 Posts
I assume you are aware of the famous rough spot known amongst classic triple owners? It's common within the different models (TB, TBS, Adv and Legend): a rough running engine around 3000 rpms in high gear (some variations in rpms due to different gearing within the model range)

This is as I mentioned a common phenomenon, and indicates nothing wrong. Just kind of a character feature....
 

·
Registered
Joined
·
13 Posts
I am dealing with very similar things. My 95 TBird has almost 20k on it, and back in November did the 18k service on it(1000 miles late). But same thing, starts in the morning, which temperatures are usually in the 40's to low 50's, runs fine until it warms up, then it starts missing. Almost like it's not getting enough gas. Especially when you are trying to give car that is not paying attention to the road a warning rev.
 

·
Registered
Joined
·
360 Posts

·
Registered
Joined
·
13 Posts
Eyun_G
Thanks for the suggestion. I am thinking it may be that or clogged jets. I put half a bottle of carb cleaner through in a full tank, and it did make a difference. Running smoother, but still feels like it is being held back a little. Maybe a combo of things.
 

·
Registered
Joined
·
108 Posts
There is a small mesh filter INSIDE the fuel pipe!.I only know this as I have a hard copy parts list.It does`t take much to get blocked and stored bikes get crystals from evaporated fuel.I tend to drain the carbs If leaving for more that a month.pipe pt.no.t3620060.....filter1240180-to301
 

·
Premium Member
Joined
·
2,626 Posts
There is a small mesh filter INSIDE the fuel pipe!.I only know this as I have a hard copy parts list.It does`t take much to get blocked and stored bikes get crystals from evaporated fuel.I tend to drain the carbs If leaving for more that a month.pipe pt.no.t3620060.....filter1240180-to301

That's the 'duckbill' filter in the fuel log 'T' that we've been mentioning for the past couple of years.

If it's badly clogged the bike will idle briefly until it starves out and quits but then won't restart for some time until some fuel seeps back into the carb bowls.

Partly clogged it presents a symptom like that of a tank vacuum build-up: the bike will run at higher rpms briefly and then quit.

Jim
 
1 - 18 of 18 Posts
Top