Triumph Street Twin Problems: 5 Known Issues (Explained)

The Triumph Street Twin is making its way into bikers’ hearts. With its unique sounding engine and head-turning good looks, the Street Twin is simply a marvel to ride.

The Street Twin sets itself apart with more torque from low gear to top speed, not confused with the Street Triple in the Bonneville family tree.

With the Street Twin, Triumph made a parallel-twined, power-ripping machine.

In this article, we’ll be covering some of the most common issues of the Triumph Street Twin, which include:

  • Wiring Harness Issues
  • Engine Heating
  • Side Stand Problems
  • Failed Water/Oil Pump
  • Street Twin Gas Cap Issues

Let’s get straight into it!

1. Wiring Harness Issue

In August of 2020, Triumph Motorcycles America announced a recall for Street Twins released in 2019 and 2020 due to the wiring.

The issue was discovered at first to be an interference between the wiring harness and the handlebars— rider input on the bars was causing damage to the wiring harness over time due to this misrouted wiring harness.

Over time, pinching the wiring harness eventually resulted in riders reporting engines stalling without warning to Triumph dealerships all over.

The lower lug on the main-frame-headstock was rubbing against the wiring through steering and countersteering.

Eventually, so many damaged wiring harnesses were reported that Triumph bit the bullet and issued a recall.

VINs of affected 2019-2020 Street Twins are:

  •  VIN SMTD31GN3KT918702 through VIN SMTD31GN6LTAB9140, on bikes, produced October 04, 2018-April 15, 2020.

If you bought your Street Twin used, there’s a chance it didn’t get fixed up with the rerouted wiring harness.

If your manufacturing date and VIN fall between the range listed above, have your local Triumph dealership take a look and make sure you’ve been upgraded.

Some symptoms of a faulty wiring harness on a Triumph Street Twin:

  • Engine turning off when turning the handlebars
  • Dash lights not functioning
  • The bike is not starting up.
  • The horn not working

Solution

Triumph prompted owners to take their Street Twins down to the Triumph dealership to have a VIN plate protector fitted on it, effectively rerouting the harness in a less problematic fashion.

Upon inspecting the harness and determining if damage has already occurred due to the error, Triumph will replace it if need be, free of charge.

2. Engine Runs Hot

The Triumph Street Twin is a monster; part of what makes it fun to ride is its accessible power.

The Street Twin’s torque impresses a lot of bikers, but with all that power-output, the Triumph Street Twin heats up quick.

The Triumph Street Twin engine has been reported to get quite hot, but only when the bike comes to a stop.

This is because when the bike stops, the radiator-fan will kick in, and you’ll feel a blast of hot air coming from the engine. The fan automatically starts to cool down the engine, but if you’re positioned in a certain way, the fins might be aimed at your feet.

This is normal, and hot motors are just a part of riding.

That said, if the engine is hotter than normal, especially if it hasn’t been ridden hard or for a decent amount of time, it may be indicative of a bigger problem.

Here are a few issues that might be the cause of the bike getting too hot:

  • Defective water pump
  • Faulty wiring
  • Faulty radiator
  • Wrong coolant
  • Lubricant leak

Most of the time, a rider was concerned about it, though; it was just the result of the fan doing what it’s supposed to do and deflecting the engine’s heat while the bike is idling.

Obviously, on a hotter day, the air blasting out of the fan will be a lot more uncomfortable but not scathing. Owners report that when the Street Twin comes to a stop, the one leg facing the fan will feel hotter than the other.

If it’s a bother, kill the motor until the light turns green or traffic starts moving.

Bear in mind that the radiator fan’s air is not hot enough to cause damage or injury.

Owners who’ve experienced this say that the air is hot but not too bothersome.

3. Side Stand Issue

A few Triumph Street Twin owners have complained about a broken side stand switch.

The Triumph Street Twin, much like other Triumph models, comes with a side stand switch.

This switch communicates with the sensor and kills the ignition if the side stand is open or missing.

The ignition off of the side stand is suspended as a safety precaution, preventing the bike from riding around with a kickstand poking out and snagging.

If the sensor is not working correctly, the engine will be killed even if the stand is up in the proper riding position.

Most owners found that the switch is easy to diagnose and fix or replace.

The Triumph Street Twin manual recommends replacing the side stand switch if it is defective.

There are ways to bypass the sensor completely, but replacing the malfunctioning switch is probably the safest and most straightforward option.

4. Failed Water/Oil Pump Replacement

This is a less common situation, but it has been reported by a few riders nonetheless.

The oil and water pumps on a Street Twin are essential because the motorcycle is water-cooled. A leak can spell disaster for the engine if not attended to immediately.

The pump on a Street Twin has been known to wear and tear easily, resulting in unnecessary heat issues and the check engine light always turning on. This is because when the pump starts wearing out, fluids are susceptible to leakage.

A fluid leak unsafe in its own right, but if coolant fluids are leaking, it also means that the engine isn’t getting cooling properly.

In the cases we found, the leak resulted from a hairline crack on the water pump.

Replacing the pump is the safest bet here. If your bike is under warranty, this is should certainly be covered, and the riders we’ve encountered had the faulty pump replaced asap at no charge.

5. Street Twin Gas Cap Issues

There are two gas cap complaints we’ve encountered from some owners of the Street Twin, both of which are easily fixed:

  1.  The gas cap seems loose.
  2. The gas cap seemed too tight.

This is certainly not a problem that would render the bike unusable, but it is still a safety concern.

A few owners have noticed that the gas cap will be so loose that it rattles and shakes when the bike is in motion.

The gas cap on the Street Twin can be locked and unlocked using the key. When locking the cap, you have to make sure that the cap is tightened securely.

If you can remove the key easily after locking the cap, it is usually secure and sealed.

If you’re sure you’ve locked the gas cap properly, there’s a chance that the rubber seals on the cap are worn, and it’s time for a replacement gas cap.

On the other hand, a few owners have had problems with the gas cap being too tight. This is usually with a new Street Twin or a new gas cap. The rubber seals are brand new and generally very tight from the dealership.

This is because the gas cap hasn’t been removed and reinserted continuously yet. Give it time; new seals will break-in.

If it is too tight, a few who experienced the problem finally got it open using a pair of rubber gloves and using a bit more force than usual.

A gas cap’s tightness on a Street Twin usually goes away with prolonged use after filling up frequently.

The few who were unable to live with their gas cap problems ended up replacing the cap. A Street Twin gas cap is interchangeable with a few other Triumph models.

To be on the safe side, if you’re having trouble sealing the gap properly, a new gas cap is recommended.

There are a few great choices for 3rd party gas caps that both work and look great on the Triumph Street Twin.

You should also be reading our article which talks about 5 Most-Common Problems With Triumph Street Triple

Pros And Cons For The Triumph Street Twin:

Pros

With a Triumph Street Twin, looks and performance are a great balance.

This iconic Triumph model is known to deliver excellent handling for both highway and city driving.

What impresses most riders and owners of the Street Twin is how seamlessly it delivers power when needed. This makes it a joy to ride when overtaking and getting onto the highway.

Triumph has designed Street Twin with a staggering 18% more horsepower. Coming to a stop is a breeze on the bike, with riders reporting that the bike’s suspension and brakes feel “upgraded.”

The bike looks fantastic, which is evident with the increase of female riders choosing the Street Twin as their daily driver. Triumph has always made great-looking naked sportbikes, but the Street Twin, and its close relative the Triumph Scrambler, is undoubtedly on a league of its own.

Most Triumph enthusiasts admit that the Street Twin is a stellar release as a modern classic.

Cons

  • Wiring Harness Issue
  • Engine Heating Up Problem
  • Side Stand Issue
  • Failed Water/Oil Pump Replacement
  • Street Twin Gas Cap Issues

What Do the Reviews Say?

“Before seeing the new Triumph Street Twin 900HT in person, riding it, and hearing all the details, I thought that liquid cooling would be an exceptional detail, but I was wrong. In fact, this is a whole new bike wholly steeped in the old yet forward-facing and executed for 2016 without trying to over-think the future. The people at Hinckley have done a splendid and comprehensive job.”

[See References: MotorcycleNews.com]

“Literally, everything about the bike has an ease of use that is hard to criticize. However, it is a polished end product, and much of the character has been buffed out of it. I’m not an old duffer who wants oil leaks and self-closing tappets, but the Street Twin reminds me of the UJMs of the 1990s, the universal Japanese motorcycles that were derided, perhaps thoughtlessly, for their soulless efficiency. If you love the looks of it, I doubt you’d regret a purchase, but there is a distinct lack of X factor.”

[See References:CycleWorld.com]

What’s The Resale Value On The Triumph Street Twin?

Year Mileage (miles) Price ($)
2016 Triumph Street Twin 2,749 7,499
2017 Triumph Street Twin 10,294 6,999
2018 Triumph Street Twin 17,000 6,500
2018 Triumph Street Twin 3,108 6,999
2019 Triumph Street Twin 5 9,550

NB: Please note that the above prices may vary according to the bikes’ location and models.

References:

www.ultimatemotorcycling.com

www.cycleworld.com

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