2024 Triumph Speed 400

I was making a right turn at an intersection while in 3rd gear with the clutch engaged, and the motorcycle stalled. I was able to restart the motorcycle while executing the turn and completed the turn without incident. Failure to do so would have put myself at risk from oncoming vehicles through the intersection. When this has happened the low oil pressure indicator illuminates. The oil sight glass shows oil level to be at max. I use ExxonMobil 93 fuel. I had taken the motorcycle in to conduct service for the same issue (the motorcycle stalled while in 1st gear at a stoplight) and an existing recall repair had been done about a week ago. The motorcycle has been emitting a strange odor since the repair that I am not sure what it is from.

Riding on a highway at about 70 mph, the bike sputtered so I got into the right lane, pulled in the clutch and the bike lost power so I coasted onto the shoulder. The bike has not started up since--I was towed home. I saw no warning lights in advance. The bike was serviced after 600 miles and now has 5200 miles. Had I been in the far left lane, I may not have been able to safely get off the road in heavy fast-moving traffic. Cause of problem: UNKNOWN. I'm assuming I'll have to have the bike towed to the dealer for repair.

On 5 different occasions over a period of 6 months the motorcycle has cut off while slowing down or at a stop. Each time it has taken several attempts to get the motorcycle to start again. This has caused extreme risk in traffic. Here are the dates, mileage and description of each incident. 8/10/25, 30 miles - Engine cut off while sitting at stoplight in neutral with no hands on the handlebar. Observed that the kill switch was off even though it had not been touched. 9/2/25, 159 miles - Engine cut off on its own while stopped in culdesac. Kill switch found off again. 12/17/25, 2183 miles - Engine cut off in traffic. Kill switch was off. Trouble starting, took multiple attempts. 12/23/25, 2305 miles - Engine died while going about 35mph when clutch was pulled in to downshift. 3/8/25, 3019 miles - Bike cut off while slowing to a stop, with clutch in, cut off as shifting down to first gear. Took multiple attempts to start again.

Bike shut off electrically while traveling at highway speeds. Signal flashers and emergencies failed and there was no throttle response. Check engine light came on and traction control disabled light came on. Bike displayed an error code of P2138 and P2122. Bike was unable to be safely ridden after being shut down and restarted. The bike could be ridden after starting for a short time before the throttle cut out again and complete loss of power. Emergency flasher functionality was intermittent with each attempt at starting the engine again.

I had been riding on a road for about 15 minutes at speeds ranging from 40-50 mph. As I came to a stop sign, I downshifted and used engine braking to assist the brakes in slowing down. After I downshifted from 3rd to 2nd gear, the engine quit and all dash lights illuminated. I pulled the clutch, pressed the starter button as I coasted, and the engine re-started. The engine ran fine before and after the incident. This happened at approximately 1,600 miles. This is the second time this happens under similar conditions: downshifting from 3rd to 2nd, and using engine braking. The first time it occurred, I was unable to restart the engine while coasting. I had to stop, turn the ignition off and on, and restart. This happened at approximately 800 miles. This seems to be a random occurrence. I have not been able to recreate it on purpose. I have not had the motorcycle inspected by the dealer for this issue, since it is not isolated to my motorcycle. Online forums for the Triumph Speed 400 and 400 Scrambler have many instances of this issue occurring: [XXX] [XXX] [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The motorcycle cuts out when slowing down—engine just dies, but all the electrical stays on. This is a brand-new bike with only 500 miles on it. It happened while I was riding, and I suddenly had no power. Luckily, I was on the right side of the road and managed to coast to the shoulder safely, but it could’ve gone a lot worse. There were no prior warning lights. I scheduled an inspection, but the earliest appointment isn’t until later this month. In the meantime, I did some digging—this doesn’t seem like an isolated issue. A quick search shows a lot of riders are having the same problem. It’s not just a software bug—forums, independent sites, even YouTube videos are all showing the same failure.

Coming to a stop the engine just quit, as if I turned the ignition switch off. The dash was also blank. I turned the switch to the off position and then back to the on position, and it started as normal. I have read about this same sort of thing happening to numerous other riders of this bike. Triumph needs to have a recall to fix the glitch in the ecu.

The contact owns a 2024 Triumph Speed 400 Motorcycle. The contact stated while driving at various speeds, the vehicle independently turned off. The MIL warning light was illuminated. The local dealer was contacted, but the vehicle was not diagnosed or repaired. The contact stated that the dealer would be towed to the dealer. The manufacturer was not contacted. The failure mileage was approximately 120.