Hi guys, my name is Sean. I just moved to California. I’m in North Hollywood after spending my life in Utah. I need help because my 2018 Street Twin won’t start. It hasn’t been started in almost two years, and it was outside in the cold northern winters for the last few years. I put in a new battery, drained the gas, and cleaned the tank. I also cleaned pretty much everything I could reach with Sea Foam. I put in new spark plugs and a new air filter, and it turns over strongly it just won’t start, like it’s not getting any fuel. I’m thinking my next option is replacing the fuel filter and everything in the tank. Before that, I thought I’d ask you guys, who I’m sure know a lot more than I do. Pretty much everything I’ve done, I’ve learned watching YouTube. Any more thoughts? I’d sure appreciate any help or ideas. Thanks!
Hello and welcome,
I’ll start with the obvious… both plugs getting a spark? And do they smell of petrol if you take them out?
Spark but no fuel - check fuel lines
Fuel but no spark - check circuits
Fuel and spark - check O2 supply, can she breathe?
Hi and welcome to the forum
What he just said - check for a spark first
Hi and welcome. What they said… 
Hi and welcome, good luck getting your bike started.
Thanks for the advice and the welcomes. So I checked, and yes, it sparks on both plugs, smells a little like gas, but very faintly, and isn’t damp at all. Air flow is good on both sides.
I don’t know how much fuel injectors squirt in for start up, so have no idea about how much evidence of fuel is normal, but to speculate somewhat wildly, there could be an issue with the fuel pressure. Do you hear the fuel pump run for a second or so when you turn on the ignition? (I think it may not run though if already up to pressure.)
Looking at the wiring diagram, the fuse for the pump is the same as for the ECU, so that must be OK. But the fuel pump is also switched through a relay so it may be worth trying to check that’s working by testing that the fuel pump (connector under tank?) is getting 12V. At least that’s something you could check first before going the whole way to removing tank to replace fuel filter (which is attached to the pump inside the tank).
The reason I thought of the relay is because I had a pin on my radiator fan relay corrode and break, but I think you have a somewhat better climate than me here in the UK 
a so don’t experience salted roads in the winter.
Edit: Actually, thinking about is again, with my relay problem I still got 12V at the fan connector which misled me lots. Turned out that the corroded contact was making a high resistance connection so showed 12V on my multimeter but it couldn’t supply the current to drive fan. So lesson is to check voltages with some load attached. E.g. a 12v indicator bulb.
Thanks Brownmouse,
Yes, I can hear the fuel pump running in the gas tank when I turn on the ignition. It runs and continues to run, so I don’t think it is ever getting up to pressure. I don’t have a multimeter, so I’ll need one since I’ve also discovered that finding a replacement fuel filter for my bike is relatively impossible. Might also take the existing fuel pump out and take it apart, and clean it based on rarity and price. Saw comments on YouTube of people saying this kind of issue could be caused by fuel injectors also. Some said it could be air in the line and recommended putting a drop or two of fuel into the spark plug holes, then putting plugs back in and trying to start it, as this will force start it and get rid of the air in the line. I wasn’t confident in any of this without more research. Any thoughts from you or anyone else on any of this?
It’s a part common to pretty much all of Triumph’s current bikes, part T2407046. So any Triumph dealer or parts supplier should be able to get one. Cost in UK is £60 so pretty expensive and no doubt it’s identical to some generic part you could get for considerably less if you knew one was compatible. Try googling that part number, here in UK that get’s cheaper sellers and some ebay hits.
If the fuel pump is running continuously that sounds like it isn’t getting up to pressure, so it seems possible that the filter or strainer is blocked. (Could also be due to the pressure sensor not cutting pump off, but then presumably they’d be pressure for bike to start.)
You said in your first post that you drained the old fuel, did you have the tank off for that? If so, then maybe the fuel hose isn’t reconnected properly. There again, you’d expect fuel to be leaking out if that was the case which presumably would be rather noticeable.
BTW, in case you haven’t come across them, there are many sites with parts diagrams.
E.g. Fuel pump for Triumph STREET TWIN - Triumph I know I’ve come across US sites before when googling part numbers but right now I can’t make Google do that.
Also, if you don’t have any kind of workshop manual, it’s possible for a modest price to get a month’s subscription to Triumph’s official service instructions at https://triumphtechnicalinformation.com/ I use that for major service and repair tasks on my bike (as well as a Haynes workshop manual.). I should warn you though that for some tasks, Triumph’s instructions have a habit of starting out by saying ‘remove part X’ which can often be a big job that is unnecessary. E.g. to get access to radiator fan it wanted me to remove exhaust and drop engine! But with much knuckle scraping and patience I managed to get it out without such drastic action. (Which proved a wasted effort as it was that corroded relay connection! 
)