Let’s Pimp My Street Twin

The standard ECU can continually adjust the mixture in real time to compensate for air temp and density changes with a standard setup but I doubt it will handle the air filter and exhaust mods you have planned and liberate any more power. As Hubaxe has said, you will need to re-map the ECU. The bikes run very lean as standard, as most new bikes do. I'd go with fitting the Booster Plug first with nothing else as some users have reported a noticeable improvement while others felt nothing. I'd then add the filter. I'd say the decat exhaust mod will have the biggest effect on mixture so I'd do that last and source a new ECU map in preparation. If you're after outright power gains, IMO you'll need at least a 10-15bhp gain to feel any difference. Use of a dyno will confirm smaller gains and alterations in the power and torque curves but if you can't "feel" the difference there's really no point.

 

I did a few mods and have a completely different bike now.
I came off a modded BMW RNineT 1200 and was almost crying into my cornflakes when I first rode the Street Twin I blindly bought... I loved the look of the ST but it was borderline useless above 50mph.
The first thing I did was do a tonne of research on the camshaft mod and settled on the Tec upgrade, after a few hundred miles of running it in, and an oil change, I couldn’t believe the difference - worth every single penny.
Next up I bought some Remus straight thru headers and V&H (USA spec with removable baffles) and the bike just sounded incredible. I popped a K&N air filter in there and removed the snorkel, more sound gains again.
Yes, the fuelling was crappy and at idle it struggled to run so I bought a booster plug and all is well. Just make sure you locate the oxygen sensor in a good place and do the correct method in cycling the bike so it can adjust the ECU.
The booster plug really helps, it would definitely be better with a remap but it works just fine. Overall I’m really chuffed with the mods, I should have just bought another 865EFI but I was in and I do enjoy doing my own mods.
I don’t know how many HP it has added to the bike but it’s not 2 or 3 or 5... it’s a good chunk and the bike rides so much better now, in all gears, at all revs.

Best advice I would give is to do the camshaft before anything else - in my experience you’ll be wasting time and money with incremental gains by doing all the other bits first. Get the camshaft done and then get to work on the bike breathing properly. She’ll be top notch once done.
Hope that helps

Jim

 

I think the the TEC camshaft upgrade is for the earlier Street Twin/Scrambler up to 2019 and brings the power up to the 2019> bikes which Triumph did several upgrades to. On the handling front I fitted some TEC progressive fork springs to my Street Scrambler which were a big improvement.

 

Ah yeah... doh!
Triumph list the 19 onwards as 65hp... I’d bet mine has more than that, has cost a fair bit tho.
If there’s no camshaft option out there and the Street Twin stays then it’s gonna be a few quid for not a lot of gains IMO.
I personally would look at swapping it for a Speed Twin, something I almost did but I have a superbike too so didn’t really need the Triumph to perform too highly.

 

I reckon Triumph could easily liberate 90+bhp from the 900 lump. The guy on the TRC website suggests the reason they don't is that it would put it too close to the 1200 in performance and hit sales of those models and I'm inclined to agree with him. Personally, I'd sign up for a 1200 version of the Street Scrambler tomorrow, same looks, ergonomics etc but even as it is I still prefer it to the current 1200 Scrambler which is a completely different bike.

 

The problem here is that you do not appear to have a target, so you will never know when you have arrived.
You need to take a test ride on a Street Triple, Thruxton or similar to work out whether their power/weight ratio is sufficient for YOU.
Once you have determined the target power to weight ratio, you will know exactly what needs to be done to the 900 to get there in terms of power increase and weight reduction.
This should speed up the modification process considerably as you will not have to go through many smaller iterations to reach your target.
I can't offer any helpful advice until you advise the target power to weight ratio.