Top speed would be governed by the rev limiter and the gear ratio, assuming you can hit the rev limit in 6th gear. You could put a performance cam in it, high compression heads, grind the valve seats and swap for oversized valves, but you're still governed by the gearing and rev limiter. Many lower the gearing a bit and enjoy the better application of power to the rear wheel at the sacrifice of a touch of top end speed and mpgs.

I've heard the T120 tops out around 108mph, the Thruxton more like 120. Maybe a Thruxton or Speed Twin would fit your needs better than the T120.

 

As far as I know, top speed is governed by the ecu, not the rev limiter. Someone did the math once and if the ecu didn't cut spark at the governed top speed, you could get up over 150 mph. Edit, now I'm thinking it was maybe closer to 140. I can't remember.

 

I also suggest getting a faster bike, as the T120 is basically set up to be an upright cruiser. The previous owner of my machine traded it for an Indian FTR1200 with 50% more power. The BMW RNineT is a good-looking Retro with 110 BHP or the Speed Twin, of course.

You may need to upgrade the brakes as the standard T120 gear is on the limit for the performance of the bike.

 

Also kinda depends on how "performance" is defined. The T120's high torque engine is designed to pull like a draft horse in any gear. Power and torque curves are nearly flat, so higher RPM doesn't net higher performance. I seldom see the high side of 4,000 RPM on shifts because I know that higher RPM gets me nothing. This is a design characteristic of this engine and this engine alone, and it's a marvel. Rowing through the gears looking for power peaks that don't exist is pointless. The engine simply doesn't require it. Learn to listen to what the bike is telling you.

 

Now, I realize my Scrambler 1200 isn't identical, but it sure makes a big difference there. Looking at the t120 dyno chart, you're making around 50hp @ 4000rpm and 70hp @ 6000rpm. Which is what I'd expect, and is definitely an increase. You'd need a very downward sloped torque curve to get a flat power output across rpm.

 

With a flat torque curve, horsepower goes up linearly. The rev limit won’t restrict power on the stock engine because the torque falls off. I think 150 mph is very optimistic without a full faring. You could do all kinds of things to the engine to get more power, including a supercharger. Why bother? It’s a Bonneville. Get a different bike for the big power. Like a Rocket or an M1000RR.

 

Top speed depends on the ability to translate that torque into HP. You could have 150 lb ft of torque but you’ll never get to 150 mph if the engine won’t rev past 2000 rpm.

 

Trade it in for a Speed Twin 😉

 

My bike will do 140 right out of the box. It’s yours for $14k.

 

Can you reach redline in 6th gear? I changed to a 42T rear sprocket on my T120, which results in 60 mph at 3000 rpm in 6th, it will pull to 6000 rpm or 120 mph. It's a naked bike and no fun to ride any distance over 70 mph without at least a flyscreen to remove some of the wind pressure off your upper body. On the other hand, my BMW K1300GT is very comfortable at autobahn speeds but it's fully faired and 160hp. Plus, if you don't live between the Rockies and the Mississippi River. It's hard to find any place with a speed limit over 70. The T120 likes the back roads and two lanes. If you need the high performance, you need a different bike.

 

Maybe another type of bike would be the best route.

 

This is how I improved performance on my T120….

136HP / 105TQ

 

This is how I improved performance on my T120….

136HP / 105TQ

View attachment 848782

Me too. If I could have replaced my 2017 T120 with a T120 with the specs of my BMW, I would have.

 

But then you have to look at that fugly BMW (IMHO) 🤣
... not worth it for me, I'd live without the extra grunt!.... but each to their own

 

That’s exactly why I sold my 2017 R1200R… great bike though.

 

Ok I see.....what size motor on the MT07......its a lot lighter that a T120.....so its very unfair on the T120 dont you think.

 

Yes it is a lot lighter, but the MT07 also only has 45ft/lbs of torque, along with a 700cc engine. I believe the t120 should be able to do it especially considering the mt07 is also a naked bike

 

The best this motor can do stock is 103 hp. If you like the brand and the classic look, wait for the new Speed Twin 1200 RS. The T120 is the inheritor of the Bonneville legend. I saw a review of the R1250R and at the end, the guy said the only competition was the T120.

 

Would increasing air flow via Air Box Delete, and some baffle less pipes give a higher top end?

 

Sounds as if you have the bike optimized for about as much performance as you are going to get out of it. Spending the money to get another 4 horsepower will take you down the road of never seeing that money again, and all things considered, seldom will you find you are in the power peak to enjoy that. Keep in mind, the bike has limitations with the frame, shocks, forks etc. that come in to play. If you want to rip and try to achieve over 100 horsepower, I think the best option is to get a bike built for that.

 

I think we are all forgetting about that Pirelli motto "power is nothing without control".

The main limits on T120 performance are not in its engine, but in its suspensions, brakes, and structure.

It is fair easy to put this engine real far in speed or power. Only a few seconds needed to set the bike to over 100MPH still in 4th gear, and still have more gears and more than 2000 RPMs over.

But unless you are in a very long straight way in a very good asphalt quality road... then you will have to brake and lean... and that's when you will easily discover you went over the limits. Or rather keep down under what the engine could do.

If feeling it not enough I would start making huge changes in suspension, brakes and probably handlebar. After that maybe you will find still in need of more power, or maybe not.

 

I think we are all forgetting about that Pirelli motto "power is nothing without control".

The main limits on T120 performance are not in its engine, but in its suspensions, brakes, and structure.

It is fair easy to put this engine real far in speed or power. Only a few seconds needed to set the bike to over 100MPH still in 4th gear, and still have more gears and more than 2000 RPMs over.

But unless you are in a very long straight way in a very good asphalt quality road... then you will have to brake and lean... and that's when you will easily discover you went over the limits.

If feeling it not enough I would start making huge changes in suspension, brakes and probably handlebar. After that maybe you will find still in need of more power, or maybe not.

In other words, buy the Speed Twin 1200 RS.

 

Speaking of money down the toilet, spending $3-$4K on the T120 to 'improve' the handling, you can kiss that money goodbye for sure. No one else is going to recognize the value of those components, and the architecture is all wrong for trying to make the classic run like a CBR1000RR. Take the Bonneville T120 for what it is, a Gentlemen's ride with good performance and great looks. Your trade in value may even be lower with all the mods to the T120, most people buying a 2nd owner bike will be looking for a pretty much stock bike, the mods may provide too harsh of a ride for the buyer who is looking for the modern classic. Best bet and overall happiness is going to be to go with the Speed Twin 1200Rs...a bike engineered more for what you are looking for performance wise. At the end of the day, you won't be spending a dime more for doing the heavy mods you are talking about.

 

Speaking of money down the toilet, spending $3-$4K on the T120 to 'improve' the handling, you can kiss that money goodbye for sure. No one else is going to recognize the value of those components, and the architecture is all wrong for trying to make the classic run like a CBR1000RR. Take the Bonneville T120 for what it is, a Gentlemen's ride with good performance and great looks. Your trade in value may even be lower with all the mods to the T120, most people buying a 2nd owner bike will be looking for a pretty much stock bike, the mods may provide too harsh of a ride for the buyer who is looking for the modern classic. Best bet and overall happiness is going to be to go with the Speed Twin 1200Rs...a bike engineered more for what you are looking for performance wise. At the end of the day, you won't be spending a dime more for doing the heavy mods you are talking about.

I considered exactly your suggestions for my 2017 T120 in 2020 plus a cam. Then I test drove an R1250R which has it all in spades and made the big move. BTW, tge Brembo kit for the T120 still doesn’t give you radially mounted calipers.

I do not even own a T120, nor would want more performance than I already have in my speedmaster.

Nor suggesting the option any one wanting to improve should take is doing mods.

But I love my bike. And if I would tomorrow feel some features needing to be improved (whatever they are), I would possibly prefer modifying than changing it. I have already invested more than that in improves in my bike not to transform it into faster, but into a comfort tourer.

I could have also taken the standard option of buying a Honda NT or a BMW RT but those are not the bike I want. And have not problem with the fact there is no "selling value increase"... i do not want to sell my bike nor will want until it dies or I get unable to ride.

And I know some guys who love their T100 or T120 in the same manner. And would not want to hear "change your bike" if asking about improves.

In fact this seems to be the position of the OP. He did not ask if he should keep or change the bike, he asked what he can do, not remarking "being cheap" or "not being too much invest for the bike value".

Knowing all the facts, everyone will be able to make the right decision for his own happiness. Being keep the bike as it is, buying a new one, or modding the T120.

 

No worries, we are just putting out there our thoughts and experience to the post asking about increasing the engine output. Having owned 49 motorcycles, and learning the hard way on what works to achieve the desired result, I put my two cents worth. Try owning a Harley someday...you will know EXACTLY what I mean !

 

Well the post is not asking about "increasing the engine output". @Dillonb is asking about "Improving performance". Not exactly the same.

And In fact I did own one Sportster 1200 in the past.

And also spend a bunch of money improving it. Though not as much and with same conviction than in my Triumph, sure.

I know a bunch of guys who changed the engine in their HDs by some of those alternate peformance units by S&S. I do even know a guy who placed a Honda CB1100 engine in a Dyna .

And also have a close friend who is a pro mechanic and a few years ago was involved in preparing an HD for some test speed racing at bonneville track:

Obviously it costed an insane amount of money, and it is hard to recognize the origin, but I am sure that bike (that started being some harley) could make a BMR 1200R seem slow.

And I bet there are many similar cases out there that started with a Triumph bonneville and ended up with a motorcycle ready for track racing.

Of course that is an extreme case, and no doubt by pure economy consideration choosing and keeping the bike to serial is the most efficient.

But many of us have that profitability very low in our priorities when speaking about "my bike" and the answer to question "what is simpler, cheaper and easier to get performance" and "what could I do to my bike" can have very different answers. 😋

 

Contact nevillelushracing.com and ask him what is possible for a 2018 T120.

 

Doug,you're taking this far too seriously .

The OP is an 18-year old with his first bike racing his friend on a Yamaha MT-07 at 90mph and wanting a higher top end.

By the time he contacts Neville Lush, he will probably have passed on!

Kind Regards,

John

 

As it has been said in engineering school for the aerodynamics principles of flight. Question - what makes an airplane fly? Answer - MONEY makes an airplane fly and the Harrier Jet proves it! Anything can be made fast, just how much money is it worth to get a few more horsepower out of the engine designed for a wide torque and power curve.

 

A few hp may not be worth it but adding 10-20% may be worth it. For $5k, you can transform a 130 rwhp Rocket III into a 200-260 rwhp Rocket III. People do it. What you’re going to do with all that power is another question.