You may have noticed there’s a lot of new motorcycles coming out lately (half of which seem to be from Yamaha). That means if you’re a person who likes to get an aftermarket exhaust bolted on straight away, you might need to wait a while until one is designed by the big brands – or perhaps they won’t bother at all if your bike is regarded as ‘niche’. Two Brothers Racing has come to the market with a new solution – design your own aftermarket exhaust.
“There is just plain and simply not enough time in the day to keep up with all of the bikes coming out” says Joel Albrecht Two Bros R&D supervisor. Joel worked countless hours with Two Bros engineers to develop all the right pieces for the job. “We wanted to find a way for people to buy each tube they need to make quality headers themselves” adds Joel never a man of too many words.
Each piece has been designed around common sizes and bends so that customers can pick the right fit for them to build whatever they can imagine. Using only high quality steel mandrel bent to precise tolerances the “Build-Your-Own” product line will work on everything from budget builds to over the top customs. The Two Brothers website www.twobros.com has also been updated to have images and detailed measurements of the available options.
“Build-Your-Own is perfect for someone looking to build headers without spending thousands on tools first” concludes Joel. Weather you build custom bikes for a living or you are just the do it yourself type Two Brothers Racing has you covered. Be sure to check out “Build-Your-Own” before your next build.
This month we installed what will be our one and only major horsepower upgrade for our Ninja 300 track bike – a full exhaust system replacement form TYGA performance. We also recouped a small amount of costs by selling some unneeded parts plus drained the battery by accidentally leaving the ignition turned on overnight. Oops!
One of the great things about spec bike series is that generally the modifications you’re allowed aren’t too expensive. It all adds up to thousands of dollars once your’re done, but at least you’re not competing with people who are willing to spend thousands of dollars alone on engine internals to get a few extra horsepower out of their bike. Instead, we’re left to focus on things like the exhaust and suspension to improve the bikes performance.
And that’s what we’ve done this month by installing a new exhaust system on the Ninja 300. Not only is the pipe design more free flowing, but we don’t have to worry about resonators and catalytic converters either. We went with an exhaust system from TYGA Performance for a few reasons.
Firstly, I’d had good experiences with the company previously. Secondly, the system is very competitively priced. The system we got with the maggot silencer is $342.47 USD – most full systems from the bigger manufactures range between $500 and $600. Third, despite that great value, the TYGA system performs very well.
This system has previously been independently tested by Kawasaki Racing Australia against a Leo Vince full system. The bike the Leo Vince was tested on had both a freer flowing race air filter and had been tuned for higher octane fuel – the dyno run gave figures of 38.3hp. The bike the TYGA system was attached to was otherwise stock and managed 38.4 hp. We think we a race air filter and perhaps some adjustments to ignition timing with higher octane fuel, we could get over 40hp out of the bike. That would be a 5hp improvement over the stock bike, or a pretty decent 15% improvement in ouput.
To get it working properly however we’re going to have to flash the ECU to deal with all the extra air the engine is now getting. You can see on the picture below a hole in our exhaust (currently sealed) – this is were the O2 sensor will go which will connect to an aftermarket fuel management system like a Power Commander V or Bazzaz Performance Z-Fi. We’ll be buying an ‘autotune’ piggyback unit which will allow on the fly management of the whole system. More expensive in the short term but we’ll save money in the long run by not having to visit the dyno whenever we change something on the bike. It will also mean the engine will perform optimally regardless of ambient temperatures.
During June we also sold a number of items that we would no longer need for the bike. Things like the rear fender, brake lights, mirrors and so forth. We gambled and put everything on eBay as auctions with no reserve and unfortunately we certainly didn’t get what their value was. All up, we sold about six items (including the exhaust can) for about $200 while their true value was probably closer to $300-$400. Such is life and we now have more room in the garage anyway.
Next month the bike will lay dormant due to other commitments, but August will be fun. We’ll be replacing all the internals of the front forks (springs, valve body, etc) and adjust them correctly for preload, rebound and compression.
If you’ve just read our article on the ins and outs of motorcycle exhausts, you may be keen to go and buy a replacement system for your bike. It’s not a cheap modification by any means but in relation to the horsepower gains and weight savings it produces, it’s good value. Some might be scared of installing the exhaust themselves given that it connects to your engine, but fear not. This is one of the easier upgrades you can do yourself.
While the specifics of removing your old exhaust and installing a new one will differ from bike to bike, the overall process remains similar. The time it takes will vary greatly depending on how many cylinders your bike has. A thumper will be nice and quick while a four cylinder will take a little bit longer. You’ll almost definitely need to remove fairings from both sides of the bike to gain access to all the places you need.
Tools we’d recommend you have at your disposal are:
Breaker bar, to loosen any bolts attaching the old exhaust to your bike
Ratchet wrench for removing said bolts
Torque wrench to tighten the bolts when attaching the new exhaust system
Thread lock to help secure bolts in place
Muffler and exhaust sealant to ensure no air leaks from your new pipes
When removing your old exhaust, start at the muffler. By detaching it from your bike and removing it from the exhaust, your removing the heaviest part of the exhaust system. This will ensure you don’t bend the header pipes which connect to the exhaust ports. You’ll need to use your breaker bar here to loosen any bolts.
Once the muffler is removed, loosen any bolts that are keeping the remaining exhaust pipes connected to your bike – but keep it attached for the time being. Remove the bolts that are holding the manifold in place next to the exhaust ports – again your breaker bar will come in handy here.
Hold the exhaust system and remove the last bolt(s) holding it in place. Push the exhaust forward so that the header pipes exit the exhaust ports smoothly. You’re halfway there! If you’re not going to immediately install your new exhaust, cover up the exhaust ports so dust and other particles can’t get in – masking tape will do fine.
Now’s the time to start installing. We’ve gone with a Tyga Performance full system. We’ll be elaborating on our choice in our next Ninja 300 Project Bike update, suffice to say that the Tyga system provides more horsepower gains compared to other systems at nearly half the price. We like that.
It’s probably a good idea to do a quick practice run of putting your exhaust together before attaching it to the bike. One thing to keep in mind is the headers. Specific header pipes will need to go into specific ports – so make sure that you know which is which (they’ll be labelled). If you’ve got a four cylinder bike, you won’t want to have to put that puzzle together without guidance.
One thing to consider is putting new crusher gaskets in your manifolds. These little gaskets help ensure a seal between your exhaust ports and the manifold, preventing any air loss. They’re pretty cheap and ensure all the money you’ve spent on your new exhaust isn’t wasted by a silly air leak.
For installation, we’ll go in the reverse order of removal. Place the manifolds onto the ports. At this stage, tighten the bolts with your hand only as you’ll want the header pipes to be able to move a bit when attaching them to remainder of the exhaust pipe.
Attach the exhaust pipe to your bike, again only hand tighten at this stage. Make sure everything lines up and before connecting, place a good amount of muffler/exhaust sealant onto the outside of the pipe that will go inside the other pipe. That generally means putting the sealant onto the outside of the header pipe and connecting it to the exhaust pipe. Put it about a quarter of an inch thick and about an inch wide – starting about a quarter of an inch from the edge of the pipe.
Connect the two pipes and then wipe away any residual sealant on your pipes. Now you can tighten both the bolts on the manifold and on the frame. In an ideal world, you’d use your torque wrench to tighten these bolts to the torque values specified by your motorcycle manufacturer. Unfortunately because of the confined spaces, our torque wrench wouldn’t fit so instead we used thread lock on the nuts and stopped tightening as soon as we felt resistance.
Depending on the fit of your muffler, you may or may not need to put muffler sealant on the pipes there too. Generally the fit here is much better than where the headers and the tail pipe connect. Attach the muffler to your bike (usually it bolts onto the passenger foot peg bracket) and you’re all good.
Wait 30 minutes for the muffler sealant to dry before starting the bike. Once the bike is running, place your hand over the connections to feel for any air leaking out. Just be careful as the pipes will become extremely hot within a few seconds of the engine running.
If you feel any air leaks from around the manifolds, it almost always means you need to install new crusher gaskets. For air leaks between the pipe connections, try and smear some more muffler sealant into any gaps (but wait until the pipes have cooled before doing so).
Keep in mind also that you should be very cautious about riding your bike with a new exhaust without having the fuel system retuned. Your bike’s engine is now getting a lot more air into it but with the same amount of fuel as before. That means your air/fuel ratio isn’t correct which causes your engine to running lean. That might just mean your bike runs a little off, but it can also mean that it overheats to the point of being destroyed.
To correct that, you’ll need a jet kit for a carburetted bike (and a dyno tune) or a fuel controller for an EFI bike (like a Power Commander) plus either a trip to the dyno or an additional module that automatically corrects the air/fuel ratio. Those automatic systems use an O2 sensor that goes into the exhaust – hopefully you bought one with the requisite opening for such a sensor. If not, you’re going to have to get someone to cut a hole into your shiny new exhaust for you.
One of the most popular modifications owners do to their motorcycles is to change the stock exhaust. But does installing a slip-on actually improve performance? What do you need to do after installing a full replacement exhaust? What should you be aware of before taking your modified exhaust onto the streets? Let’s take an exhaustive look at how motorcycle exhausts work (first time ever that pun has been used, guaranteed).
What An Exhaust Does
It’s probably first best to understand the purpose of your exhaust. While it most certainly performs the function of improving your bike’s performance, it’s just one of a number of important reasons that your exhaust system exists.
Probably the most important aspect from the riders point of view is that it routes the hot gasses from the engine after combustion. That’s somewhat critical because if you spent too long breathing those gasses in, you’d probably feel sick pretty quickly (or die). In fact, your standard motorcycle exhaust will house a catalytic converter which helps convert the carbon monoxide expelled from the engine into carbon dioxide which at least makes it slightly more environmentally friendly.
Your exhaust system with the help of the muffler also reduces noise. How much noise? A lot – disconnect your muffler from the pipe and you’ll see how much. You’d go deaf pretty quickly without it and you’d be public enemy number 1 around the neighborhood. Your muffler has nothing to do with exhaust emissions – nor with engine performance (but more on that later).
But finally, your exhaust performs a major function when it comes to how your engine performs. You may have read that aftermarket exhaust systems can help increase your engines horsepower by being ‘less restrictive’. That’s true, but does that mean that if you had no exhaust at all (and therefore no restriction) horsepower gain would be maximized? Not at all.
Your engine and exhaust system actually are designed to work together. It gets very technical and the practical application of how it all works includes things like reflected pressure waves. Suffice to say that without an exhaust connected to your engine, you’d be introducing air directly into the system in the wrong direction through the exhaust ports (consider how much would enter when riding at speed) which would throw everything out of wack.
So an exhaust system is necessary – both from a legal perspective, from a not going deaf perspective and from a performance perspective. So what can you do to make some horsepower gains? There’s two paths people take – the cheap way and the not so cheap way. That is, replacing the muffler with a ‘slip-on’ or replacing the entire system.
The Slip-On Fallacy
The subject of slip-ons is one of those things in motorcycle circles that many won’t agree on. Do they or don’t they actually help improve your motorcycles performance. In our opinion they do, but it’s got nothing to do with improving engine efficiency. It’s simply that most of the time an aftermarket exhaust will weigh less than what comes standard on your bike.
Motorcycle manufacturers are out to make a profit which means where possible, they’ll use cheaper components to save money. A muffler is usually one of those cheap components. It doesn’t hurt the engine performance in any way, but cheap on a motorcycle often means heavy – and OEM mufflers are often very, very heavy. Aftermarket exhausts on the other hand are priced in such a way that they can weigh many pounds less than what comes standard on your bike. Weight saving is a performance improvement.
But they don’t increase horsepower. We’ll probably get some comments arguing this point, but there’s nothing we’ve ever seen that indicates that slip-ons do anything to improve engine efficiency. We’ve seen some argue that a good designed muffler will reduce the amount of air reflected back up the exhaust pipe but again, we haven’t see any real evidence that this is actually true.
And yes, almost every slip-on manufacturer will provide a dyno chart showing the horsepower gains of their product. But it’s not a fair comparison. Those dyno charts are done under conditions that are favorable to the slip-on – the engine has been tuned, higher octane fuel is used and potentially even ignition timing has been altered. If the same was done with a stock exhaust, the result would be the same. Slip-ons provide weight savings, not horsepower increase.
The Pipes Are Where It’s At
Where a modified exhaust system does increase horsepower is in the header pipes connected directly to the exhaust ports. The less restrictive these are (i.e. the easier it is for the exhaust gasses to be expelled) the more horsepower gain there will be. If you compare a stock exhaust system next to an aftermarket one, you’ll often notice that the there are less bends (or gentler ones) and the headers will often direct gasses to one side of the bike instead of both – lessening the overall distance gasses need to be expelled.
This is further emphasized where you replace a 4-into-2 exhaust system with a 4-into-1 aftermarket exhaust – not only is there even greater weight reductions but you’ll again be creating a less restrictive system. That being said some engine configurations are designed to work better with 4-into-2 systems as opposed to 4-into-1, so do research before committing to a big change.
Another simple reason that a full exhaust system will increase horsepower is often the absence of a catalytic converter. A catalytic converter will restrict the airflow in an exhaust and in some cases also increase back pressure, reducing engine performance. Yes, that means that your bike won’t pass an emissions test on the street but if your only using the aftermarket pipes on the racetrack it’s not a problem
Finally, another reason a full exhaust performs better is the lack of a resonator. A resonator, like a muffler, is designed to reduce noise. You’ll know your exhaust system has one because it’s an almost rectangular shaped bulge in the pipes – usually situated halfway between the muffler and the headers. It’s just another part that restricts the exhaust gasses and hence by not having one, horsepower is increased again.
Don’t Go Riding Just Yet, You Need to Tune First
Unfortunately, not only does a full exhaust system cost a lot more than a slip-on, you’re also going to have to pay to get your bike running correctly now as well. The simple reason for this is that because the engine is now working more efficiently (in a way, it’s breathing better), your air/fuel ratio will now be out of alignment. Your engine is getting more air than before, but the same amount of fuel as previously.
You’ll probably hear the term ‘running lean’ in reference to the issue when you install a full exhaust. At best, this means your bike won’t run great and you’ll hear a lot of noises like small explosions in your exhaust when decelerating. At worst, your engine can be running so lean that it overheats and things start melting. That’s bad.
To correct this you’ll need one of two things – depending on your bikes fuel management system. For bikes with a carburetor, you’ll need a jet kit and a trip to a tuner for a dyno session. For EFI motorcycles, you’ll need a fuel controller (like a Power Commander) and either an additional module to automatically adjust the air/fuel ratio or a trip to a dyno and have a qualified technician adjust things. That’s another $300 to $500 there in addition to your actual exhaust system cost.
No doubt this cost is a reason why many take the slip-on route over the full system alternative. But in the end, if you’re making modifications to your bike for real horsepower gains and not just aesthetics/weight savings, then like all things – you get what you pay for.