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Self installation guide for Greasehouse GRUNT Performance Exhaust v2 on KTM RC 390 (2016)

by on January 3, 2018

It was just another Sunday (17th December 2017), and I was lazying around soaking some sunlight in my home’s terrace and suddenly my phone started ringing. It was my bud Siddharth Roy – sidroy0508 (will call him Roy from now on). He wanted some help in installing some accessory on his KTM RC 390 (that’s what he said). I took my trusty good’ol Toyota Etios keys and went over to get his stuff and tools to my place, as I have a decent sunlit area in front of my garage to work on such manly stuff. 😎

This guy showed up with a black box and a Bosch briefcase-like full toolkit (with drill and shit) along with a huge grin on his face. I knew at that moment, that my whole Sunday is fucked. We arrived at my place, and while unloading the cargo, I got a glimpse of the box’s internals. It was a shiny chrome…

Greasehouse GRUNT Performance Exhaust!!

We both had an eye contact and we affirmed that we are installing this beauty on his KTM today. Here are some of the key features listed on the box:

  • Weight Savings of 4.5Kg.
  • Stainless Steel Outer Shell, SS Internals, Internal DB killer.
  • Increased mid-range to top end torque.
  • Ceramic wool insulation to ensure maximum thermal efficiency and long life.
  • No chance of rust.
  • Made in India.

Disclaimer: No, I am not a Mechanical engineer. I am a *hardcore* Software engineer but I am also a biking enthusiast who isn’t afraid to get his hands dirty. πŸ˜›

>> Prerequisites

Before we start, let me explain the exhaust system on KTM RC 390 (2016) Indian edition. It didn’t ship with a tradition exhaust unit and instead had a cool underbelly exhaust which is so nicely concealed that you may easily miss it in the first glance. Since Roy got the bike, the only missing element in this beast was a little grunt as the stock engine doesn’t sound as mean as it revs. So, to replace the stock exhaust system, we first had to understand how it works. I made a nice little infographic below for ease of understanding.

Understanding exhaust system of KTM RC 390 2016

KTM RC 390 exhaust system made easy

As you can see, it’s a very smartly packaged system. Engine basically offers a bent pipe (like traditional bikes) and the underbelly exhaust directly mounts to it with a screw ring. An interesting thing to note here is that, unlike traditional bikes, the bent pipe attachment, exhaust, and the outlet are built into a single unit. We will discuss more about the same in the following segments.

>> Installation guide

I am going to categorize the installation into 4 stages of success because believe me, it was a roller-coaster ride of emotions for the whole day.

  1. The Idea πŸ’‘
  2. The Drive ⏩
  3. The Journey 🏍
  4. The Reward 🎁

#1. The Idea: Just unscrew everything & screw it up..err..

This was phase one. All we had was a toolkit, high motivation and a YouTube guide for installation on Duke.

We started with getting the fairing off. It was pretty simple, to be honest. We were able to take most of it off using the set of Allen key provided in the bike’s toolkit. Most of the front fairing for RC 390 is modular i.e. just screw with Allen (hex) screws and snap jack buttons. But make sure you are careful as some screws are almost hidden near the radiator and the underside of the bike if you are not too careful and use even a little bit of force, you may snap the plastic fiber fairing easily.

In under an hour, we were able to strip off our KTM RC and it started resembling KTM Duke.

We got stuck with one of the underbelly screws though. Thanks to low clearance of bike paired with almighty speed breakers in India, the screw head was almost shaved off, making it impossible to fit the Allen key or even a Phillip screwdriver. It was pretty sensitive as I observed a few micro-cracks near the screw hole so I couldn’t use a hammer and screwdriver to loosen the screw. In the end, I had to use a nose pliers (yes, the struggle was real) to get a grip and slowly unscrew the same.

Remember: Preservence and patience are the keystones for success!

#2. The Drive: Pfft! That was too easy. Bring it on..

Phase two started with a feeling that whole deal is n00b stuff, but it pretty much pwn3d us by the end of it.

Once the fairing was off, the second step was to remove the underbelly exhaust from the engine exhaust pipe. It sounds way easier than the real deal. This took most of our time as we didn’t find any step-by-step guide to disassemble the same. We unscrewed whatever we could see related to exhaust but it didn’t even shift a mm from its spot. I was a bit tired so went for a small nap, naturally…

Taking a nap on Royal Enfield Standard Bullet 500

A Royal Nap?

In this royal nap on a Bullet 500, biking gods visited me and asked me to apply some logic so as to why the exhaust wasn’t demounting easily. I got up and after an hour of head-banging, tilting the bike, shaking the exhaust, we n00bs discovered that there was a plate screwed at the bottom side of the exhaust to literally save it from falling down. A couple of abuses, teasing remarks later, we were able to get this black beauty off the engine pipe.

KTM RC 390 stock underbelly exhaust

Doesn’t look that good naked? Does it?

This was the most rewarding part as we had successfully disassembled the KTM’s exhaust system.

Remember: Always dry run your steps to catch the bug (or here the ignored plate) πŸ˜›

#3. The Journey: Where’s the new exhaust at?

Post 4 hours and some mandatory snacking, it was time to go ahead with the next phase aka “the fitting”!

It was time to unbox the sexy Greasehouse GRUNT Performance Exhaust. Mr. Roy did the honors. Here’s a little glimpse of the process, it looks like our little buddy (blacky) enjoyed the process more than we did:


KTM RC 390 Greasehouse Grunt Exhaust

It’s lit.

Fixing the bent pipe extension was easy, as it just required a bit of grease and a screwdriver to tighten it up. We had to make sure to screw up the underbelly exhaust outlet fairing so as to make sure that the extension bent pipe passes through the fairing as it wouldn’t have been possible once the bent pipe was fixed.

KTM RC 390 replacing exhaust with bent pipe

Bent pipe extension for the exhaust unit

Once it was done, we decided to screw up with my neighbor’s sleep by igniting the bike w/o the exhaust because if we are not getting any, neither are Y’all! πŸ˜€

The last step was to get some more grease and fix the exhaust on the bent pipe extension. It took some hit ‘n’ trial but we were able to fix it and align it properly to nail down the assembling part. I tightened up the screw to the bent pipe and also screwed up the extension support from silencer to the right foot-peg part of the chassis to make sure that the exhaust stays stable even on the high speeds. AND WE WERE DONE!

Remember: Hard work beats talent every time! 😎

#4. The Reward: Sweet sweet deep tones!

Phase 4 was all about redemption and absorbing gratification from the full day of effort. Worth it? YEAHH!

Once the exhaust was in place, we fixed up rest of the fairing. It was a breeze as we were back on the enthu-train. Our KTM RC 390 was all decked up and it was time to rotate the key, turn on the ignition, spark up the self-start and rev it up!

Greasehouse Grunt exhaust installed on KTM RC 390

Looks lit af, no?

So, before I show you the video sample for the exhaust, I would like to tell you about a little tweak called DB killer in this Greasehouse Grunt exhaust. It’s nothing but basically a hollow metal ring with a screw on the inside tip of the end of the exhaust which allows you to adjust the bass and sound of the exhaust.

Greasehouse Grunt exhaust removing DB killer

To kill em DBs

We sampled 2 videos, one with the stock sound (with DB killer installed) and the other one without the DB killer. You can hear the difference yourself.

#4a. Stock sound with DB killer:

#4b. Sound without DB killer:

This concludes this installation guide. Since I am not the owner of the bike, I can’t review the Greasehouse GRUNT Performance Exhaust here. I would suggest you folks to head over to the Facebook page and Amazon listing forΒ more insight on the same. I would, however, make sure to ask Roy for an ownership feedback shortly and update this post.

Until the next time then, ride safe guys.

Peace. ✌️




p.s: Apologies for the portrait videos as I took them for my Instagram story. You can follow me at silent_freak for such insights on a daily basis.

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