Put a new muffler on my GZ250

GrungeMunkee · 05-11-2016, 11:58 AM

As you all know, the stock megaphone muffler sounds more like a golf cart than motorcycle and the big end and angle tend to interfere with saddle bags. So, for me at least, it had to go. I swapped it for a 20in Helix Turn-out muffler from Amazon: http://www.amazon.com/Helix-Racing-P...ilpage_o04_s00

The install was a lot of fun for a fairly easy mod, but it is not a quick bolt on swap.

The first thing I had to do was pull the entire exhaust system off.

Next I had to remove the old Megaphone with a Dremel and cutting wheels, being careful not to cut the inner pipe and only cut the outer pipe.

Then I had to shorten the end of the inner pipe a bit so the new muffler would fit all the way down to the old weld; I wanted the stock heat shield to cover the joint so it still looked professional and stockish.

The muffler I bought, came with a spacer/adapter set so it would fit different size inner pipes. I welded this adapter onto the inner pipe where the old muffler was welded on and then just clamped the muffler onto the adapter.

After riding it a few times with the new muffler I noticed a better top end speed but the low end was sluggish and stuttered on take offs. The muffler I used has very little baffling inside so the lack of back pressure is what created the performance changes. As you can see in the last pic, the angle and end profile is pretty good for my saddle bags.

It was also really LOUD and not necessarily in a good way. The sound was pitchy and sounded more like a pissed off lawn mower. So I tried a lollipop baffle in the end of the muffler, but that still didn't give me what I wanted. I then bought a cheap baffle from Amazon: http://www.amazon.com/Bikers-Choice-...ilpage_o01_s00

This baffle and muffler combo is perfect (at least for me it is). It is still loud but not excessively obnoxious or pitchy/poppy. It has a bit more of a rumble (at least as much as a 250cc engine can rumble anyway). And I now have an increase in top speed and the low end performance is back up to par, and I didn't need to mod the carb at all. I might try wrapping the baffle with fiberglass just to see what that sounds like, but for now this is great.

All in all, it was a great modding experience and I am much happier with the bike now.

Vegas Street Rider · 05-11-2016, 12:57 PM

Great how to presentation and pics GrungeMunkee! Very much appreciated. Is that an '09' GZ? Looks really nice. I put some of the small Viking bags on mine and still had plenty of clearance from the muffler, but you are right. The GZ sounds pretty unimpressive. But as you say, it is just a 250cc. As always, safe riding.

GrungeMunkee · 05-11-2016, 02:19 PM

Thanks, mate! Yup, it's an '09. When I first installed the bags I apparently had them just a little low; they settled during my first ride after I put them on and rested on the exhaust. The muffler melted a dent in the bag (not all the way through, thankfully). But this pipe has a lot better clearance.

Water Warrior 2 · 05-11-2016, 05:50 PM

Love your report. The new muffler install is very well done and professional looking. Pics are great. I might add that you know a little about safety while using power tools. Hearing and eye protection are always a good idea.

05-11-2016, 11:58 AM	#1
GrungeMunkee Junior Member Join Date: May 2015 Posts: 2	Put a new muffler on my GZ250 As you all know, the stock megaphone muffler sounds more like a golf cart than motorcycle and the big end and angle tend to interfere with saddle bags. So, for me at least, it had to go. I swapped it for a 20in Helix Turn-out muffler from Amazon: http://www.amazon.com/Helix-Racing-P...ilpage_o04_s00 The install was a lot of fun for a fairly easy mod, but it is not a quick bolt on swap. The first thing I had to do was pull the entire exhaust system off. Next I had to remove the old Megaphone with a Dremel and cutting wheels, being careful not to cut the inner pipe and only cut the outer pipe. Then I had to shorten the end of the inner pipe a bit so the new muffler would fit all the way down to the old weld; I wanted the stock heat shield to cover the joint so it still looked professional and stockish. The muffler I bought, came with a spacer/adapter set so it would fit different size inner pipes. I welded this adapter onto the inner pipe where the old muffler was welded on and then just clamped the muffler onto the adapter. After riding it a few times with the new muffler I noticed a better top end speed but the low end was sluggish and stuttered on take offs. The muffler I used has very little baffling inside so the lack of back pressure is what created the performance changes. As you can see in the last pic, the angle and end profile is pretty good for my saddle bags. It was also really LOUD and not necessarily in a good way. The sound was pitchy and sounded more like a pissed off lawn mower. So I tried a lollipop baffle in the end of the muffler, but that still didn't give me what I wanted. I then bought a cheap baffle from Amazon: http://www.amazon.com/Bikers-Choice-...ilpage_o01_s00 This baffle and muffler combo is perfect (at least for me it is). It is still loud but not excessively obnoxious or pitchy/poppy. It has a bit more of a rumble (at least as much as a 250cc engine can rumble anyway). And I now have an increase in top speed and the low end performance is back up to par, and I didn't need to mod the carb at all. I might try wrapping the baffle with fiberglass just to see what that sounds like, but for now this is great. All in all, it was a great modding experience and I am much happier with the bike now. Login or Register to Remove Ads
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05-11-2016, 02:19 PM	#3
GrungeMunkee Junior Member Join Date: May 2015 Posts: 2	Thanks, mate! Yup, it's an '09. When I first installed the bags I apparently had them just a little low; they settled during my first ride after I put them on and rested on the exhaust. The muffler melted a dent in the bag (not all the way through, thankfully). But this pipe has a lot better clearance. Login or Register to Remove Ads
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05-11-2016, 12:57 PM	#2
Vegas Street Rider Senior Member Join Date: May 2015 Location: Henderson, NV Posts: 1,108	Great how to presentation and pics GrungeMunkee! Very much appreciated. Is that an '09' GZ? Looks really nice. I put some of the small Viking bags on mine and still had plenty of clearance from the muffler, but you are right. The GZ sounds pretty unimpressive. But as you say, it is just a 250cc. As always, safe riding.
	2

05-11-2016, 05:50 PM	#4
Water Warrior 2 Senior Member Join Date: Dec 2006 Location: Squamish B.C Canada Posts: 11,409	Love your report. The new muffler install is very well done and professional looking. Pics are great. I might add that you know a little about safety while using power tools. Hearing and eye protection are always a good idea.
	2