exhaust mods? - Motorcycle Forum
User Tag List

 
LinkBack Thread Tools
post #1 of 4 (permalink) Old 06-02-2011, 05:47 PM Thread Starter
Verified
 
Join Date: May 2011
Posts: 16
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
exhaust mods?

I have a gz250 and was wondering how to make the bike a little louder. I heard about drilling holes or opening the exhaust up? If I were to do either how would that a. be done and b. would I need to rejet the carbs?
Thanks
deadliving99 is offline  
Sponsored Links
Advertisement
 
post #2 of 4 (permalink) Old 08-13-2016, 03:13 PM
Newbie
 
jewman22's Avatar
 
Join Date: Aug 2016
Location: Ontario
Posts: 4
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
i just straight piped mine, i will need to rejet at some point, she is running very lean.
jewman22 is offline  
post #3 of 4 (permalink) Old 08-28-2016, 10:11 PM
Senior Member
 
Zebraranger's Avatar
 
Join Date: Apr 2016
Location: Florida
Posts: 304
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
 
On many bikes it can be done without re-jetting the carbs or remapping, other bikes not so much. You don't want to drill multiple small holes, you want one larger hole. I've drilled out the exhaust successfully on two different bikes, a Bonneville and a Thunderbird. The first was my 2013 Bonneville. It was an EFI bike, the carbs on the bike are just shells (fake) they just house the EFI. The Thunderbird had 3 carbs. The size you drill depends on the engine size, the exhaust type, and of course the sound that you want to achieve. On the Bonneville, it had reverse cone exhausts with a very small exhaust ports at the rear (see first photo). I had to drill the rear out at 2-1/4" then I drilled out the inner wall of the exhausts at 1-1/8" and then the baffles came out. You can see the size difference in the rear exhaust ports in the before and after photos of the Bonneville. It made the sound much deeper in tone and gave the bike a nice rumble.
Before

After

The Thunderbird had different exhaust ends and a much larger stock opening at the ends (see photo below). So, I didn't have to drill the large opening at the end of the exhausts. All I had to do was drill a 1-1/8" diameter hole thru the center of the exhausts, as seen in the 2nd below photo. Again with great results. A much deeper tone and rumble. If I really layed on the throttle, it was loud, but normal riding, it was a much nicer deeper tone without being too loud.
Large rear opening, stock exhaust

1-1/8" hole drilled thru

Last edited by Zebraranger; 08-28-2016 at 10:15 PM.
Zebraranger is offline  
Sponsored Links
Advertisement
 
post #4 of 4 (permalink) Old 12-08-2016, 10:21 AM
Road Captain
 
Join Date: Dec 2016
Posts: 32
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
 
You should see what the guys do to the stock exhaust on the B-King


Sent from my iPhone using Tapatalk
Zluck is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Motorcycle Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome