A question concerning carb and exhaust mod. - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 15 Old 09-24-2012, 08:48 PM Thread Starter
1st Gear
 
Two Dogz's Avatar
 
Join Date: Sep 2012
Location: Oregon
Posts: 58
A question concerning carb and exhaust mod.

I want to mod the exhaust and do the .22 cent mod as well as ditch the snorkel.
1. I plan on using the hole saw mod to remove the chamber and open up the exhaust a bit. Along with this I have ordered the down pipe to bolt onto the end.
2. Second is the washer under the needle mod and turn out the idle mixture screw.
3. Third is ditching the snorkel.

My question is will I need to re-jet due to this? I dont have access to a residual oxygen sensor yet and I dont want to run lean and I dont feel I have enough experience yet to read the spark plug accurately.
Two Dogz is offline  
Sponsored Links
Advertisement
 
post #2 of 15 Old 09-24-2012, 08:52 PM
Moderator
 
klr4evr's Avatar
 
Join Date: Mar 2007
Location: Fort Sask , Alberta, Canada
Posts: 3,468
Garage
Send a message via Skype™ to klr4evr
I didn't.

My Kaw Barn - 2004 KLR, 2006 Concours (sold), 1997 Bayou 400.

"It's a friggen motorcycle, it's not supposed to be comfortable, quiet or safe. The wind noise is supposed to hurt your ears, the seat should be hard and riding it should make you shit your pants every now and then. "

<--- Please fill in the 'Location' on your personal profile page. User CP/Edit Your Details

This information makes it much easier for other members to answer/comment on your posts.
klr4evr is online now  
post #3 of 15 Old 09-24-2012, 09:16 PM
4th Gear
 
Join Date: Oct 2006
Location: Pefferlaw,Ontario
Posts: 1,636
I haven't changed my jetting either from stock. What hole saw are you using size wise? If you make a cut that is outside that indented section at the back of the can you will remove a lot of baffles and it will be LOUD! If you stay inside the indented section it removes just the tweety tube and still increases flow and isn't that loud.....just saying....you can always go larger but you can't easily fix the larhe hole....again just saying...beware!!!

Willys
willys is offline  
 
post #4 of 15 Old 09-24-2012, 09:43 PM Thread Starter
1st Gear
 
Two Dogz's Avatar
 
Join Date: Sep 2012
Location: Oregon
Posts: 58
Quote:
Originally Posted by willys View Post
I haven't changed my jetting either from stock. What hole saw are you using size wise? If you make a cut that is outside that indented section at the back of the can you will remove a lot of baffles and it will be LOUD! If you stay inside the indented section it removes just the tweety tube and still increases flow and isn't that loud.....just saying....you can always go larger but you can't easily fix the larhe hole....again just saying...beware!!!
I had heard that a 2 1/4 inch hole saw supported by a hard wood dowel inside the exhaust will just skim the outside edge of the tweety tube. Does this seem right?
Two Dogz is offline  
post #5 of 15 Old 09-25-2012, 08:08 AM
4th Gear
 
Join Date: Oct 2006
Location: Pefferlaw,Ontario
Posts: 1,636
I'll go and measure the indentation on a stock 08...be right back......OK...back...if you make a hole bigger that 1 3/8" you will remove the entire tweety baffle and it's outer case. You want to leave that outer case in the muffler to keep the noise levels down to acceptable levels imho. You can always make it larger IF you want more noise and more flow. I never saw the need to it personally. I di however drill out my spark arrester to increase flow. I never go into an area that requires the use of a spark arrester so that is a non issue for me. I started out with a 1/8" hole and worked my way up to 1/2" all the time seeing what each gole size sounded like before moving up to the next level. Like I said once you have drilled it, it is near impossible to undrill it!! BEWARE!!!
The spark arrester in the stock can is a inverted cone shaped piece of steel about a foot inside the can. If you shine a flashight down the hole you can see it. It requires a drillextention to get deep enough to be able to drill it out. The 1/2" hole I did I used a drywall drill used to make holes for wiring etc. It's just a mild steel drill bit but is 20" long...plenty of oil and slow drilling and it went through no problem.

The result was it flowed very well and didn't have anywhere near the loud obnoxious bark the large hole mod has.

Yes you are correct about how to drill the first hole. Jam a piece of wood into the original hole and centre the drill bit that way.
Truthfully..it is much easier to use a good 1/8" drill bit and drill all the way around the indented area next to the outlet pipe and just clean it up aterwards....seriously. That way you also can make 100% sure you aren't hitting the outer case or shell of the baffle you want to leave in. IF you make a mistake with a hole saw you won't know until it finally breaks through to see where it has cut through ......plus the end of the can is hard and will eat a hole saw fast if spun too quickly and not constantly fed oil to keep the temps down on the teeth.

Your can and your choice....in the end so to speak...so choose wisely.

Good luck.....

Willys
willys is offline  
post #6 of 15 Old 09-25-2012, 08:11 AM
4th Gear
 
Join Date: Oct 2006
Location: Pefferlaw,Ontario
Posts: 1,636
If you take the outside edge out of the tweety tube, you may as well cut the last 3" straight off the can...it will be an empty box at that point....that is why it is so loud!....just saying....

I disected a can once just to see.......there really isn't much in there if you go that far. It's almost a straight through exhaust that is forced to go through two 3/4" sized tubes before getting out of the can.

Willys
willys is offline  
post #7 of 15 Old 09-25-2012, 08:16 AM Thread Starter
1st Gear
 
Two Dogz's Avatar
 
Join Date: Sep 2012
Location: Oregon
Posts: 58
Quote:
Originally Posted by willys View Post
I'll go and measure the indentation on a stock 08...be right back......OK...back...if you make a hole bigger that 1 3/8" you will remove the entire tweety baffle and it's outer case. You want to leave that outer case in the muffler to keep the noise levels down to acceptable levels imho. You can always make it larger IF you want more noise and more flow. I never saw the need to it personally. I di however drill out my spark arrester to increase flow. I never go into an area that requires the use of a spark arrester so that is a non issue for me. I started out with a 1/8" hole and worked my way up to 1/2" all the time seeing what each gole size sounded like before moving up to the next level. Like I said once you have drilled it, it is near impossible to undrill it!! BEWARE!!!
The spark arrester in the stock can is a inverted cone shaped piece of steel about a foot inside the can. If you shine a flashight down the hole you can see it. It requires a drillextention to get deep enough to be able to drill it out. The 1/2" hole I did I used a drywall drill used to make holes for wiring etc. It's just a mild steel drill bit but is 20" long...plenty of oil and slow drilling and it went through no problem.

The result was it flowed very well and didn't have anywhere near the loud obnoxious bark the large hole mod has.

Yes you are correct about how to drill the first hole. Jam a piece of wood into the original hole and centre the drill bit that way.
Truthfully..it is much easier to use a good 1/8" drill bit and drill all the way around the indented area next to the outlet pipe and just clean it up aterwards....seriously. That way you also can make 100% sure you aren't hitting the outer case or shell of the baffle you want to leave in. IF you make a mistake with a hole saw you won't know until it finally breaks through to see where it has cut through ......plus the end of the can is hard and will eat a hole saw fast if spun too quickly and not constantly fed oil to keep the temps down on the teeth.

Your can and your choice....in the end so to speak...so choose wisely.

Good luck.....
Sage advice and thank you. I will keep all of this in mind when deciding how to proceed.
Two Dogz is offline  
post #8 of 15 Old 09-25-2012, 08:18 AM Thread Starter
1st Gear
 
Two Dogz's Avatar
 
Join Date: Sep 2012
Location: Oregon
Posts: 58
Quote:
Originally Posted by willys View Post
If you take the outside edge out of the tweety tube, you may as well cut the last 3" straight off the can...it will be an empty box at that point....that is why it is so loud!....just saying....

I disected a can once just to see.......there really isn't much in there if you go that far. It's almost a straight through exhaust that is forced to go through two 3/4" sized tubes before getting out of the can.
Wish I had access to a cross section or x-ray.
Two Dogz is offline  
post #9 of 15 Old 09-25-2012, 08:31 AM
4th Gear
 
Join Date: Oct 2006
Location: Pefferlaw,Ontario
Posts: 1,636


OK, here you can see that if you take just the perforated tweety tube out the hot gasses are still forced to travel past the spark arrester cone and through the outer case of the tweety tube. IF you take the outer case of the tweety tube the hot gasses are able to pass through those 5/8" holes and then find their way straight out the end of the exhaust without being redirected past the spark arrester. Also I have never seen a can with any fibreglass left in it yet.

Willys

Last edited by willys; 09-25-2012 at 08:34 AM.
willys is offline  
post #10 of 15 Old 09-25-2012, 12:38 PM Thread Starter
1st Gear
 
Two Dogz's Avatar
 
Join Date: Sep 2012
Location: Oregon
Posts: 58
Quote:
Originally Posted by willys View Post


OK, here you can see that if you take just the perforated tweety tube out the hot gasses are still forced to travel past the spark arrester cone and through the outer case of the tweety tube. IF you take the outer case of the tweety tube the hot gasses are able to pass through those 5/8" holes and then find their way straight out the end of the exhaust without being redirected past the spark arrester. Also I have never seen a can with any fibreglass left in it yet.
Alright now that is just awesome and completely changes how I am thinking about this mod. I cannot in good conscience bypass that spark arrestor considering all of the forest roads I ride on. Guess I will have to think on this a bit more before doing any work. Thank you.
Two Dogz is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki KLR 650 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










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Carb Needle and Jet question Bigryamaha 1987 to 2007 Wrenching & Mods 9 03-29-2015 02:03 PM
Carb mod question? hinquik 1987 to 2007 Wrenching & Mods 17 11-22-2012 08:47 AM
Carb question lefty650 1987 to 2007 Wrenching & Mods 14 11-21-2012 09:36 AM
KLR Newb carb question trail70 1987 to 2007 Wrenching & Mods 13 09-26-2008 05:28 PM
Another exhaust question... Whitey 1987 to 2007 Wrenching & Mods 29 06-22-2007 08:53 PM

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