Wild-ass Backfirin'! - 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.

 
LinkBack Thread Tools Display Modes
post #1 of 8 Old 08-28-2011, 11:25 AM Thread Starter
1st Gear
 
Mr. Junior's Avatar
 
Join Date: Aug 2011
Location: San Francisco
Posts: 62
Wild-ass Backfirin'!

Hey Guys,

Just got my '08 yesterday. So far so good. One thing that the guy at Motojava told me though, was that I'd get a backfire when I'm gearing down. It happens randomly, and when it does happens, it's pretty loud. Anything I could clean out, or is it a bit more difficult than that?


Mr. Junior is offline  
Sponsored Links
Advertisement
 
post #2 of 8 Old 08-28-2011, 01:25 PM
Threadjacker
 
Lockjaw's Avatar
 
Join Date: Jul 2008
Location: Benicia, CA
Posts: 6,750
People use the word backfiring to describe different things. What exactly are we talking about here? "Backfire when gearing down?" Do you mean the classic popping on deceleration? Is it an actual BANG?




"In a car you're always in a compartment, and because you're used to it you don't realize that through that car window everything you see is just more TV." R. Pirsig

PPMC #1.
Soon, we ride.

AKA JD Mader or you can call me "Dan" just not early for dinner.

Click my handle for a link to my homepage/blog...which has nothing to do with MCs. Free literature and music! Viva La Revolucion!
-------------------
2008 KLR 650
RIP DM - Soon, we ride.

Last edited by Lockjaw; 08-28-2011 at 02:25 PM.
Lockjaw is offline  
post #3 of 8 Old 08-28-2011, 01:54 PM
4th Gear
 
Spec's Avatar
 
Join Date: Apr 2010
Location: Gateway to Death Valley!
Posts: 1,928
Quote:
Originally Posted by Mr. Junior View Post
Hey Guys,

Just got my '08 yesterday. So far so good. One thing that the guy at Motojava told me though, was that I'd get a backfire when I'm gearing down. It happens randomly, and when it does happens, it's pretty loud. Anything I could clean out, or is it a bit more difficult than that?



First check the exhaust header to cylinder bolts and the header to muffler connection. A loud backfire is a symptom of sucking outside air into the combustion chamber.

Decel popping is mostly normal. When you let off the throttle air from the exhaust gets pulled back into the cylinder creating a lean mixture and ignites. You can minimize it by doing the .22 mod to richen up the low speed carb circuit.

No eye has seen, no ear has heard, no mind has conceived what God has prepared for those who love him. 1 Cor 2:9
Spec is offline  
 
post #4 of 8 Old 08-28-2011, 10:30 PM
Moderator
 
klr4evr's Avatar
 
Join Date: Mar 2007
Location: Fort Sask , Alberta, Canada
Posts: 3,560
Garage
Send a message via Skype™ to klr4evr
Ditto what Spec said. Had that issue last year and found one exhaust header nut missing and the copper gasket partially blown out. Had to farmer fix it as I was on a trip but had no issues thereafter.

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 offline  
post #5 of 8 Old 08-29-2011, 09:23 AM Thread Starter
1st Gear
 
Mr. Junior's Avatar
 
Join Date: Aug 2011
Location: San Francisco
Posts: 62
Hey Lockjaw, no, it's not the normal pop on deceleration. I have that, and then randomly I'll get a loud as hell BAP.


Hey Spec, thanks for the suggestion. I'll check it out after work.
Mr. Junior is offline  
post #6 of 8 Old 08-29-2011, 11:48 AM
3rd Gear
 
Crazy Jake's Avatar
 
Join Date: Nov 2010
Location: Woodstock CT
Posts: 663
Quote:
Originally Posted by Spec View Post
You can minimize it by doing the .22 mod the low .
I had the same problem... this fixed it
Crazy Jake is offline  
post #7 of 8 Old 08-29-2011, 12:30 PM Thread Starter
1st Gear
 
Mr. Junior's Avatar
 
Join Date: Aug 2011
Location: San Francisco
Posts: 62
Crazy Jake,

Good to know. How'd it effect your mileage?
Mr. Junior is offline  
post #8 of 8 Old 08-29-2011, 08:44 PM
3rd Gear
 
steferf's Avatar
 
Join Date: Jun 2010
Location: Rolla, Mo
Posts: 576
Quote:
Originally Posted by Spec View Post
First check the exhaust header to cylinder bolts and the header to muffler connection. A loud backfire is a symptom of sucking outside air into the combustion chamber.

Decel popping is mostly normal. When you let off the throttle air from the exhaust gets pulled back into the cylinder creating a lean mixture and ignites. You can minimize it by doing the .22 mod to richen up the low speed carb circuit.
Interesting.

I did the Thermo Bob upgrade recently. For this I took the Exhaust header off to open up some space. While I've read this thread, I've realized my bike has been popping during deceleration more than it used to.

I suppose I'll check the torque of the bolts.
steferf 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
Engine misses, tack wild, won't start KennyG 2008+ KLR650 Wrenching & Mod Questions 3 07-01-2011 03:23 AM
Wild Hog ride 6/26/10 1moremile Upcoming Tech Days & Group Rides 4 07-08-2010 09:03 PM
Wild Hogs (rate this movie) scale of 1-10 KLR-Venture The Off Topic Lounge 12 04-07-2008 09:36 PM
Wild Hogs Daddyjoe The Off Topic Lounge 4 03-02-2007 10:16 PM
Did one of you wild and crazy guys disable Glenn's board? Hillcountryrambler KLR & Other Motorcycle Related Discussion 76 10-07-2006 07:02 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