2009 KLR Backfiring - 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.

 3Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 20 Old 03-27-2017, 05:42 PM Thread Starter
Neutral
 
Join Date: Jun 2015
Posts: 12
2009 KLR Backfiring

I've been having backfiring since I bought my 2009 KLR over a year ago, and have finally gotten around to pulling the carb. I noticed that the choke plunger (the plastic piece that threads into the carb) is broken, so the rubber seal on the choke cable is doing nothing. My question is, could this piece being broken cause an air leak to lean out the fuel mix and cause backfiring? It's a $70 part, so if it's doubtful that this is causing the backfiring, I'm reluctant to replace it...

Thanks for your help!

Dean
DeanRHolden is offline  
Sponsored Links
Advertisement
 
post #2 of 20 Old 03-27-2017, 06:26 PM
5th Gear
 
Join Date: Jan 2011
Posts: 4,332
The plastic cap fastening the "choke" cable to the carb casting is hardly a $ 70 part.

When replacing, you might consider a MadStad (Stead Engineering?) metal part; will cost you about half that; the plastic OEM replacement, much less, if I'm not mistaken.



KLR 650 Alloy Starter Choke PLunger. 1986-present day-KLRACP - Stead Engineering

Conceivably, an air leak through the STARTING ENRICHER (vice, "choke") system could produce a lean mixture resulting in backfiring, I'd think, although I defer to experts on the question.

Some "pyrotechnics" upon deceleration isn't unusual, or harmful; the air cut valve/backfire preventer/coasting enricher is explained in, "Care and Feeding of the CVK40," hosted on this website. Adjustment of the fuel screw can reduce "backfiring" sometimes.

Last edited by Damocles; 03-27-2017 at 06:34 PM.
Damocles is online now  
post #3 of 20 Old 03-27-2017, 06:36 PM
3rd Gear
 
Toney's Avatar
 
Join Date: Mar 2010
Location: Oliver Springs TN
Posts: 762
My Exhaust was loose and caused a backfire.

“Take the risk of thinking for yourself , much more happiness , truth, beauty, and wisdom will come to you that way.” Hitchens
Toney is offline  
 
post #4 of 20 Old 03-27-2017, 06:56 PM Thread Starter
Neutral
 
Join Date: Jun 2015
Posts: 12
Thanks for the responses!

Damocles, thanks for the link. The metal part sounds like a good idea, since whoever had the bike before me broke the plastic part. I wasn't able to find just the plastic part online, so the plunger and cap together were about $69. At least in my search.

Toney, thanks, I'll check the exhaust.

Dean
DeanRHolden is offline  
post #5 of 20 Old 03-27-2017, 07:08 PM
5th Gear
 
Join Date: Jan 2011
Posts: 4,332
The OEM cap hex is 12 mm; ain't sure, but . . . something tells me the Stead Engineering one may be 1/2".

Yeah, I see where the entire starting enricher assembly (plunger and all) is sold for $ 70. A rip-off, when all you need is the connecting cap. Makes $ 30 for the Stead Engineering part look not so bad! There may be a substitute cap available separately; some knowledgeable forum member may disclose this info.

Also: Exhaust air leak, as mentioned above, may contribute to backfiring.
Damocles is online now  
post #6 of 20 Old 03-27-2017, 10:09 PM
OverDrive
 
Join Date: Nov 2009
Location: Lander, Wyoming
Posts: 5,541
Dean,
K#16012-1055, Cap-Starter Plunger, from older models 1987-2007 <$17.00, Plastic cap only!
K#11060-1108, Gasket, Exhaust at the cylinder head and / or missing exhaust flange nuts are quite often to blame for "After-fire" popping out of the tail pipe.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
pdwestman is online now  
post #7 of 20 Old 03-28-2017, 03:53 AM
5th Gear
 
Join Date: Jan 2011
Posts: 4,332
Quote:
Originally Posted by pdwestman View Post
Dean,
K#16012-1055, Cap-Starter Plunger, from older models 1987-2007 <$17.00, Plastic cap only!
Good info. No need to spend $ 70 for a sack of parts you don't need, when all you want is a plastic cap.

The metal Stead Engineering cap's nice to have, but you can buy two Generation 1 plastic caps nearly 'bout for what it costs.

I think the stock caps are often broken from choke cable elbow interference when the carb is rotated. Eliminated that possibility with a straight-line "shorty" Drag Specialties Harley choke cable; took a little doin'.
klrhino likes this.
Damocles is online now  
post #8 of 20 Old 03-28-2017, 11:14 AM
4th Gear
 
Join Date: Aug 2010
Location: Kelowna, B.C.
Posts: 2,343
Yes the stead eng. nut is larger OD than the stock one. Personally I see no good reason to replace the weak and often damaged plastic stock unit with another one just like it. YMMV

Dave
DPelletier is offline  
post #9 of 20 Old 03-28-2017, 11:39 AM
4th Gear
 
Join Date: Aug 2010
Location: Kelowna, B.C.
Posts: 2,343
...and yes, check the exhaust header for a leak at the head......and keep in mind that a functioning AIS system is INTENDED to produce controlled backfires (pops on decel)

Dave
DPelletier is offline  
post #10 of 20 Old 03-28-2017, 03:00 PM Thread Starter
Neutral
 
Join Date: Jun 2015
Posts: 12
Thanks guys! very helpful. I think I'll get the the non-plastic cap, just to avoid cursing myself later when I break the plastic one
Will definitely check the exhaust too, would not be surprised if that is the culprit. Had noticed that mine has a "different" sound than my brother's 07 KLR, and that sound may be due to a bad/leaky exhaust gasket.

Cheers!
Dean
DeanRHolden is offline  
Sponsored Links
Advertisement
 
Reply

Tags
backfire, choke, klr

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
Backfiring etc pickindoug 1987 to 2007 Wrenching & Mods 10 05-27-2012 02:36 AM
Serious backfiring issue messenger1 2008+ KLR650 Wrenching & Mod Questions 5 05-13-2012 09:54 PM
Sudden Backfiring on an 08??? SteveB 2008+ KLR650 Wrenching & Mod Questions 1 08-02-2009 02:03 AM
09 Backfiring kpacman 2008+ KLR650 Wrenching & Mod Questions 8 05-24-2009 09:48 PM
Bike dying and backfiring??? joker 1987 to 2007 Wrenching & Mods 24 09-08-2008 08:46 AM

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