Engine cranks, will not start after bike has ran for a while in 100 plus temperaures. - 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 22 Old 08-10-2012, 07:22 PM Thread Starter
Neutral
 
Join Date: Aug 2012
Posts: 6
Engine cranks, will not start after bike has ran for a while in 100 plus temperaures.

Just got a new 2012 KLR 650 a month ago. Not my first KLR. After riding in extreme temperatures, turning off bike and coming back to it inside of 20 min., it will eventually start after cranking for 30 seconds. Never had problem like this with previous KLR's. Dealership, told me to use 91 octane fuel instead of 87. I don't know about that, my owners manual says 87 octane is called for. Seems like some kind of a vapor/pressure lock due to extreme ambient temperatures. Next time I will open gas cap and relieve pressure and then start. Anyone with similar issues that may have a remedy.
JJNyborg is offline  
Sponsored Links
Advertisement
 
post #2 of 22 Old 08-11-2012, 03:30 AM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
What's your starting procedure; e.g., use "choke" (starting enricher)?

Vapor lock unlikely, IMHO; also . . . doubt the octane of any consequence.

I'd look into the starting circuit of the carb; starter jet and/or pilot jet may want cleaning.

(Assume vacuum-actuated petcock operational.)

You should be entitled to warranty service on this issue; IMHO. 30-second starting interval on a warm bike ain't normal, given proper starting procedure.
LoneRider is offline  
post #3 of 22 Old 08-11-2012, 10:48 AM
4th Gear
 
Spec's Avatar
 
Join Date: Apr 2010
Location: Gateway to Death Valley!
Posts: 1,928
Quote:
Originally Posted by JJNyborg View Post
Just got a new 2012 KLR 650 a month ago. Not my first KLR. After riding in extreme temperatures, turning off bike and coming back to it inside of 20 min., it will eventually start after cranking for 30 seconds. Never had problem like this with previous KLR's. Dealership, told me to use 91 octane fuel instead of 87. I don't know about that, my owners manual says 87 octane is called for. Seems like some kind of a vapor/pressure lock due to extreme ambient temperatures. Next time I will open gas cap and relieve pressure and then start. Anyone with similar issues that may have a remedy.
Welcome to the forum!

I live about 60 miles from Death Valley, extreme temps? My 08 starts fine when it's hot.

My .02 on starting:

Don't ever give the bike any gas when you start it. When's it cold give it choke but don't twist the throttle especially when it's hot.

Has the bike been on it's side? The charcoal canister under the battery (left side) can get filled with gas and make the bike hard to start.

How's the aircleaner? A dirty filter will effect how the bike runs.

Good idea with the gas cap. If that clears it up check the vent tubes. They can get pinched under the tank seat junction.

Octane doesn't have any effect on starting or how a KLR runs. It's a low compression motor. Higher octane ratings prevent pre-detonation (pinging) in higher compression engines. It would make me suspicious if a dealer told me that.

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 22 Old 08-12-2012, 10:50 PM Thread Starter
Neutral
 
Join Date: Aug 2012
Posts: 6
LoneRider & Spec

Thanks guys for responding.
I don't apply any choke at all cause of extreme warm weather. Yeh, I think I am gonna take her down to the dealership.
That is good to know. My bike should start in hot weather. It has never been laid over. It is brand new, thus all components are new as well. Yeh, I figured octane rating had nothing to do with problem. Again, thank you for responding. I will let you know what remedies the issue.
JJNyborg is offline  
post #5 of 22 Old 08-13-2012, 12:57 AM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
My suggestion; use the "CHOKE," JJNyborg!

First, it ain't REALLY a "choke," it's a STARTING ENRICHER.

When the engine is "cold," regardless of the ambient temperature, the starting enricher, when applied, provides a fuel-rich mixture to the engine for the purpose of . . . well, STARTING!

When you engage the choke lever, you withdraw a plunger from a hole in the carburetor and also open an air passage; fuel flows from the hole and mixes with the incoming air, not unlike the starting arrangement is a "mini-carburetor," only the misture is especially fuel-rich, for the purpose of starting the engine.

Try this, next time you start your bike: Ignition switch on, kill switch in RUN position; petcock ON; transmission in neutral or clutch lever pulled; activate choke lever (choke ON). Hit starter button, 'til engine starts. Gradually move choke lever to OFF position, as engine is able to sustain operation without enrichment.

Your automobile likely has a mechanism richening your starting mixture also, but transparent to you as driver. The KLR650 requires human intervention (activating choke lever) to start easily, most usually.

Good luck!
LoneRider is offline  
post #6 of 22 Old 08-13-2012, 02:52 AM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
From, "Care and Feeding of the CVK40:"
Quote:
STARTER ENRICHER - KLR Morning Coffee


This system is referred to as the
choke. But that's a misnomer. When
you apply the choke lever, what
you're doing is retracting a plunger
that opens a tube connected to the
starter jet, allowing additional fuel
to enter the venturi just below the
vacuum hose nipple. It supplements
the pilot system at start up.
If you want to know more about your carburetor, click here: http://www.gadgetjq.com/keihin_carb.htm

If you do not click on the link, no offense taken--some motorcycle forum members prefer not to use posted links.

Regardless, I think using the "choke" will facilitate starting your bike.
LoneRider is offline  
post #7 of 22 Old 08-13-2012, 11:04 AM
4th Gear
 
Spec's Avatar
 
Join Date: Apr 2010
Location: Gateway to Death Valley!
Posts: 1,928
Quote:
Originally Posted by LoneRider View Post
My suggestion; use the "CHOKE," JJNyborg!

First, it ain't REALLY a "choke," it's a STARTING ENRICHER.

When the engine is "cold," regardless of the ambient temperature, the starting enricher, when applied, provides a fuel-rich mixture to the engine for the purpose of . . . well, STARTING!

When you engage the choke lever, you withdraw a plunger from a hole in the carburetor and also open an air passage; fuel flows from the hole and mixes with the incoming air, not unlike the starting arrangement is a "mini-carburetor," only the misture is especially fuel-rich, for the purpose of starting the engine.

Try this, next time you start your bike: Ignition switch on, kill switch in RUN position; petcock ON; transmission in neutral or clutch lever pulled; activate choke lever (choke ON). Hit starter button, 'til engine starts. Gradually move choke lever to OFF position, as engine is able to sustain operation without enrichment.

Your automobile likely has a mechanism richening your starting mixture also, but transparent to you as driver. The KLR650 requires human intervention (activating choke lever) to start easily, most usually.

Good luck!

The ambient temp is the temp in a "cold" engine.

A choke is designed to be used for cold weather starting. Small drops of gas don't evaporate well when cold. You are enriching the mixture with the choke (in the KLR application) by adding fuel not air. The higher the ambient temps the less the enriching is needed. If you choke in warm/hot weather you are providing an excessevly rich mixture and will make the bike harder to start.

When the valves are in spec the motor should start with 2-3 turns of the starter, no choke in warm (>70 deg.) weather.

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

Last edited by Spec; 08-13-2012 at 11:15 AM.
Spec is offline  
post #8 of 22 Old 08-13-2012, 03:48 PM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
Quote:
Originally Posted by Spec View Post
You are enriching the mixture with the choke (in the KLR application) by adding fuel not air.
While the mixture enhancement from the application of the "choke" (starting enricher) is fuel-rich, withdrawing the plunger opens both a fuel orifice, and an air passage, allowing air to mix with the auxiliary fuel flow.

The tip of the plunger, withdrawn from the carburetor, allows fuel to flow; the reduced-diameter cross-section near the end of the plunger, when withdrawn, allows air to enter and mix with this auxiliary fuel.

Thus, the starting enricher system comprises a sort of, "mini-carburetor."

My KLR650, perhaps, is "cold-natured," use of the choke facilitates starting, even on moderate-to-hot days.
LoneRider is offline  
post #9 of 22 Old 08-13-2012, 03:56 PM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
This image illustrates the entry of BOTH air and fuel into the carburetor when the choke is engaged:



The vertical flow, represented by the arrows shown moving from the top towards the bottom, shows AIR entering the carburetor, possible at this juncture only when the choke is ON, or "fully open" as depicted.

The horizontal flow, shown coming in from left to right in the image, is FUEL, as the plunger point is withdrawn from its orifice in the carburetor.

The air and fuel are mixed, resulting in the fuel-rich starting mixture, and this fuel-rich mixture then procedes downward from the center-line of the enricher plunger, ultimately into the venturi and the engine.

When the choke is OFF, or "fully closed" as shown, the plunger seals the fuel hole, while the larger-diameter cross-section area of the plunger seals off the air passage.

This drawing shows how the starting enricher ("choke") system functons as a "mini-carburetor," mixing air and fuel to create a fuel-rich starting mixture.

Last edited by LoneRider; 08-13-2012 at 04:02 PM.
LoneRider is offline  
post #10 of 22 Old 08-13-2012, 04:12 PM
Banned
 
Join Date: Jan 2010
Location: Mid-Atlantic
Posts: 763
Another tip, JJNyborg, KLR650's typically come adjusted fuel-lean at the factory; if you remove the tamper-resistant plug, bottom forward portion of your carburetor, and then bottom (gently!) your fuel screw, then back it out about 1.75 turns, you may realize an idle air/fuel mixture much more agreeable to your engine, enhancing starting and operation from idle to 1/4 throttle.

If you want to continue along this line, shim your needle with one # 4 washer, to fuel-enrich the mid-range air/fuel mixture, and then . . .why not go ahead and enlarge the vacuum port in your slide to 7/64" diameter, for enhanced slide response (I've outlined the "22-cent mod")?
LoneRider 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
Bike won't start Lockjaw KLR & Other Motorcycle Related Discussion 34 11-27-2010 12:19 AM
KLR Engine Won't Start - Advice Requested haosheng 1987 to 2007 Wrenching & Mods 29 08-12-2010 08:52 PM
bike wont start TEXAS 650 1987 to 2007 Wrenching & Mods 20 05-18-2008 06:09 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