02 400ex randomly revs itself - Honda TRX Forum
 
LinkBack Thread Tools Display Modes
post #1 of 5 Old 10-16-2018, 06:50 PM Thread Starter
Junior Member
Feedback Score: 0 reviews
 
Join Date: Oct 2018
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
02 400ex randomly revs itself

hey everyone, i have an 02 400ex. i picked it up from a field, so i of curse did the basics...oil change, spark plug change, rebuilt carb and cleaned out the gas tank. got it all put back together and now whenever i start it, anywhere between 30 seconds and 5 min of idling (roughly cause the carb needs to be re-adjusted), it will just rev itself all the way up to rev limit. the only way ive been able to get it to stop is to shut it off. any suggestions?
comanchenick12 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 10-16-2018, 09:12 PM
Super Moderator
Feedback Score: 0 reviews
 
Join Date: Jan 2011
Location: Smack in the middle of Illinois
Posts: 3,027
Thanks: 5
Thanked 293 Times in 288 Posts
The carb needs a thorough cleaning and calibration
Here 2 help is offline  
post #3 of 5 Old 10-16-2018, 09:15 PM Thread Starter
Junior Member
Feedback Score: 0 reviews
 
Join Date: Oct 2018
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
That's what I seem to be gathering. Is there anything in particular that I should look for in the carb? Is there something specific inside the carb that would cause this? Or would it be like you said just needs another good clean and calibration? Appreciate the feedback!
comanchenick12 is offline  
Sponsored Links
Advertisement
 
post #4 of 5 Old 10-17-2018, 07:19 PM
Super Moderator
Feedback Score: 0 reviews
 
Join Date: Jan 2011
Location: Smack in the middle of Illinois
Posts: 3,027
Thanks: 5
Thanked 293 Times in 288 Posts
Could have a partially clogged pilot fuel circuit, low float setting, dirty pilot circuit air inlet passage, perforated air cut valve diaphragm, loose linkage or missing spring on slide lifter, missing plastic anti-cavitation device that Honda lists as a main jet holder (it does not hold anything, but if it's missing, the fuel can aerate around the tip of the main jet and the additional air can cause erratic running mostly at high speed, but .......) and finally, a loose or poorly aligned throttle butterfly plate that does not close completely when the carb warms from engine heat.

There may be other possibilities, but the mechanic will discover the problems during disassembly and assembly and correct them.
Here 2 help is offline  
post #5 of 5 Old 10-18-2018, 07:16 PM Thread Starter
Junior Member
Feedback Score: 0 reviews
 
Join Date: Oct 2018
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
I appreciate the help! Ended up finding the problem, the throttle cable was too short. When the throttle cable was installed in the carb, it had the valve opened way too much. So I lengthened the throttle cable and adjusted the idle screw, and now it runs like a dream!
comanchenick12 is offline  
Reply

  Lower Navigation
Go Back   Honda TRX Forum > Honda TRX Discussions > New Member Introductions

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda TRX 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



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