Going down 2000 feet with cbr 900, will it run to lean - Honda Motorcycles - FireBlades.org
Honda FireBlade Discussion of the Honda CBR 900RR, Honda CBR 929RR, Honda CBR 954RR, and Honda CBR 1000RR Motorcycles.

User Tag List

 
LinkBack Thread Tools
post #1 of 12 Old 06-28-2013, 12:52 PM Thread Starter
 
Join Date: 01-28-2008
Location: Idaho
Age: 31
Posts: 108
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 12
 
Going down 2000 feet with cbr 900, will it run to lean

Planned a trip down to Monterey and didn't think about the change in altitude if it will lean out my bike to much. Info on the bike has big tube header, slip on, k&n filter.
95erion is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 06-29-2013, 4:40 AM
 
Join Date: 07-28-2012
Location: Dallas TEXAS
Age: 31
Posts: 1,287
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 36
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Is your bike running just Lil fat or already on the lean side? If you stay very long id be jetting it. But if your not staying long and no fast long riding and going back wouldn't worry about it. May pop some and sound different lol
Kind of a pain to just swap jets.... be on safe side id go up jet size.
900rrHonda is offline  
post #3 of 12 Old 06-30-2013, 9:02 AM
 
Join Date: 03-24-2011
Location: Waterlooville UK
Age: 47
Posts: 3,033
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Reputation Power: 77
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

If your going down in altutude wouldn't that richen the bike?



Bike build Vblog latest Update
http://youtu.be/2ISgxtQXs9o

My 900RR Winter Project
https://www.fireblades.org/forums/hon...er-revamp.html
Lambchops is offline  
Sponsored Links
Advertisement
 
post #4 of 12 Old 06-30-2013, 10:45 AM
 
Join Date: 06-26-2013
Location: SE Kansas
Posts: 94
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 7
 
Re: Going down 2000 feet with cbr 900, will it run to lean

Quote:
Originally Posted by Lambchops View Post
If your going down in altutude wouldn't that richen the bike?
No sir, they are right the lower the altitude the leaner you will get. As you increase altitude, the density of the air decreases. There is less oxygen available and the fuel/air ratio becomes rich. So just the opposite which would mean getting leaner.
Now as for the messing with the carbs because of altitude put new plugs in right when you get there after some riding check them and see how its running and it will tell you if you should do anything to the carbs or not.
jqcbr954 is offline  
post #5 of 12 Old 06-30-2013, 1:04 PM
 
Join Date: 10-03-2012
Location: B.C., Canada
Age: 35
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Reputation Power: 14
             
Re: Going down 2000 feet with cbr 900, will it run to lean

2000 ft. isn't that much. In my opinion it's not going to be as significant of a change to be worth while changing the jets. It's not going to run quite as good as it is now of course, but it's not going to kill the engine. Make sure you run good fuel.

"When you come to the end of your rope, tie a knot and hang on."
- Franklin D. Roosevelt
2002 954
maverick0716 is offline  
post #6 of 12 Old 06-30-2013, 4:35 PM
 
Join Date: 03-24-2011
Location: Waterlooville UK
Age: 47
Posts: 3,033
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Reputation Power: 77
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Thanks for confirming jq makes sense



Bike build Vblog latest Update
http://youtu.be/2ISgxtQXs9o

My 900RR Winter Project
https://www.fireblades.org/forums/hon...er-revamp.html
Lambchops is offline  
post #7 of 12 Old 06-30-2013, 4:50 PM
 
Join Date: 04-03-2012
Location: Chasing range rovers.
Posts: 3,890
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 113
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Quote:
Originally Posted by Lambchops View Post
If your going down in altutude wouldn't that richen the bike?
It gets richer as you go up, not down

If the bike isn't braking properly, you don't start by rebuilding the engine.
Sky91 is offline  
post #8 of 12 Old 06-30-2013, 4:51 PM
 
Join Date: 06-26-2013
Location: SE Kansas
Posts: 94
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 7
 
Re: Going down 2000 feet with cbr 900, will it run to lean

Quote:
Originally Posted by Lambchops View Post
Thanks for confirming jq makes sense
Np
jqcbr954 is offline  
post #9 of 12 Old 06-30-2013, 5:07 PM
 
Join Date: 07-28-2012
Location: Dallas TEXAS
Age: 31
Posts: 1,287
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 36
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Here is a tip a guidelines for good tuneing when changeing air temp and elevation.
And yes you get leaner needles or larger jetting when dropping altitude.
When I go Colorado I go down in jet size and fatter needle I'm at 700ft and there is 2200-2800 where we go.
HERE YA GO YOUR WELCOME
FAQ REJETTING FOR ELEVATION AND TEMPERATURE CHANGE

You can also change plug temp by getting hotter or colder plug to make up for changes.

Last edited by 900rrHonda; 06-30-2013 at 5:17 PM.
900rrHonda is offline  
post #10 of 12 Old 06-30-2013, 5:31 PM
 
Join Date: 07-28-2012
Location: Dallas TEXAS
Age: 31
Posts: 1,287
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 36
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Quote:
Originally Posted by maverick0716 View Post
2000 ft. isn't that much. In my opinion it's not going to be as significant of a change to be worth while changing the jets. It's not going to run quite as good as it is now of course, but it's not going to kill the engine. Make sure you run good fuel.
2000ft is a significant difference to properly tuned carb. May not be if your mis tuned carb goes to right way so was lean and you go up it'll improve some but a lot plays in when changeinv altitude and air temps humidities etc. Air fuel needs adjusting and needles taper also for best burn.
Some people can't notice difference or don't know enough for proper adjustments. So leave well enough alone. Hell I know a guy his bike runs 3cyclinders outta four and he thinks its perfect but I hear its stumble half mile away.

Last edited by 900rrHonda; 06-30-2013 at 5:36 PM.
900rrHonda is offline  
post #11 of 12 Old 06-30-2013, 8:15 PM
 
Join Date: 10-03-2012
Location: B.C., Canada
Age: 35
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Reputation Power: 14
             
Re: Going down 2000 feet with cbr 900, will it run to lean

The point I was getting at is that if you expect to have a "perfectly" running carbed bike all the time then you'd b constantly adjusting it. Humidity can have just as big of an effect as elevation.....when it's humid out do you tune your bike differently and then back again when the weather changes? I'm sure some guys do, but for most, it's not a real world situation.

"When you come to the end of your rope, tie a knot and hang on."
- Franklin D. Roosevelt
2002 954
maverick0716 is offline  
post #12 of 12 Old 07-01-2013, 12:52 AM
 
Join Date: 07-28-2012
Location: Dallas TEXAS
Age: 31
Posts: 1,287
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Reputation Power: 36
                     
Re: Going down 2000 feet with cbr 900, will it run to lean

Quote:
Originally Posted by maverick0716 View Post
The point I was getting at is that if you expect to have a "perfectly" running carbed bike all the time then you'd b constantly adjusting it. Humidity can have just as big of an effect as elevation.....when it's humid out do you tune your bike differently and then back again when the weather changes? I'm sure some guys do, but for most, it's not a real world situation.
I tune mine for the conditions espically if plan to change 2000ft of elevation.
I don't tune everytime it get humid or dry but will adjust when its not 100° here. Maybe when it don't get abouve 85. Ill play with air fuel mixture a Lil bit.
Chances of average Joe who only rides to work or once a month he probably won't worry about proper tuneing due to either changes or elevation unless they absolutely have to. Most people are scared of carbs and don't understand fully whats going on.
900rrHonda is offline  
Reply

  Lower Navigation
Go Back   Honda Motorcycles - FireBlades.org > Honda Motorcycle Models > Honda FireBlade

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Honda Motorcycles - FireBlades.org 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
A valid e-mail address is REQUIRED. You will not have access to any site features until you activate your account using the activation e-mail that is sent to this address.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
HAPPY FEET redheadedrider Streetfighter 8 03-07-2009 1:00 PM
Gear shift for big feet Cato85 Honda FireBlade 2 11-05-2008 6:49 PM
Hp @ 5,500 feet Torch Honda FireBlade 2 03-22-2008 8:27 AM
Question For Riders With Big Feet bwhip General Discussion 26 03-24-2004 6:00 PM
A good pair of boots for fat feet? MedTechRR Riding Gear / Luggage 4 05-17-2003 3:50 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 Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome