bike question - Hot Rod Forum : Hotrodders Bulletin Board -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
lost password?   |   register now

LinkBack Thread Tools
  #1 (permalink)  
Old 07-26-2003, 10:40 AM
bigwildgrin's Avatar
Join Date: Mar 2003
Location: montana
Posts: 176
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
bike question

okay, this is a bike question, so bare with me since alot of folks here have bikes and know their stuff and plus it's a hotrod bike, so you know.....

anyways my bike previously had 16" off shorty header pipes, but I wanted the rumbly backing off sound of longer pipes. I put on a set of 40" long 1 3/4 drag pipes and it sounds great, except when I let off the throttle it will backfire through the pipes a couple of times. I've tried adjusting the carb and it has helped some (leaning the carb made a noticable improvement but hasn't made it go away). is there something else I need to do to make it stop backfiring through the pipes? she's real picking about where the timing is set so I don't wanna mess with that until someone who knows more than me suggests it. if any one has any ideas I'd love to hear them.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 07-26-2003, 01:27 PM
Join Date: Mar 2003
Location: Tampa
Posts: 84
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
yes thats a hard problem to deal with and the better the engine runs the worse the problem seems to get sometimes, whats usually happening is under decelleration vacume is a little higher than it is while normally ideling, the carbs cant compensate for higher than idle vacumes due to fixed mixture settings causing missfires from overly lean conditions, miss fires are unburnt fuel weather rich or to lean, then what happens is the unburnt fuel ignites in the pipes due to heat usually from the lean conditions, leaning the fuel mixtures (idle mixtures) out even more just gives it less fuel to work with minimizing the problem but not solving it , fuel injected engines simply cut out the fuel all together untill the map (vacume) sensers see the right vacumes, mass air flow stuff can add the right amount of fuel to compensate but thats fuel injected stuff , the manifactures usually design systems that dump large amounts of air between the carbs and the valves using manifold pressure sencing valves letting the enging draw air from an outside source creating less vacume threw the carbs and sending mixtures so lean there no way they could ever fire even with exhaust heat solving the problem. some people just put enough mufflers on them till you cant hear the problem. hope i could be of some help good luck mikey
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

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

All times are GMT -6. The time now is 07:20 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.