Bike Talk Motorcycle Forum Bike Talk Motorcycle Forum
Go Back   Bike Talk Motorcycle Forum > The Garage > Motorcycle Tech Talk
Discussion on Back Firing within Bike Talk's Motorcycle Tech Talk forum.

Home Forum Register FAQ Sponsorship Search Today's Posts Mark Forums Read

Back Firing


Welcome to the Bike Talk motorcycle forum Contact Bike Talk Join Bike Talk

» Site Navigation
 > F.A.Q.
» Auction

» B-T Recommends:
Visit Biker Bids

Harley-Davison Parts & Accessories at RideGear.com


Reply
 
Old Feb 13th, 2006, 03:31 PM   #1
2fastnaz
Moderator
Has posted 500+
 
2fastnaz's Avatar
 
Join Date: Sep 2005
Location: The Shores of Tonto Creek
Posts: 689
Interests: Guns, Hunting, Fishing, 4 wheeling and riding
Occupation: Network Administrator

Hey guys can you help me narrow down what might be wrong??

82 Iron Head Sporty is back firing and raising hell. I've been thru the carb it's getting plenty of gas and no not flooding. I adjusted the push rods. I have 115 psi front and 125 rear. New plugs, new wires, routed correctly.

I was going down the road and had pulled up next to a Pete with straight pipes for a listen when she just went to crap. She'll idle OK, but any throttle at all and the banging commences.

Thanks for the help.
2fastnaz is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Sponsored Links
Old Feb 13th, 2006, 04:46 PM   #2
CD
Administrator
Has posted 500+
 
CD's Avatar
 
Join Date: Mar 2004
Location: Tucson AZ
Posts: 1,563
Interests: Fishing, wood working, flipping off Fred Fox
Occupation: Founder of Bike Talk....retired and lovin' it
Quote:
Originally Posted by 2fastnaz
Hey guys can you help me narrow down what might be wrong??

82 Iron Head Sporty is back firing and raising hell. I've been thru the carb it's getting plenty of gas and no not flooding. I adjusted the push rods. I have 115 psi front and 125 rear. New plugs, new wires, routed correctly.

I was going down the road and had pulled up next to a Pete with straight pipes for a listen when she just went to crap. She'll idle OK, but any throttle at all and the banging commences.

Thanks for the help.
Did the big Pete scare her?

What ignition is in it? If it has been converted back to mechanical, have you checked and serviced the advance unit lately?
Check for vacuum leaks?
Will it rev under no load? No smoke?

Sounds like either a timing issue or a vacuum leak.
CD is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old Feb 13th, 2006, 06:56 PM   #3
oldsuperglide
Rookie 10+ posts
 
Join Date: Jan 2006
Location: dallas,tx
Posts: 44
Interests: 80Shovel,78Ironhead,spending time with family
Occupation: machinist/welder

what speed does it start. Are in the intermediate are the main jet. CD is right, Its one are the other(fuel are timing).
oldsuperglide is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old Feb 14th, 2006, 09:53 AM   #4
2fastnaz
Moderator
Has posted 500+
 
2fastnaz's Avatar
 
Join Date: Sep 2005
Location: The Shores of Tonto Creek
Posts: 689
Interests: Guns, Hunting, Fishing, 4 wheeling and riding
Occupation: Network Administrator
I put new gaskets on everything and checked the manifold. I didn't find any vacuum leaks spraying around with starting fluid. She'll only idle won't take any throttle at all load or not no smoke. As far as I know the ignintion is stock.

A few weeks ago I dropped the clutch pretty hard withouot unlocking the rear rotor (pad lock). It bent the rotor and screwed the pads up but didn't hurt any thing else I could find. The engien stalled when I did it, could there be a shear pin (woodruf key) on the flywheel or something that I may have sheared?? I have a shop manual but haven't found anything about it.

Thanks again guys
2fastnaz is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old Feb 14th, 2006, 04:11 PM   #5
kamakazi
Very Active Poster 50+
 
kamakazi's Avatar
 
Join Date: Jan 2006
Posts: 52
Sounds like timing to me... Do you mean to say after fire right? Backfiring is through the carb, after fire is through the exhaust.
kamakazi is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old Feb 14th, 2006, 05:03 PM   #6
CD
Administrator
Has posted 500+
 
CD's Avatar
 
Join Date: Mar 2004
Location: Tucson AZ
Posts: 1,563
Interests: Fishing, wood working, flipping off Fred Fox
Occupation: Founder of Bike Talk....retired and lovin' it
Quote:
Originally Posted by 2fastnaz
I put new gaskets on everything and checked the manifold. I didn't find any vacuum leaks spraying around with starting fluid.
Thanks again guys
YEEEOOOWCHHH!!!! That is scary!
I'd be very careful doing that expecially starting fluids with high ether content. Use WD40 it is a much safer way to test.

I still lean toward timing / advance
CD is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old Feb 15th, 2006, 10:05 AM   #7
2fastnaz
Moderator
Has posted 500+
 
2fastnaz's Avatar
 
Join Date: Sep 2005
Location: The Shores of Tonto Creek
Posts: 689
Interests: Guns, Hunting, Fishing, 4 wheeling and riding
Occupation: Network Administrator
Quote:
Originally Posted by CD
YEEEOOOWCHHH!!!! That is scary!
I'd be very careful doing that expecially starting fluids with high ether content. Use WD40 it is a much safer way to test.

I still lean toward timing / advance

How did I know I'd get that reaction. LOL It's all good CD, I know all about cylinder scoring, been there, done that, got the T-shirt. I don't over do it. Less is more.

Kamakazi: I'm actually getting both, but more back than after.

Thannk guys If I can get every thing done I need to I'll pull the covers and see this weekend. Thanks again for keeping me pointed the right way.
2fastnaz is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply

«- rocker cover gaskets « Previous | Next » tire spacing -»



Thread Tools



Similar Threads to: Back Firing
Thread Thread Starter Forum Replies Last Post
Back fire terry Motorcycle Tech Talk 10 May 4th, 2008 03:44 PM
Just got back in GreyBear Trips N' Trails - the ride is the adventure 6 Nov 24th, 2006 05:58 AM
My Lights Are Back SPORSTERBOY Motorcycle Tech Talk 1 Mar 28th, 2006 10:59 PM
Old Bike is Back FLHTbiker Pull up a chair and sit for a spell 5 Oct 15th, 2005 08:29 AM
Welcome Back!!! Seahag The Welcome Mat 2 Jun 17th, 2004 02:15 PM

Powered by vBadvanced CMPS v3.0 RC1

All times are GMT -7. The time now is 04:22 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2009, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.0.0 RC8
BikeTalk Motorcycle Forum Copyright 1997-2009 all rights reserved


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107