flame thrower - Star Motorcycle Forums: Star Raider, V-Max, V-Star, Road-Star Forum
 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old 07-28-2014, 11:44 AM Thread Starter
Junior Member
 
Join Date: Jul 2014
Posts: 4
flame thrower

I am a new guy but I got a deal on a 2002 Vstar 1100 with almost 30000 miles on it because the starter clutch was bad. I push started it and it ran but it back fires and shoots flames from rear cylinder exhaust pipe. The bike has the air pump system removed with Baron Plugs in the heads and a rubber cap at the intake boot, also has Vance and Hines slip on's I tore it apart and replaced the starter clutch and the bolts that hold starter together as they were bent from starter twisting. Now I am exploring the backfiring flame shooting issue.

Found cracking intake boots and replaced them, took carburetors all apart and cleaned all the passages and jets. Found spark plugs very black and obviously running rich. While carbs apart found the needles had six grooves and they were set on the third from bottom with snap ring. I moved up one groove hoping to lean it out a little. The main jets were marked front cylinder 112.5 and rear 110.0. Pilots were both 17.5. I reassembled the carbs reinstalled with the new boots and new fuel filter. NO CHANGE still back fires and pops with flames from rear cylinder pipe.

This is bad even at idle popping is obnoxious. I am at the end of my ideas. Anybody else have a cure?
rlast1 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old 07-28-2014, 11:01 PM
Senior Member
 
Sick Mick's Avatar
 
Join Date: Oct 2011
Location: Corona De Tucson, AZ
Posts: 2,181
Quote:
Originally Posted by rlast1 View Post
I am a new guy but I got a deal on a 2002 Vstar 1100 with almost 30000 miles on it because the starter clutch was bad. I push started it and it ran but it back fires and shoots flames from rear cylinder exhaust pipe. The bike has the air pump system removed with Baron Plugs in the heads and a rubber cap at the intake boot, also has Vance and Hines slip on's I tore it apart and replaced the starter clutch and the bolts that hold starter together as they were bent from starter twisting. Now I am exploring the backfiring flame shooting issue.

Found cracking intake boots and replaced them, took carburetors all apart and cleaned all the passages and jets. Found spark plugs very black and obviously running rich. While carbs apart found the needles had six grooves and they were set on the third from bottom with snap ring. I moved up one groove hoping to lean it out a little. The main jets were marked front cylinder 112.5 and rear 110.0. Pilots were both 17.5. I reassembled the carbs reinstalled with the new boots and new fuel filter. NO CHANGE still back fires and pops with flames from rear cylinder pipe.

This is bad even at idle popping is obnoxious. I am at the end of my ideas. Anybody else have a cure?
The cure for the back fire is to adjust the PMS out to 2 1/2 or 3 turns and see what happens. Also check for exhaust leaks especially where the slip-ons connect and at the front head.

Did you synch the carbs after you put them back on? That could also be a big part of your issue.

6 groove needles are not stock...and harder to tune. Most just toss 'em in the garbage and get a stock set. They are either 1 groove or 5 groove (use middle groove).

I used to lean out my PMS at night when I had a Thugstar pipe just to see the flames......that was fun...lol

Sick Mick* 2006 V Star 1100 Custom

--- Striping, lettering and paint by Sick Mick 6* Tree - 2" extended forks 21" front wheel - HK Sideburners - Progressive rear shock Pods Sick Mick solenoid delete - Spring seat - and other stuff

Last edited by Sick Mick; 07-28-2014 at 11:08 PM.
Sick Mick is offline  
post #3 of 5 (permalink) Old 07-28-2014, 11:32 PM Thread Starter
Junior Member
 
Join Date: Jul 2014
Posts: 4
Flame on

I did remove the plugs and PMS screws are backed out 2.5 turns with no change. Synced the carbs and it idles better but no other changes. Problem seems to be with rear cylinder my next step is a compression test and valve adjustment if it needs it. I have looked the exhaust over real well and see no signs of leakage.
rlast1 is offline  
Sponsored Links
Advertisement
 
post #4 of 5 (permalink) Old 07-29-2014, 09:04 AM
Senior Member
 
Sick Mick's Avatar
 
Join Date: Oct 2011
Location: Corona De Tucson, AZ
Posts: 2,181
Quote:
Originally Posted by rlast1 View Post
I did remove the plugs and PMS screws are backed out 2.5 turns with no change. Synced the carbs and it idles better but no other changes. Problem seems to be with rear cylinder my next step is a compression test and valve adjustment if it needs it. I have looked the exhaust over real well and see no signs of leakage.
2 1/2 is probably not enough. I'd go to at least 3 1/2 or 4 and see what happens. If it stops the backfire, slowly turn them in until it starts again, then back out 1/8 turn.

Backfire on decel is a lean condition at idle. So it's either air getting in, or too little fuel. When you had the carbs apart...did you run something through all the small holes in the pilot jets? If those get plugged even slightly it will cause the same issue. I always run a stiff brush bristle through them when ever I have my carbs apart just in case.

Maybe I needed to read your post closer.....are you saying that while the bike is sitting still idling, it is throwing flames out?

Sick Mick* 2006 V Star 1100 Custom

--- Striping, lettering and paint by Sick Mick 6* Tree - 2" extended forks 21" front wheel - HK Sideburners - Progressive rear shock Pods Sick Mick solenoid delete - Spring seat - and other stuff

Last edited by Sick Mick; 07-29-2014 at 09:07 AM.
Sick Mick is offline  
post #5 of 5 (permalink) Old 07-29-2014, 04:44 PM Thread Starter
Junior Member
 
Join Date: Jul 2014
Posts: 4
Flame thrower

I have now backed the screws out 3.25 turns and it is better. Will ride tomorrow if I get time.
rlast1 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Star Motorcycle Forums: Star Raider, V-Max, V-Star, Road-Star 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 not post new threads
You may not 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