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Discussion Starter #1
I have an 03 1100 Custom which I really enjoy but lately have had issues with backfiring. I took off the surge tank to check to see if all hoses were connected and all were in good shape. However, I did notices that the "horseshoe" shaped device on the left side seemed to have a slack in the "back" cable. When throttling up, the "front" cable is tight and fits nicely in the groove of the "horseshoe" device and the return spring seems to work well. However, the back cable seems to have about 1/8 to 1/4" slack in it. There is a horizontal "peg" that holds the cable in place. Is there a way to take out the slack? I have a feeling that this possibly may be contributing to my backfiring issue because it may not be "cleanly" releasing when I let off the throttle. Any and all advice will be greatly appreciated.
 

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Many guys have gone with the single cable setup, no return cable without backfiring. So while it needs adjusting I don't think this is your problem. The adjustments are made at the top of the bracket surrounding the "horseshoe" or quadrant for the throttle cable and also at the upper end of the throttle cables near the handgrip. Adjust the pull side first leaving about an eights inch of rotation on the handgrip before the quadrant rotates. Then adjust the return to about the same tension. If it drags its too tight.

What do your plugs look like?
Is the idle smooth?
Have you done any other mods: ie jetting, pipes, intake?
 

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I have an 03 1100 Custom which I really enjoy but lately have had issues with backfiring. I took off the surge tank to check to see if all hoses were connected and all were in good shape. However, I did notices that the "horseshoe" shaped device on the left side seemed to have a slack in the "back" cable. When throttling up, the "front" cable is tight and fits nicely in the groove of the "horseshoe" device and the return spring seems to work well. However, the back cable seems to have about 1/8 to 1/4" slack in it. There is a horizontal "peg" that holds the cable in place. Is there a way to take out the slack? I have a feeling that this possibly may be contributing to my backfiring issue because it may not be "cleanly" releasing when I let off the throttle. Any and all advice will be greatly appreciated.
There is....just adjust the nut and sleeve on the cable.....read your owners manual, it's covered in there.
 

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Discussion Starter #4
OK-here's an event timeline.
1. In early spring, a buddy of mine rode about 100 miles round trip to a BBQ joint-no problems. I almost ran out of gas near home. Added gas from my lawn mower gas tank (no additives).
2. Went to Myrtle Beach for the spring rally. Had to put the choke on more than half way to keep it from choking out at stops. My buddy helped me adjust the thumb screw idle setting to take care of that.
3. The bike sat for a while and when it was idling, it was crack and pop. Figgering I had put in bad gas, I drained the tank, put in fresh premium with both Sea Foam and Lucas fuel treatment-that has almost taken care of that issue. That's also when the backfiring started.
4. I have put in new plugs-no other mods.
5. I removed the surge tank to be sure all hoses were connected. Every one that I can see is properly connected.
6. I checked the exhaust pipes to be sure they weren't loose and they are nice and tight.
7. I did find that the oval air intake that runs from the hypercharger to the intake of the surge tank had come loose from the clamp and has partially collapsed. My buddy and I were not sucessful in reusing the clamp so we tried a long zip tie but that did not hold the tube in place and it had partially collapsed.

When the bike is on the road, it runs great. Could it be that because the air intake is not fully closed with the partial collapse of the hose and is "sucking cold air" would that be the reason for backfiring?
Thanks.
 

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From the sounds of it, you may have an air leak in your system. A few questions that may help out I figuring your challenge.
Is your AIS still connected? How are your intake boots? When was the last time the exhaust gaskets changed? Your hypercharger being disconnected would only cause unfiltered air to enter the airbox. I recently tuned a buddies 1100 and found several exhaust gaskets worn out. His exhaust system was tight but when we took it off to do some other mods we found them worn. The other thing we did was check his carbs. The PMS setting were way out, so we adjusted them back to nominal and then fine adjust and synchronized.

Food for thought.
 

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OK-here's an event timeline.
1. In early spring, a buddy of mine rode about 100 miles round trip to a BBQ joint-no problems. I almost ran out of gas near home. Added gas from my lawn mower gas tank (no additives).
2. Went to Myrtle Beach for the spring rally. Had to put the choke on more than half way to keep it from choking out at stops. My buddy helped me adjust the thumb screw idle setting to take care of that.
3. The bike sat for a while and when it was idling, it was crack and pop. Figgering I had put in bad gas, I drained the tank, put in fresh premium with both Sea Foam and Lucas fuel treatment-that has almost taken care of that issue. That's also when the backfiring started.
4. I have put in new plugs-no other mods.
5. I removed the surge tank to be sure all hoses were connected. Every one that I can see is properly connected.
6. I checked the exhaust pipes to be sure they weren't loose and they are nice and tight.
7. I did find that the oval air intake that runs from the hypercharger to the intake of the surge tank had come loose from the clamp and has partially collapsed. My buddy and I were not sucessful in reusing the clamp so we tried a long zip tie but that did not hold the tube in place and it had partially collapsed.

When the bike is on the road, it runs great. Could it be that because the air intake is not fully closed with the partial collapse of the hose and is "sucking cold air" would that be the reason for backfiring?
Thanks.
That could be part of the issue...you mentioned the fact that the bike went unused for a while. My guess is that your pilot jets are partially plugged....check the small side holes. Just remove the carbs, pop off the bowls, remove the pilots, then run a small bread wrapper wire through all the holes.
 

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What do the new plugs look like and how many miles on them. Pics please label front n rear. Pics of old plugs and if you can remember f & r. I tend to agree with Mick old gas can be a killer. For cleaning I prefer StarTech fuel additive better for alcohol clogs. (ethanol breaks down quick n jells). Check to see if your caps on intake vacuum ports are good. I've replaced three sets. If you need them use the Yamaha ones they are heavier duty.
 

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Discussion Starter #8
Throttle cable questipn

Thanks to all for your suggestions and input. FullTilt, if you will send me your email address, I'll be glad to send you plug pics. Additionally, I had studied my Clymer manual to see about the AIS vacuum line. From the pic in the manual, it appeared to be right behind the "horseshoe" throttle cable control but I'll be damned if I can find it. Every other hose I can see seems to be properly connected. In terms of the carbs, if I was more mechanically inclined, I would not hesitate removing the carbs. If I did take them off, I might never get the bike running again. That;s my 12th Commandment. The 11th is: "Thou Shalt Not Do Transmission Work"
 

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I don't give out my email address. Just attach the pics to the reply window use the paperclip. That way everyone can see and if someone gets some info they were wondering about all the better.

As to the AIS line it is located on the aft cylinder intake manifold. Between the head and carburetor. Both intake manifolds have a nipple that sticks out they are used for the AIS and syncing the carbs. The fwd intake manifold is capped and these crack and allow air in after the fuel mix and will lean out your mixture. If you have to replace one of these use the Yamaha ones they seem to last much longer.

As far as the Clymer Manual. This site has alot of great info for the 1100. If you go to the Library you can d/l a Yamaha shop/service manual.

https://sites.google.com/site/vstar1100kb/home
 
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