XJ1100 Popping after sync

I was given a 1982 XJ1100 that hade been sitting for about 4 years.
The first thing i done was pull the carbs cleaned them up and put them back together. (thanks for all the info on this site.) I set the mixture screws to 4 turns and it started right but was sluggish. I just syncd the carbs and now I have a low idle popping. What else do I need to do. I can make a small block chevy speak in tongues but this is my first time dealing with a bike. Would love to hear from you guys as it sounds like ya'll know what you doing.

 

Did you check your valve clearences before sync?

 

Yes i checked and was within specs. before the sync the only real problem was with the idle it was going up and down about 500-1000 rpms

 

Firstly welcome to the world of the 11. You are now in possession of one of the most fun 2 wheeled machines there is on the planet (think I'm a fan?). The popping usually means you are lean. In contrast to the XJs these engines like to run a little to the rich side. If you have a color tune use it. On mine I adjust the idle mixture screw then sync and readjust the idle mixture then check the sync one last time. That being said with the screws out 4 turns you should be well to the rich side. On a good set of carbs 1 1/2 to 2 turns should have you close. The XJ has the YICS system so when you did the sync after removing the tool are you sure you have it sealed up? Are your carb boot caps in good shape? You just had them off after a 4 year sit so they may have developed a crack after being handled. Another question. What exhaust is on it? The aftermarket exhaust will do that if even a little lean. Is the problem with just one cylinder popping? The Mikuni's are very intolerant of any dirt or crud, The pilot jets and the emulsion tubes must be perfectly clean. There have been reports from guys on the XS11 site of problems after installing aftermarket carb kits which contain pilot jets that do not have the proper amount of holes in the sides. How do the plugs look? Lastly we need pictures

 

it appears to be just one cylinder. the carb boots are good i sprayed carb cleaner around them and got no change in idle. it has an aftermarket exhaust on it and i found a dynojet paper under the seat. i may be running to rich i just tried to start it after it cooled down it wouldnt start i pulled the plugs and they were wet i cleaned them put them back in and it started right up. but still has a popping at idle and no signs of a popping at cruise speed.

 

Mine was popping but after I would let off the gas. The throttle shaft seals wrer rock hard and would not seal anymore. Thus vacuum leaks on the throttle shafts. If its just popping at idle , I would check for vacuum leaks around the boots.

 

The popping is only coming from the right side cyl 3 or 4. The idle is setting steady at 1100 rpms with no sign of the up and down from before.
how much does the float level have to do with idle or popping. Like i said this is my frist time to get into rebuilding a bike. I have always hade someone else do work on the ones I have owned.

 

Float levels are the key to tuning any CV carb. They have to be right first. When you had the carbs off did you do a bench check of the levels? If your plugs are wet you may have an issue there. Another thing to check is the wires in the plug caps. Make sure that the connection between the caps and the wires is good. Still thinking you have a mixture problem at idle. With a wasted spark system you can get popping if the mixtures are overly rich. Are you running the stock airbox or pods?

 

i set them like i did my dirt bike back when i raced straight edge and set them level. I called a yamaha dealer near by and thats how they told me to set them. but then again that same tech told me that the front brake master cylinder hole didnt go all the way thru. What is the correct way to set the floats. im figuring its something i didnt do right before i did the sync as i didnt have the problem till the sync.

 

Im running airpods

 

Clamp them to a board up right and level. Supply fuel to the pair you want to check. Take a clear tube and attach it to the nipple on the bottom of the bowl on the carb in question. Open the drain screw while holding the tube up so that you can see the level of fuel in the bowl. It should be 3mm down from the flange where the bowl meets the carb body. Dowa search of the forum. I think Rick did a step by step tech tip on the proceedure. Its also described in the XS 1100 manual.

 

Christ...I wish someone would give me an 1100. You sure your name is hardlucktx?

 

The way I got I was helping a buddy put a new exhaust on his road star snd a guy he knows stopped by and was talking to us. He asked if we knew anyone that wanted a bike he had one he wanted to get rid of. I asked what it was he said a 1982 maxim xj1100. I asked what he wanted for it and he said come get it out of my garage and you can have it. so the cost of me helping my buddy I made him help me get it home. and the work began. what made me sick when i seen it was the custom paint job he had done on the tank was rusted and the paint was coming off.

 

I just had a thought on the popping. (Wasted spark ignition system). The o-rings on the float valve could be shrunk up on one or two carbs and it might be running rich and raw fuel is igniting on the middle stroke. I agree to check the float levels but with the bike running and see if you have one carb overflowing. The Makuni carbs have o-rings on the float valve seats and they do shrink up over time. Just another thing to look at.

 

wow i just came back in from checking a few things on it. I left the pitcock in the primary postion and found that carb 1 and 4 were leaking not much but it could be enough to cause the problem so after work I will check the levels and take them back off and check all the seals and o-rings

 

If the float levels are right and the needle valves are dong their jobs you can even have leaking petcocks and it will not hurt a thing. Check the levels as per the manual. If they are good I would say get 4 replacement needles and new orings if you haven't already. The seats can be polished with semi chrome to clean them up. While you are in there pull the main and pilot jets and clean the emulsion tubes again.

 

Thanks for the advice wingnut tore the carbs back down and recleaned them even some places i didnt even know were there. Benched sync'd she fired right up and was able to vacuum sync and the popping is gone

 

P.M. Sent

 

PM didn't come thru.

 

PM sent round 2

 

I am in need of an ignition cover for a 79 XS1100 was the P.M.

 

Must be something wrong with the address in my account. I'll check it out. An Ing cover? Not sure what you mean. Are looking for the cover that goes over the Ing switch? If so I can't help. There is a guy on the XS11.com web site with the handle of andreashweiss. He may have what you are looking for.

 

I mean the left side engine cover that covers the pick ups and advance unit.

 

I have one from a 79. It will need bead blasting and polish. I cheched my settings but can't figure out why the PMs are not coming in. I'll try sending you a PM with my email address.

 

doesn't need to be pretty I'm gonna paint it black anyway.