popping from airbox???

[bluepinner]

80 gs450lt. Cleaned carbs (using the info on here) 3 times. Fresh o-rings (from cycleoring). Performed a bench sync. Now I have a popping noise from the airbox. The carbs are cleaned and clear. Float levels are good. Any ideas??

[BassCliff]

Greetings and Salutations!!

Hi Mr. bluepinner,

Good work on the carbs!

There are other maintenance tasks that should be performed, to eliminate known issues with these often abused and neglected classics, before we can do more in-depth troubleshooting. Did you also replace the carb intake boots and their associated O-rings? Adjust the valves? If I may, it's all here in your "mega-welcome".

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[srsupertrap]

You never had the problem before cleaning the carbs? If that statement is true then it's something you did related to the carb cleaning process. If not verify your timing is correct. Popping is generally associated with backfiring or perhaps a lean mixture.

[bluepinner]

I replaced the intake o-rings, the intake boots were still good (no cracks, splits). I planned on checking the valves next week. I will check the timing. I set the mixture screws to 1 1/4 out. I forgot to write down what they were set at.

[nutsandbolts]

I have the same issue bluepinner- popping through the air box. Now the carbs act like they're flooding and it won't idle. Turning the throttle kills the engine immediately. I've replaced every o-ring and rubber realted to intake and carbs and carbs have been dipped and compressed afterwards
I haven't been able to do a running timing check but a static check tomorrow might help.
Definately check the timing if I was you.

[bluepinner]

Could it be a coil problem? I looked at the coils and they seem to be the originals. I am going to check the voltage but not sure how to and how much they should have? Any ideas for this and could this be part of the problem? I found the coil relay mode from basscliff and have most of the stuff available.

[nutsandbolts]

I am not sure but they're easy to check.
Try this;
Check resistance across the terminals on the coil with a multimeter. It should read 3 ohms for an electronic ignition or 5 ohms if you have a points type ignition system. Resistance through the spark plug caps should be 18,000 to 50,000 ohms.
Thanks to Suzuki Don for that and his comments in post

[nutsandbolts]

bluepinner,
my coil was fried on 2&3 plugs. suspect yours is the same. I had 4.5 ohms resistance on two control leads but 0 ohms when testing through the plug cap ends. #1&4 ohms testing had 4.5 through control leads and 23000 though plug caps.
good luck

[bluepinner]

My coils checked out but the valve clearance was messed up. The exhaust valves were in constant contact with the cam thingy (rocker????). Just waiting on new shims from ghost1.

[nutsandbolts]

Well, that's kind of a relief. Shims are cheap. Coils cost about 135 each. When I put my shims in spec- made a big difference.
Good luck

[SqDancerLynn1]

Their is an order to what needs to be done to revive an old bike. One of the first things is a valve adjustment After the bike has run for a few minutes. Keep at it and eventually everything gets done