Valve Problem?

[Maynard70]

Gentlemen:

Greetings... New here. Glad I found this site! I have an '81 GS450-T I've had for about a year now. Many, many, many miles on her but the compression is still strong and she (usually) runs pretty good.

Need some help, though - strange recurring problem, maybe someone here will know what's going on. Cold starts are OK and she'll run fine for awhile but won't re-start after, say, I stop for a 5-10 minute gas or store stop. Big time popping and backfiring issue on the left side only. I let it sit for awhile, maybe 10 minutes, it will start and run normal again.

Replaced the coil and plug, but it's still doing it. I have two sets of carbs (that are as clean as I can get 'em) for the bike, and it will exhibit this same backfiring and popping issue regardless of which one I have on, so I figured the carbs are unlikely the cause.

I found this on youtube: https://www.youtube.com/watch?v=TJyBWh9SDWg

I'm getting the same noise, as well. Could it be a timing issue and in need of a valve or cam adjustment?

This is driving me insane. I'd be happy to wrench in there myself and do my own work if I could get pointed in the right direction, but I can't even get an honest opinion or assessment from a local shop or mechanic around here - quite simply, if you bring in a bike as old as mine, they don't even want to talk to you.

Any help or suggestions would be welcome!

Thanks..... M

[BassCliff]

Greetings and Salutations!!

Hi Mr.

Old bikes need lots of maintenance in order for them to run properly and be reliable. You'll find most of what you need to know in the links below, i.e. properly cleaned carbs, properly adjusted valves, etc.

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

Let me dump a TON of information on you and share some GS lovin'.

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", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. 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!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[eil]

Have you done a valve adjustment?

Do you get a hanging idle when the engine is hot?

The noise in that video is reminiscent of the classic (and harmless) "cam walk" noise. But I don't own a 450, so I can't be sure. Does the noise go away at higher revs?