wooshing sound 81 gs750

[Guest]

So I have a misfiring problem/ no firing in 1 and 2 and a wooshing sound. 3 and 4 are fine wondering what the possible problems could be. I know I need to adjust the valve and all that other maintainance. I'm working on a budjet and can only do a piece at a time. Just curious as to what it could be and what to expect when I get to that part.

[BassCliff]

Greetings and Salutations!!

Hi Mr. bartmancometh,

So you haven't given us much to go on. So how much maintenance have you done to the bike? So are the plug wires crossed on 1 and 2? It doesn't sound like a coil issue so it's probably dirty carbs. So have you cleaned them? So go through all the items on the maintenance lists so we'll have an idea of what we're working with. Until you get all of those things done properly we're just guessing.

So now I'm going to 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!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[tkent02]

1 and 2 not running, probably clogged up carbs, it's only 1 and 2 because it sat on the side stand for months (years?). Whatever fuel leaked through the leaky 30 year old petcock flowed down into the down hill left side carbs and turned to goo.

The whooshing sound? Maybe air leaking throughout the valves which can't close because they haven't been adjusted in years?

Just a wild ass guess.

[bartmancometh]

The carbs have been cleaned and adjusted. And the plugs and wires are ok.

[tkent02]

The carbs have been cleaned and adjusted.

We get that a lot around here.

[cowboyup3371]

How were they cleaned? Were they fully disassembled, dipped for 24 hours each in Berryman's, reassembled with new orings, floats adjusted, bench synched, and then put back on the bike? Were your valves adjusted so that they had the proper clearance? Did you do a vacuum synch afterwards? How many turns out are the mixture screws?

Were the intake boot orings replaced and even the boots themselves if they are cracked or hard? Both sides (intake and airbox)?

[Pendulum]

The carbs have been cleaned and adjusted. And the plugs and wires are ok.

Did you soak the carbs in Berrymans AND install new o-rings from Cycle O-Rings? If not, the carbs need more attention.

Have you checked resistance on the coils and plug wires? If not, do that.

Assuming your carbs are done properly, and you're getting a whooshing sound I'd bet it's either valves or real bad air leaks. Have you done a valve adjustment? If not, do that. Once the valves are adjusted and we're on the same page as far as carb condition we can start doing some real troubleshooting.

[bartmancometh]

And how do I determine what model my bike is. I know its an 81 750 but how do I know if its an e , g an l or whatnot

[koolaid_kid]

Bart, we are not picking on you, I hope you don't take it that way. But we do get a lot of folk who claim the carbs were cleaned and adjusted, but they were not done according to the procedures outlined on BassCliff's website, and it turns out to be the issue.
Since you stated you have not adjusted the valves yet, I suggest you make that the first order of business. You have the nut/screw adjustments, rather than the shim over bucket enjoyed by the 8 valve models, so your cost will be minimal, mainly time, and a set of metric feeler gauges if you do not already own one. SAE feeler gauges can be used in a pinch, just to get you in the ballpark.
After you do this, please report your findings AFA what they were prior to adjustment, if any.

[cowboyup3371]

Post up a picture and we'll be able to tell you

[koolaid_kid]

And how do I determine what model my bike is. I know its an 81 750 but how do I know if its an e , g an l or whatnot

For engine work, it does not matter. They are both 16 valve motors. The 750 never came in a G model, btw. The L model was delivered with a stepped seat and buckhorn handlebars.

[Larry D]

And how do I determine what model my bike is. I know its an 81 750 but how do I know if its an e , g an l or whatnot

Here's a picture of my '81 GS750L. Notice the leading front axle, stepped seat, fancy buckhorn handlebars, megaphone mufflers and smaller gas tank.

To repeat what has been said, there really are no shortcuts to getting an older bike up to road-worthiness. The carbs must be cleaned properly and rebuilt with new o-rings, it must have absolutely no air leaks and the electrical connections must be cleaned and/or redone.

[Larry D]

For engine work, it does not matter. They are both 16 valve motors. The 750 never came in a G model, btw. The L model was delivered with a stepped seat and buckhorn handlebars.

Actually George, the 16V 750's were available with a shaft drive......but, they were only sold in Japan.

[tkent02]

Actually George, the 16V 750's were available with a shaft drive......but, they were only sold in Japan.

Are you sure?
I thought it was the 8V 750 that were sold as shafties in Japan.

[koolaid_kid]

I'll have to check it out the next time I visit Japan. Not.