bike just wont run right

[boxchevyman]

ok so i got mt 77 gs750 running like a champ after i bought it a month ago. i have put 800 miles on the bike without any problems. then i take it out the other day and it starts to bog down. pulled over revved it up a few times problem went away. drove it 20 more miles gassed up drove it another 20 miles then turned it off. when i restarted it, it was backfiring and had no power barley got home. when i got home i messed with the plugs and carbs. i tried to adjust the air mixture screw and now i can barley get it to start. im out of ideas. it has new plugs. i went through the carbs a month ago. i just dont know why it would go from great to horrible like that. any help would be awesome!!

james

[Nessism]

You replaced the points lately? Battery fully charged and charging system working properly?

Also, I doubt this is the problem but have you ever adjusted the valves?

[boxchevyman]

hey thanks for reply! the battery is currently dead for cranking over so much. i have never had a problem with the charging, i dont have a volt meter. i havent checked the points yet but i will when daylight comes around. i have never checked the valves i need to though. ill do a little research and figure out how.

hope this helps!

ps. i thought this bike was magneto ignition therefore not requiring the battery to be fully charged am i wrong?

[Steve]

"Messing" with the air screws is not generally recommended.

"Setting" them, however is.

If you have stock airbox and exhaust, set the fuel screws (the ones on the bottom) 3/4 turn out from lightly seated. Set the air screws (the ones on the sides) double that, or 1 1/2 turns out. That will get you going (assuming that mixture is the problem), then you will need to fine-tune the mixture by using the air screws.

Of course, this assumes that the valves are within specs, the ignition is within specs and the carbs are CLEAN.

.

[boxchevyman]

hey so i guess using the word "messing" wasnt the right one. i set them i put them 1 and 1/2 out (found the specs online). still nothing so i put them out at 2 full turns. somewhat of an idle but still dies. i may of posted this in the wrong section. but do you think this is an electrical problem? i dont have a clue at this point.

thanks for the reply!

[boxchevyman]

hey forgot to mention that i have stock airbox and exhaust. i have taken measures to seal the air box. but that was last month. i checked the seal it looked ok but i will reseal it again tomorrow.

[Big T]

A sudden loss of power like this is generally

1. Points/condensor
2, Clogged carbs - how clean is your gas tank?
3, Inline filter

[SqDancerLynn1]

I remember one time on my 79GS850, I was running about 90mph suddenly lost power. Thought I did something to the motor. Just got some crap in the carbs had to re clean them..

[BassCliff]

Greetings and Salutations!!

Hi Mr. boxchevyman,

You'll find lots of GS lovin' on my little website. 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

[550ERAT]

I went through all of this too. Ended up replacing my Stator and R/R and that had no effect other than fixing my charging issue. In the end, it ended up my bike jumped time. ONE TOOTH. That seemed to change alot once fixed. Of course I now am replacing the tensioner to be safe. Keep us posted.

[boxchevyman]

hey guys thanks for the replys! ok so i took a look at alot of the stuff mentioned here. cleaned carbs, changed fuel filter. checked air filter then points. all looked good. then i checked for spark by grounding the plug to the head. i got nothing on all four. so i started checking around no fuses are blow. i wish i had a volt meter but i "think" the coils are ok? i checked the wiring for shorts. and generaly gave the wiring a good look over. i didnt find anything wrong. but there is obviously something i missed if im not getting spark. lol any ideas? im giong to get a voltmeter from some freinds so i will test coils. but do you guys think i could of over heated something? or burnt something up?

thanks
james

[Big T]

Burnt something up is always possible!

Start with your voltage checks, clean the connections as you go

[boxchevyman]

ok so i got it to start!!!! my point were in bad shape i know i said i checked them but im new to mags and bike in general so i didnt know how to check them out. but i sanded them down and she started. whoo hoo. she is still running a little rough but im guessing thats because i need to readjust the air screws. i just wanted to say thanks for your quick replys and this site is great!!! learning so much.

james

[chuck hahn]

once you sand the points you also have to regap them...this ensures they close properly and open to the correct gap.

[chuck hahn]

Just an after thought here..Now that she will run again, i think if it were me and one of my bikes..I would remove the carbs and be sure they are clean, then reset the fuel mixture screws on the bottom..do a search and find the settings chart that was posted here a while ago because the fuel mixture setting is based on the model AND the engine numbers so be sure of these two factors and set them accordingly. Then i would set the air screws 1 and 1/2 turns out. Then i would put the guages on her and vacuum sync the carbs, making fine adjustments as you go...anyone have anything else to add?? the engine number is the number stamped on top of the tranny just above the clutch cover on that small flat area.