'77 GS750 issues

[rightious]

alright, ive got a 77 gs750, and it was running great around town, but then...

i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

any help would be GREAT... thanks

 

[Larry D]

alright, ive got a 77 gs750, and it was running great around town, but then...

i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

any help would be GREAT... thanks

Welcome !!

We need a little more info. You say it was running great around town. How long was it running great ? Just one ride, or have you been riding it for years ?
When did you take the muffler off and WHY ?!?! It ran very well and then you removed the muffler ??!!??!! WHY ?!?!?!

You've really changed the way the bike bike breathes. They are very particular about the air/fuel mixture and the exhaust pressure.

 

[mike_of_bbg]

My first instinct is that the gas cap is plugged up and isn't venting. Thus you got too much vacuum built up in the tank after burning enough fuel and it starved. If it happens again try removing the gas cap and immediately re-starting it.

You'll have to tell us the muffler story...

 

[rightious]

well, i took off the muffler for a few reasons

1. loud pipes save lives.
2. sounds better to me.

i have been riding for only a few weeks, but the most i had gone was probably 5 mi. through those times, it ran and pulled, the muffler was off the whole time, it ran without it, that is not the issue.

about the gas cap, if it was vapor locked, wouldnt that have a lean situation?

 

[Rudeman]

well, i took off the muffler for a few reasons

1. loud pipes save lives.
2. sounds better to me.

i have been riding for only a few weeks, but the most i had gone was probably 5 mi. through those times, it ran and pulled, the muffler was off the whole time, it ran without it, that is not the issue.

about the gas cap, if it was vapor locked, wouldnt that have a lean situation?

Did you check for an airflow restriction (air cleaner)? Is your breather inlet clear?

Put the mufflers back on loud pipes don't save lives they just make it harder to hear ANYTHING but your motor and that includes you. You won't hear the horns or sirens, etc and it may result in dire consequences for you. Not to mention you're pi$$ing everyone else off...and yes you SHOULD care.

 

[rightious]

Did you check for an airflow restriction (air cleaner)? Is your breather inlet clear?

Put the mufflers back on loud pipes don't save lives they just make it harder to hear ANYTHING but your motor and that includes you. You won't hear the horns or sirens, etc and it may result in dire consequences for you. Not to mention you're pi$$ing everyone else off...and yes you SHOULD care.

that is what i thought about originally, being that the air filter is dirty (need to find a local shop to buy parts), so i took off the side of the air box while i was stranded on the road, to allow air to freey flow into the carbs temp. that did not help. i am going to buy a new filter asap, but my thinking is i ruled out that problem.

my main question is it was running great up until 1 point. now i can not get it to go more than a block without bogging out

 

[Spyderman]

alright, ive got a 77 gs750, and it was running great around town, but then...

i went for a 40 mi ride, and about 3/4 the way threw, it died on me. i waited for a little while, and got it to start, but it drove for about 2 more miles, then died again. then it got started and went about 2 blocks.

prior to these issues, it ran very well, pulled like no ones buisness... at this point, i can get it started and it will idol all day. but once i get going, it seems to flood out and bog real bad. i know im running a little rich, and to me it seems to be flooding.

i have taken off the muffler, as i have been reading, might need to rejet, but my question is, why did it run very well for a while, then **** out?

it is running rich, my plugs are black, that is another issue i know, but what im trying to figure out is why all the sudden it just crapped out?

any help would be GREAT... thanks

ok so here we go lets start with
what maintenance have you done to this bike ther are some basics that you need to do
1 adjust the valves
2 clean the carbs this means dip em and put new o-rings in and set them back to factory settings (if your bike is stock IE: no pods no aftermatket pipe)
3 check and set the timing and also check the points for wear
4 vacum sync the carbs

once these things are done then you can start to sort out what is happening with it quitting on a long ride
you said it's running rich have you pulled the plugs and looked at them (posting a pic of the plugs would be good )
and yes you can have a rich condition and have a vapor lock
removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow

as for loud pipes well it's been in my experience that a louder pipe will make cagers look around for you but make it too loud and it just upsets them not to mention it upsets your neighbors as well
find a good pipe that is not too loud and put it on
and with these bike it is best to have a muffler
just because the it ran with the muffler off doesn't mean it's not contributing to the problem

if you think it's flooding then that would point to a float height problem so thus performing setp 2 would be a good place to start but before you put the carbs back on after cleaning them perform step 1 then run the bike and then move onto steps 3 & 4 once those things are accomplished and you know there set right then you can start to look elsewhere for your problem it could be that you have a dirty fuel filter as well there are a number of things that it could be
start with the steps that i have laid out for you and go from there
and more info about the bike and some pics of the plugs and bike would be good and help us to help you

 

[rightious]

SPYDERMAN -
"removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow"


well sir, when i took the side of the air box off, it bypassed the filter and ran straight into the carbs(i know its bad, but i wanted to get home).
so i think that i did rule out the filter. im going to change it, but i can't see spending $50 on the stock air cleaner. so im giong to get pods, which i know i need rejetting, and im not positive where to start. like i said i have 4 - 1 exhaust right now, no muffler, and i want pod filters...

i would love someone to tell me where to start.

thanks again for all your ideas

 

[sparki]

where to start.... before you start changing stuff that directly contributes to bad running if not setup correctly, get it running correctly FIRST then make changes. what does the filter loook like... is it clean or grubby looking? can u use an air hose to blow it out if dirty.... if it's cleanish looking chances are it's not yer problem.

if you've only ridden it for approx 5 miles the entire time you've had it chances are it never properly warmed up and the ride you went for where you experienced iussues it was nicely warmed up.... that would point to a fuel problem as per the crap running, black plugs and it cutting out..... way over rich. pop the carbs out and clean em properly along with a set of o-rings.

that's a good place to start.... let us know who ya get on after thats done

 

[Spyderman]

SPYDERMAN -
"removing the side cover from your air box will indeed produce a lean condition by letting in more air but with a dirty filter your not accomplishing much (change the filter) you haven't ruled out that problem yet a pluged filter will no matter if the side cover is on or off not let the air flow"


well sir, when i took the side of the air box off, it bypassed the filter and ran straight into the carbs(i know its bad, but i wanted to get home).
so i think that i did rule out the filter. im going to change it, but i can't see spending $50 on the stock air cleaner. so im giong to get pods, which i know i need rejetting, and im not positive where to start. like i said i have 4 - 1 exhaust right now, no muffler, and i want pod filters...

i would love someone to tell me where to start.

thanks again for all your ideas

ok i understand wanting to get home not a problem there
however i have a 77 50 right now as well as having owned 2 others in the past and know for a fact that unless you took the filter out as well as taking the side cover off then you didn't bypass the filter any how not going to argue with you about this it's just not worth it
what you do need to understand is that myself as well as other have out lined what you should start with then once you have the problem solved then you can move on but if you try and make changes right now it's only going to make things worse for you to sort out
you need to do the steps as outlined for you as well as checking the fuel flow to the carbs once there cleaned if that solves the problem then move onto putting on the pods and rejetting
get it running right first then do the pods because if you do it now you won't be able to jet the carbs correctly no matter how hard you try
also by cleaning the carbs you will then be able to tell us what jets you have in it and the position of the clip on the jet needle and then we can point you in the direction of where you need to go to jet it correctly
are you seeing what i am saying to you now i hope so because it will make it easier and take less time to get it sorted if you do

 

[rightious]

ok i understand wanting to get home not a problem there
however i have a 77 50 right now as well as having owned 2 others in the past and know for a fact that unless you took the filter out as well as taking the side cover off then you didn't bypass the filter any how not going to argue with you about this it's just not worth it
what you do need to understand is that myself as well as other have out lined what you should start with then once you have the problem solved then you can move on but if you try and make changes right now it's only going to make things worse for you to sort out
you need to do the steps as outlined for you as well as checking the fuel flow to the carbs once there cleaned if that solves the problem then move onto putting on the pods and rejetting
get it running right first then do the pods because if you do it now you won't be able to jet the carbs correctly no matter how hard you try
also by cleaning the carbs you will then be able to tell us what jets you have in it and the position of the clip on the jet needle and then we can point you in the direction of where you need to go to jet it correctly
are you seeing what i am saying to you now i hope so because it will make it easier and take less time to get it sorted if you do

yes sir, what do you think is the best way to get around buying a new $50 stock air filter in order to get it running right without changing anything?

if i put on the air box on withoutthe filter, will that help? or is that the same as no air box?

thanks again, and spyder, dont mean to argue, just trying to understand

 

[sparki]

what is it and your fixation with bypassing/removing the air filter.... CLEAN THE CARBS and see what happens.

 

[Spyderman]

yes sir, what do you think is the best way to get around buying a new $50 stock air filter in order to get it running right without changing anything?

if i put on the air box on without the filter, will that help? or is that the same as no air box?

thanks again, and spyder, dont mean to argue, just trying to understand

ok no problem i hope that i explained it a little better then so that you do understand what i was getting at
so just how dirty is the air filter and is it the stock paper one ?
as suggested by someone else here can you use some compressed air to blow the filter out to get it somewhat clean (not too much pressure though don't wanna blow a hole in it ) is this doable for you ??

if the filter is that dirty then using the air-box with no filter will be better but there is the chance that you'll still get a lean condition problem is that until you try you won't know and you won't know how lean of a condition you'll get till you try kinda a catch 22 i think at this point try the air box without the filter and see if it'll behave better

have you looked at the plugs do you know for sure that it's rich?
have you checked the fuel flow

i had an issue with my bike earlier this summer where when i put my new exhaust can on that it was breathing so much better that it would suck the float bowls dry at anything over 3/4 throttle i had to go to a 3/8 fuel line and a high flow fuel filter to solve the problem

so this is another area that you can look at you may have created the same situation as i had by taking off the muffler
honestly try putting the muffler back on and see if that cures the problem if it does then you know that you need to give it more fuel flow and then if i were you i would spend the time and do the steps mentioned and then put the pods on and a good pipe the Vance & Hines pipe is nice has a really nice tone and look good then rejet it for the pods and pipe
it is better to have some type of muffler on it to tone it down a bit and help the engine out
not to mention keeping the police from ticketing you every-time they see you

 

[rightious]

ok no problem i hope that i explained it a little better then so that you do understand what i was getting at
so just how dirty is the air filter and is it the stock paper one ?
as suggested by someone else here can you use some compressed air to blow the filter out to get it somewhat clean (not too much pressure though don't wanna blow a hole in it ) is this doable for you ??

if the filter is that dirty then using the air-box with no filter will be better but there is the chance that you'll still get a lean condition problem is that until you try you won't know and you won't know how lean of a condition you'll get till you try kinda a catch 22 i think at this point try the air box without the filter and see if it'll behave better

have you looked at the plugs do you know for sure that it's rich?
have you checked the fuel flow

i had an issue with my bike earlier this summer where when i put my new exhaust can on that it was breathing so much better that it would suck the float bowls dry at anything over 3/4 throttle i had to go to a 3/8 fuel line and a high flow fuel filter to solve the problem

so this is another area that you can look at you may have created the same situation as i had by taking off the muffler
honestly try putting the muffler back on and see if that cures the problem if it does then you know that you need to give it more fuel flow and then if i were you i would spend the time and do the steps mentioned and then put the pods on and a good pipe the Vance & Hines pipe is nice has a really nice tone and look good then rejet it for the pods and pipe
it is better to have some type of muffler on it to tone it down a bit and help the engine out
not to mention keeping the police from ticketing you every-time they see you

ALRIGHT! now thats the kind answer i was looking for.

i will defenatly try those steps, the plugs are coal black, so i know i am rich, i just got new plugs, and tryed to clean the filter (its foam over paper) but its pretty damn dirty. so i will try air box - filter. i'll let you know how it goes, thanks again man...

 

[rightious]

well, i put the airbox, and muffler back on to no avail. it is acting the same way, so i pulled the carbs off and now am tearing into them. nervous, but hopfully it will help.
the situation is that it is definitely rich. when i pulled the carbs off the rubber mounts off the motor, it was soaking wet with gas. i just had it running, so that was the sign that it has waaaay too much fuel.
when i crack the throttle, if it doesnt bog out, then it has a black plume of smoke that comes out. i can get it not to bog by slowly bringing the rpms up to about 2500, then crack it wide open. if i just crack it open from idle, it bogs out. the floats look good, i dont know that much about rebuilding carbs, so i dont know if the needle valves great or not... they all look the same and seem to close when the float hits it.

help??

 

[Spyderman]

well, i put the airbox, and muffler back on to no avail. it is acting the same way, so i pulled the carbs off and now am tearing into them. nervous, but hopfully it will help.
the situation is that it is definitely rich. when i pulled the carbs off the rubber mounts off the motor, it was soaking wet with gas. i just had it running, so that was the sign that it has waaaay too much fuel.
when i crack the throttle, if it doesnt bog out, then it has a black plume of smoke that comes out. i can get it not to bog by slowly bringing the rpms up to about 2500, then crack it wide open. if i just crack it open from idle, it bogs out. the floats look good, i dont know that much about rebuilding carbs, so i dont know if the needle valves great or not... they all look the same and seem to close when the float hits it.

help??

well that is a good place to start you need to measure the float height while you have it apart take a look at the jets (main and pilot and let us know what the #'s are that are stamped into them) and also take a look at the position of the needle clip and what position it's in
this will help you with the rebuild
http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

also take some pictures of your bike so we can see what else has been done to help guide you in the right direction

 

[rightious]

well that is a good place to start you need to measure the float height while you have it apart take a look at the jets (main and pilot and let us know what the #'s are that are stamped into them) and also take a look at the position of the needle clip and what position it's in
this will help you with the rebuild
http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

also take some pictures of your bike so we can see what else has been done to help guide you in the right direction

i measured the float hight, it was to spec (28mm). the main jet was 102. the pilot jet i didnt get a chance to look at ( i just orderd rebuild kits ) so i will have to take a look.

what is a good carb soak to use, and where do i get it locally? would they have it at a dealer?

 

[TheCafeKid]

i measured the float hight, it was to spec (28mm). the main jet was 102. the pilot jet i didnt get a chance to look at ( i just orderd rebuild kits ) so i will have to take a look.

what is a good carb soak to use, and where do i get it locally? would they have it at a dealer?

Spec is not 28mm on the 77 750. Its 26mm. Might want to fix that. Main sounds like its a size to big maybe? Been a while since i looked at the stock set up. But i do know the pilot SHOULD be a #15, and no need to change it with pods/pipe combo..

 

[rightious]

carb dip

carb dip

so i got my berrymans carb dip, but everwhere i read about it, it says not to leave anything in it for more than 30 min. i've heard you guys saying to leave it in for 24 hrs... are they just being over careful, or will if mess it up if i do leave it in for a long period of time?

i plan to clean them tonight.

:clap:

 

[tkent02]

ok i understand wanting to get home not a problem there
however i have a 77 50 right now as well as having owned 2 others in the past and know for a fact that unless you took the filter out as well as taking the side cover off then you didn't bypass the filter any how not going to argue with you about this it's just not worth it

Opening the side panels on that airbox allows air into the carbs without going through the filter, I am sitting here looking at one. Without those covers, the filter is bypassed. The filter is on the large passage between the two levels, either level is open to airflow without the covers.

so i got my berrymans carb dip, but everwhere i read about it, it says not to leave anything in it for more than 30 min. i've heard you guys saying to leave it in for 24 hrs... are they just being over careful, or will if mess it up if i do leave it in for a long period of time?

Mine have been in there a week now, they look OK. But it is Gunk, not Berrymans.