'77 GS750 issues

[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

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.

[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.

[TheCafeKid]

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.

24 hours is likely going to be NECESSITY if you want them clean for sure... 30 mins will clean off gunk, but not 30 years of varnished gas...

[rightious]

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.

right on dude, thank you. thats what im saying.

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

so you think that 24 hours wont duck anything up? i was going to do it tonight, but i ended up going to the bar... the can says 30 min, i just want to make sure 24 hours wont do any harm, i.e. eat any aluminum or anything. if it wont mess anything up, then i'll let them soak for as long as necessary...

[rightious]

carb specs

ok, so here's what i got:

1977 gs750
102 mains
15 pilot
my bottom screw is 3/4 out
my side screw is 1 1/2 out

i have used the search, but i get a couple different specs for it.
when i re assemble my CLEAN carbs, is this right, or is this off?

thanks peeps

[tkent02]

so you think that 24 hours wont duck anything up? i was going to do it tonight, but i ended up going to the bar... the can says 30 min, i just want to make sure 24 hours wont do any harm, i.e. eat any aluminum or anything. if it wont mess anything up, then i'll let them soak for as long as necessary...

Dipping a set of black carbs, it ruined most of the paint. So I left them in a week to get the rest of the paint off. Didn't hurt anything. Again, it's Gunk, not Berryman's.

ok, so here's what i got:

1977 gs750
102 mains
15 pilot
my bottom screw is 3/4 out
my side screw is 1 1/2 out

i have used the search, but i get a couple different specs for it.
when i re assemble my CLEAN carbs, is this right, or is this off?

thanks peeps

That should be about right to get you started for a 750 with stock intake/exhausts.

[rightious]

to add to the specs of my carbs:

my clip is in the 2nd position.

i bought the berrymans 1 gal can of carb dip, so i can only do 1 at a time. i hope this makes the difference. i will put the muffler and air box back on just so i can get the rest of the dwindling season out of this beast...

[rightious]

hopefully someone is still following this post...

so i dipped my carbs, re-assembled them with rebuild kits, bottom screw out 3/4, side screw out 1 1/2... i am having the exact same problems. when i rev it from idol, it boggs out. if i slowly bring up the rpms, then i can rev it up fine.

help!!

[Coady]

Did you clean/replace that airfilter? If so try opening up the side air screws some more - another half turn to start and see if that helps the bogging.

[rightious]

missing parts...

so i reassembled the slides with the needle, but when i took it apart, it didnt have a spacer or spring... after looking at the vm carb rebuild...http://www.thegsresources.com/files/vm_carb_rebuild.pdf... it shows the spring and spacer, if i do not have the spring, could that be my problem?

also, where does the spring go, i bought the rebuild kits and it came with an 'extra' spring that goes on the needle, does it go right below the clip?


thanks guys

[Coady]

I'm no expert, but when I pulled my carbs apart they had the fat spacer above the e-clip, the thin one below and the spring on the bottom of the needle as per http://www.thegsresources.com/files/vm_carb_rebuild.pdf.

To me the spring looked essential to maintain the needle in the correct position, as its the top spacer which dictates the needle height and the spring pushes up on it to ensure this.