NO NOT ANOTHER CARB QUESTION ,,,,sorry but

[Anonymous]

Howdy,,, I have a 1980 gs1000g I've just recently bought.The bike didn't run when I picked it up and the first thing that I did was tear it down to the block and had the head and cylinders reworked. I put new rings, oil seals, and gaskets in it (I did all of this before on other models so I have a good idea what I'm doing) and I took the carbs in to a shop and had them clean them up and reset them to factory settings (or close to it). Ok,,, the bike has stock air box and stock cv carbs. I do have a supertrapp 4-1 exhaust and dyna coils.
Here is my problem and question: the bike runs great under 5000 rpms. The plugs say that it is running rich (almost fouled) and I keep making adjustment to the gas-air mixture screws and synchronizing the carbs, but no change on the plugs. So I've screwed all 4 mixture screws all the way in thinking that the bike should die but it didn't--it just sat there and idled at 1200 rpms. Should the bike have died
I've also been trying to fix the high end of my problem. At 5000 rpms and over the bike spits, sputters and cackles. The stock main jet is a 115 so I've put 122.5 in it to see what would happen .............. same thing, no change. I've also added and removed disks on the Supertrapp. Now I'm stuck. Help me Obi Wan Kenobe--you're my only hope

[shaftzuki]

Sounds to me like your going to have to go through the carbs again Your not getting enough air into the mix. You need to take the carbs completely apart, soak and clean - make sure you clean all of the passages that seem to lead to no-where. If the pilot screws still have caps on them - drill them out and remove and clean the jet passageway. Be extremely careful when re-assembling - take your time. A manual will come in handy for the float settings etc. 8)

[earlfor]

Re: NO NOT ANOTHER CARB QUESTION ,,,,sorry but

I would put the 115's back in it. A dirty airfilter can make a big difference. Is it clean? With the 115's in it, try turning up the idle to 1800 rpm and checking the vacuum. On the ones I have worked on, they seem to draw just under 10 in hg at 1800 rpm. If you can get that vacuum across the board at 1800, it should be about right. I dont think the carbs are blocked because your problem is too much fuel, not starvation. Adjusting the mixture screws isnt going to do you any good for midrange cruising as that rpm would be out of the effective range for mixture screws.

Do you have the stock non adjustable electronic ignition on it?

Earl

Howdy,,, I have a 1980 gs1000g I've just recently bought.The bike didn't run when I picked it up and the first thing that I did was tear it down to the block and had the head and cylinders reworked. I put new rings, oil seals, and gaskets in it (I did all of this before on other models so I have a good idea what I'm doing) and I took the carbs in to a shop and had them clean them up and reset them to factory settings (or close to it). Ok,,, the bike has stock air box and stock cv carbs. I do have a supertrapp 4-1 exhaust and dyna coils.
Here is my problem and question: the bike runs great under 5000 rpms. The plugs say that it is running rich (almost fouled) and I keep making adjustment to the gas-air mixture screws and synchronizing the carbs, but no change on the plugs. So I've screwed all 4 mixture screws all the way in thinking that the bike should die but it didn't--it just sat there and idled at 1200 rpms. Should the bike have died
I've also been trying to fix the high end of my problem. At 5000 rpms and over the bike spits, sputters and cackles. The stock main jet is a 115 so I've put 122.5 in it to see what would happen .............. same thing, no change. I've also added and removed disks on the Supertrapp. Now I'm stuck. Help me Obi Wan Kenobe--you're my only hope

[Anonymous]

thanks Mark and Earl
yes, i do have the stock non adjustable electronic ignition. The air filter is old (new ones on order) but ive cleaned them up with kerosene and them reoiled them I tried running the bike with the airfilter off but got the same results I did put the 115 main jets back in the bike it helped alittle.
Here is what is weard the more disked that i took off of my supertrapps the better the bike ran
As for the vacuum my carb synchronizer starts at 10, but im sure that its not 10 inches would I use a measuring tape on it to find 10 inches?
Thanks again!!!

[earlfor]

I've never seen one marked in anything other than inches or centimeters.
Since 2.54 cm equals an inch, then 10 inches would be 25.4 cm on your scale.

Earl

As for the vacuum my carb synchronizer starts at 10, but im sure that its not 10 inches would I use a measuring tape on it to find 10 inches?
Thanks again!!!

[Anonymous]

Earl
Here is a link to a pic of my synchronizer http://www.bikebandit.com/partsbandi...dept_id=792268 its kinda hard to read but the first line up from the mercury is 10

[earlfor]

Mine looks just like yours. The first line up from the mercury on mine is 4 and I know mine is graduated in inches. 1 inch equals 2.54 centimeters.
If your first line is marked 10, that would be centimeters. 10 cm equals 4 inches. 25 cm would be 10 in.

Earl

Earl
Here is a link to a pic of my synchronizer http://www.bikebandit.com/partsbandi...dept_id=792268 its kinda hard to read but the first line up from the mercury is 10

[Anonymous]

Ok, well i was able to get about 9 in hg across the board and made some other adjustments, such as adding and taking off disks on the supertrapps, taking off the air filter and im still running rich and its still cutting out at 5000 rpms . It runs GREAT under 5000 rpms im just wandering if im running rich on the low end and lean on the high end? I assume anything possible
Thanks you very much for your help!!!!!!!!!!!!

[earlfor]

If it idles fine, throttle response is crisp and it runs well up to 5k rpm, Your only problem may be the main jet size. If it had been lean, reducing backpressure in the mufflers and removing the airfilter would not have improved its running, it would have probably quit running altogether.
If your timing was adjustable, I would think someone had mismatched the timing between the 1,4 and 2,3 side then collectively retarded everything, but without having adjustable timing, that cant happen. Are the little rubber plugs in place in the float bowls over the ends of the jets?
Are the jets you are now using new ones or are they some that came with the bike? Is it possible someone had drilled them out to who knows what?

Earl

Ok, well i was able to get about 9 in hg across the board and made some other adjustments, such as adding and taking off disks on the supertrapps, taking off the air filter and im still running rich and its still cutting out at 5000 rpms . It runs GREAT under 5000 rpms im just wandering if im running rich on the low end and lean on the high end? I assume anything possible
Thanks you very much for your help!!!!!!!!!!!!

[Anonymous]

Okay, everything is fixed and running GREAT!!!!!!!!!!!
I just thought that I would do a follow-up to let you know what I did to fix it in case anyone is having the same problem. First, where the bike ran fine at low RPMs and then bogged down over 5000 RPMs: I found that inside the airbox, there was a seal that went between the airfilter and the airbox that was missing (actually, it looked like it was on fire at one point and burned up). I used some 3M window seal to replace it and that fixed the problem there.

It still was running very rich, so I tore the carbs apart again and looked everything over. The pilot jets caught my eye: they were different than the others that I have seen. The jet hole was at the top (someone told me that these were for a dirt bike) but it had the mukuni marks on it and the jet size that my bike called for (40). I had the standard style of pilot jets (with the jet hole at the bottom) left over from my gs550 that were 40 as well. I compared the two and noticed that the jet hole of the jet that was in the bike was almost twice as big. I used the ones from the 550 in it and it ran to lean, so I bought some 45's and now it runs great. I bumped up the main jet from a 115 to a 122.5. I might be changing it down to a 117--a friend that I was riding with said that when I opened it up he saw some black smoke come out the pipes.
Thanks again for everyone's help on this and I'll see you all on the road!! :P

[Carter Turk]

carbs 1000G

Might check the float height (too much gas) and needles for dents or debris. Carter