Still runs like crap....83 GS750es

[rvnkvn]

Hi Billy,
I did do a bench sync, got the factory manual out and set them all to the small hole in the carb per the instructions... I'll call DJ after work, and see if I can get the missing parts to put the pods back on. I don't mind moving the engine to get the box back out if it fixes the problem AND makes things easier to work on...K

[rvnkvn]

I called DynoJet today, I can send back my 3 aluminum needles and they will replace them with the new titanium ones for $50.00. I may do this. I also have a Uni filter ordered for the airbox. Should be here anytime.

Valves were right on .005 across the valves.

Should the box be sealed completely to make the engine die with the intake hose blocked off? i tried this without a filter while it was running, and it did not seem to even have any vacuum on top of the airbox.

[MilesDad]

I had a similar issue until a couple of days ago. It sounds like you have been very thorough, but double check your throttle cable tension and your idle knob position. Even a bit out of whack, as mine was, made a substantial difference.
This is an easy thing to adjust just to rule it out.

Good luck.

[rvnkvn]

Would a bad fuel petcock problem show up after the bike gets up to normal temp, and shuts off the fuel supply? I have NO problem with the bike with the aux gas tank(motion pro) but as soon as it put the gas tank back on the bike, hook up all the lines, it quits running on a few cylinders, and dies shortly after.?

[chef1366]

Do you have the idle adjustment knob out at all? Are the butterflies open with the throttle released?

[koolaid_kid]

Sounds like you are using the fuel in the fuel bowls and then running out of fuel. A couple of things to try:
With the fuel line pointed toward or in a container, try switching the petcock to PRI. Fuel should flow. If it does, switch to ON. Fuel should stop flowing. Now take the vacuum line and apply a vacuum (sucking on it usually works). Fuel should flow. Do the same for RES, results should be the same.

[rvnkvn]

Prime works, when I switch to on OR reserve, and Try and suck on the vac line , lots of resistance, lots of effort, no fuel out of the petcock.

Idle set know is perfectly at 1100 to 1200 rpm with the aux tank..

[SVSooke]

Sounds like new petcock time for sure.

[Billy Ricks]

When you suck on the vacuum line you should get resistance. If it leaks down you have a problem. You'll probably even suck fuel through if the diaphragm in the petcock is punctured. Suck pretty hard so vacuum holds to see if fuel flows.

[rvnkvn]

Wow.... Found a small crack in the vac line going to the petcock. I'm going to re-install this on the bike and see if I finally fixed it. Thanks Billy, SV!!!

[Billy Ricks]

I just reiterated what koolaid kid said. There's a couple of springs and a pushrod of sorts in these petcocks that can make them a little finicky.

[rvnkvn]

Just got back from a 25 mile road test. Absolutely ZERO problems. Runs smooth, idles, doesn't die at a traffic light. I can even roll in to 5th gear from 45 and watch the world pass me in the mirrors.

Sure feels great to be riding again!!! Thanks to EVERYONE here.
I'm glad to be involved with such a surperb group of enthusiasts!

[chef1366]

A cracked vacuum line
Whoda thunk

[Buffalo Bill]

First thing to replace…

Wow.... Found a small crack in the vac line going to the petcock. I'm going to re-install this on the bike and see if I finally fixed it. Thanks Billy, SV!!!

Wow! Those old petcocks are always trouble.
I rode my GS1100G 25 miles home the day I picked it up. Ran like crap, flooding like the Mississippi. All a learning experience, turned out to be a worn out diaphragm in the petcock, not the carbs at all.
Now when I buy an old bike, I give the petcock one chance to work, or replace it complete, washers and gasket.

[rvnkvn]

The Line physically LOOKED ok..had the seem running along the whole length of the hose. I could hear a "hiss" but could never figure out where it was coming from...