79 GS1000L right side carbs!!!

[feelergaugephil]

I'll try make this short.........
Another member gave me his GS1000L and he spend a ton of $$$ on it, he'd not ran it for some years and advised that it did run when put away.
I get it home and cleaned out the carbs (not CV's) which were not that bad...
Cranked it up using a funnel on the main feed to carbs, it runs on 2 cylinders (left) if I spray carb cleaner in the 2 right ones it still wont fire on them... BUT!!! if I gently blow down the breather tube on the far right carb it then runs on 4 cylinders until I stop blowing!!!!!!!!!!
Compression across the board is approx 160lbs (hot engine)

Also, the tank pet cock looks great inside, but wont flow freely, it also has a flat head screw on it, if I turn this out fuel will run out of it, but not down the main fuel line, the fuel lever has two options, "on or res" is this pet cock the correct one? as it has 2 outlets and a diaphram!!!!!!!!!!!!!!

Any ideas guys??????

[uudfourty]

light the irregular fuel flow on fire and run.

just kidding.
were it me, which it obviously isn't, I'd take the carbs out and just clean them. if they sat at all, there is a chance for googobs.

Or you can get it running, put some sea foam or similar cleaner in the tank at high concentration, and do your breather trick in hopes of dissolving whatever blockage may be in the way.

It's worth a shot.

One's time and they're both money.

[TheCafeKid]

Sounds like the petcock is NOT stock, you say two lines? One should be fuel and one should be vaccum. Im guessing from the year of the bike and the fact that you said they arent CV carbs that its using the VM26SS carbs like my bike. Assure that you have a vaccum line attached to the number three carb, where the vent hoses would connect on the others. If you do have a vacc line attached, check to see that its not sucking fuel down it thru the petcock. Another thought, if the carbs had ever been disassembled, that they were put back in the rack in the right order. Check float levels in all, check that the fuel rail tube orings are new. If its not sealing properly, its not going to draw fuel.

[SabreJim]

Gs1000l

Hello,
this is my petcock, there are only 2 positions that I am aware of..."ON" and "RES".

[earlfor]

Someone had your same problem about six months ago and I'll be damned if I can remember what they finally found out was causing it. I've never seen a 1000 with dual gas feeds plus a vacuum line, so I have my doubts what you have is stock. Since you can blow into the breather tube on the 3,4 side and it fires on all four, I dont think you have a carb problem. At least not a blocked jet or fuel passage obstruction. Have you tried switching the gas lines so that the line feeding the 1,2 side is routed to the 3,4 side and vice versa? With only on and res options, fuel would not flow without the engine turning over since vacuum is required to open the petcock. You might try running the bike from a gravity feed, test tank, directly to the carbs. If it runs on all four, I would think the problem is a vent obstruction

Earl

I'll try make this short.........
Another member gave me his GS1000L and he spend a ton of $$$ on it, he'd not ran it for some years and advised that it did run when put away.
I get it home and cleaned out the carbs (not CV's) which were not that bad...
Cranked it up using a funnel on the main feed to carbs, it runs on 2 cylinders (left) if I spray carb cleaner in the 2 right ones it still wont fire on them... BUT!!! if I gently blow down the breather tube on the far right carb it then runs on 4 cylinders until I stop blowing!!!!!!!!!!
Compression across the board is approx 160lbs (hot engine)

Also, the tank pet cock looks great inside, but wont flow freely, it also has a flat head screw on it, if I turn this out fuel will run out of it, but not down the main fuel line, the fuel lever has two options, "on or res" is this pet cock the correct one? as it has 2 outlets and a diaphram!!!!!!!!!!!!!!

Any ideas guys??????

[feelergaugephil]

I stripped the carbs down and they look great inside and no wear, all syned properly too!
I stripped down the complete top end, here's what I have found.
Far right piston kind of loose in the cylinder, can move the piston (TDC) side to side.
All exhaust valve stem oil seals worn.
All valves are straight, but shims were BADLY out of sync, mainly I could slide a .10 feelergauge under most of the shims to cam shaft.
Timing was spot on.
Rings in the cylinders (no pistons) look pretty good, very small gaps.

I am going to get it rebored to the .50 pistons/rings that came with it (genuine Suzuki) and have already beadblasted/glass the head and everything looks great.

The last owner (who was/is a member on here) bought the new petcock and was 100% it was for a 1979 GS1000L, but he too never could get it to run on the 2 far right cylinders.

My question now is, once the whole top end is rebuilt properly, what if the same symptoms still persist? maybe another set of carbs?????????????????????????
Phil.

[feelergaugephil]

Not dual feed and a breather! only one main feed and a breather, just to clear things up there.....

[Big T]

My question now is, once the whole top end is rebuilt properly, what if the same symptoms still persist? maybe another set of carbs?????????????????????????
Phil.

No new carbs. You probably need a new petcock. Or correct connections Take it off and post some pics of the petcock and carbs so we can see what's what

[Nessism]

First of all, if you had 160 psi compression the top end is in good shape. All pistons have clearance, that’s what keeps them from sticking themselves to the cylinder walls.

Now that you have the engine apart, have someone measure the cylinders and pistons for wear if you don’t have the proper tools. There is a fair chance that the parts are going to be in spec based on your compression readings, and you will only have to replace the rings and gaskets.

While that’s being sorted out take the carbs fully apart and go through them. Don’t assume they are clean just because they are clean in the float bowl. Take out the pilot screws and pilot jets, and replace all the various o-rings, including those on the rubber intake pipe boots.

Lastly, make sure the fuel line is properly hooked up and the vent lines are not plugged. Turn the petcock to prime and fuel should flow. Fuel should not flow with the tap in the On position unless you suck a vacuum on the petcock vacuum line fitting. Turn the line to prime and fill the float bowls with gas. Take a couple of the float bowl drains loose and check to see if gas is inside.

If you do all this the bike should run, assuming there is not an ignition problem.

Good luck and report back with your findings.

[salty_monk]

I think blowing in the vent tube probably helps pressurise the fuel & get it past a blockage....

Will it run 4 cylinders at any throttle position?

If it will run two cylinders & 4 cylinders when you blow into that vent tube (on the carbs) then I can't see there is an issue with the petcock.

If you ask me you've just pulled apart a good engine for no reason other than dirty carbs. At least the valves had big gaps... that's better than the other way.

Dan

Dan

[Cajun Cycler]

There is NO prime setting on GS1000L petcock (1979) period. Make sure you don't have a manifold leak that could reduce your vacuum on those cylinders.