Engine Not Getting Fuel After VM Rebuild

[slaveforthewave]

i never had to adjust anything on the carbs when i got the bike. slides were siezed but after some carb cleaner they moved again and the bike fired right up but the bowls leaked pretty bad so i decided a rebuild was the next step.

i have a picture of a fuel screw and the bottom of the carb. looks like a little gold dowt in the middle of each passage.

http://i51.tinypic.com/vdd5rl.png
http://i55.tinypic.com/2cmxcw0.png

 

[Adler]

i never had to adjust anything on the carbs when i got the bike. slides were siezed but after some carb cleaner they moved again and the bike fired right up but the bowls leaked pretty bad so i decided a rebuild was the next step.

i have a picture of a fuel screw and the bottom of the carb. looks like a little gold dowt in the middle of each passage.

http://i51.tinypic.com/vdd5rl.png
http://i55.tinypic.com/2cmxcw0.png

That little dot... is bad. Its supposed to be a clear, tiny hole right into the air tunnel.

Here is my old thread from when this happened to me...
http://www.thegsresources.com/_forum/showthread.php?t=165403

 

[slaveforthewave]

i actually read that 5 minutes before you posted. haha. if it's not one thing it's another i'll tell you what!

here goes nothing. i just sharpened my screws, hopefully i can manage to trick these things into coming out and into having a running bike once more!

thanks all for the help.

 

[portdave]

i actually read that 5 minutes before you posted. haha. if it's not one thing it's another i'll tell you what!

here goes nothing. i just sharpened my screws, hopefully i can manage to trick these things into coming out and into having a running bike once more!

thanks all for the help.

I am about 45 minutes away from you and may be able to help if you can't get it sorted out. I have some extra carb bodies. That one you had a pic of was broken off pretty bad.

Just keep at it...

 

[slaveforthewave]

thanks dave, i'll keep that in mind definitely! turns out all four tips were broken off in there. sharpened an old screwdriver and a few minutes of tapping later and they were all home free. put the newly sharpened fuel screws back in their homes carefully and maybe tomorrow i will have an idle again!

 

[portdave]

thanks dave, i'll keep that in mind definitely! turns out all four tips were broken off in there. sharpened an old screwdriver and a few minutes of tapping later and they were all home free. put the newly sharpened fuel screws back in their homes carefully and maybe tomorrow i will have an idle again!

Just set those screws like mentioned above (lightly seated) and you should be in business. Best of luck.

 

[Big T]

Your problem might also come from your bowl gaskets blocking a passage

Isn't the one at top right in your picture supposed to have a hole (where the knock out is)?

Edit - there's a tube that runs down there and it's at lower left, so that should be open

 

[slaveforthewave]

same thing, bike won't start at all. has spark, if i pressurize the funnel the bike will run while there is pressure in there but when i let up the bike dies. weird thing is, when i blow into the funnel gas comes from one port on one carb and none of the others. i circled it in the attached picture. what is that about?!

 

[Big T]

same thing, bike won't start at all. has spark, if i pressurize the funnel the bike will run while there is pressure in there but when i let up the bike dies. weird thing is, when i blow into the funnel gas comes from one port on one carb and none of the others. i circled it in the attached picture. what is that about?!

Well, I'm sure by now that you've discovered that the passage leads to your main jet. So, you're flooding the carb, like an Amal "tickler"

Once you've pulled out the broken tips and cleared the enrichener "choke" circuit, I think you'll find your idle. The enrichener is that copper tube sticking down into the float bowl

 

[KEITH KRAUSE]

I believe they block off the fuel flow, not the air

Just so everyone knows, the pilot fuel screws assist the pilot jet. They regulate the mixture of air and fuel passing around them. Their purpose is to fine tune the pilot circuit mixture for each cylinder.

 

[KEITH KRAUSE]

I haven't read every post so I'm sorry if I missed something.
I think you should "start over" or at least double check everything you did.
I think, for one thing, your carbs are way out of synch. Your bench synch in this case. Running as you described earlier without the idle adjuster tip contacting the throttle pulley stop is a dead give-away. And the carbs may not be as clean as you think. Many have made that mistake. The damaged pilot fuel screws should be REPLACED. If you enlarged the holes the PF screws regulate then that too will compromise how it performs.
I'd go back and verify the carbs are clean. That means all jets, including the air jets on the filter side. REMOVE all rubber parts first and shoot all jets/passages with carb cleaner and blow out with compressed air. LOOK through ALL holes to verify. Check the choke starter tubes too. Blow through all holes/passages. You should get air coming out and all four carbs should have similar air flow when blown through.
Then check float levels. .95" is right in the middle of the factory range. Make sure BOTH sides are equal by lightly bending them first if needed.
Bench synch the slides. I have detailed synch info if you search. Check out Hoomgar's thread titled: "GS1K rejet/bad fuel economy, attn Keith Krause" should help you. Go to reply #36 I think. Do the job as described and the bike will start/run decent but you still need to follow any bench synch with a vacuum tool synch.
Not sure if you have any mods besides the pipe (stock airbox with lid still on?), but for starters I'd set the pilot fuel screws underneath to about 1 full turn out from lightly seated. This assumes the screws are in good shape and also the port each regulates. The bike will never idle right or run correctly at throttle positions at or less than 1/5 throttle if the screws and ports are damaged.
The side air screws are adjusted using the highest rpm method. INITIALLY set them 1 1/2 turns out. Once the bike is running and fully warmed up, you can adjust them.
I can only assume the o-rings in the manifolds are good.
Also I assume the jetting is correct but would like to know what you have before you re-assemble.
If running stock air box then be sure the two floatbowl vent lines are clear/not kinked and they are routed up and on top the air box lid area.
Do the above and with clean carbs, no damaged parts, good bench synch, and proper jetting the bike will run decent.

 

[slaveforthewave]

pretty excited. after full disassembly, blast with 150psi of air in every crevice of the carbs, and 7/8 on the fuel screw and 1 1/2 on the air screw and i have a decent idle. much better than it was before! still cuts out after a a little running, but the idle isn't way too high or irradic. i didn't see anything come out of the carbs, but there must have been something going on there.

this bike has the v&h 4-1 exhaust with pod filters. i never messed with the needle height so i do not know where it's set but i know the main is a 135. with that knowledge do you think 7/8 and 1 1/2 is an acceptable setting for the air/fuel screws or should i go a little richer?

 

[Big T]

A 135 what?

Mikuni or Dynojet?

The Mikuni will have an interlocking box symbol on them

Typical set up is

Fuel screw - 1 - 1 1/4 turn
Air screw - 2-3 turns
Needle - up one notch (4th from top)
Mains - 122.5 - 125 Mikuni
Pilot jet - up one size if needed

Your plugs will tell the story

Were there any broken off tips in your carbs?
Did you sharpen the broken needles?

 

[slaveforthewave]

i believe the main to be a dj jet. there was nothing on it but the stamped number. is this an unacceptable number? i have teh stock mains that came with the rebuild kit, i just assumed since this was a running bike before i got my hands on it the jet sizes were probably within range.

as for the fuel screw tips, 4 were broken off and 4 were removed. sharpened all 4 screws on a bench grinder and finished them off on a da sander just to get them a bit smoother.

still seems really hard to start. i'm trying to figure this manual sync thing out. i have a few resources online with tutorials but it's a little hard to wrap my head around. if i loosen the nut on top of the slide arm and then turn the screw, the slide keeps dropping until the nut is seated again and there is no more threads to back it off any more.

if i figure out this manual sync i'll start at the benchmark points and try to get this thing dialed in.

 

[KEITH KRAUSE]

Bench synch info, just search GS1K carb rejet. That's only part of the thread title but it's enough. I just typed it in and it's on the list of threads. Go to reply #36 I believe. It's explained as simple as you'll find and still details the entire job. You have to have decent eyesite to watch the slides move and just be patient. Like it says in the post...when the slide stops dropping, stop turning the screw on top. Keep in mind the bench synch's purpose is to get the bike to start well enough and then you can follow that with a vacuum tool synch. The tool synch is mandatory if you are re-jetting and for good performance.
With your mods, you need either DJ 138 main jets, or 130 Mikuni jets (same size). They have different numbers because their sizing is determined differently.
Look at your jet needle to determine if it's stock or a DJ needle. 5 grooves or positions for the e-clip= stock, and 6 grooves =DJ. The stock needle MAY be made to work but the DJ is a better needle, tapered differently, with better results.
If stock, my opinion is the 4th position from the top is still too lean. It's more trial and error. 5th (bottom) position sometimes works but could be rich. Only testing can tell. Trying to guess right the first time I'd try position "4 1/2" which means you place the e-clip in the bottom position BUT you also need a jetting spacer approx' .022" thick to place directly on top the e-clip and this will then equal a 1/2 position change...4 1/2 in this case.
If a DJ needle, then position 4 from the top is by far the most common setting I've found. After any needle disturbance/change, you need to re-bench synch the VM carbs. Be SURE the factory nylon spacers are replaced correctly on each jet needle regardless if it's a stock needle or a DJ. Thicker spacer or "ring" goes directly on top the e-clip and thinner one goes directly under the clip. Any jetting spacers used go directly on top the e-clip and the thicker ring on top the jetting spacer.

 

[slaveforthewave]

awesome, keith. thanks! i will be doing this tomorrow most definitely and will post the results back here.

for anyone trying to find keith's original post on the vm carb manual sync i did a little screen shot for you.

fingers crossed for tomorrow!

 

[KEITH KRAUSE]

Ah. There it is. I'm really bad with computers and don't know how to do what you did.
Just a few notes about things other owners have commonly done when doing the work you are.
Be sure you turn up that idle adjuster knob enough so the bike will start. Many owners set it minimally and wonder why the bike won't start. If the idle jumps as you start it and it's not because of the choke, you can always turn it down quickly. Better to over set than to kill a battery.
If you get a vacuum tool and synch, don't forget to plug the #3 carbs vacuum port for the factory petcock. That assumes you use some kind of temporary fuel tank that's properly VENTED. I find it easier to use the gas tank with longer lines and set it on a workmate or similar stand close by. Just hook it up like normal. Then you know the fuel is vented and flowing well. But temp tanks work fine too if you like.
Brush up on synching with a vacuum tool if you've never done it. It can be frustrating if you've done something wrong. Many owners don't hook up the fittings correctly at the manifolds and they get leaks. Some don't pay attention and get the lines kinked or too close to a hot part. Some back off the throttle too quickly and the motor sucks up mercury (if a mercury tool).
Probably the most difficult for some is adjusting the adjuster screws and not realizing how sensitive they are and how an adjustment at one carb may effect the others. That's where a CAREFUL bench synch helps. If done properly and you have no mechanical issues, the levels you see upon start up should be in an acceptable range, not too low or sky high. With a careful synch you may be lucky and upon start up you may find two of the levels are very close and a couple others not too far up or down from them. I always find it easier to adjust the higher one(s) down to match the others first. If one is then still low then you can bump it up a tad to match the other 3 already set. It's easy to lose your adjustment too if you're not careful holding that adjuster screw still while lightly torquing the holder nut. It just depends on what you see when you start it up. It sometimes goes well but many end up for whatever reason adjusting to the point the idle screw knob is no longer touching the throttle pulley and the bike is "idling" way too high. At that point you stop and re-bench synch and start over. Once you think the levels are reasonably close be sure to double check them by lightly operating the throttle a few times and observing the levels are where they should be.
Let us know if you have trouble and most of us have been through it and can help. Just be sure to synch with a couple large fans. Over-heating is too easy if you're not careful. Some of us can synch in a few minutes while others have more trial and error. If it takes too long then it's best to turn off and let the bike cool down some and maybe yourself too. Taking too long with a mercury gauge can get condensation in the mercury reservoir. Start it up and there can be condensation gaps in the mercury levels which make it difficult to set the levels. Sometimes the tools vent doesn't help release the mercury. That's why the Morgan carbtune is much easier to use though it costs about $110 or?

 

[slaveforthewave]

after many hours of playing with these carbs, something is still off. i think i am just going to take it somewhere to have it dialed in. makes no sense to me that the bike has spark, and gas is in the bowls and the bike will run perfectly for 30 seconds and then peter out... carbs were sync'd to the best of my ability and nothing changed. hold your hands over the carbs and block off the air and the bike will crank up and run, but will die shortly there after.

anyone have any recommendations for carb tuning in the central florida area?

 

[portdave]

Do you have the air pods on the bike when doing this testing?

I am no expert but I do have the morgan carbtune and would be happy to help sometime.

I also have a few other sets of carbs etc.

 

[Guest]

It's never going to run without some sort of air restriction, air box, or pods with proper jetting. Band a couple layers of oiled T-shirt over each carb and see what you get.