Carbs or valves? Just need opinions & input

[justme1100]

I was out last weekend with a friend when he decided to crack open the throttle on his really nice H-D and with the Beast running as well as ever I had to follow suit. After he caught up to me we rolled up to a stop light and when we left the intersection, at a proper speed, I had issues as I was reaching my shift RPM which seemed as if I was running out of gas. Backing the throttle down and shifting at a low RPM I was able to make it home. My question is more of a poll. Does it sound as if I might be starving for gas? Float adjustment needed? Could it be something else? I did a quick compression test and am a little low in one cylinder. Would that cause the lack of power. It was about 15 psi lower than the rest.

[Bonz]

Gas cap vent, checked if it's venting? Also can switch petcocks on special or standard to "prime" and see if that makes any difference.

[justme1100]

???

Gas cap vent, checked if it's venting? Also can switch petcocks on special or standard to "prime" and see if that makes any difference.

I thought it could be a venting issue but even the next day after sitting all night it was still the same. It idles fine and is ok until I start to climb the RPMs. I know i am running a little lean but dang. I was getting an occasional backfire or pop from my outboard left carb. I had sync'ed them late last year and I have the YICS eliminated as well. I am in the process of checking the floats, just got the carb rail off this morning. It did this to me last year twice but went away after shutting her down for a few minutes. Is there a vent for the float bowls? I don't remember. I need a slow night at work to read up on this. I have an XJ and fuel seems to be flowing well to the carbs. I suppose I better check the screens in the tank too.

[foreda]

I thought it could be a venting issue but even the next day after sitting all night it was still the same. It idles fine and is ok until I start to climb the RPMs. I know i am running a little lean but dang. I was getting an occasional backfire or pop from my outboard left carb. I had sync'ed them late last year and I have the YICS eliminated as well. I am in the process of checking the floats, just got the carb rail off this morning. It did this to me last year twice but went away after shutting her down for a few minutes. Is there a vent for the float bowls? I don't remember. I need a slow night at work to read up on this. I have an XJ and fuel seems to be flowing well to the carbs. I suppose I better check the screens in the tank too.

Try running it with the gas cap open.

[Bonz]

Right, it is still the same because, correct me if I am wrong, the mostly clogged vent does equalize over night very slowly and things cool down. When starting up the next day you get fuel flow initially until the fuel leaving the tank creates a vacuum, then fuel cannot flow well at that point when the bike is under load while being ridden. It starves out.

Yes, vents come out the top of the carbs. All carbs have them as a necessity of function. If you are digging into the carbs, you should know that?

You are making more work initially than needed by taking off carbs, checking fuel screens in the tank, etc. Do a gas cap vent check by riding with the cap ajar and let us know.

How did you come to tell there is a left outboard carb pop? That would be a backfire into the airbox, and telling which carb did it isn't possible in my mind. More than likely you have lean pop on decel out the left exhaust. Fix the fuel starvation from the tank not venting and it might take care of itself.

Float adjustments don't go bad, and if they do, they dont work again after a few minutes like you mention. Gas cap vent.

Hopefully that is helpful and can save some work so you can get riding ASAP!

[justme1100]

I can tell which carb was popping as I run pod filters and yes I do know about the vents I am just tired, third shifter and just got out of work a couple hours ago, sorry. I have been reading as much as I can find about these carbs and I think I just over loaded my brain. I found the tops of my diaphragms (again, thanks spell check) were wet, really wet. Hmmm Could it been from hard acceleration then a quick deceleration? Forcing fuel back through the vacuum for the slides? Floats seem fine too. Gas flow from tank is not restricted and steady. I had popped the cap open before restarting last I ran it. I am going to reattach the carbs and try again. I am also going to check and make sure the enrichener isn't stuck part way.

[justme1100]

Thanks, I really mean it!

Oh and by the way, THANKS for the replies all. It means a lot. I love this old Beast and if it wasn't for this forum I wouldn't have ever got her resurrected or been able to keep her running. 7th season we have been riding now. Hope for many more too.

[TopCatGr58]

Hey there Just,

Okay, by this photo, it looks like you have the EMGO tapered pods!


IF they are the EMGO brand, they have a prominent mounting lip that can interfere with the air flow of the intake inlet bell ports. Also, have you checked your pods for air flow...they look a bit dirty here.....possibly clogged?? Take a look at the tech tips for different ways to make modest velocity stack type mounts for those pods....can help remove the inlet bell restrictions as well as straighten out the air flow into the carb throat.

I can't tell if that's the OCTOPUS hanging down below /behind the carbs? I looked at the photo from the other side, but it didn't show in that one at all??



IF it is the Octy, then it's TOO LOW...and the fuel is having to flow too much up hill before it can get into the carbs.

You were able to make a high speed run to beat/get ahead of the HD, but then it does sound like it ran low of fuel, yet you found extra fuel on TOP of the vac. slide diaphragms???? What's the last time you cleaned the carbs?
Do you run Techroline or Sea Foam?

T.C.

[justme1100]

Hey there Just,

Okay, by this photo, it looks like you have the EMGO tapered pods!


IF they are the EMGO brand, they have a prominent mounting lip that can interfere with the air flow of the intake inlet bell ports. Also, have you checked your pods for air flow...they look a bit dirty here.....possibly clogged?? Take a look at the tech tips for different ways to make modest velocity stack type mounts for those pods....can help remove the inlet bell restrictions as well as straighten out the air flow into the carb throat.

I can't tell if that's the OCTOPUS hanging down below /behind the carbs? I looked at the photo from the other side, but it didn't show in that one at all??



IF it is the Octy, then it's TOO LOW...and the fuel is having to flow too much up hill before it can get into the carbs.

You were able to make a high speed run to beat/get ahead of the HD, but then it does sound like it ran low of fuel, yet you found extra fuel on TOP of the vac. slide diaphragms???? What's the last time you cleaned the carbs?
Do you run Techroline or Sea Foam?

T.C.

Pods have since been replaced with K&N because of the reason you stated. No Octy just two lines with in-line filters ( the stone type) and there is a cross over line, H shape. I have a line between the front nipples on the petcock, just because I can't find a gas resistant cap for the nipple. I checked flow today and I am going to shorten the fuel line, your idea. I have run Seafoam this year I tried Berrymans. Carbs were cleaned last year and sync'd. I think I need to pull them back apart and check the jet size. I didn't change anything when they were cleaned. I assumed they were stock until my brother said not and could tell the needles had a different taper. Well now is time to put them back on and see what happens now. Thank you for your input.

[justme1100]

OK, after making sure carbs were mounted properly, shortened fuel lines, checked to make sure there was uninterrupted fuel flow. The "issue" starts at about 3000 rpm. Bad coils?

[motoman]

OK, after making sure carbs were mounted properly, shortened fuel lines, checked to make sure there was uninterrupted fuel flow. The "issue" starts at about 3000 rpm. Bad coils?

IF it has sat for a few monThs, ya' got a 'science project' goin' on in the carbs. SeaFoam, Berraymans won't touch that 'project'....DAHIK. Your gonna have to pull them apart, including the slides and emulsion tubes. Pay close attention with a magnifying glass(unless you got Superman vision) to insides of pilot jets. Also, tooth-pic all those sideholes of pilot jets AND emulsion tubes. Laquer thinner is bout only thing I've found to hand wipe all those pieces including the sticky crap that seperates from fuel when things dry out from sitting. It'll definitely make floats stick to the float pin. Your gonna have to be a bit anal cleaning those carbies, after which if that issue still exist, your carbs are having ignition issues, pic-up coil wire(s), low secondary voltage, etc.

[Bonz]

So does the problem still go away after sitting a few minutes?

[motoman]

So does the problem still go away after sitting a few minutes?

.......only if left under a 'shade tree'.

[Bonz]

I am perplexed, need clarification...

Issue starts at about 3k rpm but goes away after sitting for a few minutes is what I understand.

Then how long before it starts again? As soon as the bike gets to 3k rpm? Or after running for a while?

[justme1100]

NO, the issue does NOT go away. Last year it acted like this a couple of random times but always cleared up. When it started this year it has not cleared up. The bike will start, idle and be fine to about 3000 rpms then act like it is running out of gas. No acceleration but if I shift and bring the rpms down I can build speed. Thats how I got home, couldn't get past the 3000 mark. I am going to check the wiring, the coils and install a different set of plugs. If nothing else it will eliminate the ignition as the cause and I have been meaning to up-grade the coils anyway. Anyone think it could be an ignition issue?