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48 Pan
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Discussion Starter · #1 ·
Hello fellas and ladies,

Here's a wrap up and lessons learned from the thread I had going on Side of the Road Crapout.

1. Bike was crapping out so suddenly it acted like electrical, but it was fuel. Carb seals were coming apart after 5 years of no running and moving. Rebuilt with a Bendix (knockoff version) rebuild kit. Half parts usable, half in the trash.

Lesson Learned: Use Bendix original builder parts. Available from Dennis Kirk, last I checked JP Cycles were using only trash grade.

2. Quest to do the ignition timing. After much help from this board, I learned the marks on the flywheel and the position to have the lobes in for front and rear timing. After tinkering A lot, I figured out that I was advanced too far. Still wondering about this though, because now and then it burps back and slaps my boot for my transgressions, but that's actually a warning the next kick is going to work.

Lesson Learned: Do NOT get the cheap points / condenser stuff. Get Blue Streak. Connectors and wiring cores in these newer cheap parts are low grade and seem to vibrate out of spec. Be damn picky about the .022 gap on front cylinder on the CENTER of the small lobe.

Additionally: Thought the original coil was shot. Ordered a Skyfyre (?) coil. Lasted 2 weeks. Tied in a coil from a 98 R1100RT-P. Bike started, a bit rough but it was running. Fine tuned the timing, retarded a bit more. (no timing light). With this revelation, I tried the old coil I thought was shot, it was not shot and is currently running the bike.

Lesson Learned: Old cop coil from a BMW R1100RT-P provides hellish fire, especially with the cop grade spark plug wires, though they look a bit odd :)

CURRENT ISSUE: The bike runs powerful and idles perfectly, problem is getting it to start initially. Sequence of events.

1. Multiple attempts at combinations of pre-start kick throughs on full choke, half choke, full throttle and no throttle. Kept getting NO SMELL of gas at the filter.

2. Took filter off and placed my hand over the inlet, kickthrough 3 times till my hand had gas on it. Turn on key, several kicks half no, half or full throttle, 3-4 kicks, it would fart through the carb, next kick started the bike.

3. Last 3 days that has been the protocol, I stopped shutting off the fuel at the tank to preserve the fuel flow. Excess gas is NOT leaking into the engine. It's starved for gas.

4. Thought occurred to me. Is this the dreaded air leak that I hear about? With the engine off, is there no vacume to keep fuel in the line and carb ready for the next start up?

Attempted Resolution: I put a hemostat clamp on the fuel line just below the inlet into the carb to see if that kept the gas in the line enough to make a fuel starve state more unlikely. This worked for the last 4 start up. So, if that's the case and gas is back draining out of the carb, what might the problem be?

Bad Rebuild? Intake manifold seals at the heads? BTW on several attempts this last weekend to get the bike to start I whiffed some starting fluid at the intake, ..... one kick and the bike was purring and idling at 800 rpm with no throttle assist from me and no choke.
 

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My thoughts & musings on the gas/start problem. Remember, I know nothing about Bendix carb. I don't understand the "vac. in fuel line", or back draining. Tank is higher than carb. Carb is open to atmosphere all the time via jets. Possible air bubble in line preventing flow? Does the Bendix have an accelerator pump? Can you see gas squirt when you activate throttle when not running? Most choke systems (not enricheners) restrict air from entering the mouth of the carb (like your hand does) and cause extra gas to be pulled through the jets. Kicking does not create enough air flow for venturi effect. Engines require an overrich condition to start easily.
VERY little starting fluid is required to make engine start.
I doubt bad intake seals are playing part, not enough air/fuel flow at kicking speed.
My shovel is very particular to it's start sequence. It took me a while to figure it out, but now it's a 2-3 kick (after prelim's) starter. Prime kicks w/o ignition are mandatory.
Above questions are just for your thought, not to be answered to me. Thanks for all of your replies, it has been an interesting read.
 

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48 Pan
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Discussion Starter · #5 ·
My thoughts & musings on the gas/start problem. I don't understand the "vac. in fuel line", or back draining. Tank is higher than carb.

I put a new kickstand on the bike and the lean IS quite a bit more than the older kickstand. Eyeballing it, the carb is at least at the same level as the gas lever, but if the fuel level is in the bottom half... well, I could see even barometric pressure and temp play into that problem.

Does the Bendix have an accelerator pump? Yes, and I used to see fuel spurt through that tiny jet. But now, when not running I can't see it, but the acceleration and performance suggest it's working while the engine is running, make sense?

Can you see gas squirt when you activate throttle when not running? Not at the accel pump fuel jet.

VERY little starting fluid is required to make engine start. Roger that, I open the throttle and give it the fastest possible burst at the edge of the intake and immediately kick it, it fires up and idles perfectly at that point.

I doubt bad intake seals are playing part, not enough air/fuel flow at kicking speed. Roger that.

My shovel is very particular to it's start sequence. It took me a while to figure it out, but now it's a 2-3 kick (after prelim's) starter. Prime kicks w/o ignition are mandatory. I've been playing with different techniques, the weird thing to me is how easy it runs ONCE it's fired, don't have to blip the throttle, turn up the idle speed, heck I don't even have the choke on and let it off as it warms up. It idles perfectly

Above questions are just for your thought, not to be answered to me. Thanks for all of your replies, it has been an interesting read.
Thanks, I've learned tons from other folks posts, I'm a nut for detail and follow up, so that others may learn. Much appreciated.
 

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Sounds like there is a problem at the float needle not letting fuel into the bowl when on its kickstand.

Should have fuel squirting into the venture if the bike is running or not.

When sitting on the kickstand, what fuel is in the bowl will evaporate.
And with the fuel valve left on, the fuel should be replenished in the bowl.

Sounds like this is not happening.
 

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48 Pan
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Discussion Starter · #8 ·
Sounds like there is a problem at the float needle not letting fuel into the bowl when on its kickstand.

Sounds like this is not happening.
I'm new to some of this but catching on fast, so I'm guessing if the float is the problem, which makes sense, it must be the float has TOO MUCH GAP, resulting in the float setting lower in the bowl, lifting as it fills with fuel, and that seats the needle, which cuts off fuel supply.

That make sense? The float bowl gap, needs to be set so that the gap is LESS. I know, that is a recurring post issue, sorry if this is old and older ground.
 

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Right.

With the carb body held upside down, there should be a 3/16" gap between the float and the gasket mating surface of the carb body.


SettingtheFloatLevel.jpg
 

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48 Pan
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Discussion Starter · #10 ·
Right.

With the carb body held upside down, there should be a 3/16" gap between the float and the gasket mating surface of the carb body.


View attachment 405569
Feedback on the drillbit... I started with the 3/16" db, that a lot of gas as the needle didn't seat at the right time, OR, something else was in play. I've since read the 3/16 is the starting point, which makes sense considering the "quality" of some of these rebuild kits. Out of spec stuff etc.

Being a old gun wrench, I used to machine my own long range optical sight bases and understand angular relation in relation to physical measurement. I was putting the drill bit Across the body of the carb, seeing in that drawing that the big is against the jet results in a bit of a math error in the value of that 3/16". (lots of reasons why).

My point being my method was stupid, having the bit the same was your drawing makes better sense. Carb teardown coming up. Fuel filter is coming out also.

[/Last question. Does the long leg of that spring being UNDER the gasket make that much difference if there is no leaking going on?B]
 

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It might. If the spring was on top of the gasket, it would increase the spring tension to lift the float.

May contribute some to the symptoms you are experiencing.
 

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When starting old Panheads , you need to advance the timing by turning the distributor by hand, once it is started it can be turned back.
 

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When starting old Panheads , you need to advance the timing by turning the distributor by hand, once it is started it can be turned back.
I think he has an automatic advance (centrifugal) timer.

The reason I asked about the inline fuel filter is that it can restrict flow even if only very slightly dirty, especially when the tank is low. The only fuel pressure you have is the weight of the fuel.

Another thing that can restrict fuel flow is a plugged vent in the cap. I think you have fat bobs, so the right side fuel cap should be vented. If the vent is plugged, fuel will not flow. You can test this by loosening or removing the cap.
 

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48 Pan
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Discussion Starter · #14 ·
Roger that on the manual advance, except this one has an automatic advance dist. Here's a counter question, when I had buggered the timing earlier on, I had advanced the timing per instructions in the book, and other sources, response was either a kickback of high order, or a ball of fire out the carb :) that was kinda cool though. A war vet buddy of mine was standing in the garage door had a once word response.... "cool". Ball of fire rapidly dissipated and no damage occurred, good thing I had long pants on. I could stunk in there otherwise !!
 

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48 Pan
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Discussion Starter · #15 ·
UPDATE: Mission success so far. Came home removed the hemostat clamp I had on the fuel line below the carb to prevent any loss of fuel to the carb from fuel maybe leaking back into the tank (steep kickstand angle, other stuff). Full choke, 2 primer kicks, power on, 1st kick and it belched. hmmmm, very good I thought. Second kick it fired and sat idling at 800 rpm.

I removed the inline filter and replaced the entire line with new 7/16" ID fuel hose, clamped with fuel injection clamps (left over from BMW work). Power on, 1 kick and she fired up instantly and idled beautifully and steady while the engine temp came up. Here's the odd thing, I still can't see fuel spray out of the accelerator pump nozzle. The main jet holes in the out of center (because it sits crooked) release fuel, but it's not a pretty site at idle, sputtering etc. BUT, it idles smoothly and on the test ride it ran HARD. Great power, so i'm wondering if the accel pump isn't doing it's thing at idle, but eventually catches up. I can't detect any lack of performance.

3 stops, all for more than 10 minutes, she fired on first kick. No clamp needed on the fuel line to prevent leak back.

Observation... At this point, i'm calling the issue cured. Have an original Bendix rebuild kit coming and i'm going to put that new pump arm in and be done with it. It runs close enough to be perfect for my eye and feel. Plugs are maybe a little sooty, but exhaust in clean and doesn't sting they eyes in the garage with the door open.

If I can post a video on here i'd upload one of the bike at idle. It's badassss......

Thanks gents for all the help. I'll keep updating so that others may learn. Tomorrow i'll write up the repair synopsis from front to back.
 

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48 Pan
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Discussion Starter · #17 ·
The problem re-entered the lead. The evolution of this thing has been interesting. In the other postings, this started with the bike crapping out on the side of the road. That lead to a carb rebuild with one of the myriad of substandard rebuild kits that are invading the US. Get a Zenith original kit, period.

Then came the ignition issues, the fuel again. 2 days ago, I reported the issue resolved, except the exact same issue started over again.

Fuel line was replaced, inline filter removed and new fuel line installed. Yesterday, 24 hours after a thought resolution, I tried to start the bike and it did the same non-sense it has been doing since this started,,,,, no fuel to the carb. After 10 minutes of trying all sorts of combinations, confirming spark etc. I blew a sniff of starting fluid into the carb and bam, it was running in one kick. Smooth idle.

Going to rebuild the carb again totally today. If that doesn't do it. I'm pitching the POS bendix carb and calling it a black heart. Then it's an S&S.

[/Question for you all.... can out of spec adjustment pushrods (solid) effect initial startup? What are the other signs that the pushrods need adjustment?I]

Thanks for putting up with this thread :)
 

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When it starts, it starts easily and idles well. When it don't, it don't, so I doubt it is pushrod related, and lean towards carb/fuel problem.
 
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