Its me ( Mush) but im on my mobile not at work on their computer ok so bit of an update .. ive had the carbs fully apart again , no blockages in any jets or emulsifier tubes etc etc the carbs internally absolutely sparkly clean , the fuel i drained out into clear jars and zero particles etc in any jar . Nice clear fuel ,, so I've checked ALL of the electrical items stated in the manual and everything has been within tolerances . I changed the plugs , leads and caps just because they were old and hey lets face it they are cheap Anyway .., yesterday i put carbs etc all back on , filled the petrol tank , had my camera in there and theres no rust or any floaty particles Replaced the inline filter , and new rubber fuel hoses . Ever put a clear inline filter between the pump and carbs . So it fires up once carbs were full , sits ticking over nicely and revs up , i think ok ill take for a test ride then while having a smoke the tone changed from nice burble to a popping , just from the right side exhaust cover it over and the bike is reasonably quiet then uncover it and its popping again , do same on other pipe and it is still popping ( i know that doesn't change anything im just saying ) . So then it starting to die and run crappy again , this is roughly 10-15 ish minutes on tickover ( not ridden ) i look at the inline filter between the pump and carbs and its about empty of fuel , the pump is giving a pulse every say every 2 seconds which you can see is letting fuel in but it is only obviously a little drip . I disconnected the fuel line put into a jar and turn ign key - nothing .. put kill switch on and a good squirt of fuel comes out for 5 seconds then stops .. ALL GOOD yes Start engine and fuel gushes out constantly -SO the pump is working as should ..power to and from the relay is good , ohms are good at pump etc etc .. took cap off fuel tank - no pressurisation .. the ignition switch , kill switch , relay , connections on the system are all sound and correct on multimeter , brand new full charged battery . So why would the fuel NOT be pulling through as it should do ? This is obviously why it dies and splutters etc after 3-6 miles of tootling along the road Any ideas ?
brain fried .. help ..
- Thread starter Mush
- Start date
Help Support VMAX Forum:
For the purposes of trouble shooting, can you suspend a temporary tank above the carbs and gravity flow the fuel in?
That would at least eliminate any carb issues and isolate the problem from the pump back upstream.
Is your tip-over valve free...or better yet, disconnected until you get this sorted out?
That would at least eliminate any carb issues and isolate the problem from the pump back upstream.
Is your tip-over valve free...or better yet, disconnected until you get this sorted out?
Be-sure to hang that temporary tank high! If you just do it where its bottom is just-above the carburetor rack, you don't have enough 'head' to properly-fill the float bowls, get it elevated. Another thing to look-for is a gas line with a hole in it. Have you looked closely at the molded 'T' gas line in the middle of the carb bank?
Ok so tomorrow i shall wire a can from the beams so its a good 3 ft above .. now does the pipe from can go straight to the carbs OR through the pump ?
It's easy to hook it up after the pump. Just be-sure to unplug the fuel pump, or its fuse, though I don't know if anything else is on that circuit too.
Straight into the carbs.
3 ft will give you about 1.3 pounds of head on the fuel which should be enough to close the float needles.
ga_max
Well-Known Member
Could it be the tank not venting correctly ?
He said he checked that.
Yes i did that and its venting correctly .. as soon as i get chance i shall suspend a can from the ceiling and see what happens and let you all know the result but at present what with the global pandemic im rather flat out with work and too knackered to mess with the bike when i get home from work .. stay safe all ;-)
sdt354
Well-Known Member
Just for info. What is the voltage when hot, and idling for a bit? After a sync, and warmed up, are the A/F screws all responsive? When turned all the way in and lightly seated, one at a time?
Hi Danny ,
initially yes , before i pulled the carbs the bike was really struggling to run at low speed / junctions etc . after the strip , clean and reset the bike was better but only id say for another couple of miles run than previous . I've replaced the plugs , leads , caps , had the multimeter on coils , pick up coil etc etc etc and all fall within the required values in the manual .
Last night i put a camera into fuel tank and cant see and rust or crud in there , the filter (new) is spotless . pumped fuel through the pump and that was clean aswell .
Fired up perfect as it has done and sits ticking over no issues , after possibly 30 seconds to a minute can turn choke fully off . it starts playing up when actually riding , possibly after around 5 miles , temp gauge isn't overly hot , fan hasn't kicked in . when it is spluttering , coughing and dying i give it some revs and it appears to clear then it will accelerate perfect but as soon as i back off it then returns to spluttering and dying . if i stop and feather the throttle down to tick over it will sit quite happy ticking over but then need a bit of feathering to get off the line again .
when i get home from work tonight i will have another look at it again
If i could trust it not conking out and leaving me stuck id run it to work and back but its a long push mostly up and down hills so i dont fancy that
redbaron13
Well-Known Member
yep, sometimes they pump and sometimes they do not. put in a Mr Gasket green pump, it is electric, pumps around 2.3 psi. I installed one under my seat about a year and a half ago and all the stalling problems left with the old pump. i finally caught my pump screwing up after several cycles into a bucket.
enzodo
New Member
Yes, the fuel pump may overheat. The rear exhaust heat raises and heats up the pump. It gets worse in summer particularly in hot places like south Florida. I replaced mine with a Motor Works fuel pump model #USEP8016HPT @3-5 psi and relocated way back under the seat; no issues after 3 years.
Ride safe...
Hi all , hope everyones keeping safe .. ok so i tied a new fuel can with fresh clean fuel to the ceiling , ran a new clean pipe from the can to the carbs ( i have a clean fuel filter there ) disconnected the fuel pump and pipes /wiring , started the bike and i thought id got it as for 15 odd minutes it ticks over , revs etc then i saw the air bubble appear in the filter again ! It very very gradually gets bigger .
So ... its obviously a carb / Fuel issue BUT where do i go from here ?
The float levels are all good , the air pilot screws all good , new battery , starts great , ticks over great , but the gradual fuel starvation is why it conks out after a few miles BUT WHY ???
My Harley has never given me even a quarter of the problems this damn bike is ! really getting to me know ... help
So ... its obviously a carb / Fuel issue BUT where do i go from here ?
The float levels are all good , the air pilot screws all good , new battery , starts great , ticks over great , but the gradual fuel starvation is why it conks out after a few miles BUT WHY ???
My Harley has never given me even a quarter of the problems this damn bike is ! really getting to me know ... help
enzodo
New Member
Hello, I would try the following in order to isolate the problem. *** Disconnect electric wires to the fuel pump, "VERY IMPORTANT" you don't forget to disconnected it. Disconnect the fuel line from the fuel pump. Make a gravity fuel bottle (see attached pic) and place it at least 2 feet above carburetors level. Use a splicer to connect the bottle hose to the carburetor fuel hose. Fuel will run into carburetors by gravity. Start the bike and let it run for at least 20 minutes and remember to keep the gravity bottle with enough fuel to keep the bike running.
If the bike didn't give you a problem, now you can focus on the fuel pump. Maybe a fuel pump issue, a faulty wiring or control module.
NOTE: electric wire terminal will expand when heated up and bad contact may happens, ensure you still have power on the electric terminal going to the fuel pump during this procedure. A voltmeter or 12V light bulb will work to determine if power still present.
If the bike didn't give you a problem, now you can focus on the fuel pump. Maybe a fuel pump issue, a faulty wiring or control module.
NOTE: electric wire terminal will expand when heated up and bad contact may happens, ensure you still have power on the electric terminal going to the fuel pump during this procedure. A voltmeter or 12V light bulb will work to determine if power still present.
Attachments
Sounds like somewhere you have a fuel hose split. Have you checked the molded T-hose in the carb bank? It's possible that air entering the fuel plumbing system is going back to a high point. That would be where your filter is, now, and the air bubble forming. I'd check all the hoses in the carb block. Sometimes it can 'look-good,' but be split.
I've never-done this, but it seems like a way to try to locate a fuel line split, if you don't 'eyeball' one. Pressurize your fuel delivery system. Carbs off the bike. Open your float chamber fuel drain screws. Feed pressurized air into the fuel inlet, and search for a bleed-off source of air from somewhere along the fuel delivery system. The opened float chamber drain screws should allow air to escape from the float bowls, so you aren't over-pressurizing the carbs. If you have a pressure regulator on your air supply turn it down to something like 30 psi. Use a rubber tipped air nozzle to get a good seal into the hose feeding the carbs.
Normally, I think you should be able to see a leaking hose dripping gas, or to eyeball a split hose. I have had the molded T-hose split before.
I've never-done this, but it seems like a way to try to locate a fuel line split, if you don't 'eyeball' one. Pressurize your fuel delivery system. Carbs off the bike. Open your float chamber fuel drain screws. Feed pressurized air into the fuel inlet, and search for a bleed-off source of air from somewhere along the fuel delivery system. The opened float chamber drain screws should allow air to escape from the float bowls, so you aren't over-pressurizing the carbs. If you have a pressure regulator on your air supply turn it down to something like 30 psi. Use a rubber tipped air nozzle to get a good seal into the hose feeding the carbs.
Normally, I think you should be able to see a leaking hose dripping gas, or to eyeball a split hose. I have had the molded T-hose split before.
Sounds like it's calling for more fuel than it can supply
Is it possible after 15 minutes of running your temp fuel supply was getting too low to create adequate head pressure to push the fuel?
All connections tightly clamped?
All connections tightly clamped?
Hey all .. so ... progression I got around to suspending a can of clean fresh fuel a good metre above the bike and took the pipe straight to carbs , al ran fine . Re-checked all hoses etc etc then started playing up again so multimetered everything again , reseated the carbs and airbox ( just to be sure ) remeasured the float levels , got the gauges out again and balanced the carbs ( bang on ) , restarted bike and all good .. got up this morning and took for test ride . Went really well and i thought yes ive cracked it job done then 47 miles in and on way back home came to a village and started spluttering again . Jumped off and the clear filter was still full of fuel but was running poor . Set off again and got home .. was running poor as i pulled in home , checked everything again and all is as it should be .. now it seemed like it was dropping onto 2 cylinders when it started playing up , around 20 - 40 mph feathering the throttle it seems to jump in and out of running on 2 or 4 cylinders . Give it the beans and it goes well again .. ive checked the coil measurements again and they are all good so ... ‘if ‘ and i cant imagine 2 coils going down at same time but if they are then how do i tell which etc .. what am i missing ?
OK, it may seem like a pain in the ass, but before you go buying anything expensive (see later comments), you need to check some things.
First, which cylinders are 'dropping-out?' And, how-do you park the bike? Are you putting it onto the sidestand, as most of us do? I know it's been mentioned before, but unless your entire gas tank is shiny-clean inside, you may be getting debris in the pilot jets of the jet block (inside the float bowl). I know you said in post #21 that the gas tank was clean. Those pesky pilot jet passageways inside the jet block are terribly-small in-diameter! It doesn't take much to obstruct them, and at small throttle openings, or at idle, your bike will run poorly, cylinders will cut in-and-out, the exhaust pipes for the cylinders which have plugged pilot jets will be noticeably-cooler, if you have an infra-red temperature gauge, or if you spritz a bit of water onto them (the exhaust headers, as-close to the cylinder heads as you can manage), the water will instantly evaporate into steam on clear/clean carbs, but the one(s) with blocked pilot jets (inside the float bowl) will allow the water to run-off, and then evaporate, the difference is immediately apparent.
I asked-about 'how do you park your bike,' because it seems as though as-often is the case, any particulate material blocking the pilot jets seems to have an affinity/likelihood to block the left-side cylinders, where the float bowls are lower on the left side, because of the bike being on the sidestand. It's only time, and maybe a jet block gasket, if yours tears during disassembly, to check the pilot jet(s) for debris. If you know what cylinder(s) is/are cutting-out, you could gamble on only inspecting that one (or those) but if you've got the carbs off, I would inspect each carburetor.
In your post #34, you mentioned that the air pilot screws all good, I forget where you said they're set, how-many turns out from fully-in?
The reason I said to check the pilot jets in the carburetor jet blocks first is because it costs-you only time to remove the carbs and to inspect them. Of course, since they're off, that means to use a can of spray carb cleaner and the little red wand it comes-with, to clean the carburetor passageways, and the jet block.
OK, let's assume that you did the time-consuming but free in cash-outlay carburetor cleaning. You re-assemble the carburetors, you start the bike, and you again synch the carbs. It's very-important to synch the carbs every time you remove/replace them, because they need to be done for your bike to work properly. Problems with the idle not-returning, and the engine racing, can happen because of a poor carburetor synchronization.
If your bike still shows the problem of 1 or-more cylinders dropping-out, and you've also eliminated the possibility of intake leaks, and you know that the primary ignition components (spark plugs, spark plug caps, spark plug wires, ignition coils) are all good, then probably the only thing left is the ignition box. Sean Morley has a loaner kit [email protected] of electrical components, you install one at a time, and see if that cures your problem. In this case it would appear that the ignition box behind the steering head is in-need of replacement. Like Progressive Insurance, Sean's VMax kit, you only pay for-what you need. That's where I'd be going next, if I was you.
First, which cylinders are 'dropping-out?' And, how-do you park the bike? Are you putting it onto the sidestand, as most of us do? I know it's been mentioned before, but unless your entire gas tank is shiny-clean inside, you may be getting debris in the pilot jets of the jet block (inside the float bowl). I know you said in post #21 that the gas tank was clean. Those pesky pilot jet passageways inside the jet block are terribly-small in-diameter! It doesn't take much to obstruct them, and at small throttle openings, or at idle, your bike will run poorly, cylinders will cut in-and-out, the exhaust pipes for the cylinders which have plugged pilot jets will be noticeably-cooler, if you have an infra-red temperature gauge, or if you spritz a bit of water onto them (the exhaust headers, as-close to the cylinder heads as you can manage), the water will instantly evaporate into steam on clear/clean carbs, but the one(s) with blocked pilot jets (inside the float bowl) will allow the water to run-off, and then evaporate, the difference is immediately apparent.
I asked-about 'how do you park your bike,' because it seems as though as-often is the case, any particulate material blocking the pilot jets seems to have an affinity/likelihood to block the left-side cylinders, where the float bowls are lower on the left side, because of the bike being on the sidestand. It's only time, and maybe a jet block gasket, if yours tears during disassembly, to check the pilot jet(s) for debris. If you know what cylinder(s) is/are cutting-out, you could gamble on only inspecting that one (or those) but if you've got the carbs off, I would inspect each carburetor.
In your post #34, you mentioned that the air pilot screws all good, I forget where you said they're set, how-many turns out from fully-in?
The reason I said to check the pilot jets in the carburetor jet blocks first is because it costs-you only time to remove the carbs and to inspect them. Of course, since they're off, that means to use a can of spray carb cleaner and the little red wand it comes-with, to clean the carburetor passageways, and the jet block.
OK, let's assume that you did the time-consuming but free in cash-outlay carburetor cleaning. You re-assemble the carburetors, you start the bike, and you again synch the carbs. It's very-important to synch the carbs every time you remove/replace them, because they need to be done for your bike to work properly. Problems with the idle not-returning, and the engine racing, can happen because of a poor carburetor synchronization.
If your bike still shows the problem of 1 or-more cylinders dropping-out, and you've also eliminated the possibility of intake leaks, and you know that the primary ignition components (spark plugs, spark plug caps, spark plug wires, ignition coils) are all good, then probably the only thing left is the ignition box. Sean Morley has a loaner kit [email protected] of electrical components, you install one at a time, and see if that cures your problem. In this case it would appear that the ignition box behind the steering head is in-need of replacement. Like Progressive Insurance, Sean's VMax kit, you only pay for-what you need. That's where I'd be going next, if I was you.
Similar threads
