Bike Fuelling Issue ?... or electrical when hot ?

[Dave.n.Shirley]

Hoping someone can make a suggestion. A couple of weeks ago after driving approx 20 miles, (countryside then village) , and on entering slower moving traffic in the village, the bike started to stammer as if it was going to break down. It didn't and I stopped for petrol (it wasn't too low). The bike started fine, but stalled , then 'surged' on restart. It gargled a bit as if it wasn't getting fuel, but once on the open road outside the village it ran fine again. On getting home, and slower traffic, the bike started to stammer again at lower speeds, but I made it home ok. It wasn't too much of an experience, and my first thoughts were that the stock fuel pump was on its way out. (the bike starts, runs, and idles, fine from cold). I ordered a new solid state type fuel pump from Exactrep, and fitted it a day or two back. Today, I went out for a run, did approx 20 miles in varying traffic and thought all was well........ I went back out , did approx 10 miles , and the bike 'threw the dummy out the pram' whilst driving approx 60mph. It chugged to a stop. It was reluctant to start again, but would turn over easily. I waited 5 mins and it started and I got a couple of hundred yards under stressed revs before it chucked it again,. I repeated this four times until I got home (approx 3 miles). I thought I had a fueling issue, but not so sure now. Is it possible my new pump is heating up and misbehaving ? Am I misdiagnosing the fuelling issue.? (I've had the bike a year now and have experienced the 'surging' when hot at lights before, and irregular idle when warm, but nothing like the last couple of rides. I've put the old pump back in for just now and the bike once again starts and runs easily from cold...... but I'm not going out to test how far I get . Could the electrical system heating up somewhere be causing this? The engine doesn't overheat, and maintains a constant halfway dial position at all times.

 

[Radioguylogs]

My kickstand swich gave me sudden drop-outs last spring. I'd be driving along and at ramdom times, the engine would suddenly stop and sometimes jerk and sputter. It always started up and kept going until the next occurance.

I cleaned the kickstand switch and never had any more trouble.

In your case, surging would not be caused by a kickstand switch, and I don't know about stammering.....but JAT in case you don't find the cause somewhere else.

 

[gentsvmax]

My kickstand swich gave me sudden drop-outs last spring. I'd be driving along and at ramdom times, the engine would suddenly stop and sometimes jerk and sputter. It always started up and kept going until the next occurance.

I cleaned the kickstand switch and never had any more trouble.

In your case, surging would not be caused by a kickstand switch, and I don't know about stammering.....but JAT in case you don't find the cause somewhere else.

Great suggestion! I will add ,this not at all far fetched tip, to my strange running symptom check points list.
I tell ya LOL the Max can throw even the best diag pro a curve ball once in a while.

 

[gentsvmax]

Hoping someone can make a suggestion. A couple of weeks ago after driving approx 20 miles, (countryside then village) , and on entering slower moving traffic in the village, the bike started to stammer as if it was going to break down. It didn't and I stopped for petrol (it wasn't too low). The bike started fine, but stalled , then 'surged' on restart. It gargled a bit as if it wasn't getting fuel, but once on the open road outside the village it ran fine again. On getting home, and slower traffic, the bike started to stammer again at lower speeds, but I made it home ok. It wasn't too much of an experience, and my first thoughts were that the stock fuel pump was on its way out. (the bike starts, runs, and idles, fine from cold). I ordered a new solid state type fuel pump from Exactrep, and fitted it a day or two back. Today, I went out for a run, did approx 20 miles in varying traffic and thought all was well........ I went back out , did approx 10 miles , and the bike 'threw the dummy out the pram' whilst driving approx 60mph. It chugged to a stop. It was reluctant to start again, but would turn over easily. I waited 5 mins and it started and I got a couple of hundred yards under stressed revs before it chucked it again,. I repeated this four times until I got home (approx 3 miles). I thought I had a fueling issue, but not so sure now. Is it possible my new pump is heating up and misbehaving ? Am I misdiagnosing the fuelling issue.? (I've had the bike a year now and have experienced the 'surging' when hot at lights before, and irregular idle when warm, but nothing like the last couple of rides. I've put the old pump back in for just now and the bike once again starts and runs easily from cold...... but I'm not going out to test how far I get . Could the electrical system heating up somewhere be causing this? The engine doesn't overheat, and maintains a constant halfway dial position at all times.

Any chance some rain water got in the storage tank where you picked up said petrol?
We just had a Valero station here profiled in a news report for having 10" of water on top in their premium storage tank.

 

[Dave.n.Shirley]

Thanks for the replies folks........ I'll give the sidestand switch a clean thanks just in case. Yesterday was the first time the bike had cut out completely. It was a slowish and gradual starvation of fuel feeling. The previous time when it almost packed in and I was going to the petrol station it had been driving great... it was on the approach to the station that it started to feel like it was going to break down (I still had a 1/4 tank). After filling up, it stalled, and resisted starting but it did spring back /surge back into life and I made it the 20 miles back home. Both times it seems to be when I pootle about village roads, and then the bike seems to object. As if something is warming up and causing a cut out. I did read that solid state pumps can heat up , but that doesn't explain the first occasion when the original mechanical pump was still fitted. (unless I've had the original pump about to go, and then replaced it with something worse.... )

 

[MaxMidnight]

Have you checked that the fuel tank breather is clear? When it misbehaves stop and when removing the fuel filler listen for the sound of air being sucked in.
If it is electrical insulation or an electrical component these can break down as they heat up but I would have thought that would be a permanent issue until they cool down?
It would be helpful if you put the year of your bike in your profile.

 

[Dave.n.Shirley]

Thanks for the reply .......... I'll check the breather . The bike is a 2000 model .

 

[Dave.n.Shirley]

Well, I ran a length of fuse wire through the metal tank breather hose, but there didn't seem to be any resistance . I've left the breather hose off for the minute and might try a run with it detached ; do you think the roll over valve could cause a blockage ?

Just out of interest, as I had the seat off again, I removed the old fuel pump once again and took it apart. Typically I'm used to hearing it click rapidly every time I turn the key. Even the new pump clicked rapidly, and 'very' loudly, prior to starting up. The diaphragms in the pump were still in place but there was a large piece of hard plastic debris lodged in one (see pic). I popped the diaphragm out and removed the debris (it was just one piece until I broke it to see what it was . I put the pump back together and re-fitted it. I thought I'd done something wrong as there was no clicking or noise whatsoever .... except a short hum (I had turned the key an hour earlier so there would've been fuel in the carbs)... turned the key and it fired up ....... 'really' smoothly. Even my partner, and she doesn't give a hoot !, said, " that even sounds better". It might not be the issue, and it still doesn't explain what happened with the new pump........ but it was interesting

I've had loads of bikes over the last 30 years.... and this thing has kept me busy over the last year and 4000 miles : fork seals, a new stanchion, coolant leak, clutch slave rebuild . Damned if I want it to beat me. ... but I do love it.

I'll let you know how I get on with another run. I hope no plastic (whatever it is ) made it beyond the pump.

 

[Fire-medic]

Fuel filter clogged, sometimes worse than others? Migrating crud occasionally obstructing the gas flow? What does the inside of the gas tank appear to be? It should be shiny metal bottom to top unless someone treated the tank to a liner product.

That random plastic in the pump may have come from a deteriorating jerry can someone used to fill the gas tank. I think I'd carry a screwdriver and some sort of plastic transparent small container to drain the float bowls, one at a time, emptying the gas in-between, to see if you can spot a 'lens' of water floating on the gas in the container. You can get an inexpensive cellphone fiber optic cable to scope the gas tank or wherever you need to see inside a confined space. There are also units that are video/picture monitors with recording, and a 3' long fiber optic cable and the one I have, has b&w and color capabilities, and it records video too.

 

[Radioguylogs]

Maybe someone cracked the nylon barb on the fuel fiter when they were changing it?

 

[Parminio]

My bike acted that way once right after the first time I changed the battery back in 2011. Turns out my ground cable was loose and was making intermittent contact with the battery, so I'd start losing power then get it back then loose it then get it back.

Re-tightened it and that sorted it.

 

[Dave.n.Shirley]

Thanks everybody for your suggestions. I'm inclined to think that the small piece of debris in the original pump has been the source of my initial problems and what prompted me to buy a new pump. The solid state pump I bought and fitted, on further reading, seems to be possibly ill-suited to the V-Max application; ie, they are supposed to be fitted 'below' the fuel / tank upper level so that they are effectively part gravity fed . I'm thinking the new solid state pump has been overworked, overheated , and left me stranded ....

I took the bike out today on a short 25 mile run (with the old pump back in) , and the breather pipe disconnected (temporarily just to see if it made a difference) , and the bike seems to be running better than it has in a long time. (picture taken with the bike idling happily away)

fingers crossed .... Thanks everybody for all the input

 

[Fire-medic]

I hope that's it. Members had many suggestions, many from their own fuel supply issues. I was thinking about your solid-state fuel pump, and how you thought it could be an issue of it needing gravity feed to make it function, and I thought of a way to take care of that. On the fuel hose from the gas tank, install a squeeze bulb like a portable tank uses on a small outboard motor. A few squeezes to get fuel to the filter, where you could see the fuel pass-through, or the use of clear-plastic fuel-rated hose one side or the other of the priming rubber bulb, and that should take care of getting fuel to the carbs. Here's one from Harbor Freight, $6.49.