1985 Vmax Losing Power then stalling

[schenckster]

Hello, I've been a lurker in the forum for a few months now and this is my first post, so I apologize if my formatting is incorrect.

I bought a 1985 Vmax about 3 years ago, it wasn't running when I bought it. Just needed some love and cleaned up a bit. I was plagued with an issue quickly after. The bike would what seemed to be random, start starving for fuel.
Essentially, I would feel the bike start to lose power, then one cylinder would cut out, followed by another, until it was stalled The fuel line and filter were in bad shape so I replaced those as well as the fuel pump (previous pump was electric as well as the new one). The bike ran great for a week or so. Then the problem occurred again.

After looking at many different things, I pulled the pump and examined the pump, I found it wasn't pumping near enough fuel. But after charging the battery it starting pumping great.

The fan is shorted to keep from overheating, the speedo was converted to digital, and the fuel pump is electric. Every time after trying to diagnose the issue I found the bike magically started working for another week or so. My thoughts are I am pulling too much power and the alternator can't keep up and charge the battery enough. The common denominator in trying to diagnose the issue was charging the battery.

What confuses me, is the battery has enough power to pump the bowls full then turn over again at least 3 more times until the battery is completely dead.

Has anyone experienced this?

Edit: I have cleaned the carbs and performed the shotgun and it hasn't had a impact on the issue.

 

[Parminio]

The Vmax is rather notorious for having, at best, a bare minimal charging system. People that run the fans constantly have pretty much no hope at all of keeping a battery charged. Add to that more lights / digital gauges and there you go.

First thing to do is put a volt meter on the system and see what it's charging at. It being an 85 the rectifier assembly is probably on its way out, making a barely minimal charging system just completely give up the ghost.

 

[one2dmax]

agreed. Most likely a charging issue. Check the regulator and if bad replace it with a 96-up finned version (I have them for $75).

 

[schenckster]

So I found the issue and man do I feel dumb. I checked the battery multiple times and it the voltage came back optimal every time. The voltage was above optimal, but I never pulled the battery because a wire was spliced over the battery and needed to be cut to remove the battery. From the top the battery was the correct size, well I decided the remove the battery and it turns out it had what I would call a power wheels battery in it. The previous owner put it on stilts to make it look like it was the same height, it had the same width but was only about 2 inches tall. I'm assuming he bought a new battery and wanted to save some money when selling it and put an old small battery in. New battery in, and the bike is running great now. I just have a shot to my ego haha.

 

[Parminio]

Buddy, it takes all kinds. If that's the worst thing you ever find on a vehicle you bought used, consider yourself lucky.

 

[Radioguylogs]

Like Parminio alluded, I've had my share of PO disappointments:

 

[Parminio]

This image takes me back.

Years ago in 1987, I was working at a NAPA machine shop. I did pretty much everything from the machine work to complete engine assembly.

So one day the shop foreman calls me up to his desk and I get there to find a fellow looking really pissed off. The foreman (Orin was his name) tells me, "This guy had his entire engine machined here and he says about 30 seconds after he fired it up it seized and is locked up solid. I need you to tear it all down and find out what happened."

So I get an engine hoist and get the engine out of the bed of the guys truck, mount it on a stand and roll it back to my work area. It was a Ford 427.

The teardown went pretty easy at first. Valve covers off, intake off, pull the heads, flip it over, flywheel off, oil pan off, pull the number 1 rod cap nuts off...

And that's where it all came to a screeching halt.

I turned my mallet upside down to knock the rod bolts with the wooden handle (which normally knocks the rod loose instantly), you pull the cap off, put two pieces of fuel line over the rod bolts so you don't scratch the cylinder walls, and you push the piston/connecting rod out the top which is now the bottom of the block.

But that wooden handle hit that bolt and THOCK!!! Nothing. It didn't budge a micron. I might as well have been knocking on the reinforced concrete floor the shop was built on.

I then go ahead to the next rod cap, pull those nuts off, take the mallet and THOCK!!!

Same thing.

So I go over to Brad, another machinist that was older and had far more experience than I did and tell him what's up. He gives it a go and has the same result. His response was, "Well...that's damn peculiar."

So we come to the conclusion that we'll try some heat. So he rolls over the acetylene torch and starts heating up the number one rod cap. We both start to smell something odd. It's not burning oil, but it's burning something.

Finally, Brad gives me the nod and I knock on the bolts hard and it pops just a hair loose. At that stage I stuck a chisel edge in the gap and pried it open.

You could see the blue RTV smoking, turning black, but still stretching out like so much chewing gum.

Apparently, that idiot coated his main and rob bearings in blue RTV. To this day I don't know why. If I had to guess, somebody told him it was molly lube, or was a necessity for some other stupid reason as a joke and he didn't know any better.

The next day when he came in to see the cause of his motor's demise, he was very calm. He didn't say a word at first. He walked off with Orin and they had a very calm conversation.

Orin came back over a few moments later and said, "Strip it, vat it, re-machine it and assemble it."

I often wonder if that guy ever touched another engine again. Seeing a picture like this makes me think that surely he did.

 

[Fire-medic]

Someone who knows 'a little,' but not-enough. That was an expensive mistake for him.

I had a Honda shop replace my Accord timing belt /water pump/seals, my wife suggested I let them do it instead of me doing it. We got it back, and after something like 500+ miles, the crankshaft pulley retaining bolt fell-off, as it wasn't torqued properly, This Accord has an 'interference' engine, and after three attempts by the dealership to fix it properly, it finally was warranteed with a OEM new cyl head, and I promptly sold it. It was a good car, a 5-speed, BBS wheels and in good shape, I'd bought it from the original owner, a co-worker. The tech was fired, I was told by the assistant shop manager, whom I had on speed dial while I went through months of trying to get things fixed.

After it happened the first time, I asked the ass't. manager to give me a decent trade-in evaluation and I'd look at a recent used, or possibly a new car. He refused, for some reason. I was surprised at that.

 

[Fire-medic]

Like Parminio alluded, I've had my share of PO disappointments:

View attachment 83782View attachment 83783

I wonder why the P.O. attacked the slave cyl with a cut-off disc? And a tube of RTV is probably a third the cost of a rebuild kit, why not fix the slave cyl properly?

 

[Radioguylogs]

The cut-off disc was used to roll back the odometer. Police were involved in that episode.

The RTV was used to "fix" or mask the leaking clutch pushrod seal behind the slave. On that V65, the seal is installed from behind. To fix it properly, the swingarm and output gear have to come off.

 

[Parminio]

The cut-off disc was used to roll back the odometer. Police were involved in that episode.

That's federal. They don't play around with that. I wonder what happened to him.

 

[Radioguylogs]

That's federal. They don't play around with that. I wonder what happened to him.

The police scared him so he wouldn't do it again, but they honestly couldn't prove who actually did it.

 

[DreamV4]

Apparently, that idiot coated his main and rob bearings in blue RTV. To this day I don't know why. If I had to guess, somebody told him it was molly lube, or was

I bought Grand Cherokee 4.7 with brand new crank(never started engine). Guy installed timing chain wrong and messed up valves. 4.7 engine needs special tool to install timing chain, it took me awhile to figure out how to install it w/o this tool.

 

[schenckster]

Well I finally found the problem. The fuel tank inlet is clogged/closed off. There was very little rust in the tank, only 1 spot with a 3 or 4 small dots of rust. I used compressed air to try and clear it but it didn't do anything. Got a guitar string and ran it into the main inlet and saw a small amount of debris lining the guitar string but not significant.

I also used compressed air through the fuel tank overflow inlet and found it takes about 15 seconds for the main inlet to let the pressure out. So it must be pretty bad.
It looks as through the bottom of the main inlet is sealed the the bottom of the tank, is that normal? It could be possible that the tank was resealed and it closed around the inlet but I'm not familiar with the sealing process and not sure if that's possible.