Well, I want to pick your brains. I've finally been able to get my '84 VF500C to run long enough for it to warm up, but shortly after the temperature gauge started to rise, the bike stalled out. I tried to restart it, but it sounded like the battery was dead. Sure enough, I place my battery tester on it and it read 11.5v. I charged it for roughly 30 mins., then tried to restart it. It initially wouldn't start, so I filled the carbs with a funnel. It then started, but would only run for a minute or so then stall. It sounded like it ran out of fuel. I would restart it, and the same results.
My question to you all is, where do I start to diagnose the problems I'm having. Is it possible that the problems I'm having are related? Thanks for your time.
How long has the bike been sitting or not ridden? You mentioned the temp gauge started to rise; it didn't over heat did it? My money says, if it didn't over heat on you, it just sit up too long and the entire fuel system will need cleaned. Try cleaning the tank, petcock and fuel lines to the carbs first; you may get lucky and not need to go into the carbs; it's a slim chance, but possible since it would run after filling the carbs with fuel..
Ditto what John said. When I first got my bike it had been worked on by a so called expert. The guy I bought it from had all the receipts showing the work he had done to it. The mechanic told him the carbs needed to be synched but he didn't have a synch tool. I bought one but couldn't get them to sync. It would start but the choke and idle were all over the place and it would stall just like yours.. Finally bit the bullet and pulled the carbs off after we narrowed it down to which cylinder was starving with a heat laser. Sure enough, found a plugged jet. Replaced that, cleaned the carbs again and it ran like a champ after synching it again. When I told the guy I bought it from what I found wrong he almost had a heart attack because he paid for shoddy work. Bottom line though is that it had sat for 5 years before this guy worked on it and the carbs were dirty and plugged. I would guess that's what you've got off the top of my head. These 4 cylinders can do funny things when the carbs is out of whack.
I'm not sure how long the bike has been sitting. It was last inspected in 2005 I think. The guy I bought the bike from didn't have much information about it. I have been able to run the bike back in March, but I would have this problem with it running for a minute and then stalling. Thats when I found that the fuel filter, and the secondary tank were filled with rust. I by passed the fuel filter for the time being, and replaced the secondary tank as it somehow sprung a leak all of a sudden.
The carbs were bought off of ebay, because the carbs that came with the bike were completely apart. There was no way I could figure out how they worked. When I received them, I cleaned them as best as I could. The secondary fuel tank was also purchased on ebay. I cleaned that one as best as I could, and cleaned all the fuel lines. There maybe a chance that there is some blockage in the lines, as I bypassed the fuel filter. I will tear into it this weekend and see what I can find.
If a specific carb had some kind of blockage, wouldn't the bike still run the other three cylinders? I had a KZ that had a carb with blockage, and the bike was still ridable.
As for the battery going dead, is it possible that the bike was running solely off the battery? Would that kill the battery and make the bike die after ten minutes of continuous running? Would wiring that isn't connected correctly (say the turn signals) make the bike not charge properly?
It's possible that the bike overheated, but I can't be for sure. The temperature gauge was just barely moving up after 10 minutes of running when the bike died, but them again the temperature in my barn was about 95 degrees with high humidity. What signs would the bike give me if it overheated?
I also noticed that when the bike was running, there was white smoke coming out of the exhaust. Could this have anything to do with my problem?
Thank you any help I can get.
White smoke is usually a sign of moisture in the system. A little bit for a short while is probably only condensation in the exhaust being vaporized as the bike warms up. However, if it smoked heavily the entire time it was running, that's probably not a good thing (unless you were burning off a heavy dose of some soft of gasoline additive like Seafoam). It could be that there's water in tank (or very old gas) or that you have a leaking head gasket and are burning off antifreeze.
I hope it's just condensation! My brother-in-law looked at the oil and didn't see milky colored oil. Figures crossed! We figured out the fuel pumping issue, and haven't had a problem with the battery dieing again, but did encounter a new problem. We ran the bike long enough for it to warm up, and I wanted to see if the cooling fan kicked on. The temperature started to rise, but did not get to the "high" area of the thermostat, when antifreeze started spewing out of a tube under the bike. I think I have a closed thermostat, but I'm not sure. I also wonder if the cooling fan works knowing that the antifreeze spewed out. Any clues? Thanks.
I'm not sure if this applies to your bike but on the 3rd gen, the thermoswitch simply provides a ground when it reaches the appropriate temperature. This makes it easy to test the fan itself (just pull the connector and run a line to the frame). Testing the thermoswitch is a bit more difficult.
Quote from: LIMagna on July 12, 2010, 11:21:47 AM
I'm not sure if this applies to your bike but on the 3rd gen, the thermoswitch simply provides a ground when it reaches the appropriate temperature. This makes it easy to test the fan itself (just pull the connector and run a line to the frame). Testing the thermoswitch is a bit more difficult.
I agree, grounding the connector from the fan switch should cause the fan to come on; if it does not come on, check for power at the fan. If you have power at the fan and it's not running, it's bad; no power at the fan and you will need to trace back until you find where you are losing power.
If the fan works as advertised I'd look at a possible bad radiator cap allowing pressure by at too low a PSI or the thermostat being stuck closed.
Thank you for the info. I will try the fan thing tonight.
I ran into yet another problem. I tried to put the bike into gear last night while it was running, and the bike lurch forward then stalled. I purged the hydrolics, but the clutch level didn't feel any different. It was very easy to pull. I'm just wondering where should I start to look. Thanks.
Flush and bleed the system first, if that doesn't get the clutch to working, you will need to rebuild the master cylinder and or the slave cylinder. I have had to lean the bike almost all the way over on its side and lightly tap on the bleed port area to get a good clutch bleed on the system; even while using a power bleeder.
Benny, if the clutch is still soft after bleeding you probably still have air in the system, try bleeding it at the master cylinder bolt. If that does not work you may have to rebuild the master and slave cylinders or the clutch plates may be stuck together and these will have to be cleaned.