Need Help- New owner of a non starting 85 VF700 Interceptor

Hello everyone! I have just acquired a 1st gen VF700 Interceptor so I joined up to see if I can get some help and hopefully get this thing up and running and be a part of VFRWorld for years to come.

I picked this bike up from a guy across town for $300, so I figured why the hell not. He bought it from the original owner, 16k miles, still has the manual in the pouch and the original tool kit. Overall, the bike is actually in great shape. This guy is 5'1", 90 lbs and just couldn't handle the bike, so he bought a little Rebel 250 instead. He laid it down lightlyin his parking lot and after that, it wouldn't turn over anymore, and he hadn't the faintest clue about bikes. Or so he claimed.

Basically, the bike turns and turns but won't fire up. I pulled the plugs, the front 2 were pretty black and the back 2 were brown, so I replaced them. With the tank off, it doesn't seem like there's gas getting into the carbs when I crank the throttle. It's got plenty of battery power and a little THUMP THUMP in the exhaust when it's trying to turn over but just won't. I drizzled some gas into the carbs but still won't turn over.

I am pretty good at bolt on mechanics and following instruction, just not so great at diagnosis. If anyone has any input I would greatly appreciate it. I know there are mixed emotions about the 1st gens, but for $300, if I can get this thing going, I'd love to tool around on it for a good while.

 

first off welcome to the forum. what area are you located in?

have you checked to see if there is spark? tried a little shot of starting fluid to see if it "hits"?

if it just stopped from being dropped I would go out on a limb and say it's electrical.

also a carb cleaning should also be high on the list, order new carb boots before you start and if you've never done a v4 carb set before your in for a real, ummm treat when you take them off and more so when you put them back on. real PIA.

also if you don't have one, get a honda shop manual.

 

Ok so its getting spark just fine, battery is fully charged and staying charged. Carbs definitely not getting gas so I'm picking up some starting fluid/carb cleaner today since drizzling gas in isn't doing the trick. Is there a link to dropping it and the carbs not getting gas? Do these bikes have some sort of fuel cutoff?

 

Picked up some starting fluid today. Nothing. Drizzled more gas in. Nothing. I'm not seeing any gas entering the carbs when I yank the throttle but shouldn't spraying the fluid or drizzling the gas in at least get her to fire if it has plenty of battery power and spark? What am I missing?

 

the starting fluid alone should make it sputter if nothing else. You don't need any gas anywhere if your using "liquid courage" to see if it'll start. you say it's getting spark, is it a good strong blue spark or a light weight puny orange spark. when the pressure rises in the combustion chamber the air/fuel charge becomes very dense and increases the resistance between the electrode and strap on the spark plug. I built a drag engine once that had this problem, could not figure out why it wouldn't start went through it twice before I found out about this and put an MSD box on it, bumped the starter and it came to life (12.8:1cr sb chevy). a little after that I ran into week coils on a bike that did the same thing, would fire out of the engine but under compression nothing. the same sb knocked me against the wall once from bleed off through brand new 8.8mm wires. out of the engine you could put the plug wire in your mouth if you wanted to and never get shocked, put em in the engine and the internal resistance was high enough to make the power look for an easier path which was though a very well insulated set of wires. to give you an idea of that, the industrial machines I use to work on only had about 1mm of plastic insulation between you and the wire with 440 volts with an 80 amp load and still never attempted to penetrate the insulation. check the wires first to make sure they are "holding" the spark. I'd strip the bike and in total darkness turn the engine over and look for arcing. if there is your "spark" is going to the wrong place. make sure you have the correct plugs, not just ones that fit the hole, different plugs have different resistance. After that I would check the coils (per the manual) to make sure they are not weak and finally the pick up inside the right cover. that roughly covers the spark side of combustion now for fuel, that's where the starting fluid comes in, of course your going to get the oxygen needed taken into the engine with it. then there is timing, which really shouldn't be an issue and compression which could be a huge number of things.

 

Strong blue spark, battery fully charged, can of starting fluid.... no go. no idea.

 

check your ignition boxes, the connections are in the tail section just in front of the tail light. They will corrode. May need cleaning. Is the kill switch off? How about the right hand switch assembly that has the kill switch in it? Broken wires? Bad switch?

In order to spray anything in the carbs twisting the throttle does nothing for you. Because the slides are down. They raise by vacuum only or a finger. Even though starter fluid any where near the carbs should start it. I'm assuming the motor has compression, right?

 

blue spark- kill switch, corrosion most likely aren't the problem or a strong blue spark wouldn't happen. twisting the throttle does actually do some thing, the slides don't completely close an have nothing to do with the first 1/8-1/4 throttle. I agree, compression test is in order. I also agree to hunt a local gear head down. starting to sound like a major problem, even with low compression and spark the starting fluid should get some kind of response out of it.

 

I'll pick up a compression tool tomorrow. Anyone know what the readings should be?

 

the HSM I have says 184 +/- 28

 

check all your fuses as well... which way did he drop it left or right? I would double check the kill switch make sure that it is connected ..un plug it and replug it make sure its getting a good solid connection.... have you tried to check the spark plugs while they are out? you know pull the plug ground it to the frame and fire the bike off? sorry if this seems redundant...but rechecking everthingwith 16K on it I would doubt that your compression is bad.... but hey, if tink says so ..... lets see anything else? good luck

 

I put new plugs in, they are all getting nice blue spark. If the kill switch or ignition or a fuse were an issue, wouldn't it not even try to start? It's a nice, strong try and will go and go just not turn over. I'm no guru but I know the basics and it just doesn't make sense. I've got the full power, good spark, and the starting fluid. Is there a possibilty that the starting fluid isn't getting where it needs to go due to something closed up in the carbs?

 

I agree with all the above but would also pull valve covers and see if timing chain is on.
my son took a spill on a xt 225 a few min later it stopped running do to timing chain falling off.
it also had good spark.

 

The timing chain is right under the valve cover?? Thats interesting. That will be my next task.Are they easy to get off?

 

Those would be the cam chains under the valve covers. I hope to god one of THOSE didn't fall off.

 

If it is getting spark and not firing then it is not getting fuel or air. If I were you I would make double sure that it is getting fuel. If it sat for a long time the jets might be clogged. Check to make sure your choke is working properly

The likelyhood of the timing chain actually being off the cam gears is about 1%. The way it is designed the gear itself would pretty much have to break for it to come off. I've high sided the shit out of a VF500 and then drove it home so most likely just dropping it wont mess it up enough to keep it from running.

Start with the simple stuff first. I would exhaust all fuel and air options before getting into the timing