need a little mechanical help with my new 87

New owner of an 87 VFR700 w/23000 miles. It was running and in daily use about 2 years ago. It then sat for about a year outside and neglected. I recovered it and have been slowly piecing it back together. I've drained all the fuel and removed and cleaned the carbs and replaced the fuel filter and plugs. It came with a trashed ignition switch, which I have replaced also. This morning I tried to fire it up and have a few questions. It isn't getting fire to the plug and it isn't getting juice to the fuel pump. The ignition switch appears to work fine, the dash lights come on like they should and the starter turns over fine. But no spark. I jumped the fuel pump to get fuel to the carbs but still no fire. Is there a switch somewhere that I am missing, that tells it not to start? I found the switch on the fuel tank and I guess it will shut everything off if it is tipped over. I jumped those wires together and still nothing. Should the fuel pump come on as soon as the key is turned on? Should I be able to see the plug spark if I ground it? Yes, the kill switch is on! it is in neutral and I tried with the clutch pulled in...still nothing. Has plenty of oil. Thanks for any help.

 

Kill switch in the RUN position?

The Kill switch prevents juice going to the spark boxes - which trigger the relay for the fuel pump and also trigger the coils for the sparkplugs. It does not prevent the starter from engaging.

Open up the right control pod and clean the contacts. Be CAREFUL, small springs in there.

 

Kill switch is on but I will take apart and clean.
Should the fuel pump come on as soon as the key is turned to on?
What are the two wires that get hooked up to the gas tank?
I see that the red gas light on the gauges goes off after a few seconds even if the gas tank is removed. The oil light does not go off. Does it need oil pressure to make it go off?
I don't see any switch on the kickstand.
I gotta be missing something simple....I'll find it! With all y'all's help of coarse!

 

87 vfr700 mechanical help

New owner of an 87 VFR700 w/23000 miles. It was running and in daily use about 2 years ago. It then sat for about a year outside and neglected. I recovered it and have been slowly piecing it back together. I've drained all the fuel and removed and cleaned the carbs and replaced the fuel filter and plugs. It came with a trashed ignition switch, which I have replaced also. This morning I tried to fire it up and have a few questions. It isn't getting fire to the plug and it isn't getting juice to the fuel pump. The ignition switch appears to work fine, the dash lights come on like they should and the starter turns over fine. But no spark. I jumped the fuel pump to get fuel to the carbs but still no fire. Is there a switch somewhere that I am missing, that tells it not to start? I found the switch on the fuel tank and I guess it will shut everything off if it is tipped over. I jumped those wires together and still nothing. Should the fuel pump come on as soon as the key is turned on? Should I be able to see the plug spark if I ground it? Yes, the kill switch is on! it is in neutral and I tried with the clutch pulled in...still nothing. Has plenty of oil. The red gas light on the guage pod goes out after a few seconds. Does the tank being unplugged stop it from starting? Does there have to be a certain amount of gas in the tank to actuate the switch? Thanks for any help.

 

do you have a manual?
www.evfr.net/uploads/VFR750F_Manual.pdf

Take a look at the wiring diagrams. Check all fuses and connections. Get a good multimeter and make sure there is power where it should be.

 

NO. It only runs when the kill switch is on and the start button is pressed or the engine is running

I believe they are the fuel gauge wires

Yes. Oil light should go off when you start the bike. Other red light is probably tail light warning.

Too old to have one.

 

Thanks for the help. I have a few more questions and concerns.
I was never able to see or feel any spark from the one plug that I tried. It was an old plug, but I thought it still should fire enough for me to see or feel?? I will try a new plug to see what happens.

I was never able to get a test light to light up when checking for juice going to the fuel pump, with the switches on and starter button pushed. Is there less than 12v going to it?
Do the 2wires coming from the tank tell the fuel pump not to run under certain conditions?

So, after I fooled with the plugs and jumped the fuel pump to get fuel to the carbs, tried to get it running and nothing! I then removed the tank and let it sit for a couple hours, hit the starter button just for the heck of it, and it fired right up? It idled for about 30 seconds and then quit. Since the tank is removed, it only had so much fuel....I forgot to check to see if the fuel pump was running. But I feel better that it has some life in it somewhere, even though I haven't figured it out completely. Between you guys and all the manuals, I will eventually win......

 

Fuel pump should run when the key is on, with kill switch set to run, fuel pump should be running. It did on my 86 vfr700f2, stiil does on my 06. check the manuals to be sure.did you check fuel flow from tank while it was off. open petcock fuel should flow out hose ,gravity feed.check fuel lines, filter
wires on the tank are for the reserve fuel light a red light on the dash says fuel, I believe

 

fuel pump cutout relay

Pump gets excited when the cut out relay is tickled by the ignition pulsation that signals the tach. If you have a wiring diagram carefully note that the power to the pump is routed through a relay that has three wires going to it. The black wire is power into the relay from the ignition. The black with blue stripe wire ( or the reverse) is the power out of the relay to the pump. The control is a yellow with green stripe wire which you can trace back to the ICM ( ignitiion control module) this wire controls the flow of current through the relay to the pump. When the motor ain't rolling the pump ain't flowing. It a safety feature to stop fuel from pumping if the bike goes down and you are out. When you start the bike there is a residual thump as the relay figures out that there is no signal coming from the tach signal (yellow with green stripe). The Pump cut out relay is electronic rather than mechanical. Its a power transistor. If the tach is giving you a reading then the Pump cut out is getting a signal.

The problem is that you have to get the bike to start and run to test the tach signal. But you aren't going to get the the bike to run unless the cut out relay is OK. Catch 22.

Check the pump for condition first. This is done by jumping over the relay.
To do this remove the 3 wire connector to the relay and place a wire jumper across the connector. Make sure the ignition is off and that no gas is going to spray when you make this test. Test black wire coming in to connector for battery power when ignition is switched on. Turn ignition off if power comes to black wire. Jump black wire to black and blue wire that goes to pump. Turn on ignition. you should hear a thump as the pump stops when pressure builds up. To check flow or volume get a receptacle to catch gas. Ignition off, remove fuel line to carbs from pump. Place open end of fuel line in receptacle and turn on ignition. Fuel should flow. Spec is 700 ml per minute. let it run for 10 sec and multiply amount by 6 to get flow rate.

If pump works and everything else works then assume its a bad cut off relay and purchase a good used or new one and try swapping parts. If the new one works you know that you successfully covered all the bases. If not you own an extra cut off relay.

 

Thanks again for all the info. I can now start it and it will run.....barely. It will only start and run with the choke all the way on. If I try to rev it up too fast, it will stall. I can rev it up slowly with the choke on but it is slow to make the RPM's. If I tach it up a little with the choke on, then turn off the choke, it will run O.K. as long as the rpm's are up. As soon as the rpm's drop, it stalls. Seems like it is starving for fuel. I replaced the fuel filter and have taken all the carbs apart and cleaned them. Could the fuel pump be weak? or on its way out? I will check for the 700 ml/min. Or could it be a spark problem and it isn't running on all 4 cylinders? I removed the two rear plug wires, one at a time, to verify that they are getting spark....and they definitely are. Tomorrow I will do the same to the front two.

 

I used to have to start my 86 with the choke on full. I let it run till it was warmed up and then I could turn off the choke and it would idle fine. if you cleaned the carbs what did you replace? and have you synced the carbs since ?. they need to be synced to balance the flow to the cylinders.

 

one thing at a time

You obviously have the confidence to tear the carbs apart and put them back on without a helping hand. So you must have confidence to struggle with the electrical part of the problem. Once you have established that the pump can deliver if its getting power you need to focus on one thing at a time. You say it does not want to run but that it gets spark and that its getting fuel. Get a manual. You need it to check out the ignition components. You need to get the specs on the ignition components and test them with an ohmmeter. There are three inductive coils in the motor to time the ignition system. They all have to be working correctly for the ignition to operate properly. There are 4 HT coils and they have to operate properly as well. All the connectors have to be tight and there has to be good continuity through the entire wiring harness for the bike to operate properly. If the bike actually runs for more that a minute thats a good sign. It means that the ICU is working and you should also see the tach working. An operating tach means that the timing coils are working and that you are getting a signal at the shutoff relay. Get the manual and concentrate on making sure that all the wiring and components of the ignition are in good shape and properly connected. If the Bike still runs rough after you have throughly gone through the ignition, and the pump circuit, figure you have an issue with the fuel delivery system. Switch over to the Fuel issues. You should get the manual for that as well. Eliminate the ignition problems and then go on to the fuel and carb problems. You need to get a manual and a decent VOM. Eventually you will need some tools for checking float levels and vacuum pressures when you start dialing in the carbs. But, unless the carbs are totally blocked up, once you get the ignition straightend out the bike should run and possibly idle. But do one thing at a time and make sure you know that its right before you run down the next alley.

 

Thanks again guys!
I did not replace anything in the carbs, just carefully took apart, cleaned, set the floats per the manual and put back together. I didn't touch any of the adjustments that linked the carbs together. I figured when I get it running right, I'll get them synched to fine tune it.
I don't remember any other adjustments on them, but if I removed anything that was adjustable, I counted the turns to tight, removed, cleaned and then replaced it back where it was.
The bike will run and idle for as long as it wants, as long as the choke is on.
I have a couple manuals and an ohmmeter and will start trouble shooting the ignition system next.
Would the valves needing adjusted create this condition?
The previous owner says it was doing this same thing when he decided to leave it sit.

 

The way the choke on this bike works is it allows more fuel to flow into each carb therefore richening the mixture. sounds like at idle the mixture is too lean for it to run. what could cause this? 1. Too much air. where is this air coming from? 2. Not enough fuel. why isn't fuel getting in to carb. Since it runs. Does it run smoothly? I don't think it's an ignition problem. How does it act on throttle up throughout RPM range? Just my opinion. trying to help.

 

It idles smooth and at a decent RPM(with choke on full), can't remember exact RPM.
It throttles up slowly and you have to wiggle the throttle as it revs up. If you just twist it hard, it dies. Once the RPM's are up, it seems to be O.K.
And while the rpm's are up I can turn off the choke and it will continue to run OK as long as I keep the rpm's up over 5000 or so.
The air box and filter have been cleaned. The filter is not new but seemed to be in good shape, so I just blew all the dirt out of it. Could it still be restricting too much air. I guess that could mess up the mixture too.

More information just in from previous owner:
Bike ran fine. Clutch reservoir started leaking. Let sit outside for a couple months. Fixed clutch reservoir. Had to push start because battery was dead from sitting. From that time on, it has had this condition. Did he disturb something else while doing the clutch? Did him push starting it do something? He did say that he had to really really rev it up to keep it running while trying to get it started and keep it running. Did this overrevving damage something internally to create this condition? Valves, compression...I have not checked compression yet. He also said that he always had to ride with the choke on a little bit so it didn't stall, but it ran fine otherwise.

 

You are doing great!

You might not believe it but you are doing great. My point is that you shouldn't leap into the xxxx without a plan. If you go every which way at once you won't know where you came from when you get there. And then the next time you'll be back to square one again. Danimal smell's carburation problems, and I tend to agree with him. But don't shoot first and draw your gun later. You had a great idea in checking the compression. Make sure that you have all the plugs out, the battery fully charged, starting system in good order, and use a compression tester with a threaded plug hole adaptor with an o-ring seal on a flexible hose type compression tester. They sell a compression tester with three different size spark plug hole adapters at a place called Harbor Freight around where I live. Its about $30 and worth the expense if you keep a hold of your tools. The same sort of tool was over $100 at my local Honda dealer if I special ordered it. Do the compression test both warm and cold. Do the teaspoon of oil trick if you want, or if you have a low cylinder. Do the test more than once to make sure its repeatable.

Once you know the compression you will have a better idea of how good or bad the condition of the engine is and what expectations you have for a smooth running machine. If the compression is low or bad don's throw in the towel. You had a another question about valve adjustment. If the vcalve adjustment is off it will affect the flow of fuel/air mix into the cylinders. So after you do the initial compression test adjust the valves. If they were tight it means that you might have had a valve hanging open too long. If they were too loose that you were not getting enough mix in to fully charge the cylinder before ignition. Both conditions will upset air flow through the carbs. So you want to adjust the valves before rebuilding and adjusting the carbs. While you have the cam covers off its a good idea to retorque the heads as well. You might as well use the fact that you had to buy cover gaskets for that as well as the valve adjustment.

So now you have knowledge that the engine is in good repair or not. If the compression doesn't come up to snuff after the valve adjustment you can make a judgement about spending more time/money on the cycle. If you did have low compression before valve adjustment and it changes for the better after valve adjustment you have some hope that at least part of the running problem you have had may have been solved. Each little thing you fix will be another step to getting the bike back in form.

Now you know that the ignition is correct. The bike will idle and you can use your timing light to check the timing marks dynamically to make sure the plugs are firing at the correct moment. You've checked and adjusted the valves and you know they are correct. You know the compression is normal. What else can be wrong but the carburation. So now Danimals questions come into play. Are you getting too much air in the mix? Vacuum leak between the carb and the head? Are you getting too little fuel? You already measured fuel flow volume, so you know the answer is no (or you know its yes and you' re about to fix that). Then its time to remove carbs and get to cleaning them up and putting them back together with new gaskets etc.

When you have the carbs back together and new intake manifold seals in place you are going to be putting the intake side of the bike back on as near perfect an engine as you are ever going to have baring a complete rebuild. Now you can spend $100 bucks on a fancy sycronizing tool and get some value out of it right away. Good luck. I don't doubt that you can do it. YOu have the manuals and you have some help. Go to it.

 

Me again! I am still thinking about all this and trying to make sense out of the symptoms.
If it were a lack of fuel problem, why does it run OK at higher RPM's? Seems to me if it was lacking fuel at idle it would be lacking fuel at the higher rpm's when it needs even more fuel. Is the bad air/fuel mixture not as noticable at higher rpm's, or does something else take over at higher rpm's? I recall some motors having carbs with an idle jet and a high speed jet. Do these carbs use different jets to idle?
Does it get spark from a different source when at higher rpm's?
How about timing? I recall when working on older cars, when the timing isn't right it will cause this non-idle condition but OK at higher rpm's.
Sorry for all the questions, but I will not be able to read the manuals or work on it again for a while and I want to have as much info as I can.
Later, Doug

 

You need to read this article. It describes how carbs work.

Motorcycle Jet Kits & Carburetion Basics - Tech - Motorcycle Cruiser

 

Thanks, great article. Of coarse now I am even more confused. It says that a rich condition will cause black plugs, which I did have. Which means If I remove the air box lid, it should run better?
But.... I am creating this rich condition by having to run it with the choke on. The reason I have to run it with the choke on, which adds fuel to it, is because it is lean from getting too much air???
Therefore, I should be looking for an air leak around the carbs...like danimal said a long time ago!
Or the jetting is off. How does the jetting change from factory? This bike has run fine in its life previously, so why would the jets need to be changed now? Maybe one of the PO's changed them?
When I read the carb. article it leads me to believe that the main jets need to be bigger.
I should find a cracked carb boot if I look close enough, right?
Or, find that someone has changed the jets from stock due to having an aftermarket exhaust and/or air box?
Or, it really isn't a carb problem....I will find out and have fun doing it. By the way, this is my 10 year old son's project bike for him to learn some mechanical and painting skills on, so thanks for the help.

 

I believe this is your problem.

The first part of the carb that gets clogged are the very fine idle and off idle passageways. It's almost impossible to get them 100% clean without separating, dunking, and blowing compressed air through them.

The normal fuel passageways cannot move enough fuel through them so you use the choke. The choke is actually an enrichening device that adds fuel. You are intentional making the fuel mixture overly rich - hence the black plugs.

It could possibly be an air leak around one of the carb boots. While it's running, spray WD-40 around the boots one at a time. If the idle changes, you've got an air leak.

The jetting could be off. But that would not affect idle. There's really no way to tell unless you are sure that everything else is fine. But you said once you turn the throttle, it is running fine which (according to the article) means that you are running on the slow then the main jets. So I would say they are "OK".

So if the slow jet and the main jet are OK, what's left? The pilot jet, the idle fuel passageways, or a carb boot leak.

If you don't want to dig into the carbs, you can run a can of Seafoam or Techron through the tank and see if that clears up the idle issues. It can't hurt.

If it's not the carb boot, and the Seafoam/Techron doesnt work, it looks like a full carb teardown is in order.