1987 VFR700F2 Won't Start - Posible Spark Generator Issue

I got mine from a breakers yard for $5, not sure what you have over there

 

That might be an Australian only part and hard to aquire elsewhere.

It occurs to me I might be over thinking the situation. It should be very easy and cheap to install a basic pushbutton hidden on the bike with wires bypassing the safety relay. Just press the button with the ignition on to prime the carbs. I think that would be better than some have done of removing the safety relay and wiring the pump directly. That does work, but I don't feel good about it.

 

Jason these are new ones here, I'm sure you would have something over your side. Very simple to wire, one power supply,one earth,one to pump and one has a wire twisted around a plug wire or it can be wired to one of the coils
http://www.ebay.com.au/itm/Brand-Ne...340001?hash=item3d2f865da1:g:sgoAAOSwA3dYPK~7

 

There is something to be said about the factory design of giving weak voltage to the pump at idle and higher voltage to it at higher rpms. It might be better to keep the factory safety relay and just add a bypass button or TR7 relay to prime the carbs.

It's not really something we need, but it's nice to have.

 

I enjoyed your conversation. I had a Ducati 900SS where the fuel pump primed the carbs at startup. Once it reached the desired pressure, the fuel was diverted back to the tank. I think the pump ran all the time.

Anyway, before I try to rig up a fuel bottle I thought I'd let you know the results of JasonWW's first question about the amount of fuel in each bowl after the bike sat all night. To my surprise I think I might have set the float heights correctly. All 4 carbs have close to 50cc (probably between 40-45cc) of fuel in them. The first mark on the measuring cup was 50cc. Hopefully you can see that in the pics. Should I proceed with the fuel bottle or does this mean the carbs are getting enough fuel supplied to them, they are just not getting it to the jets?

 

It seems we have a pretty good mystery here.

So if you start the bike right now using the choke, will it crank up? Wil it only run a short time? Are you adjusting the choke less and less as it warms up to keep the idle about 2,000 to 1,500? After a couple minutes a can fully close the choke.

If I crank my bike cold, using the choke, and walk away for a few minutes it will get overly rich as it warms up and the engine dies.

I want to confirm your slowly reducing the choke as the bike warms up. I know it's common sense and I don't mean to sound insulting, but I just want to confirm this as I'm running out of ideas.

If you can run the engine enough to get it warmed up thoroughly, you can sync the carbs. That definetly improves the cranking and running of the engine and might solve your current problem.

One other thing to check. Grab a flashlight and small mirror and make sure all the rubber boots between the motor and carb are seated correctly. I once had a rubber boot lip fold over and make a vacuum leak. I couldn't see it because it was hidden.

 

Don't worry about insulting me, I get it. If I start the bike right now I will need to start it with full choke. I never take it off full choke as it only runs for 5 to 10 seconds. I've actually tried to drop it to half choke and it will die.

I think the syncing of the carbs is my next step. My motion pro manometer dried up so I had to order new fuild. It came in the mail today. So that's what I'm doing this weekend. Any chance you could describe to me where to attach the vacuume tubes on the carbs. The manual has a crazy picture.

I was thinking about the air fuel mixing valve (I call it the pilot jet). The manual said to set them at 2.5 out for California bikes and 2 turns out on non-California bikes. Mine is a California bike with the EPA crap removed. The way I understand it, screwing it in reduces the fuel and screwing it out increases the fuel. Is that Correct? We thought it might be rich in the video above, so I screwed it in 1/2 turn, making the bike more lean. Maybe I should try going the other way, screwing it out. Maybe my bike is too lean.

 

Have you tried adjusting the idle speed knob? When it first cranks up, is it running at 2000 rpm or so? If it's running much lower than that, try increasing the idle speed knob.

There are vacuum ports, but they have screws in them. You have to remove them and then you have 5mm threaded holes. You'll need some adapters to thread in. Motion Pro makes a kit or you can make your own.

Your correct on the pilot valves, they are needle and seat type. I assume you saw them when you were cleaning the carbs. Didn't you replace 2 of them? Anyway, you turn them in all the way in until you feel them gently stop, then turn them out however many turns you want. These effect the idle and steady cruising air fuel mixtures. California tends to set these leaner than the other 49 states, unless Cali uses a different needle valve or something. I would expect cali setting to be 1.5 turns out and the other 49 states 1.75 turns out. Something like that. I've found my 49 state bike to run best at 2 turns out. Generally going richer than the factory settings does help it crank more easily.

I'd talk to toe cutter about cali specific carb stuff, I'm sure he knows more than me about it. It's possible whoever removed the emissions stuff, might not have done a good job, so I'd inspect all the modifications. Maybe there is a vacuum leak making it too lean.

 

Sounds good. I've got the adapters. I now know what screws your talking about. I found this picture in another forum of where the vacuume line attach. Just at the base of the intake manifolds.



For kicks I might try backing the pilot screws out another 1/2 turn to see if it makes a difference. I did replace 3 of these valves. They had a spring, washer & o-ring on them. They are all 2 turns out right now.

I'll double check the intake manifolds and where the smog was removed. I looked at all the points when the bike was apart and they seemed to had done a good job of removing the smog stuff. But take another look.

 

Backing out the screws might help.

Here's a diagram that shows how the mixture screws work.

 

I read the following in another thread about removing the CA smog hardware. My 1987 VFR700F2 is the CA version with all the CA smog hardware removed. When I cleaned the carbs there were rubber plugs on the vacuume ports that I think lead to the charcoal filter, that has been removed on mine. I made sure these plugs were in good shape and replaced one that was split. The text below (see bullet #5) seems to indicate that with these ports plugged the carbs will not work correctly. Do you think that's the Problem?

"A lot of misinformation here. You cannot just yank the charcoal canister off. It has vacuum lines connected to it and each vacuum line does have a function. The workshop manual for each motorcycle shows the vacuum line diagram and many motorcycles have a vacuum hose routing diagram under the seat or some place on the motorcycle. The charcoal canister has vacuum hoses going to it that have fuel vapors going through them. If you park your motorcycle in your garage and too many fumes are going through it or one of the floats stick the fuel could come out onto the garage floor and the hot water heater or any open flame could ignite the fuel. Some garages have electric hot water heaters. 1. One of the vacuum lines from the fuel tank has fuel vapors and that goes to the charcoal filter. 2. One of the vacuum lines (second one) has fuel that tries to over flow the gas cap ( over filling of gas. or sloshing) and that goes to a fuel/air separator and then to the charcoal canister. 3. When you start your engine there is a PURGE hose from the charcoal canister that takes all of the unburnt fumes that accumulate in the filter and sends them back through the engine to be reburnt. 4. One opening on the charcoal canister DOES go to atmosphere. There are variations . 5. One of the vacuum lines going to the filter comes from the float bowls on carbed bikes. That is a very important system. If that hose has vacuum then you cannot just pull it off because you would have a vacuum leak. A serious vacuum leak and you cannot just plug it or the float bowls would not get any gas. That is why it is hooked to a vacuum switching valve that closes on start up. Some 49 state bikes have the float bowl vent go back into the intake and has a flap over it to keep intake from sucking all the gas out of the float bowls on acceleration. The charcoal canister weighs almost nothing. It robs NO power from your bike. It is usually hidden. IT helps the environment ,and prevents fumes from building up in your garage. It is not a problem.

You could remove the charcoal filter and fuel/air separator and an vacuum switching valves and figure out how to vent the float bowls without losing vacuum. but you will have gained nothing. You motorcycle would just be like any other 1950 year motorcycle . Vents lead to atmosphere and DO NOT GO THROUGH A CHARCOAL FILTER."

 

I have de-Californized 4 1986 VFRs now. It is certainly not as complicated as this makes it seem. Hoses that vent or drain are not "vacuum" lines. There is a shit load of brackets, hoses and a canister that I did not feel any remorse about removing. Simply making the VFRs just like all my other 49 state bikes.

 

Good to know Captain. I was just in the garage making sure each smog port was plug on each of the carbs. They were. And that the large tubes connecting the carbs were also plugged. They were. Now back to the issue. I thought I might have discovered the cause...thanks

 

Please clarify this statement. Huge potential issue.

 

Bad choice of words...I think the official Honda names for these tubes "air joint pipes". Carbs 2&4 are connected with one and carbs 1&3 are connected with one. There is a flexible line connecting both of these and the rear air joint pipe has a cap over the pipe where it used to connect to the smog tubing I assume. Yes, it is still plugged.

 

The "air joint pipes" are the vents for the float bowls. They pair up into a single hose and on the 49 state bikes, like mine, are open to the atmosphere. Maybe you should make sure it is NOT capped. Check out this picture, you can see the vent tube is simply turned downward. I think the guys familiar with cali bikes should get the final say, though. I understand EVAP systems in general, but not the exact setup on these model bikes.

 

Needs to be NOT plugged. Vents to atmosphere with a down turn so nothing can go in. If that is not THE problem, it is a BIG problem. I ran it on one of my race bikes to a small Uni pod filter.

 

AS stated above, the air joint pipes are vents and must not be plugged.

Have you tested that the vacuum slide diaphragms are installed properly ?? Have you put a thin .010" steel wire clear through the idle jets so you're certain they flow?? For testing purposes the fuel pump relay should be bypassed.

 

Captain, can you list the differences on the cali bikes?
I know they have their own fuel tank with unique vent.
Their own gas cap with no vent.
A charcoal canister to hold the fumes.
What are the other parts?

Are these the parts?


Holy cow, that's a lot. It seems they had an air injection system on the exhaust ports to fully burn the fuel as well.

 

Wow! All those parts have been removed from mine... It must be lighter...

Jason, Good catch! I'll remove that cap today and hopefully you have fixed the problem. The cap was there when I bought it but the bike did not run...

Squirrelman, Thanks for the advice... I didn't test the diaphragm but I did inspect them and they appeared to be like new. When I did have the bike running (with starting fluid), the pistons attached to the diaphragms all worked together in unison. I think they're Okay. I did run a very small wire through all the jets. I also blew air and brake cleaner through each one and visually confirmed that the jet was open. I blew air through all the passages in the body also. I've restored a number of GL1000s, CB750s, and SL350s but never a VFR700, but it's basically the same exercise.

Just to make sure I've uploaded two pictures of the carbs. Each carb has a vent that is capped (see light blue arrow), The air vent is currently capped (yellow arrow) but will be opened up, and one carb had an additional tube on it (red arrow) that is also capped. Are there supposed to be caps on these other ports (light blue & red arrows)?

I should have time today to sync the carbs. Maybe once the cap is removed it will actually start without starting fluid!