1987 VFR700F2 Won't Start - Posible Spark Generator Issue

I like the whilte paint idea! Good one. It will make the adjustment much easier to see. The drian line missing, is with the tank. It was easier to keep it attached. Personal preference.

I'll make sure I clean the choke circuit today.

The carb manifolds were missing 4 of the OEM clamps. He had pipe clamps on them. I ordered 4 replacement clamps last night. @ of the 4 pilot jets were broken (near the head) so you couldn't get a srew driver on it if you wanted to. I ordered 2 pilot jets from eBay. 1 of the choke valves was broken at the head also, so no choke one one cylinder. I ordered a used one off eBay. Crazy...

The bike was pretty clean. Not at all what I'm used to finding with 1970 vintage bikes. I did was it with S100 cleaner and Pig Spit! I love that suff. The exhaust was pretty much just what you see now. Now the fairings are a different story. The lower left fairing has serious road rash. One of the side covers is all broken up and the tabs are missing. The rear plastic is cracked but doesn't look bad. I think I can restore more all of it back to stock.

I should replace the radiator cap. Good idea. It's much easier to get to now. I made the mistake of changing the antifreeze too early, but I should be OK. The boses look and feel fine.

 

OK, I'm getting closer! I've cleaned the carburetors and all the jets, replace some of the pilot screws, replaced the gaskets and all the Philips head screws. I'm waiting on the last part which is the choke valve as one was broken. Is there anything else I should do while they are still off the bike? I thought about replacing the fuel hose going to the front and rear set of carbs, but decided not too as they didn't leak before. I decided using the ol "if it ain't broke, don't fix it" rule...

The pilot jets are 2.5 turns out which is the non-California setting. I used the 2.5 versus the 2 out for CA because all the SMOG crap has been removed and sealed off. Anything else to do?

 

I polished by needle and seat bodies to make sure they moved up and down smoothly. The inside bore of the brass seat sometimes gets gritty so I broke the end off a q-tip and put it in my drill, then used some rubbing compund and polished the bore. I did the same on the edges of the needle valve. This way the floats will be less likely to get stuck.

Did you pull the seats out and clean the tiny little filters?

Did you set the float heights?

Did you check the floats for holes?

Did you bench sync the carbs?

Did the jets look stock size?

Did the needle jets and jet needles look worn at all?

 

I answered your questions above...Thanks again for your help, and Merry Christmas.

 

I'm not sure, but you might have mixed up thd float needle with the jet needle. They sound very similar. The float needle and seat are composed of a stubby steel needle inside a stubby brass body that lets fuel into the float bowl. It's usually the brass seat that will get wear grooves in it from the floats going up and down all the time.

The jet needle is long and skinny and the needle jet is pressed into the carb body. These parts tend to wear since the vacuum diaphragm is moving them up and down. I had some pretty good wear on my jet needles as you can see from this thread.
http://vfrworld.com/forums/showthre...arb-Needle-Wear-Like-This-86VFR700?highlight=

Hopefully your wear is minimum. If it's excessive it can make that cylinder run a bit rich.

 

My Float valves and seats were fine. The little spring loaded extention on top of one was sticky but after cleaning it worked fine.

My jet needle was what I was referring to above. One of them was rough to the touch, but I think it will be fine. I've found a number of problems most of which were in the pilot jets. Some were way out of spec and others were missing parts. 2 of the heads were broken off completely so adjusting them was impossible.

I just got done re-syncing the carbs using the 1/8" piece of paper method I found in another thread. I've ordered one more choke valve to replace a broken one (head was broken off). Those are a pain to change with all the 4 carbs still together. Maybe I'm missing an easy way to do it...

 

Nope, it's pretty much impossible to change it with the carbs together. You might have to separate them. Just be super careful not to crack the brittle plastic pipes between the carbs. You'll need to do the bench sync again when done. Take lots of pics so you can put the springs back on the linkages correctly. Change the o-rings on the pipes as well.

BTW, the bench sync is just to get them close so the bike will crank and run. You'll probably need to do a more proper sync later. It's a pain, but it makes the bike run so much better.

Do you have any pics of the busted parts?

 

JasonWW,
I couldn't have done it without your help! Thank you! I was actually able to replace the choke valve with separating the carbs. I really didn't want to deal with those plastic fuel pipes. It was a pain but worth it. I now need to sync the carbs with my vacuum gauge.

Are the carbs slow to return to idle?

[video]https://youtu.be/Bc5kgbEt7ZQ[/video]

 

It does sound a little slow to return to idle. It may just be that you have your pilot screws turned out a little too far. If you get those a little too rich it will do that. You might try setting them to two turns out. I would wait until you're able to get the engine fully warmed up first. There's no point in trying to tune a cold engine.

The throttle response will also improve once you've got the carburetors synced up.

By far, the easiest way to adjust the pilot screws is to use a tool called a snake driver. It's so easy with this.
http://blogs.qvcuk.com/wp-content/uploads/2014/09/6a00e54eff270488340192aa1f3d1e970d-pi.jpg

 

Thanks Jason...Right now they're at 2.5 turns out. I'll try 2 out tomorrow after she warms up.

 

Just when you think it's safe to go back into the water!

OK... When I start the bike with starting fluid (I know I shouldn't do it) It idles and revs like it did in the video for as long as you want it to. I agree it sounds rich and that the carbs need to be synced, but I have bigger problems I think. When I start the bike without starting fluid, using the choke, it idles for about 5 to 10 seconds and dies. It also dies as soon as you touch the throttle. Does that sound like I'm back to needing a fuel pump? I remember someone saying during starting the fuel pump only pumps every 4 cycles or something like that. Maybe Toe Cutter's services are needed at this point... Thoughts?

 

If you suspect the fuel pump, just crank it and let it idle till it dies 10 seconds later and then check the float bowls. Attach a hose to the drain and open the drain screw. If all 4 carbs drain a healthy amount of fuel, then it's probably not a fuel pump issue.

If 1 or more carbs have only a little fuel in them, then that's what is causing it to die.

You can also check your float bowl fuel levels with the engine running by attaching clear tubing to one of the drains and opening the drain screw. You hold the tubing so it makes a tight 180°turn and you hold it next to the float bowl. The fuel level in the tube will exactly match the level in the float bowl.

Did you adjust the choke rods so they all open at the same time and then adjust the cable so it cycles all the way open and all the way closed? Maybe only 2 or 3 of the fuel enrichment circuits are flowing?

I'm not seeing a difference in the way the bike is started cold to cause it to either run or die. That's pretty strange.

When it dies after opening the throttle, that means it's not getting enough fuel.

When my bike is really cold I have to open the choke all the way and leave the throttle closed.

 

Thanks JasonWW. Good suggestions on the float levels. I'll check it out tomorrow. I didn't spend a lot of time on it but I did make sure all 4 choke valves closed all the way and all 4 opened as much as possible.

What I can't explain is why after starting it with starting fluid it will run until I turn it off and start fine, but let it sit over night and try starting it without starting fluid it dies. I agree it's got to be a lack of fuel problem. Do you know what controls the fuel pump to pump less fuel during starting? Also I don't think I've ever told you today fuel pump is not the original pump. It's a mitsubishi but the input and output put tubes are not bent... They're straight. If I do need a new pump, any replacement Suggestions? I read the relay that controls the pump goes bad more than the pump does.

 

I sure do! Just read my posts in this thread:
http://vfrworld.com/forums/showthread.php/29665-87-VFR-700-Fuel-Pump-not-pumping

The relay almost never goes bad because it's solid state, no moving parts.

Your pump is probably a generic one. A lot of bikes run these low pressure, plunger style, contacts on top, type of pump. No worries there. Some generics may be of questionable quality, but if yours is a mitsibishi, then it's good quality, just from a different model bike.

Have you checked the contacts in the top of the pump? They may be pretty worn and give you inconsistent output. Sometimes you can give them a good filing to clean the contacts and it will be back to normal.

 

I haven't been following this but what I would do is disconnect the fuel pump remove the tank and hang up a fuel bottle and just gravity feed it, this will tell you straight away if it is a fuel pump problem. If the starting problem remains with the fuel bottle then I would discount the pump as the problem. So much can be achieved using a fuel bottle, you can see what is going on under the tank. You can then also hook the fuel bottle up to the pump and see what that does

 

That's a good idea, but fuel bottles are quite expensive. I think they were $60-$70 which is why I never bought one. Have you seen any cheaper ones?

 

There's also a test that can be done to measure fuel flow from the pump. You just bypass the safety relay with a jumper wire and measure the amount of fuel it pumps in 10 seconds and compare it to the specs in the manual. I've seen videos on YouTube showing fuel pump tests. You can just tell if it good if it starts pumping a crap load of fuel, more than the carbs could ever use.

I've been looking into changing the fuel pump electronics on my bike to a style I've seen on other bikes. My brother had a suzuki 1400 intruder and it had a circuit that feed the pump constant power for a few seconds when you turn on the key. It basically primes the fuel system like a fuel injected car.

I think that would be great. It would mean better starts when the bike has been sitting for a month or more and the fuel in the float bowls as evaporated down to a low level. Or if you run the carbs dry by accident. Instead of cranking it a really long time, it would self prime. Just turn the key on and off a few times until you hear the pump stop. That would be sweet.

I think a pac tr7 relay can be programmed to bypass the safety relay giving the pump 12 volts for 2 or 3 seconds, then turning off. They cost about $15. I'm still doing research on it though.

 

Jason, all I have used for years is a 1 liter oil bottle, I put a valve in the bottom of it and a piece of fuel hose on it. I put a wire ring around the top of the bottle and hang it from the roof or whatever I can hook it over

 

Jason, I fitted a Carmtrol to mine, they are used here on cars converted to LPG, you turn the ignition on it provides power for a couple of seconds then switches off and once the motor is started it picks up a signal from a wire wrapped around a plug lead and then it supplies power to the pump constantly until the ignition is switched off or the motor stops running such as in a crash. Stops the pump from continuing to pump fuel everywhere if the bike is laying on its side, and we have all seen pics of those sort of incident

 

Hey, that sounds pretty good. The question then becomes price. Are these Carmtrols affordable?