big problem

the bike was running then after the rain wouldn't start so i was checking for spark put a aligator clip on the #1 spark Plug wire turn the engine over touching the wire to ground got shocked and the engine started so replaced the plug warm the bike rode for about three miles came home turned the engine off then wouldn't start any suggestion some said something about a capacitor ia there one around ?? or something

 

Faulty kill switch? or a ground out? maybe even in the ignition switch, what model would you happen to be talking about?

 

OK, first things first..."Not Starting" as in, the starter motor will not engage and spin the engine over when the starter button is depressed, or, "Not Starting" as in, the starter motor spins the engine over when the starter button is depressed but it won't fire up?

It is also helpful if you provide the model year of your VFR when you are asking for diagnostic assistance.

 

1986 vfr 750f, wont start as in wont run, it spins

 

hi, first thing to do : check fuse box
Maybe the rain penetrated in the fuse : what about the ignition (pump fuse ?).
Lamps, Carmine.

 

also. the kill switch may be the cause. It happened to me after parking the bike under the rain.
My bike is 1987 vfr 750 F.
Ciao.

 

OK, engine spins over, but will not start, let's go down the list and check a few things:

Connect a multi meter to the battery and confirm the actual condition of the charge on the battery, it should be around at least 12 volts with the key off.

Are the carburetors recieving a good supply of fuel?

Is/are the air filter(s) clean and dry?

Do you have a nice blue spark at each spark plug, while cranking the starter? I recommend checking this by removing and inspecting each spark plug, cleaning it, then grounding the plug and cranking the engine to visually confirm spark at each plug. I would towel dry any moisture or sitting water from the coils, coil leads, and associated wiring

In summary, the next diagnostic step is to check and verify that you have the necessary components required for ignition:

1. The battery is in good condition
2. That an adequate amount of clean, fresh fuel is reaching the carburetors
3. That dry, clean air is available (air filter(s) are clean, dry and correctly attached, with no intake tract air leaks)
4. You have clean plugs, each indicating a nice blue spark kernel when the engine is cranking.

 

what size is the plug 3/4 or 5/8 and how do I lift the seat

 

The spark plug size is metric 17mm I believe and is best removed using the spark plug wrench in the bikes tool kit. Who can help him with seat removal on a 750? IIRC the fuel tank needs to be removed or at least raised on one end to access the plugs???...

 

unlock the seat on rear letf side by means of the ignition key (usually it is so). Then pull the back of the seat just some inches to free the seat from the little "wings" mounted on left and right side of the tank. That's all. Move the seat carefully to avoid breaking the "wings" along the tank.
Good luck!

 

to access front pugs u need to remove 2 lower radiator mount bolts and swing rad forward.
be careful not to bend fragile rad fins.

 

You can get to the rear plugs by removing the side panels and you'll need a thin wall 18mm socket and a short extension 1" works well. WD40 will help dry out your electronics.
good luck

 

There is a lot of good advise said. Pretty much spot on too. Lets us know how it goes.

 

haven't had time to look at the bike probaly on my off days thanks all for your help got the seat up

 

After reading this, I had to go out to the garage to see if the VFR plugs were a different size than the plugs for my CB. They're the same size, 18mm, not 17.

 

After running in the rain, my guess is an ignition problem. Do all the ignition checks as described in this thread.

If you want a quick way to make sure it is not a fuel problem, go to the auto parts srore and buy an aerosol can of starting fluid. Spray this into the air intake while you try cranking the engine. If the engine runs only while you are spraying the starting fluid and dies when you stop spraying, you have a fuel problem.

Be very careful with starting fluid it is highly combustable!

 

Oops, my bad. They are 18mm............

 

now that he knows how to remove the seat,
success will follow.......right?

 

found out what it is, the main fuse plug is burned and theres a short. first I put the newly recharged battery in the bike the bike started went up and down the street a couple of times came in turned the bike off using the run switch and didn't start back so I was looking around and removed the main fuse plug and seen the burn so moved it around a little poked a screw driver to clear things up so wham o its started but once you get things going and turn it off with the switch you have to fool around with the main fuse plug to get things running so I'll start by replacing the plug and go from there

 

Take a good look at the Regulator/ Rectifier (R/R) and have it checked.

This is how the problems started on my son's '95 CBR900RR. When it was all said and done we had to replace Starter Solenoid, R/R/ and a new battery. The main fuse on the 900 is part of the Starter/solenoid. The first indication was melting of the fuse holder. I never could figure out why the fuse didn't blow.

After we replaced the starter/solenoid the bike ran great for about two weeks. Then the fuse blew and the connector to the stator melted and the battery got fried. Just putting a battery charger on the bike made the R/R get hot. After replacing Battery, R/R and the connector, the bike runs great.

I'm pretty sure it was the R/R that caused all these problems from the very start.