[FalkenPunch]

I bought an 03 636 the other day. This morning, it fired right up, and I started it to test its ability to start cold. I let it run for a bit and adjusted the idle since the previous owner had it really low. After that I had stuff to do so I left.

I came back a few hours later to actually ride, but when it started, the idle was insanely high around 7k so I twisted the idle cable to lower it, and all of the sudden, it died. Now it won't start. It cranks, but it just won't fire/run.

I tried giving it a bit of gas to get it to start. Didn't work. Then I tried it at WOT and the bike did fire up, but it stayed a 1k rpm then died like 2 seconds later.

Any idea what it could be?

 

[Scorpi0]

Bad tip sensor? Also try starting it with the kickstand up and clutch pulled in at the same time.

U sure u didnt close ur idle screw too much?

 

[FalkenPunch]

I tried all of that. Clutch in, kickstand up and I get the same result. Cranks but doesn't start. And I also tried it with the idle screw all the way up as a last resort and nothing.

How do I check for a bad tip sensor?

 

[Flash636]

Assuming you are talking about the "vehicle-down sensor", and from the service manual we can get it's normal output voltage: "with the sensor tilted 60~70º or more: 3.7~4.4V. With the sensor arrow mark pointed up: 0.4~1.4V".
Sorry I can't help you on exactly how to perform that test though...
I would also try to pull the FI codes to try to find out some more information...

Edit: You can get the procedure to test that sensor on the service manual (page 3-93).

 

[EvilTwin]

If it was the vehicle down sensor the bike wouldn't start at all, even at WOT, and there would be a check engine light on your dash. I would screw the idle adjust most of the way back in, then use the "choke" lever on the handle bars and try it at different positions to try and start the bike that way.
Also, does it have plenty of gas in it? Any aftermarket electronics?

 

[zx racer]

Like Evil mention if it was the down sensor it wouldnt start at all. Try adjustin the idle knob clockwise till its idlin 1300rpm cold then let us no how it goes.

 

[VULGR]

? The battery. It might have enough charge to turn over but not enough to start it

 

[Scorpi0]

Like Evil mention if it was the down sensor it wouldnt start at all. Try adjustin the idle knob clockwise till its idlin 1300rpm cold then let us no how it goes.

The down sensor will let it crank but not start. It will sound like it wants to start tho.

 

[EvilTwin]

That's why I said "start" and not "crank"

 

[FalkenPunch]

Well the bike doesn't start at all. Same scenario, cranks but won't start. I tried it with the choke on and I tried various settings on the idle adjuster and nothing. The exhaust doesn't smell like raw fuel so I assume I'm getting spark.

Could it possibly be the battery?

and how do you take off those damned clips that are connecting the tank to the fuel pump?!?! They're so hard to take off, I can't get them

and quick question. Is it possible to flood the engine by putting the key in the on position repeatedly over time when I try to start it? because the fuel pump primes fuel every time you turn it on.

 

[FalkenPunch]

update: I charged the battery and the bike started again at WOT but it stayed at 1k rpm, and if I let the throttle off, the bike dies.

 

[EvilTwin]

When you key on the bike do you hear the secondary throttle plates moving? And is the FI light on on the dash?

 

[FalkenPunch]

I hear a bunch of stuff when I key on, but I don't think the secondary throttle plates are moving because when I took off the airbox, they were wide open.

and the FI light is not on.

Well I took off the tank to see if the secondary throttle plates moved. When I took off the airbox, they were wide open. When I key on, the plates close then open again so yes they move.

 

[Scorpi0]

Ok... Bad batteries have a tendency to cause the same symptoms u are experiencing on the 05/06 models. I would start with a new battery cause that seems to solve most of these no start issues.

The secondary butterflies....those are just there to supplement your primary butterflies. If they are full open that is not considered WOT. Your primary flies being fully open would actually be WOT. (Just an FYI....Your secondary butterflies will go to an almost full closed position after the bike is warmed up, then operate properly).

If the battery doesnt fix your issue, I have a feeling your idle adjustment screw isnt working properly. Try cracking the throttle open by hand a little bit and try to start the bike.

 

[EvilTwin]

Do me a favor and just ignore Scorpio for now.

If you haven't already done so, hook your battery up to a charger, and leave it connected through all this testing.
Does it have plenty of gas in it? Any aftermarket electronics?
Hook the tank back up, but leave the airbox off, and have the tank propped up (securely). Now do your starting method with the throttle wide open. Do you see all of the injectors squirting fuel?

 

[Scorpi0]

Do me a favor and just ignore Scorpio for now.

Dont make me go Rivers on u...

 

[EvilTwin]

Dont make me go Rivers on u...

:roll:

 

[FalkenPunch]

Yes theres enough gas and no aftermarket electronics. And I will try checking for the injectors squirting fuel when I figure out a way to prop up the tank. I had to reassemble the bike to make room in my garage.

I plan on changing the spark plugs soon. How do I test to see if the cylinders are getting spark?

 

[Rickthefix]

Use a spare plug, put it in the plug wire cap, make sure the base (threads) are touching metal. Push the starter button & watch. I have a spare plug that I attached a jumper wire to so it can hang down & connect the jumper to ground.

 

[FalkenPunch]

It started! It turns out it was the plugs. They were fouled.

Thanks for the help everyone!