Bike cuts off

[jjbing3]

Ok, some of yall might remember me, others not. Anyway, my brother has a 2000 Kawasaki Ninja 500. It sat up for a while but he took it to the mechanic and got everything serviced. He says that now, every time that he comes to a stop (ex: at a light at the intersection) the bike just cuts off. He says that he can start it right back up and go but that it will not stay on if he doesnt rev the engine. Anyone have any idea what the problem is or even better how to fix it. I'm pullin my hair out. :pullhair:

[Lazarus]

So he recently got it serviced and now hes trying to ride it but its cutting off? What exactly did the mechanic do? Does it shut off if he starts it up and lets it idle?

[patri0t]

I had that happen to my bike once when i went in to get the cam chain tensioner adjusted... the mechanic overtightened it and the bike would start to choke itself out unless i kept the RPMs up when coming to a stop. the fix was to get a new cam chain tensioner. it cost me around $200 installed if i remember correctly.

I had the cam chain tensioner adjusted due to the "Kawi clack" that is predominate on my model bike ('04 ZX6R). Basically you hear a loud clacking sound from the engine area. The mechanic told me about it, I did some research and found that it is a common issue (although not something that would damage the engine). Maybe his mechanic noticed something similar and tried to adjust it???

[Over TWO Customs]

The EX500 is closer to the EX250 if I remember correctly... havent seen a 500 in a while, probably 4 years. Could be a valve clearance issue as well. I would have to ride it to get a jist for it.

[jjbing3]

So he recently got it serviced and now hes trying to ride it but its cutting off? What exactly did the mechanic do? Does it shut off if he starts it up and lets it idle?

Yes, it cuts off when he comes to a complete stop. No it doesnt shut off when he starts it up because he gives it a little gas. I dont know what the mechanic did. I'd have to ask.

[NiceGuysFinishLast]

Could be anything from tight exhaust valves (Same scenario on my gs500) to idle set too low. Need more information. Does it happen with bike in neutral? Does the bike idle ok when it's not moving?

[wallypiper]

Accom's razor guys.
This is probably a carburetor problem.
Remember - fuel, air, spark. Most likely, one of them is missing.

[jjbing3]

Could be anything from tight exhaust valves (Same scenario on my gs500) to idle set too low. Need more information. Does it happen with bike in neutral? Does the bike idle ok when it's not moving?

I thought that the idle may be set too low too but I dont know how to adjust it. If thats the easiest thing to try first, I'll tell him to try that and then if not we can move on to the second diagnoses. He said that it does cut off in neutral, btw.

[SlowMotion]

To adjust the idle there should be a little twist knob on the left side below the fuel switch (if I remember correctly). It has been 3 years since I had my 500. Check the manual to get the correct idle speed. It should be around 1200 rpm's.

[MX Tuner]

Sounds like he needs a new mechanic.

[jjbing3]

Sounds like he needs a new mechanic.

Maybe so. I expressed that sentiment as well.

[jjbing3]

To adjust the idle there should be a little twist knob on the left side below the fuel switch (if I remember correctly). It has been 3 years since I had my 500. Check the manual to get the correct idle speed. It should be around 1200 rpm's.

He said he went underneath and changed the fuel switch. He said he thinks it was on either "off" or "reserved." He says it hasnt been doing it as of late so hopefully that fixed it. Thanks.

[NiceGuysFinishLast]

Neither of those should have affected his bike. Reserve is simply a lower tube for fuel pickup in the tank. If it was off, the bike wouldn't have run at all. So he's still got whatever his problem was.

[jjbing3]

Neither of those should have affected his bike. Reserve is simply a lower tube for fuel pickup in the tank. If it was off, the bike wouldn't have run at all. So he's still got whatever his problem was.

Ok, damn.

[NiceGuysFinishLast]

Ooh.. just a had a thought. If he messed with his fuel petcock... It could, theoretically, have been on PRI, which is Prime. Instead of using vacuum to pull fuel into the carbs when necessary, it uses gravity to feed gas into the carbs. Theoretically, he might have been flooding the bike at idle if he was on PRI AND his floats are sticking, allowing fuel to run non-stop. Just a thought, but that's the only thing I can think of that would involve the petcock and the bike dying at idle. I'm not a mechanic, though I work on my own bikes/cars.

[jjbing3]

Ooh.. just a had a thought. If he messed with his fuel petcock... It could, theoretically, have been on PRI, which is Prime. Instead of using vacuum to pull fuel into the carbs when necessary, it uses gravity to feed gas into the carbs. Theoretically, he might have been flooding the bike at idle if he was on PRI AND his floats are sticking, allowing fuel to run non-stop. Just a thought, but that's the only thing I can think of that would involve the petcock and the bike dying at idle. I'm not a mechanic, though I work on my own bikes/cars.

he said that he turned a switch but he doesnt know which one. He may have turned it from prime. He said it hasnt been a problem anymore since he turned a switch.

[smokintalon]

sounds possible that he could have had a piece of trash clogging the petcock, or it was on prime.. wouldn't know without looking. And something like that can be a number of problems from the fuel line being clogged, petcock clogged, one or more idle jets clogged on carbs, valves too tight, timing chain too loose or tight. If he has anymore problems, let me know. I live in Grayson and would be glad to take a look at it for him.

-Chris

[jjbing3]

sounds possible that he could have had a piece of trash clogging the petcock, or it was on prime.. wouldn't know without looking. And something like that can be a number of problems from the fuel line being clogged, petcock clogged, one or more idle jets clogged on carbs, valves too tight, timing chain too loose or tight. If he has anymore problems, let me know. I live in Grayson and would be glad to take a look at it for him.
-Chris
Thanks, I appreciate the offer too, but the bike got shipped to his house in houston.

[jjbing3]

I'm know its been a while but I'm finally in the same place as the bike so that I can troubleshoot it myself. The bike wont start unless you turn the choke all the way up. Then if you turn it back down, the bike turns off. The fuel reserve is turned to off btw. Any suggestions?

[wallypiper]

The fuel reserve is turned to off btw. Any suggestions?

Turn it to "ON".

[jjbing3]

Turn it to "ON".

(Smacks self) Ok

[smokintalon]

Sounds like he needs a new mechanic.

Agreed! Mechanic should have never let it leave like that.. atleast I wouldn't have

:headpop:

[MX Tuner]

If it runs with the choke on and shuts off whent eh choke is closed, that's a typical clogged pilot circuit issue. Sounds like it has been sitting for a while sometime in the past long enough for the fuel to dry and varnish the carbs.

[jjbing3]

If it runs with the choke on and shuts off whent eh choke is closed, that's a typical clogged pilot circuit issue. Sounds like it has been sitting for a while sometime in the past long enough for the fuel to dry and varnish the carbs.

It was working fine when it first came from the mechanic. It started doing it after like a month.

Damn. Thats what I been reading and seeing. It did sit for a while. Does that mean that the carburator needs to be taken apart and cleaned? I read that somewhere else.

[smokintalon]

Agree with Mark.. if it runs with the choke on and won't with it off, the pilot circuits are clogged and the carbs will need to be pulled and cleaned. You might be able to get away with draining the bowls and filling the carbs with Berrymans or something similar in strength, but chances are you will have to pull them. I've never had much luck with doing it that way and just pull every set I touch, which here lately has been 2-3 bikes per week.

Just pull them, make sure you take everything out including the venturii tubes, jets, and ALL o-rings & rubber, then make sure to take your time cleaning with Berrymans or some really strong carb cleaner. Use compressed air to blow the carb bodies out. Allow everything to dry thoroughly, then reassemble. Check your float heights while you have them apart and make sure they are set to factory height (unless you have other mods like headers/high flow exhaust). When you take the pilot jets out, tighten them just until they touch and count the turns in from where you started. Make sure this is close to factory specs as well and don't forget the tiny washer and o-ring under the pilot jets! They're special order parts and only available from the dealer!

Let me know if you need any help!

-Chris

[MX Tuner]

Instead of hte very caustic carb dip like the Berrymans, use the Yamaha carb cleaner. Comes in 1 quart (liter?) bottles for about $12. We stock it. It doesn't deteriorate rubber parts like the caustic stuff does.

The fuel screws and pilot jets are two completely different animals. The fuel screws come from the factory with aluminum or brass plugs covering the heads. Once those are removed, they are usually set too lean and can be safely backed out to about 3 turns out. The pilot jets screw into the body of the carbs right in front of the main jets and emulsion tubes. The pilot jets have to be securely tightened or they will fall out. The fuel screws will have the spring, washer and o-ring in that order. I keep the washers and o-rings in stock.

[jjbing3]

Thanks guys. I wont be here long enough to take his bike apart though. He's gonna be on his own with it. I cant believe he paid 500 for a tuneup and the carburetor didnt get checked.

[smokintalon]

I've used the Yamaha stuff you're talking about and it really works great.. maybe I just enjoy the smell of Berrymans....... hmm

And $500 for a tune??? WOW!! That's outrageous! Our average for tune ups is around a couple hundred tops and thats if a valve adjustment or something time consuming is done. WOW! (picks jaw up off the floor)

[Desmodude]

$500 and no run is redonkulous!! Have the carbs rebuilt correctly. I have seen a stupid amount of bikes having issues do to the new hippie gas with ethanol. The float bowl will more than likely have some nice green fuzz in there. If the bike isn't a daily rider I would suggest using Yamaha fuel stabilizer. Make sure it's the new formulation for ethanol gas. Gas has been going sour in as little as 3 weeks. Best of luck to you!!

[nhs]

I had the exact same problem with my bike or a while - root cause was believed to be "bad gas" by dealer, i.e. either gas with too much water in it, or too much ethanol. Only ever a problem when coming to a complete stop. Also had the issue of it dying upon start-up unless I revved it. The latter could be fixed, btw, by turning off the ignition, and THEN restarting - then it would idle fine. Anyway, fix was to add StarTron to the fuel ("cures ethanol"), and bump up the idle a tad. That solved the problem - which was intermittent. If he always fills up at the same brand of gas station/location, avoid that one for a while. Mine seems to like Shell a lot more than Chevron, for example. Try this before you start tearing the bike apart.