Need some 426 help

I have a 2000 YZF 426 and I'm having some issues.

The bike starts up good (I'm a master at starting it after riding it for years) and it runs fine for a couple of minutes (longer if I am moving, as it stays cool longer), but as soon as it heats up to a certain level it dies on me.

After it dies, when I kick it, it doesn't feel any different than normal, but the sucker just won't start.

The carb is good, cleaned a million times, pilot jet is good and everything else. It runs fine until it gets warm and then it just dies.

I got a cdi from another 426 and the exact same thing happened, so I don't think it is the cdi.

At this point I am guessing the coil or something of that nature. Can anyone give me any suggestions or tips? I don't have the tools to get to the pick up coil or any of that but I really need some help here. I don't want to take it to the dealer as I don't have $500 to drop on fixing my beast.

Thanks guys!

You don't need access to the stator itself to test it, but you will need to have an Ohmmeter. The tests are in the manual, and by now, you know where to get that, if you don't have it.

When it quits, shut the gas off immediately. Then open the bottom of the carb up to see if it had a full load in the float bowl. Make sure it will run a decent flow of gas out when you turn the fuel on with the bowl open. If not, loosen the gas cap and see if that fixes it. If so, you have a cap or vent problem.

Then check for spark (you may want to do this first, rather than while there's a bunch of fuel running loose). If you don't have any, test the stator while it's still in it's "quit" mode. Test the coil, too.

Yeah, my manual looks like it has been read a million times by now ha ha. I'll pick me up a tester and see what I can find out. I'm thinking I may have had the machine set up too lean or something and burned the coil out or something. Thanks for the help.

I'm thinking I may have had the machine set up too lean or something and burned the coil out or something. Thanks for the help.
There's no relationship between jetting and coil failure.

I thought that if you have the bike too lean it will get hot and the coil could end up melting. I'm not sure, I thought I read that somewhere on here. Isn't the issue heat if the coil end up melting?

It was weird, took it out to the sand one day, rode for about 10 minutes and then it just died. It's now been sitting for a few months, but when I took it out the other day it did the same exact thing.

I'm gonig to buy an ohmmeter today and I'll post the results later this afternoon. Thanks.

I thought that if you have the bike too lean it will get hot and the coil could end up melting.
Before it ever got lean enough to run that hot, it would run so bad you wouldn't be able to ride it. And, if it ever got hot enough to melt the coil for any reason, you'd have more than an electrical problem on your hands.

Ok, well that may be the case. I got a ohmmeter and everything checks out. I went by the book and tested all the coils and such and I couldn't find any bad readings at all. Is my engine screwed???

Did you check the coil and stator directly after the engine stopped? If it is heat related then you need to test these components as soon as possible after the failure. They could test good after they have cooled again.

Ahhh, thanks brooks, I'll do that this afternoon. I did test them when cooled and yeah, it runs like a champ for the first 5 minutes. Once it gets warmed up that is when it dies on me.

I really hope it comes back bad when I try it as tearing apart the engine is territory where I don't think my bike would come back alive from.

Did you check the coil and stator directly after the engine stopped?

That is what I said in post #2, you know. Apparently, it needed a "second coat". :crazy:

That is what I said in post #2, you know. Apparently, it needed a "second coat". :lol:

ha ha duh. :crazy::eek:

i would sure go back and check the fuel tank cap/vent like gray said...

easy enough to check, just open the cap up about a half a turn. I could hear air escaping when i opened mine. I had never seen a cap go bad before that one.

just a thought

Ok, guys the struggle goes on.

I checked the gas cap, just to be sure. I would have killed myself if I had missed months of riding for that. I loosened it and rode around and the same thing happened. I had never heard any release of pressure when unscrewing the cap so I really didn't think that was it.

Next, I checked the ohms when the bike was hot and not working. The source coils and pickup coil came back the same as always - no problem there. However, both the primary and secondary ignition coil winding (that's how they write it in the manual) came back very messed up from normal levels.

So I took the ignition coil off my buddy's 2002 426 (the little fat cylinder that screws to the frame and attaches to the spark plug), and slapped it on mine, hoping that it would be perfect. I started it up and it rode fine for a minute (as it had a little time to cool down) but then it died just like always.

Is there a part in that circuit I should now be looking at, because as far as I can tell it's not the ignition coil, but it has to be something right in line with it.

Thanks guys.

One last thing - I also have my buddy's carb on there just to rule anything in that area out. So the carb and everything in it should be without problem.

Did you check for spark right after it quit?

Was the coil disconnected from the harness when it was tested?

Have you checked the fuel flow as I suggested?

Sounds like the coil is out of the picture. If it's electrical, it should not have spark while it's in shut down mode.

When it's in shutdown mode it still has spark. I have a buddy who thinks there is something wrong in the engine, like a valve or a ring that works ok when the bike is cool, but once heated up it doesn't seal correctly and the the bike loses compression. Think that could be it?

Does it loose compression when it quits? Or does it still feel normal?

If it still has spark, I'd go back to the fuel question. Have you done the fuel shut-off test I mentioned yet?

I am not totally sure about the compression. I bought a tester to make sure.

I did the gas check, and after it died there was plenty of gas still in the carb. I tried to start it again once I drained it and refilled it and it was still a no go.

When I ride it at first when the engine is not warmed up yet, the engine sounds sharp and good. But once I hit the "point" where she dies on me the engine sounds dull and muffled. It almost sounds like at first the spark is good and strong, but once it warms up, for some reason the spark goes down to a 2/10 or something like that. Anyway, I'll check the compression and see what I can find.

Is there someone you can borrow a CDI from to try?

From my buddy's 2002 426 I have on there right now, the carb, the ignition coil and the cdi. The kill switch is a little different so it's not connected, but I don't really have a problem with getting my bike to shut down. grrrrrr

Anyway, I tested everything before putting the stuff on, and after. Nothing seems to change at all. Everything comes back with the same values, and nothing different happens when I ride it. I did the gas tests, took my cap off and put his on to make sure there wasn't some kind of vapor lock, and even rode it with the cap partially unscrewed. Checked the amount of fuel in the carb when it dies and (after turning the gas valve off) the carb has plenty of gas in there. And once I turn the gas back on it comes pouring out the bottom of the carb as fast as anything.

I bought a compression tester yesterday, but found out when I got home from the date with the wife that the size is a 14mm and I need a 10mm so I have to get a little piece to convert the sizes to fit. But I am going to check compression tomorrow. With everything I've tried I really don't think it is anything but something going on inside the engine.

But (cross your fingers) my buddy may be buying an 06 kawi that he looked at on friday. And if he is, I may be able to have his old beat up 2002 426. With the two bikes I'm sure I could make a pretty sweet ride. But for the time being I still gotta try to fix my beast as that deal may fall through.

Couldn't hurt to check valve clearances, they could be on the verge of being too tight, but that would usually cause a hard starting issue. Another thing to look closely at would be grounds. All of your components could be OK, but a faulty ground will cause unpredictable issues. Hope this helps.


Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now