Power problem revisited (with audio!)

[VTXorcist]

Ok, I posted about this a while back but wasn't able to make any headway. My GZ, especially when I start out, has some serious power issues. If i twist the throttle, the engine revs very unevenly. If I twist too much, it dies out and will stall if I don't let off some. I thought it was only when I was in certain gears, but then I started playing with the throttle while in neutral and noticed it's just a rev issue.

I took the pipes off the bike just to make sure the problem wasn't related to my leaky exhaust (which I'm very aware of). Unfortunately, it isn't related; same thing happens. I used the computer to record me revving the bike while it's in neutral. It's very choppy and almost dies out at the beginning. I kept the throttle on steady the whole recording except for when it almost stalled; I had to let up a bit to keep it from dying.

Anyone have any ideas about my next step? If I can't fix it myself, I'm probably just going to sell it. I already have more money into this bike than I wanted.

Thanks so much for all the advice so far and any you can give me on this issue, too!

[Sarris]

Bad Plug or bad ignition module (igniter), perhaps?? A plug is cheap enough.

:??: :??: :??:

[Easy Rider]

Originally Posted by VTXorcist

Ok, I posted about this a while back but wasn't able to make any headway. My GZ, especially when I start out, has some serious power issues.

This would have been MUCH easier if you had CONTINUED the thread you had already started.
MUCH EASIER.

I would like to try and help further but I'm not going to go searching for your original thread to refresh my memory as to what we have discussed already.

I will say that modern bike engines are pretty closely tuned; that is, you can't just go removing things or adding them to the intake, fuel or exhaust and still expect them to run right. It IS a little more complicated than a lawn mower.....even though it kind of sounds like one.

So.....before you panic and make (yet another) bad call, you need to get everything back together; exhaust, air box and filter, etc. Then you need to realize that, when cold, some choke is required for the first minute or so.....or maybe more. Not fully choke but some.

It does appear that you are in over your head. If you get it all back together and it still doesn't run right, it might be worth the $50 or so diagnostic fee to have a shop look at it. 'twould be a shame to sell it if the fix was something simple.

[VTXorcist]

My bad, Easy. viewtopic.php?f=7&t=2628 is the original thread.

Summary:
- Thought it was related to my cracked exhaust
- New exhaust didn't fix it
- Bonehead speculated it might be a valve adjustment problem (I do need to adjust the valves, so that's still a possibility)
- You speculated it might be an air intake issue and to clean the filter (did that); you did note it was most likely an air-fuel mix issue

That's about where it left off. I probably missed some glaringly important details, but after a quick read-through, those seemed to be the highlights to me.

[New GZ250]

Just can't believe all these/other issues could happen to one person.
:kneel:

[dhgeyer]

At the risk of asking the obvious, have you run a couple of tankfuls of fuel treated with Chevron Techron Fuel System Cleaner through it? Or a similar product? Some people swear by Sea Foam. Both available at just about any auto parts store. Be careful to use the right proportion. The directions will say something like "Treats up to 20 gallons", so you don't dump the whole bottle in your little tank.

Carbs get gunked up by the lousy fuel we have to run these days. They're not as simple as they used to be, and if anything's clogged or not moving freely you get a lousy running engine.

The float valve (or the float itself) got stuck in my carb a week or so after I got the bike. I ran a couple of tankfuls of Techron through it and it cured the problem. Carb could use a good cleaning, I'm sure, but it's running fine now, so I'm not going to mess with it till it's down for the Winter anyway.

My daughter's Ninja 250 sounded and acted like your recording after sitting for a while a couple of years ago. Ran some Techron through it and it was fine. Stuff works pretty well.

I run a tankful of treated fuel through my bikes every 5 to 10 tankfuls as a routine practice now, more often if they sit for a while. Seems to prevent problems before they occur.

[Water Warrior 2]

Just a passing thought. Have you tried running the bike with the fuel petcock in the reserve position and the prime position to see if there is a difference ? Just a wild a$$ idea to eliminate a couple things running around in my head.

[VTXorcist]

I'll put 'er back together today and ride around with the petcock in both of those positions and report back. If it can't hurt, I'll stop by the autoparts store and grab some seafoam, too. I used some regular old carb cleaner, but I haven't even used half of the tank of gas I added it to, and that was a week or two ago. I should probably finish that off and refill before I add anything else.

More info to come...

EDIT: Make that chevron techron instead of seafoam. I want the stuff with proven, first-hand results.

[Sarris]

Brother, upon second listen, it really sounds to me like an ignition issue. The way it's cutting out sounds (to me anyways) like the plug stops firing, not a fuel supply issue.

If the carb cleaner etc. doesn't work, try a plug. They're only $3 at Advance. After that, it's the ignitor.

Just my opinion, and worth every penny you paid for it.

:2tup:

[dhgeyer]

Y'know, Sarris has a point. A spark plug costs less than the Techron, is easy enough to replace, and you'll know right away if that was the problem. Since it's still the height of riding season and you want your bike, why not try both approaches? From your written description, I still vote for carb issue. If the plug or a coil was bad, I don't think it would improve with warming up the engine, and I'm pretty sure that it wouldn't matter how much throttle you gave it. But, for the price of a plug and 10 or 20 minutes to swap it out, why not? You could then at least look at the old plug and "read" it, which could give you valuable information on where to look next. I generally keep spare plugs with me when I ride, especially on a "thumper". Even if they aren't the original problem, they can be the victim of other issues (like getting fouled up from way too rich of a mixture), and need replacing along with whatever else needs to be done.