'06 GZ freeway driving problems

[cfsmith]

Hey guys,

First post, want to indtroduce myself but at work and have to type quickly :roll: I'll get to the intro at lunch!

A quick question for those of you mechanically inclined... recently bought an '06 gz250 as my first bike, lovin' it (~1,100 miles in 2 weeks!!), but have noticed a bit of an issue the last couple of times I commuted on the freeway. Y'see, I can cruise on this bike at 55 all day long, and get about 65 mph on freeway commutes, but twice this week I've noticed that, instead of the normal performance I get (between 60-65 mph, no noticable slowdowns), after a few minutes on the superslab I'll find myself slowing way down on any sort of incline (to about 52 mph) and then it crawls back up to about 58 mph at full throttle.

Once I exit the freeway my acceleration is waaaay down, it doesn't seem to have the normal 'oomph'. It just takes a while to accelerate again in 5th gear.

I let it sit all day while at work, jump back on, and it's back to normal!

Anyone have any inkling of what this may be?

Charlie

[JWR]

They all lose speed up hill.

Down shift to 4th gear and wind it up.

Let us know what the results are.

I believe a windshield will give you more top speed. Plus is is much easier on your body.

[Moedad]

Since you just got it and have put 1,100 miles on it in two weeks, do you have any idea when the last time it had fresh oil in it was? Maybe your oil is old and cruddy and is making your motor work too hard..

[cfsmith]

@JWR, it didn't seem to lose as much speed a week ago, but maybe I'm 're-breaking' it in or somesuch. I'm definitely interested in a windshield. Just gotta find one :)

@Moedad, I had the bike serviced prior to riding it as it had sat for about 6 months with the rare back-and-forth in the driveway according to the previous owner. So, at least the oil is clean. I'll be checking fuel filter and spark plug this week-end.


Maybe I haven't experienced the bike long enough, but from some of the posts here about 70 to 80+ mph, I was a little surprised at the perceived under-performance of my machine.
-c

[Moedad]

Maybe I haven't experienced the bike long enough, but from some of the posts here about 70 to 80+ mph, I was a little surprised at the perceived under-performance of my machine.

The difference in power thing is somewhat odd, but as far as not being able to go 70-80 mph, that's not surprising. Anything--head wind, inclines, low tire pressure--will start to affect the GZ's speed right away when you're above 60. The little bike just isn't made for that stuff. It'll do it, yeah, but not well for very long. If somebody spends a lot of time going 75 mph, they are most likely going to need a motor rebuild in a couple of years unless they are maintenance fanatics and even that might not be enough. Treat them right and these little bikes are bullet-proof, but they will knuckle under to abuse sooner or later, depending on the degree of abuse.

[alanmcorcoran]

Most of us ain't getting 80 so don't feel like that's likely. In my case, it takes a bit of coaxing to get it up over 70. Realistically, I'm pretty happy with 65 on the freeway. (I have a windshield.) With no windshield on, if you stick your chin on the speedo, you can get another 10mph.

BTW, it'll go 60-65 in fourth. You'll need it uphill or into wind.

I'm thinking maybe your mixture is too rich? It works okay when it's cold, but then when you are good and warmed up it's too rich. But i don't really know much about engines.

I would also say it might be a little psychological. Wait until you get a bigger bike and then go back on the GZ. It's not built for acceleration.

[cfsmith]

Honestly I'm happy, very happy, with a consistent 65. I've never had it past 70 mph and even that single instance was by accident O.o

I was just worried about some sort of sign of engine trouble as it **seemed** to be fine on week 1, then 'problems' popped up on week 2. It could just be a perception thing, not sure.

Is 60-65 mph considered abuse on the gz250??

Alan, no idea on the mixture - I'll be checking when I know more. In any case it's up for its 6000 mile checkup, I'll be taking it in next week when it turns. You may be right about the acceleration, but I could've sworn it was better last week - or, at least not as weak. e.g. heading up the Arkansas River bridge last week I noticed no slowdown, 60 mph all the way up (not a steep bridge, just a clean, steady incline); this week, I sink quickly to 52 mph.

I'll be checking into some things this weekend, and maybe in the end I'll find out that it's just me . :)

-c

[alantf]

A lot of people (me included) have found that carb cleaner in the tank works magic. If, as you say, it's been standing for a while, then there may be some shite in the carb. Check the posts for which is the best carb cleaner. As I'm not in America, I can't pass an opinion on different types as we get different stuff over here.

[alanmcorcoran]

Try the suggestions (4th gear, higher rpms.) You have to get used to having the bike really wound up at high speeds - that's its happy place. I don't think there is an official book on what's considered abuse, but I think the majority of readers on here ride 60-65 regularly. There was one guy who rode his WTFO all the time and i think his piston eventually blew up, some of it is probably more due to how you GET to the 65 rather than the 65 itself.

A clean steady incline, plus a little headwind, *will* take you out of 5th gear and into the 50's (or even lower!). Learn to only use 5th on flats or downhill.

I think your bike is bahaving normally. You just are getting used to the freeway speed and it seems a little poky when you go back to the surface streets. Don't expect much in the way of acceleration out of the GZ. It's more of a slow and steady bike. You can make it a little zippier if you wind it out a little more before you shift, but, really, it's best to just let it be what it is. If/Once you get the big bike fever, you'll be getting something a LOT quicker if that's what you want.

Meanwhile, enjoy the lightweight, low operating costs and the gas mileage.

[cfsmith]

Thanks for all of the advice, I'll be checking it all out this weekend. The carb tank cleaner (?) sounds like an idea - in any case, I think I'll be learning a lot over the next couple of weeks on how to keep this bike clean and maintained.

Also, I don't want to give the opinion that I'm not pleased with the bike; au contraire, I've really enjoyed it! I've circled through counties around my own, around the hills, over the rivers, through the woods, put miles to grandma's house, etc. I'm lovin' it, no worry cruisin'. First bike and all mine.

I just perceived a potential problem that I'm learning may not have been an issue with the bike, but rather with myself. Plus, trying to get to work on a Monday morning and you ain't worried about the view but rather that 8 am shift change!

;)

I'll give a riding report after I've taken a look at some of what you've suggested and tried to clean 'er up a bit.

Thanks and good riding this weekend

-c

[Easy Rider]

The carb tank cleaner (?) sounds like an idea - in any case, I think I'll be learning a lot over the next couple of weeks on how to keep this bike clean and maintained.


Welcome, newbie! :)

I see you have gotten some good advice already; I won't repeat it all but add a tiny bit.

There is NOT a fuel filter.....unless the previous owner added one.

It is called carb. cleaner. Original Gumout Carb. cleaner or Berryman's B12 Chemtool are the best. Certainly can't hurt to give it a shot.

Spring head winds can make a BIG difference; new riders sometimes haven't developed a feel for the difference between a head and tail wind yet. The combination of an uphill grade AND a slight head wind can be a KILLER in 5th gear.

A windshield might help a bit but not a lot. It is what it IS; not very powerful. :cool:

Edit: Almost forgot, our resident non-mechanic, Alan C. may have the right idea.......but 180 degrees out of phase. :whistle: (He is usually somewhat "out of phase") :shocked:

Check the rubber boots on both sides of the carb. One goes back to the air filter box and the other goes to the engine. Either one being loose can cause a loss of power when hot (too lean condition). So can a missing plug on the bottom of the air box drain hose.

[cfsmith]

Guys,

Sorry for the late update but it's been a bit busy what with Easter upon us and all. Still, I wanted to update:

Ride Report #1

I think I may have found the culprit, though I'm not really sure... I had filled up with 93 octane and began having problems, refilled with 87 as the Manual suggested and... voila, problem solved??

Not sure if higher octane gas really affects the engine like I was describing earlier, or if I just had a bad tank of gas, but now I'm running 65 mph strong and steady with a decrease in speed on those inclines taking me to about 60 mph. This does include some decent wind resistance.

In any case, I'm glad to say my lil' GZ is back in the game and I'm havin' a blast again with no mechanical concerns. I've yet to get the carbs cleaned but it's on my to-do list (though I'm nervous to get in and do it myself... I may need it professionally done).

Also I have the 6k mile check-up to do with the dealership so they may catch some issues too.

Overall, however, I'm very content with the bike. People made fun of me picking up a 'small' 250, but they've been a bit quieter since I've been the only one to actually ride to work every day on it. It's my mule - the daily driver, the hill climber, the slap-a-grin-on-my-facer. I'm lovin' it :)

-c

[Moedad]

Right on! Glad you're lovin' it! It's a great bike.

[alanmcorcoran]

One of the other scientists on here posted something about the higher octane having less energy. Not sure if I understood it correctly, but it sounds like you may have proven his point. Your speeds are in line with mine. You can probably do a little better if you get a good mechanic on the carb and valves at one of your service internals. Also, I don't remember the mileage, but they get a little zippier at 1500 -5000 miles.

[Water Warrior 2]

Higher octane fuel has a more controlled burn while lower octane just goes poof all at once.

[Easy Rider]

I've yet to get the carbs cleaned but it's on my to-do list (though I'm nervous to get in and do it myself... I may need it professionally done).


Just my humble opinion of course but there really is no good reason to take the carb apart to "clean" it if the bike is running OK. An occasional shot of carb cleaner in the gas is highly recommended.......to keep from having to do a tear down. Berryman's B12 Chemtool is good stuff; it comes in a metal can for a reason !!
Seafoam is OK for preventative maintenance; lots of folks swear by it.

[music man]

Easy, Seafoam comes in a metal can too ya know :retard: :neener: :poke2: .

[Easy Rider]

Easy, Seafoam comes in a metal can too ya know :retard: :neener: :poke2: .

Copy cat !! :shocked:

[burkbuilds]

I think you found the "culprit" with your change in octane gas. Higher octane rated fuel has additives to retard combustion due to compression from high compression engines. Since the GZ is not a high compression engine, it should be fed 87 octane fuel, which, as someone already pointed out, explodes more quickly than high octane fuel.

[cfsmith]

Hey guys,

Thanks for the advice. I'm coming on to 6K miles and will need the service soon, so I'm going to pop on over to General Maintenance for a new thread.

Again, thanks a lot and I'll check out that carb cleaner suggested , Easy. The info is appreciated.

-c

[GZ250]

i do not feel any difference in speed (power) when i use 93 or 87 except that with 93 its more smooth. i recently had the valves adjusted and i felt a huge difference in power. i was not able to touch 70mph, now i have to keep it down. so use carb cleaner, change the spark plug if its old (even one year is old enough and its not expensive) or clean it. Air filter in 06 could be old if that was not changed. Things that I did recently and made a difference. Valve adjustment and using Rotella T motor oil (full synthetic) in blue jug. Gives power and smoothness.

One thing that should be taken as Rule of Thumb by everyone who buys a used vehicle. Change the obvious things that matter the most if they were not already changed by the first owner recently. filters, oils, brakes and get a tune up. it gives peace of mind and life to your machine.