What is the redline for the GZ250 engine?

[Quimrider]

Does anyone know what the redline RPM is for the GZ250? I plan on buying a tach. and want to get one with an appropriate rev range. Also if anyone has suggestions on where to get an inexpensive tach, I'd appreciate that too.

[jonathan180iq]

good luck with your search. As far as I know, no one here as been able to come across an affordable one.

As for redline, who knows.... When the engine starts doing this :cuss: :drool:, it's probably time to back off.

take care,
Jonathan

[markboy]

While I was looking for a tach one service guy said "Why don't you just wait for the rev limiter to kick in and then shift". This was on the phone and I couldn't tell if he was joking or serious but it got me to thinking - does the GZ even have a rev limiter? (I've never actually heard of such a thing)

[jonathan180iq]

So a service guy told you to drive it until it won't rev any higher and then shift...

That's pretty a pretty smart service guy.

You know, I'm going out to my car right now to practice this very behavior on the way home from work.

Don't worry, I'm sure I'll make it.

[trykemike]

The engine in a GZ250 is the same block as the GN250 but with different tuning characteristics. The GN250
produced max hp @ 8500 rpm the GZ250 produces max hp @ 8000 rpm so the engine should rev safely to 8500 rpm. It may not be smooth @ that rpm due to spark advance mixture etc.

[Badbob]

GZ250s do not have a rev limiter.

Put it in neutral and go to WOT and you will see this for yourself. However you might be picking up your engine with a broom and a dust pan.

The service manual does not mention rev limiters and there is no sign of one in the electrical schematics.

[Quimrider]

I got my tach and will be posting a "how to" soon. The tach only goes to 8k RPM. It shows idle at about 1000 rpm and ~7600 rpm at 75mph. I've revved it in neutral until it sounded like it was reaching the end of it's rev range. Based on the where the numbers stop and their spacing I'd say it went up to 10-12K rpm. Not something I intend to do again as I do not like my engine in little broken pieces.

[davidc83]

Quimrider:
Where did you get your tach? how much? Pictures?

[Quimrider]

see my post in this thread from july 15 http://www.gz250bike.com/viewtopic.php?t=420 it was about 57 dollars delivered. Sometime soon I'll write up a "how to" with pics. It was easier to than I thought it would be. Took me about 1.5 hrs. most of that was figuring out where to mount, connect and route wires. I'd say it could be done in a half hour or less. When I find time I'll write up a "how to", prolly this weekend, I took plenty of pictures.

[Jaime]

The GZ250 revs up to around 9000 rpm until the rev limiter stops the ignition. At least my 2006 unit has limiter, as all electronic ignition vehicles (injected and carburated).
It's not good to run for a while at highest rpm, but there's no problem if you shift up when the rev limiter acts; it's there just to protect the motor of overreving.

[Quimrider]

Interesting I wonder what other differences there are between the model years. Mine is a 2000 and I'm almost sure it doesn't have a rev limiter. I about loaded my pants when I was playing with the new tach and saw it rev way past the 8K mark. Not ALL electronic ignitions have rev limiters. Although I'd believe about 99% of them do. I converted my air cooled VW to a solid state electronic ignition system and I am certain it has no rev limiter of any sort. The tach I have on that goes up to 8K RPM and bad things start to happen to an aircooled VW engine when you get much above 4000 RPM

[Badbob]

The GZ250 revs up to around 9000 rpm until the rev limiter stops the ignition. At least my 2006 unit has limiter, as all electronic ignition vehicles (injected and carburated).
It's not good to run for a while at highest rpm, but there's no problem if you shift up when the rev limiter acts; it's there just to protect the motor of overreving.

Do you know there is a rev limiter? How?

Do you have schematics that show one or a service manual?

[Jaime]

Interesting I wonder what other differences there are between the model years. Mine is a 2000 and I'm almost sure it doesn't have a rev limiter. I about loaded my pants when I was playing with the new tach and saw it rev way past the 8K mark. Not ALL electronic ignitions have rev limiters. Although I'd believe about 99% of them do. I converted my air cooled VW to a solid state electronic ignition system and I am certain it has no rev limiter of any sort. The tach I have on that goes up to 8K RPM and bad things start to happen to an aircooled VW engine when you get much above 4000 RPM

Transistorized ignition doesn't limit the max revolutions. It's used in older GZ250s.
The full electronic ignition "chip" can be programmed to stop the ignition at certain revs, it's not an independent system, so if you adapted a kit to your VW it won't have the limiter pre-set.

To check if your bike has rev limiter, you simply have to run on a leveled terrain on 3rd shift till it wouldn't accelerate anymore, just a couple of seconds. If it reaches relatively constant rpms, it doesn't have limiter. If it does a regular oscilation like the bike of this video (http://youtube.com/watch?v=D52JFxCOdpo), it's the rev limiter. When it acts, the initial feeling is like you were out of gasoline.

[Quimrider]

Yup that is what a rev limiter does. Depending on the vehicle it will either cut the ignition or the fuel (fuel injected vehicles.)

[riceboy131]

I have had my gz 250 for about two years now and so far I have formed the habit of shifting at wot when it won't rev any higher and I guess I probably shouldn't do that even though it's a trooper and haven't blown up YET