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View Full Version : Gn250 and a yoshimura rmz250



TeknoRob
21st May 2012, 18:11
G'day all,

I got myself a gn250 a whiles back n was wonderin if any of you kiwis had done exhaust mods so it doesn't sound like my dog snoring?
I want it lounder, and a nicer tone as well, so I found this guy sellin an rmz250 yoshimura exhaust on eBay for $50. Anyone know if ill run into problems if I get that?

Cheers,
Rob.

SS90
26th May 2012, 10:58
The G Mobile engine is just a 1980 DR250 engine, with an electric starter and no kick start.

As far as I am aware, there has never been any changes to the engine it's whole model run.

I have to say I don't think you will manage to find anyone with a performance exhaust for one these days, (a 1980 DR250 exhaust will fit as far as the header pipe goes, but the muffler is, well, a little higher than a GN being an off roader (and perhaps there was "performance exhausts" available when they where current)

I know there is a 300cc kit available, an interweb thingy search thing will unearth one, but I seem to recall them being pricey. At the very least a bigger bore size will unshroud the valves when they open, which might give a noticeable power gain. Maybe.

I personally have never seen anyone that has been able to get one to go any faster than standard (even knew someone way back that went to the effort of raising the compression, but it made no difference (other than wrecking the already weak starter clutch)

I was always flabbergasted that a 250cc engine, with 4 valves was, well, so, erm, Feeble.

Millions of the things around though, and pretty much anyone that has been into bikes for any length of has either owned one, or knows someone that has. And they still make the bloody things, so the market still wants them.
They where even restricted for some markets, but I can't imagine why!:lol:

All that aside, GN's are iconic, and if you keep oil in them, just keep on trucking, gotta love that!

ktm84mxc
26th May 2012, 11:24
The first DR was available in NZ 1982 there were two models T off\on road minimal lights in white only, S more like a TS\ER lower suspension softer tune blue\red color . The first GN's appeared at this time also most came with wire wheels and drum brakes, electric start, mag wheels and disc front around 86/87 . Many a GN motor has been fitted to a DR/XR chassis mainly due to the electric start , the engine tune is mellower in the GN mainly due to cam timing and CV carb.