right ive had the cover off now and its got a 15 fr cog on, i cant find any specs of the early jap spec one anywhere so not to sure if its right or not

im at a loss with this now, im being beaten by a 250 grrrr

time for ebay me thinks

Time to review the basics:

Several of us have said that the GZ is an under-powered bike that won't pull 70 reliably in any but the most ideal conditions. Having a 300 LB rider and no windshield only makes matters worse.

There is no reason to think that your similar bike would be any different.

I (several of us ?) think what you are describing is VERY likely normal.......and so far, you haven't said anything that would tend to indicate that it is NOT normal.

Before you spend a lot time, effort and maybe money on this "problem" you need an onsite test ride by someone who is experienced in small bikes like that. Seriously.

Hell, I'm happy when I can get 60mph.

yh im happy with it, but from everything i can work out and the little bikes ive had before they have all been able to hold the speed in 5th and atleast accelerate a little bit, this just rolls off 15 mph as soon as its shifted

my options are give it absolute death up the bypass in 4th or risk getting rear ended, either raise or lower the gearing, fors and againsts for each option or lob it on ebay and make a profit on it

everyone drives faster round here and most on there phones and so it would seem none of them are arsed about watching for bikes, ive got the scars to prove it

The 2 250's I had back in the 70's would haul my ass around at hiway speeds no problem, then I bought this one and could'nt figure out why I can't get over 60. Then it hit me, the other 100 lbs I'm carrying around. DUH!!!

hahaha ive been this big before n had 250s n been skinny as hell n still theyd only do 80 at a max, bar the rgvs
i just want it to sit n cruise at say 65 without it blowing itself to bits

From what I can gather, there are two versions of the gz250 - the American & the European - I think that the emissions regs in America make their version even slower than ours. When I say "ours", I'm assuming that the English/European versions are the same. I can join the autopista (motorway) at 60 km/hr (just under 40 mph) in 5th, & accelerate to 100km/hr(62mph) with no problems. (although it's REALLY happy at 90 km/hr) I'm 12½ stones (185 lbs) & don't have a windshield. Going on all this, I don't know what the answer is, but I DO think that you have a problem.

hello

TRY A BIGGER MAIN JET 125 PERHAPS. iT WORKED FOR ME . i'M 5'6" 165 LBS i CAN TOP 80 MPH MOST DAYS IF NEEDED.

right as strange as it is its now pulling higher speed in top, aslong as i shift in early, i shifted up a few times tonight at under 60 n kept it wide open n slowly it lost 5 or so mph as usual and then would slowly chugg thru what feels like the motor really strugling to breathe and then got upto just over 60 almost 65 sat half up and after a few trys and some serious tucking in, which is hard at my size lol i saw just over 110 kph on the jap clocks
although after a mile like this is starts to stop fueling, its really weird
i did try a few shift up at high revs tho and it still did the same jerking n lack of fueling and it still goes quicker in 4th

it seems happy around town at 40kph, sits there nice, likes to be just under 100k on the clocks on the open road but just not in top

i think maybe this bikes just got some sort of self harming issue i dont know about, its defo a bit emo

Reading your last post reminded me of how my GZ ran when I took a couple of two hour highway trips on it. I remember that I was having trouble trying to even get to 65 mph for the first 30 minutes or so, then I started noticing that I could hit 70 and occasionally 75 mph briefly as the bike got warm, well probably hot for that matter. Maintaining those speeds on a GZ is practically impossible though, but I've actually hit 82 mph once going downhill with a tailwind for about 5 seconds. I am about 80 lbs lighter than you are and my guess would be that you are going to have difficulty getting to 65 and maintaining it will be even tougher no matter how well the bike is running. That was the only reason I finally sold my GZ and bought a Vulcan 500. Like you, I needed to be able to run with the pack in fast moving highway traffic to keep from getting run over. If that's as important to you as it turned out to be to me, then you probably need to consider buying a bike with more displacement. The 250 only puts out somewhere around 20-22 horsepower, my Vulcan 500 is only about 30% heavier than the 250 but it puts out twice that amount in horsepower and it makes a difference when you need to go faster.

yeah ive got a currently in bits cbr 600, this was pressed into action early as it was originally going to be next yrs winter hack

its not fast but its good fun dragging the pegs everywhere, just a shame theres only the fast roads to get out of the village i live in, its sound round town n even handles the back roads well enough to have some fun, itll sit at 70 in 4th all day but it sounds like its going to throw its rod lol

im thinking fix the cbr n flog it n maybe flog this too as theyre fetching good cash atm and then get an old yzf 750 cos theres not much better comfier way to hit 170 daily :D

Did you try running wide open,shutting down,and checking plug for lean mixture.If plug is white,need larger main jet.

yeah i didnt tonight, it was 2 am and pitch black and only just above freezing, tbh i think the only thing i havent done is a plug chop, but the old plug looked nice n right when i swopped it out a few weeks back

its still doing it, ive kind of got a way around it figured out, but ive actually been trying to ride it how its meant to be ridden and i tell u what, i love it, proper good little bike
dragging the pegs in the ice, bouncing off potholes etc, copes with it all, around town speeds its a little rocket and i really dont want to sell it now lol
see why you guys built a forum for these things :D

You have been assimulated. It really is a magic little bike when ridden within it's abilities and design.

yeah i thought today id play in the traffic as i was in no rush and it shined, ive seen glimpses but obviously been trying to sort this fueling issue out
im made up, just a shame i have to use some fast roads around mine, if i end up working local or living at my girlfriends in town itll be laughing and im toying with an sv again for bigger duties

Whereabouts are you, near Liverpool? Just idle curiosity, but I've got my English road atlas on the bookshelf.

Formbingtonshire upon the sea, its shit, bypass in bypass out and a fast back road across the moss, not little bikes friendly til you get off those roads

I can only assume you're joking. No such place in my road atlas, & google's telling me to p**s off!

formby, its shit so we gave it a gay name hahaha
as said 3 fast roads out, the back roads even faster than the bypass, spot on, on a 600 for some good fast fun, not so friendly to a little 250

O.k., so no jokes about leaning on a lamp post, eh George!

Also back in the 70's they didn't have the emission standards for motorcycles they have now, so the motorcycle manufacturers could squeeze more out of the little 250 engines.


P.S. the extra 100 pounds probably wouldn't have anything to do with it

ALSO back in the 70's, quite a few 250 bikes were 2-cycle....which makes up to 2X the HP of a 4 stroke.

yh ive had a good few 2t 250s and a few 4ts ones aswell, been heavier and still got 80 out of the 4ts
this is still weird, some days itll do 70 fine, then others it cant do 60 and if i draft a car i can get nearly 80 out of it.
im putting it down to being an old style really basic engine tbh now, fuelings as good as its going to get

Very true Easy