Issues with GN250

[GDOBSSOR]

My GN250 has a clattering noise. By itself, that isn't so bad, but over the past week or so, it's been getting louder. I got someone to rev it and listen to the cam chain, and he said he couldn't hear anything wrong. That was Monday. There was nothing really wrong with the performance of the bike then, and hasn't really been anything wrong with the performance of the bike any of the times I've ridden it this week, except for today. I rely on it to get to work/uni, and today, it wouldn't go above 40 kph, and that was in 4th gear. It was even worse in 3rd gear. The clattering noise was horrific. I checked the oil - when the bike's on its side stand, I can't see anything in the sight glass, but when it's on its centre stand on the garage floor, it looks almost full. I changed the oil filter the other day, and the oil three weeks ago. I've also smelt a burning smell occasionally, but not always. I might take it to Wellington Motorcycles, but in the interim - what could be wrong with it?

[FJRider]

Get a short length of hose (garden hose works well) ... stick one end in your (best)ear and move the other end about the engine. (Like a stethoscope). Find the source of the clatter ... and probably the problem.

Sounds like clutch clatter. Not ultra expensive issue ... but still serious.

[jellywrestler]

My GN250 has a clattering noise. By itself, that isn't so bad, but over the past week or so, it's been getting louder. I got someone to rev it and listen to the cam chain, and he said he couldn't hear anything wrong. That was Monday. There was nothing really wrong with the performance of the bike then, and hasn't really been anything wrong with the performance of the bike any of the times I've ridden it this week, except for today. I rely on it to get to work/uni, and today, it wouldn't go above 40 kph, and that was in 4th gear. It was even worse in 3rd gear. The clattering noise was horrific. I checked the oil - when the bike's on its side stand, I can't see anything in the sight glass, but when it's on its centre stand on the garage floor, it looks almost full. I changed the oil filter the other day, and the oil three weeks ago. I've also smelt a burning smell occasionally, but not always. I might take it to Wellington Motorcycles, but in the interim - what could be wrong with it?

did you put the correct grade of oil in?
did you do the filter and the oil at the same time?
if not what order did you do it in?
where in wellington are you?

[GDOBSSOR]

did you put the correct grade of oil in?
did you do the filter and the oil at the same time?
if not what order did you do it in?
where in wellington are you?
No I didn't change the oil and filter at the same time, stupidly not.
My father told me I didn't need to, despite not having worked on motorbikes for forty years. Absolutely the last time I take ANY advice from him.
I changed the oil first, three weeks ago. I then changed the oil filter, one week ago.
I'm in Karori.
Did I use the correct grade of oil? Uh... Not sure. I went into Wellington Motorcycles, told them what make, model and year I had, and asked them what grade of oil I needed to buy and they gave it to me.

[FJRider]

when the bike's on its side stand, I can't see anything in the sight glass, but when it's on its centre stand on the garage floor, it looks almost full.

Check the oil with both wheels of the bike on the ground. With the bike upright. (Ask somebody to hold it for you) otherwise you can get a false reading.

[jellywrestler]

No I didn't change the oil and filter at the same time, stupidly not.
My father told me I didn't need to, despite not having worked on motorbikes for forty years. Absolutely the last time I take ANY advice from him.
I changed the oil first, three weeks ago. I then changed the oil filter, one week ago.


did you recheck the oil level after doing the filter as they take oil to fill them up?
and yes FJrider is right oil needs to be checked on its wheels

[GDOBSSOR]

did you recheck the oil level after doing the filter as they take oil to fill them up?
and yes FJrider is right oil needs to be checked on its wheels

On its centre stand only.

[GDOBSSOR]

Thing is, this guy I kind of went out with a while ago who owns a GSX250 said that if a bike engine's going to seize, you can tell because it makes a loud, "CLATTER CLATTER" sound, and that if it started making that sound, pull on the kill switch or pull in the clutch if possible. My engine hasn't seized, but what he said makes me worry.

[FJRider]

On its centre stand only.

The center stand raises the rear end of the motorcycle. Enough to make a big difference on the correct oil level. With bikes that have the sight glass at the front would/could cause you to believe it was full. When in fact it would be low.
Those bikes with the sight glass at the rear ... would/could cause over filling with oil.
Both could lead to serious issues.


Thing is, this guy I kind of went out with a while ago who owns a GSX250 said that if a bike engine's going to seize, you can tell because it makes a loud, "CLATTER CLATTER" sound, and that if it started making that sound, pull on the kill switch or pull in the clutch if possible. My engine hasn't seized, but what he said makes me worry.

I hope it's not the same guy that told you to buy a scooter.

Most bikes that seize ... go remarkably silent and stop. (understatement)

"Clatter clatter" CAN be serious ... so don't ignore it. Use the hose method (I know it sounds crazy but it works) and see where the noise is coming from.

The burning smell you spoke of might be slipping clutch, which accounts for lack of ability of speed. And the clatter might be a few missing/broken fibre clutch plates. (not a major job for those that know how ... and easy to learn how to do)

Learner bike clutches DO get a hammering .. so I doubt if it's anything you've done wrong.

[GDOBSSOR]

[QUOTE=FJRider;1130453385]The center stand raises the rear end of the motorcycle. Enough to make a big difference on the correct oil level. With bikes that have the sight glass at the front would/could cause you to believe it was full. When in fact it would be low.
Those bikes with the sight glass at the rear ... would/could cause over filling with oil.
Both could lead to serious issues.


I hope it's not the same guy that told you to buy a scooter.

Most bikes that seize ... go remarkably silent and stop. (understatement)

QUOTE]

No, no no, completely different guy.
I just got my boss to hold the bike for me while I looked at the oil. It looked as if it was a little bit overfull.

[FJRider]

I just got my boss to hold the bike for me while I looked at the oil. It looked as if it was a little bit overfull.

If the top of the oil level is still in the sight glass it should be ok. If it's not ... while it is on it's wheels, lean it slowly away from the side the window is on to see how far you need to lean it to see the top oil level. If it isn't much ... the engine may use it pretty soon (if I recall another thread of yours)

If it IS ... it would pay to drop the oil out and fill again (with the same oil is ok) to the correct level.

And well done for looking ... you are learning fast.

Start chatting up bike shop mechanics ... it might come in handy .. :msn-wink:

[ducatilover]

Did you put the oil filter in the correct way?
If you put it in backwards you'll lose oil pressure, then you'll eat the piston, bore, bearings, gearbox, and the valve train.

I would check the filter is in, with the spring against the cover.
The I'd pop the little rubber nipple off the cam chain tensioner (right hand rear of motor), get a small-ish flat blade screw driver and gently turn it anti clockwise half a turn, then let it re-set and wind it a quarter of a turn clockwise

If you're still rattling after this
Do the valve clearances
Drain the oil, look for metal poo
Pull the oil pickup screen off (three 8mm bolts under the engine for the cover, then two phillips screws to get the screen out) and check for metal poo in it.

If it's still rattling
pull the valve cover off (10mm bolts, plus top engine mount which is three 12mm bolts)
and check for grooving/burning on the cam shaft, burns happen with low oil pressure
Check the cam chain slack and movement on the pulley, there will be a small amount, but more than a few mm left to right/up down is fucked
Check the cam has it's half circle retainer under it near the sprocket side
Look for bent valves and broken springs
Look for burns and wear on the rocker faces
Look for cracks in the rockers
Make sure they rock easily

Pull the spark plug too, it it's completely white your valves need clearances set, or you have a fucked carb
Take the carb off (there's a nice fuel drain under it, be very careful with it as they can crack the bowl when tightened, I can supply you with one if it breaks) make sure the slide isn't wobbling around and the butterfly is on securely

If you still have a rattle, the fun begins
I would then:
Take both engine covers off (after draining the oil...)
Check for rattles if you turn the flywheel, it could have a fucked starter clutch (can be rebuild, I have a spare too)
Check for up down, side to side and in and out movement on the crank and output shaft

Check the clutch basket is tight and not pulling in/out
Check the cam chain at the bottom
Check all the gears in it for signs of wear


Find the oil pump (clutch side, gear driven) and make sure it's tight (there's some in out movent on the shafts, just a tiny bit)

If it still rattles, you have a shot bearing, conrod or gudgeon pin.

It's not uncommon to get rattle because the oil galleries are blocked in the head and the one at the top of the gearbox.

That's all I can think of off the top of my head without ripping it apart, fortunately they're a properly simple engine

[GDOBSSOR]

Which way did I put the oil filter in? I put the filter in according to the pic in the book - in other words, the side with the number on it went in facing the front. I'm 99% sure I coiled the spring around the cover centre, and I also fitted a new o-ring.

[FJRider]

Which way did I put the oil filter in? I put the filter in according to the pic in the book - in other words, the side with the number on it went in facing the front. I'm 99% sure I coiled the spring around the cover centre, and I also fitted a new o-ring.

Take the bike into Wellington motorcycles ... I'm sure they will be able to tell you what the clatter issue is.

Any other issue ... don't stress over. First things first.

[ducatilover]

Which way did I put the oil filter in? I put the filter in according to the pic in the book - in other words, the side with the number on it went in facing the front. I'm 99% sure I coiled the spring around the cover centre, and I also fitted a new o-ring.
Yup, that's the correct way.