2004 Suzuki GN250 issues: smoking like crazy, burnt oil smell

[SJizzle]

Hi guys. I recently put another motor in my gn250 as the old one was completely shot. Today I filled up the second hand motor I got with oil 15w40 oil run of the mill type and she ran fine for about twenty minutes until I took her for a ride. All of a sudden I smell burning oil and a whole bunch of smoke is coming out the exhaust. Any theories as to what may cause this? I am a car mechanic by trade and admittedly this is my first time working on motorcycles.
Any comments would be helpful.
cheers guys
Sj

[ducatilover]

Over filled? They only take 1.3L of oil
Do a compression check.
You can buy a barrel and piston for $150 locally (cheaper from China)

A GN motor works like a cars...

[skippa1]

Check the engine on the garage floor....chances are it's the good one......pickin you took the fucked one out, went upstairs for a cuppa, came back and reinstalled it:lol:



PS.......a car mechanic should know what the likely culprits are.......it's only a 4 stroke motor ffs

[nzspokes]

Check the engine on the garage floor....chances are it's the good one......pickin you took the fucked one out, went upstairs for a cuppa, came back and reinstalled it:lol:



PS.......a car mechanic should know what the likely culprits are.......it's only a 4 stroke motor ffs

Many years ago I worked as a lawnmower mechanic. Ginny motor is a B&S 4 stroke that stands up.

Mind you a B&S puts out more powa.....:killingme

[AllanB]

Over filled the oil? Or the second motor is a dud.

[SJizzle]

Hahaha I know I put the right engine in cos I had to swap over some bits from the old one that was missing on the one I just installed. New motor is a japanese one from an older gn. Maybe car oil is not ideal for it?

[SJizzle]

Over filled? They only take 1.3L of oil
Do a compression check.
You can buy a barrel and piston for $150 locally (cheaper from China)

A GN motor works like a cars...

No compression issues bud. Just a whole bunch of smoke under throttle

[skippa1]

Hahaha I know I put the right engine in cos I had to swap over some bits from the old one that was missing on the one I just installed. New motor is a japanese one from an older gn. Maybe car oil is not ideal for it?
Depends on what part of the car you took it out of, the diff oil might not be so good.

im no oil expert but I have always used motorcycle specific oil as it cost fuckall more, seems like false economy to use car oil for the sake of a few bucks

[SJizzle]

Depends on what part of the car you took it out of, the diff oil might not be so good.

im no oil expert but I have always used motorcycle specific oil as it cost fuckall more, seems like false economy to use car oil for the sake of a few bucks

I used SAE 15w40 sinopec oil. They are one of my suppliers. Engine oil not diff oil. I may drain the oil tomorrow and put in some Motul 10w40 as the service manual recommends that particular viscosity of oil

[AllanB]

Blocked crankcase breather or something forcing oil into the air box? Check the air box - it should be nice and dry in there.

[ducatilover]

No compression issues bud. Just a whole bunch of smoke under throttle

What'd the comp test show? Dry/wet hot/cold?

You have a GN, which fucking sucks

[SJizzle]

Blocked crankcase breather or something forcing oil into the air box? Check the air box - it should be nice and dry in there.

Has no airbox. Has a pod filter ans breather hose is just there not connected to anything. Bought it like this

[SJizzle]

What'd the comp test show? Dry/wet hot/cold?

You have a GN, which fucking sucks

Compression test showed good results from memory. Did it when the bike was cold. In between working on a customer's car and doing a wof lol

[ducatilover]

Probably oil control ring then.

[Big Dog]

You definitely want bike oil I there. Bikes use the same oil for their tranny as engine. Won't cause your smoke in such a short time , will happily cause your tranny or engine to wear at some point in the future as it becomes less slippery every time it passes through the gearbox.

Smoke is blueish or smells of oil I'd check the head gasket.
Black and stinks of fuel check you have not dropped a valve.
If the engine has spent any considerable amount of time on its side since it was last run rip the headers off and see if you still have smoke.
A mate had his bike on its side to pull the engine out and found it smoking badly whenever the pipes got hot.
Problem not there with the pipes removed and engine hot. Put some degreaser down the header (cold unless you want a fire) swirl it and hang it muffler up. A mall amount if thick black goop dripped I out overnight.
Next day light grey smoke when the pope first heated up, then a bit of a back fire and back to normall.


Stupid phone / Tapatalk, apologies in advance.

[unstuck]

It's fucked. Remove the cam and rockers and send them to me and I will send you some that are already worn in.:blip:


Sounds like the oil ring, like that duke freak said. Or the pipe is somehow filled with oil, or a valve guide is shaggered. Send the whole lot to me, and I will send you a perfectly running 125 version to chuck in it.:2thumbsup

[SJizzle]

It's fucked. Remove the cam and rockers and send them to me and I will send you some that are already worn in.:blip:


Sounds like the oil ring, like that duke freak said. Or the pipe is somehow filled with oil, or a valve guide is shaggered. Send the whole lot to me, and I will send you a perfectly running 125 version to chuck in it.:2thumbsup

Hahaha will I get it back when you're done? Lol

[SJizzle]

You definitely want bike oil I there. Bikes use the same oil for their tranny as engine. Won't cause your smoke in such a short time , will happily cause your tranny or engine to wear at some point in the future as it becomes less slippery every time it passes through the gearbox.

Smoke is blueish or smells of oil I'd check the head gasket.
Black and stinks of fuel check you have not dropped a valve.
If the engine has spent any considerable amount of time on its side since it was last run rip the headers off and see if you still have smoke.
A mate had his bike on its side to pull the engine out and found it smoking badly whenever the pipes got hot.
Problem not there with the pipes removed and engine hot. Put some degreaser down the header (cold unless you want a fire) swirl it and hang it muffler up. A mall amount if thick black goop dripped I out overnight.
Next day light grey smoke when the pope first heated up, then a bit of a back fire and back to normall.


Stupid phone / Tapatalk, apologies in advance.

mate you might be right about the exhaust thing. I will rip it off today and give that a go. The problem only started once the pipes got home. And it did that before also when I just changed over the piston and head of the old motor. Runs fine with no smoke without the exhaust on and ran fine with no smoke for around five maybe ten minutes until the pipes got hot. Degrease and waterblast on the cards today lol

[unstuck]

Hahaha will I get it back when you're done? Lol

Your thinking too far ahead. :lol: Oil is getting into somewhere large amounts of oil are not supposed to go. Like all things mechanical, it's a process of elimination. :2thumbsup

[neels]

Has the engine you've put in been sitting for a while?

I've had a few bikes that have been parked for a long time, smoked quite a bit and used oil until everything settled back in again, I'd try getting it hot a few times and see if it gets any better before I started pulling things to bits.

[SJizzle]

Has the engine you've put in been sitting for a while?

I've had a few bikes that have been parked for a long time, smoked quite a bit and used oil until everything settled back in again, I'd try getting it hot a few times and see if it gets any better before I started pulling things to bits.

yes it has from what the guy told me. it's been sitting for a wee while. I think changing the oil and filter should be the go today, also running car oil in it wasn't a good idea, I checked both the exhaust ports and there doesn't seem to be any oil in them, just carbon built up. also the intake port is clean as a whistle. I got some castrol 10w40 motorcycle oil for it today so I will need to put that in. It should do the trick hopefully. valve clearances are spot on also. exhaust at 0.10 mm and intake at 0.05 mm

[unstuck]

Inlet :0.03-0.08mm, Exhaust:0.08-0.13mm. :scratch:

[Tazz]

yes it has from what the guy told me. it's been sitting for a wee while. I think changing the oil and filter should be the go today, also running car oil in it wasn't a good idea, I checked both the exhaust ports and there doesn't seem to be any oil in them, just carbon built up. also the intake port is clean as a whistle. I got some castrol 10w40 motorcycle oil for it today so I will need to put that in. It should do the trick hopefully. valve clearances are spot on also. exhaust at 0.10 mm and intake at 0.05 mm

Have a read and make your own mind up regarding the oil. You don't have to believe all the marketing hype that others do. There are some very good threads scattered around the internets on the subject ;)

The correct weight is definitely important though, like any vehicle.

[SJizzle]

Inlet :0.03-0.08mm, Exhaust:0.08-0.13mm. :scratch:

Yeah sounds about right mate

[nodrog]

What mechanics do you work at? So we can avoid it.

[SJizzle]

What mechanics do you work at? So we can avoid it.

Lol ha ha ha funny guy. The type of cars I work on are incomparable to motorcycles mate. Two different worlds all together

[SJizzle]

Lol ha ha ha funny guy. The type of cars I work on are incomparable to motorcycles mate. Two different worlds all together

So I pulled apart the old motor. Nothing is wrong with it all except the clutch being burnt out. Bummer. Looks really clean besides the clutch

[nodrog]

Lol ha ha ha funny guy. The type of cars I work on are incomparable to motorcycles mate. Two different worlds all together

Are they electric cars?

[SJizzle]

Are they electric cars?

I do work on some hybrids but mostly European BMW Mercedes, Audi, Volkswagen, Old Cars such as Oldsmobiles,Cadillacs,Fords, Also the run of the mill japanese 4 cylinders and above, even light trucks,toyotas,nissans, whatever has an engine can be worked on, so yeah the only mistake I made was assuming motorcycle oil and car oil were similar,turns out they aren't :(

[BuzzardNZ]

Lol ha ha ha funny guy. The type of cars I work on are incomparable to motorcycles mate. Two different worlds all together

Do you put bike oil into the cars you work on? ;)

[bogan]

Do you put bike oil into the cars you work on? ;)

I do, in fact I run it through my bike first so it loses enough Ws to suit the van.

[unstuck]

So basically the motor has been upside down and all around before you got it, and stuck it in your bike. :2thumbsup

[SJizzle]

Do you put bike oil into the cars you work on? ;)

Nope. Fully synthetic oil lol you guys are too much ae

[MVnut]

Burning GN250 ???? best thing that could ever happen (to all GNs) some of the worst bikes ever built:lol: :lol:

[SJizzle]

Burning GN250 ???? best thing that could ever happen (to all GNs) some of the worst bikes ever built:lol: :lol:

Problem sorted. Left it draining the whole day and then chucked a new oil filter and some Castrol Power1 GPS 10w40 semi sythetic oil in and no more smoking or burning oil yay. Took her for a long ride and she seems mint. Riding beautiful. But I found its a bit small for me even though im only 5'8 but I'm around 220 pounds. Thank my south african genetics for that

[SJizzle]

Burning GN250 ???? best thing that could ever happen (to all GNs) some of the worst bikes ever built:lol: :lol:

Problem sorted. Left it draining the whole day and then chucked a new oil filter and some Castrol Power1 GPS 10w40 semi sythetic oil in and no more smoking or burning oil yay. Took her for a long ride and she seems mint. Riding beautiful. But I found its a bit small for me even though im only 5'8 but I'm around 220 pounds. Thank my south african genetics for that

[SJizzle]

So basically the motor has been upside down and all around before you got it, and stuck it in your bike. :2thumbsup

Hahahaha pretty much. It layed on its side and slid around the back seat of my beemer before I got it up to Auckland on the way from rotorua. But naturally I had it in a box with the seat belt tucked around it like a little baby

[SJizzle]

I do, in fact I run it through my bike first so it loses enough Ws to suit the van.

Lol good on you bruv. Wouldn't recommend that though

[Drew]

What mechanics do you work at? So we can avoid it.This seemed a bit premature, given the info the guy had supplied...Untill I read this!


So I pulled apart the old motor. Nothing is wrong with it all except the clutch being burnt out. Bummer. Looks really clean besides the clutchWhat sort of mechanic doesn't pull a running motor apart, that simply has no drive but isn't making horrid noises?


Lol good on you bruv. Wouldn't recommend that thoughMany of us have been doing exactly this for decades. Prolly wouldn't do it with a GT3 or summat, but in a shitty old petrol van, fuck yeah.

[Big Dog]

Problem sorted. Left it draining the whole day and then chucked a new oil filter and some Castrol Power1 GPS 10w40 semi sythetic oil in and no more smoking or burning oil yay. Took her for a long ride and she seems mint. Riding beautiful. But I found its a bit small for me even though im only 5'8 but I'm around 220 pounds. Thank my south african genetics for that
Bollocks.
Too small is a frame of mind... especially when you are modding it already.
Nice wide bars, bigger tank, flat seat, high pipe and some chunkier tyres... brilliant!!!
I rode my wife's GN for a few months while I sorted out buying a more viable commuter.
I thought it incredibly small, especially for my 6'4" 310lbs.
That is until I put wider bars on it, a gs550 master cylinder, decent tyres and ditched the ego.

I wanted to get a flat seat and a high pipe, turn it into a scrambler. The mrs wanted to sell it. It was sold...
It was jolly good fun but would have been a money pit to keep when we did not need it.

[Akzle]

lose some weight you fat fucks

[Big Dog]

lose some weight you fat fucks

I'm a little deaf sonny, did you just say you want to fuck my fat?

[Big Dog]

lose some weight you fat fucks

To be fair, my optimum body weight is 265lbs.
Any less and I look like a sack of coat hangers.

[AllanB]

NZ has been metric since 1967.......

[Akzle]

NZ has been metric since 1967.......

some people are opposed to progress.

[Big Dog]

NZ has been metric since 1967.......

To metric it up 194cm 140 kgs. Ideal weight 120 kgs.

I had to convert it for the OP who posted in imperial.


Stupid phone / Tapatalk, apologies in advance.

[SJizzle]

some people are opposed to progress.

Fine. Im around a hundred and ten kgs and bench almost twice that. So yup oldschool is cool

[Drew]

Fine. Im around a hundred and ten kgs and bench almost twice that. So yup oldschool is cool

Are you Kerry Dukie?

[ducatilover]

Many of us have been doing exactly this for decades. Prolly wouldn't do it with a GT3 or summat, but in a shitty old petrol van, fuck yeah.

I reckon the oil from the rally car should be good as in my cage, seeing as it's only doing one event between changes :2thumbsup

[Drew]

I reckon the oil from the rally car should be good as in my cage, seeing as it's only doing one event between changes :2thumbsup

Yip, oil comes out of the sidecar and is used in the cars.

[ducatilover]

Yip, oil comes out of the sidecar and is used in the cars.

Bloody expensive shit to waste eh? It's me doing my thing for the environment

[unstuck]

Bloody expensive shit to waste eh? It's me doing my thing for the environment

Strain it through your stockings first do ya? :whistle:

[ducatilover]

Strain it through your stockings first do ya? :whistle:

You wanna watch?

[unstuck]

You wanna watch?

Maybe, as long as you let me sit in the rally car. I promise not to touch anything.:oi-grr:

[ducatilover]

Maybe, as long as you let me sit in the rally car. I promise not to touch anything.:oi-grr:


:crazy: hmmm. Dunno bro

[SJizzle]

Are you Kerry Dukie?

Hahaha firstly I dont know who that is. No im not lol im just me

[SJizzle]

To metric it up 194cm 140 kgs. Ideal weight 120 kgs.

I had to convert it for the OP who posted in imperial.


Stupid phone / Tapatalk, apologies in advance.

Lol imperial and metric. Its all the same. Ha ha ha