Mechanical advice needed?

[Lias]

My GN250 is not well.

Its a new bike, and thus hopefully it will be covered under warranty. Its booked into road and sport in a few hours, but I thought I'd run its symptoms past you guys and see what you have to say.

Bike had its 1000km service just over 2 weeks ago, full oil change and all bits. They said that my tappets would need adjusting at the next service (6000km), but otherwise all was fine.

Since then I've racked up ~1800km's on it , with my big cruise to wellington, a trip to west auckland, and a nice sunday cruise yesterday.

The last week or so I've noticed the bike backfire a few times, something it hasnt done before. This didnt have me too worried until this weekend. I went out for a nice sundaty cruise around the waikato yesterday afternoon (Hamilton -> Cambridge -> MataMata -> Morrinsville -> Hamilton). On the trip I noticed the bike sounding diffrent, and it was particualrly noticable towards the end of the trip.. When I got home I called my missus out to listen to it and she agreed soemthing didnt sound quite right. At this stage I was planning to take it into the shop sometime this week (wasnt too worried yet). This morning thou when I went to jump on it to go to work I noticed that the back of the exhaust is missing! The whole "back plate" of the exhaust has been blown off, and it looks quite stained/burnt. the exhaust also looks quote hollow.. Not sure how much baffling and stuff is supposed to be in there but I dont think its all there, and the back plate is definitly missing. I also checked the oil, and noticed it was WAY down (on the low mark), which also concerned me bloody greatly because it was fine ~10 days ago.

Anyone have any ideas whats happened/gone wrong?

[jrandom]

Keep that oil topped up, whatever you do. GNs eat oil and have a very small sump, which makes them prone to going dry and seizing.

*Every* GN owner has 'Ach, mein Gott, ze oil! He was fine a few days ago!' moments on a regular basis. Just remember to check it before every ride, it's the price you pay for riding an otherwise-great bike saddled with the GN's design flaws.

The exhaust just sounds like a shoddy build job falling to pieces. It'll be covered under your manufacturer's warranty; you shouldn't have any trouble convincing the shop to sort it all out for you at Suzuki NZ's expense.

[Lias]

Just shot downstairs to show the munted exhaust to Wolf, and with the bike cooled down and on its center stand on a definitly plat area, the oil looks ok.. So hopefully it was just an uneven bit of ground the bike was on when I checked it before.

Wolfs comment at the state of the exhaust was unprintable thou :-)

[Wolf]

Yeah, looks kinda rooted. Anyone's guess (or a mechanic's knowledge) whether there should be anything down inside the deep dark hole of the exhaust. Back plate gone, two rivets missing, remaining two munted, lotsa carbon everywhere.

And LiasTZ is wrong - I've seen way worse than what I said printed on this very forum.

[strayjuliet]

Wolfs comment at the state of the exhaust was unprintable thou :-)

Wolf's comments are always unprintable. :killingme
Not good about ya bike LiasTZ, hopefully the servicing will sort it out for ya, oh and I'm keeping a note on the problems you are having so that when I get my gn i will have an idea of what is wrong. Just thinking maybe it dont like all those long trips you been having on it. :spudwhat: Hope you get it sorted.

[Silage]

My GN250 is not well.
The last week or so I've noticed the bike backfire a few times...

It sounds like the backfire may have shot the backplate off the muffler, but it would have to be poorly fitted as well.

I suggest you get them to check and adjust the tappets now (if needed). My GB, at considerably greater age and km, backfires if fully throttle off coming into a corner or a stop. I think it has a burnt valve ie burning gas getting past the valve. The same could happen if your tappets are tight.

[Ixion]

It sounds like the backfire may have shot the backplate off the muffler, but it would have to be poorly fitted as well.



Might just be crappy workmanship (I believe these bikes are now made in China). Air leak into the exhaust system (due to bad assembly) can cause backfiring. The backfiring blows the end off the silencer, aided by said crappy workmanship.

[Wolf]

The backfiring blows the end off the silencer, aided by said crappy workmanship.
I hope there wasn't supposed to be any sort of insert in the zorst - bad enough a plate blowing loose, imagine being hit by a hot, soot-covered pipe with holes drilled in it...

[jrandom]

I hope there wasn't supposed to be any sort of insert in the zorst - bad enough a plate blowing loose, imagine being hit by a hot, soot-covered pipe with holes drilled in it...

It'd leave a nice 'BBQ grill' pattern...

[Lias]

The dude at the counter was quite impressed with it, but the mechanic sort of shruged and said "its fucked".. They said its ok to ride on for the moment, and they will ring me after they talk to suzuki.

[Ixion]

..the mechanic sort of shruged and said "its fucked"..

Note the technical terminology there. You need to do a 4 year apprenticeship before you can bandy technical stuff like that around :whistle:

[Wolf]

Note the technical terminology there. You need to do a 4 year apprenticeship before you can bandy technical stuff like that around :whistle:
We use similar technology in the IT field - and you've got to have CompTIA's A+ or equivalent experience in the field.

[Ixion]

We use similar technology in the IT field - and you've got to have CompTIA's A+ or equivalent experience in the field.

In IT it would be fsck'd

[Wolf]

In IT it would be fsck'd
Only in the world of RealOS(tm) in MicroShaft's world, it's just "fucked"

[Jackrat]

I hope there wasn't supposed to be any sort of insert in the zorst - bad enough a plate blowing loose, imagine being hit by a hot, soot-covered pipe with holes drilled in it...

Actualy there's a young lady (she was at the time)down Hamilton way, that could tell you just what that feels like. :whistle: :o

[John]

Ah sorry to hear about this, sucks when your bike decides to fuck itself.

But at least it sounds like a beast now, until you get a new one or it gets fixed, good luck!

[Wolf]

Ah sorry to hear about this, sucks when your bike decides to fuck itself.

But at least it sounds like a beast now, until you get a new one or it gets fixed, good luck!
Yeah, but sounding "like a beast" can have it's down side - like cops tend to notice you more. Years ago my old TS125 used to keep the muffler bandage market afloat single handedly and in between applications of muffler bandage it used to sound like an incoming squadron of heavy bombers - like riding around with a target painted on your chest.

I swear cops homed in on me from the far side of town.

"A noisy bike is a safe bike" is a workable argument when you're a six-foot-six patched gang member on a Harley or a Norton but doesn't go down as effectively when you're five-foot-seven, scrawny and riding a TS125...

[John]

Yeah, but sounding "like a beast" can have it's down side - like cops tend to notice you more. Years ago my old TS125 used to keep the muffler bandage market afloat single handedly and in between applications of muffler bandage it used to sound like an incoming squadron of heavy bombers - like riding around with a target painted on your chest.

I swear cops homed in on me from the far side of town.

"A noisy bike is a safe bike" is a workable argument when you're a six-foot-six patched gang member on a Harley or a Norton but doesn't go down as effectively when you're five-foot-seven, scrawny and riding a TS125...
Yea I got alot of attention when my header bolts popped off the ZZR, hell even the rugged harley ridders gave me the nod, and it was a 250 LOL!

And I'm 5'6 and 55kg so the cobblers showed much interested one asked what was going on I said the header bolt fell off he told me to fix it right away, as it was way to audable. :9

[Wolf]

I said the header bolt fell off he told me to fix it right away, as it was way to audable. :9
Bombing down Norton Road (50k zone) well in excess of the speed limit (as "well" as you can get on a 125cc Road/Trail, anyway) come to a halt at the rail crossing at Rifle Range Road and a cop pulled up behind me and did the "fweep" on the siren to signal me to pull over. I nodded and pointed across the lights hile my heart pounded and I did the "Christ, how long has he been behind me?" thing.

Lights change and I park up on the other side of Avalon Drive on Rifle Range and he stops behind me.

"What's wrong with your baffles?" he asks.

"The exhaust pipe's fucked" I blurted, overwhelmed by relief that he hadn't said a thing about speed.

"Get it fixed, it's way too loud." And off he went, didn't even dress me down for public obscenity which was an offence in those days.