View Full Version : GPZ500 gone bang
Mates GPZ died on motorway the other day. Apparently after stopping to fill up bike was backfiring a bit, then one massive backfire and engine died. Engine fired up again with starter motor but stopped with thumb off the button. Lots of white smoke too.
This is approx. 300-400 miles after adjusting valve clearances and new air filter. Bike has something like 28000 miles on the clocks.
Any ideas before I head up to the toon to help him fix it? I'm thinking it could be a piston ring.
Cheers
andrewsmith
18-04-10, 11:27 AM
it sounds like the piston rings or a gasket that has sounded its last.
I would strip the block and see what has happened before shelling out for parts.
Was the valve clearances done by a mechanic?
cheers mate thats what i thought.
valve clearances were done by two ham fisted amateurs but i dont suspect thats the problem as bike was definatley running sweeter after adjustment
andrewsmith
18-04-10, 12:14 PM
i would speak to spannerman he'll probs be gave to give a better diagnosis
Spikenipple
18-04-10, 07:19 PM
Lots of white smoke sounds like a head gasket.
dizzyblonde
18-04-10, 07:22 PM
It wasn't a YC, GPZ special was it??:jocolor:
not chris' but one of the same. seems everyone i know has owned one and ive had enough of tinkering with them. bah 180 parallel twins, worst kind of motor.
Spanner Man
21-04-10, 06:15 AM
Good morning all.
GPZ 500= Hand grenade looking for a war!:D
It sounds like a piston issue of some sort, or the head gasket has gone pop! Your best bet would be to acquire a second hand engine, get it running & flog it. Or cut your losses & flog it as a non runner.
Cheers.
MrMessy
21-04-10, 07:01 AM
Just a thought, he did fill it up with petrol and not diesel did he. I got some diesel in my lawnmower and that was terrible to start then kicked out loads of white smoke.
haha yep definatley petrol. he says...
spanner man- do you really think its not worth cracking it open and fixing the problem? it's going anyway when he can afford a fazer but ideally it needs to live for at least another 3000-5000 miles.
davepreston
21-04-10, 09:48 AM
for what the parts etc will cost you id just buy yc's ,then sell on runner and full bike spares when he gets the fazer
right, got the head off with minimal effort (downipe nuts slid off like a dream!). our findings:
1) bores look fine, so piston ring failure doubtful
2) pistons look absolutley hideous, covered in brown cokey stuff. i dont know what they should look like, is this normal, or just from running rich?
3) there doesnt seem to be any trace of head gasket... i am baffled. could it have disintegrated completley?
pics to follow
andrewsmith
25-04-10, 11:56 AM
right, got the head off with minimal effort (downipe nuts slid off like a dream!). our findings:
1) bores look fine, so piston ring failure doubtful
2) pistons look absolutley hideous, covered in brown cokey stuff. i dont know what they should look like, is this normal, or just from running rich?
3) there doesnt seem to be any trace of head gasket... i am baffled. could it have disintegrated completley?
pics to follow
I think the pics are needed.
Item two could be rich running but sounds the motor is facked
yorkie_chris
25-04-10, 01:25 PM
Bit of muck on pistons is normal, deposits from combustion.
Agreed about parallel twins being the worst kind of motor, another shall never cross the threshold of my garage! (and MYC is looking with gleeful eyes at an ER6! NOOOO!)
Heres pics. I know I said we couldnt find the head gasket... I blame the low light levels and crashing hangover but it shows up on the pics :smt105
anyway here you go, mr. kawasaki's finest bag of spanners
Spanner Man
26-04-10, 06:49 AM
Good morning all.
It looks like the lefthand cylinder is somewhat damp. So, maybe you have a carburetor issue. Other than that it doesn't look too bad.
Many moons ago I had a GPZ5 to bits, as it was boiling & bubbling, so a duff head gasket was suspected. Back together with a new gasket, & the bugger still did it! GRRRR! As the customer had a spare engine we swopped the head with the one off the spare motor. Problem sorted.
We assumed that there was a crack inside the head which was allowing the combustion pressure into the cooling system. If you had the same problem theoretically it's possible that coolant is getting into one of the cylinders.
Cheers.
MJC, the reg of the bike your working on doesnt end in LAM by any chance does it?
nah its AOK, altho the bike is definatley far from being AOK :smt040
spanner man- thats interesting, as the coolant was low when we drained it. i'll try the new head gasket first and then consider finding a replacement head.
cheers, Mike
Phew, thats a weight off my mind. Thought the old girl that I sold to a welsh bloke had died a death already! Which would have been unfortunate. Good luck with it, I never dived that far down into the depths of the Geeperz, so cant really offer anything constructive.... Other than gaffa tape, super glue and a hammer 60% of the time work every time :P
Other than gaffa tape, super glue and a hammer 60% of the time work every time :P
worked for kawasaki in the factory too...
yorkie_chris
26-04-10, 02:33 PM
offer anything constructive...
Unleaded marinade and a match :)
Unleaded marinade and a match :)
that would be a beautiful sight
Miss_Undaztood
26-04-10, 05:26 PM
I`m no expert on bikes, a fact which i`m sure will soon enough be all too apparent, but, I have sorted a fair few car engines.
The second picture, the piston on the left, at the top, looks to have a crack in it, although its probably just layers of cokey crap needing cleaned off.
Also the left hand side of the head in the first pic, the gasket around the waterways looks brown stained quite far towards the cylinder, and white smoke comes from coolant getting into the cylinders.
The cylinders look awfy black to me, and the wet blackness inside makes me think the rings on their way out, or valve stem seals.
Fire on a new gasket and rump the head bolts up :)
Miss_Undaztood
26-04-10, 05:29 PM
Good morning all.
It looks like the lefthand cylinder is somewhat damp. So, maybe you have a carburetor issue. Other than that it doesn't look too bad.
Many moons ago I had a GPZ5 to bits, as it was boiling & bubbling, so a duff head gasket was suspected. Back together with a new gasket, & the bugger still did it! GRRRR! As the customer had a spare engine we swopped the head with the one off the spare motor. Problem sorted.
We assumed that there was a crack inside the head which was allowing the combustion pressure into the cooling system. If you had the same problem theoretically it's possible that coolant is getting into one of the cylinders.
Cheers.
If it still throws out white smoke, ( which is actually steam if its a coolant issue ), try running the engine with no rad cap on to and see if it gets any better.
You may even notice bubbles coming through the rad if combustion pressure is forcing its way through.
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