My Chinese 125

[Lawrence]

Did my mod 2 test two weeks ago now, just prior to that I'd bought a cheapo (£200) 125cc bike to practice on and get into work for a week.  The night before my test this POS died on the A12 at about midnight - just suddenly lost all power and then had no compression on the starter.

Anyway, a couple of days ago I took the head off to see the damage, think I got the job done pretty well  :rollin  Thought you guys might be interested in the pictures of the damage done...

Bear in mind that this bike was registered in July 2010 and had under 7500 miles on the clock  :eek  On the plus side I sold it for £100 so got half my money back 

[Tefer]

You can't complain with money spent really as you got £100 back, but bit of a pisser to be stuck out in at night. I would never recommend these cheap bikes, just fall to bits. I remember following a trainee once and she has a Shindogua or something like that, the footpeg fell off in the ride!  :rollin

[Dave48]

You are supposed to put petrol in the tank not nitromethane! :eek

[Lawrence]

Yep, I never expected to keep it for more than a few weeks but it turns out that was a bit optimistic.  £100 for a week and a half practice and commuting wasn't so bad, I passed my mod 2 the day after anyway so picked up the Fazer from my friends house (was in his garage til I passed) and wouldn't go back 

[paul1606]

Confucius he say ...................Its Flucked

[breadlord]

Holy crap, I'm not sure what I'm seeing. Has the piston *melted*?

[Lawrence]

Yep, piston has a big hole melted in it.  Exhaust valve has also melted and the end of the plug is too.  We took the exhausts off to load it onto the trailer and they rattled - turned them over and bits of metal fell out  :lol

[badger]

Jees  :eek  following on from breadlords comments, the damage looks horrendous, would it of been repairable ? i.e. source a new piston and valves etc or would the engine be totally fubar'd and the only economical solution to buy a complete new engine? mainly curious as i've have never stripped an engine down to this extent. Also what would of caused such an extreme failure? cheap parts, no oil, thrashing the balls off of it? I had many years ago a honda cg125 and the engine was bullet proof and outlasted the chassis and frame easily.
badger

[Lawrence]

Not sure on the condition of the bore but I'd guess the block was scrap.  Head was definitely scrap.  Sump will have been full of bits of piston so that may well have screwed the gearbox and clutch... It's possible that it would've been fixable but would've cost more than it was worth.  Bloke that bought it had a spare engine lying about so is going to fit that and then possibly sell it on.

As for the cause of failure, possible overheating caused by oil pump failure, possibly just not up to the job of 40+ minutes flat out down the A12 twice a day...

[badger]

thanks lawrence, made me a bit wiser   i couldn't fault my little 125 although it only ever had 10 minutes or so flat out. at least it wasn't too much of an expensive breakdown. enjoy your fazer 
badger

[Fazerider]

Oil pumps have a pretty easy life so long as there's something there for them to pump.
This looks more typical of a dropped valve: either metal fatigue causes the head of the valve to drop off or over-revving gives the retaining collets at the top of the stem the chance to jump out.

[Lawrence]

Collets were still there - cam cover came off first and the top end all looked ok until the head came off...

Maybe the valve has stuck or something and got a smack from the piston, it was going flat out at the time for a while although I don't know what revs as the rev counter didn't work...

[solorider]

i would say the engine dropped a valve,that would cause the damage shown,it is a shame as the engine is based on a honda cg125,where that was generaly bullet proof the chinese used inferior quality materials,some chinese bikes are ok but most are a waste of money

[Kosmic Kartman]

Jeez Lawrence..."Lost power and died"  :lol

What monster was lurking in your engine?

I'd say valve dropped and meltdown. I've never seen a valve smash a hole in a piston crown like that before, at least not on a 125. Probabley a combination of a few things. Valve, melt down (maybe very lean mixture), and maybe screaming the granny out of it. The valve has obviously bounced about in the top of the pot for quite a few engine revolutions before making its escape.

[slappy]

Its not just cheap chinese bike engines this happens to.Last place I worked at one of the stores guy had a Harley "sportster" and just as he pulled into the bike shed the engine made a horrendous noise.It was a quiet night shift so we stripped the top end and it looked just like your engine.When he got it taken home he found bits of metal in the sump.He ended up having to buy a second hand engine and working over for 3 months to pay for it.

[Slaninar]

A friend drives Chinese Keeway Speed: a 150 cc Suzuki GN look alike. Has worked no problems for the past five years. He bought it new for 1000 euros.

Still prefer Japanese above all.

[chris.biker]

The Japanese factories are all about quality, you check the quality of your own work and the quality of the worker on the process  before yours. Quality is everything. This is not the way in China it appears all they do is copy the shape at best.

[Major Rant]

as he pulled into the bike shed the engine made a horrendous noise.

Its not confined to the Chinese ... I had a fine 6 cylinder BMW "Made in Germany" Uber-motor engine snap its camchain in 1996.

4 years old, 35K miles, full BMW service history - Muffled thud from under the hood - then nothing.
And I wasn't even thrashing it!

Result ... 24 valves that looked like the one in the picture.

Culturally, the Chinese are working on it. They have a fine space program and they make these ...

[Major Rant]

and they make these ...

[His Dudeness]

i'd never trust my life to a chinese motorbike. people gets sucked in buying cheap low miler chinese bikes when you'd be far better off with a well ridden japanese bike.