Engine completely failed, no compression

[The Artist]

This isn't asking for advice just telling you what happened.

Ragging it today on my Gs125, very hot as I had been stationary for a while and had been out a while already.

Anyway, suddenly it died. Pulled over and there was almost no compression.
Wheeled it home where me and Chris took the cam cover off and found that one of the tappets had come loose and the little lock nut had come off meaning the inlet valve was doing nowt.
Popped it back on and it was fine.

Lesson learnt. If valve clearances need doing, check locknut is tight

[joan_worthy]

Sound like what happened to me on my cg125... Difference is - i was in motion at the time, doing 'some' speed on an A road at 1am. Scared the shit out of me as the back wheel locked up because the collet dislodged a valve, the piston had smashed the valve completely bending it, knackered the piston which had in turn screwed the barrel...

[The Artist]

I was doing 60 round a corner overtaking a mate

Embarrassing slowing to a stop. Back wheel didn't lock up thank god.

[joan_worthy]

Sorry read it wrong, thought you said you were stationary... Lucky you didnt lock up, going round a corner

[N cee thirty]

hmm don't think i'll touch my valves now if you can't get it right D:
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[joan_worthy]

I think my problem wasnt that i had done it wrong... More probable is that its because they were never done... Plus i used to ride it to its limits... Use to do 25 mile trip to work and then back every day at full throttle, pegs to the floor on every corner... You know, the usual stuff

[Blue_SV650S]

Surely you should have noticed a gradual power loss as it gently undid, not just a sudden loss!?
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The purpose of life is to fight maturity.

[27cows]

One of the numerous reasons I love 2 strokes
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The RXS100: vehicle of choice for Chuck Norris

[The Artist]

Any tips to make sure locknut doesn't come undone again? It lasted for about 3 months since I last adjusted them, maybe the heat today just loosened it somehow.


I will try and get hold of a couple of nuts exactly the same to lock onto each other sometime but for now what shall I do?

[The Artist]

Now that you mention it, I just remembered, for about 200 metres before it happened a tapping noise from the bike. I thought it was my loobman hitting the teeth on the sprocket. Completely forgot about that noise.

The power loss was minimal before hand, like I said I was full throttle overtaking someone round a bend which was fun till power loss. The actual tappet hadn't moved much but the locknut was the problem I think wedging the valve.

[27cows]

The obvious answer would be to use Lock & Seal or similar thread locking compound.
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The RXS100: vehicle of choice for Chuck Norris

[joan_worthy]

Nope... Held a steady ??mph and all of a sudden the rear locks. The valve had come out of place, dropping into the piston chamber jamming the piston down, all of this happened VERY quickly

[The Artist]

[Alexio]

Clearly you require either some blue tac, sticky tape or super glue
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will never give up his CG. I look at my fuel gauge more as a progress bar than a fuel gauge.
G: With my GSXR I do often effectively use it as a scooter with a clutch in town.
ms51ves3: why does it need 500 miles? Are you teaching it how to be a piston?

[Blue_SV650S]

Tappet locknuts have been around since the dawn of time being ... well just done up, don't see the needs to do anything special to stop it coming undone!!
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The purpose of life is to fight maturity.

[joan_worthy]

A garage had recommended lock-tight to me... Besides most things like that will say what levels of temperature etc they can withstand

[neil.]

Very weird, never ever had them work loose on the YBR after lots of miles and adjustments and that's a SOHC as well. I'd just do them up tight but not stupid (thread strippingly) tight.
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CBT February 2008 | A2 June 2008 | Yamaha YBR125 (written off) | Honda CBF125 (current)

[27cows]

[Cigaro]

It's happened to me before. I think the locknut must have got wedged under the other rocker arm though as it came out oval-shaped

[The Artist]

It is still confusing me how it came undone. Ah well, I am waiting till it is cool again to adjust because just been to work and they were only set by eye yesterday.

[temeluchus]

I wouldnt use any thread lock. The Adjuster and Locknut, I would be tempted to replace as they can wear.

The upside with the oldschool rockers and locknut adjusters is they are more likely to fail like this than go tight and destroy your top end like shim adjusted engines.
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Some shite cruiser. Now with guns and FREEDOM!

[The Artist]

Well coming home today it started tapping again so I crawled home at 5mph for the last 2 miles and it didn't get louder. I am going to tighten and then locktite tomorrow and order a new adjuster and locknut when I can.

[nightshaddow]

[The Shaggy D.A.]

[Alexio]

Clearly you require a welding rod
____________________
will never give up his CG. I look at my fuel gauge more as a progress bar than a fuel gauge.
G: With my GSXR I do often effectively use it as a scooter with a clutch in town.
ms51ves3: why does it need 500 miles? Are you teaching it how to be a piston?