engine cutting out (not the valve clearance)

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when you say it like that its quite easy to see what your getting at, but i wasnt about to jump the gun and say "hey get your hammer ready" .

and going by the couple of posts that you deleted, neither were you. (yes as a mod i get to read deleted posts lol)

and after all 0.5 of mm on a bent valve is fark all, but who knows his 0.5mm might be 5mm..

anyways this is why i was pushing for the second opinion
 
Yeah I know you can read everything that's been posted then pulled ... but outside readers can't ...

I didn't discount or go against what anyone else said ... and that's the point I'm getting at ...

His statement that his engine was running "better than ever" before his mate got on it over-rides anything else ...

If it already had a bent valve from when he took the head off and put it back on OR the cam timing was out , it would have stuffed up on whoever rose it first ... (Most likely HIM) ...

The ONLY way that could change is if his mate rode / treated it "differently" to how he rode / treated it ... IF the cam timing was out without affecting the engine when ridden "normally" then it wouldn't take much to make a valve "kiss" the piston thru abusive treatment such as I suggested ...

And his ".5 of a mm " is more than likely a lot bigger than he thinks ... LOL ...

At any rate everything that's posted gives punters something interesting to read other than the usual repetitive renditions ...
 
lol.. first of all i took off the head after this happened, then put it back on and the 0.5 is more like a 1-2.

The reason it wasn't idling is because there is less compression and most of it escapes but when u have some throttle it has enough compression to keep going well thats what i think and got of another video but who knows i could be completely wrong.
 
Maybe the mods should make a dedicated engine trouble shooting thread ... complete with a layout template ... something like what Thump*140 did in his carb spec thread ...

It could save a ton of repetitive threads and questions that "annoy" them ...

--------------------------------------------------------------------------------------------------

Engine size , type and brand :

Carb type and jet sizes :

Are the valve clearances and the cam to crank timing (indexing) set right :

Is there spark at the electrode gap of the plug and is the plug the right colour :

Does the compression feel normal :

Has any recent work or modifications been done to it ... if so give complete details :

Symptoms exhibited :

Circumstances leading up to said problem :

And ... Since we've got at least 1 interested reader who wants to learn something ...........

How to do basic tests could also help ...
 
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hey Sean as i have said before i am a mechanic by trade but have actually been a postman for some time now riding a postie bike everyday and let me tell you i flog them having said that i have put these bikes away only to have them not start the next with no compression from a bent valve for no apparent reason,a quick head off and tap with a hammer and we are good to go,thing is dont know why it happens it just does.
 
Valves can become sticky in the guides from congealed dirty oil after a bike has sat for a while ... especially the exhaust valve which also cops carbon getting pulled or forced up the guide ... the weak valve springs can't pull them back up after they are pushed down during an attempted re-start ... so they get bent by the piston on the upstroke ...
 
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Cactus Jack said:
Maybe the mods should make a dedicated engine trouble shooting thread ... complete with a layout template ... something like what Thump*140 did in his carb spec thread ...

It could save a ton of repetitive threads and questions that "annoy" them ...

--------------------------------------------------------------------------------------------------

Engine size , type and brand :

Carb type and jet sizes :

Are the valve clearances and the cam to crank timing (indexing) set right :

Is there spark at the electrode gap of the plug and is the plug the right colour :

Does the compression feel normal :

Has any recent work or modifications been done to it ... if so give complete details :

Symptoms exhibited :

Circumstances leading up to said problem :

And ... Since we've got at least 1 interested reader who wants to learn something ...........

How to do basic tests could also help ...
Click to expand...

funny you say tht..

there was one but im stuffed if i know where is it..
 
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