screaming engine

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apwrigs
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screaming engine

Post by apwrigs »

Need a bit of advice here fellas. Out for a nice run in the sun today on the A, everything going tickityboo all day, then on route home i noticed the throttle response wasn't quite right.
When i pulled up at a junction the engine began screaming, i mean all the way round the rev limiter, tried switching off, nothing kept on going, kill switch, nothing, plug caps of, nothing, in the end i had to place it in gear and stall it.
Very wierd, never happened before nor since. I've gone over the bike looking for faults but nothing jumps out at me. The engine was rebuilt around 500 miles ago and has run as sweet as a nut, so this has baffled me.Any suggestions would be welcome,,,,,,,,,,
All cables checked and free running.
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BAZ
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Re: screaming engine

Post by BAZ »

what year is the bike ie what carbs..
apwrigs
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Re: screaming engine

Post by apwrigs »

76 A MODEL Baz.
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BAZ
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Re: screaming engine

Post by BAZ »

It must be a carb problem, remove them and check the Butterflies are aligned I have a video clip if required.
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Alan H
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Re: screaming engine

Post by Alan H »

Rev limiter? :shock:
Sounds like it needs a damn good decoke.
What plugs are you running? Take them out and check colour.
Proof that four strokes are over complicated
apwrigs
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Re: screaming engine

Post by apwrigs »

Cheers chaps. Alan it would appear you've hit the nail on the head. Just asking around the consensors of opinion is carbon build up.
It was a slow memorial ride most of the day with slow speeds and stop starting etc. This would explain the carbon build up and with a hot engine you have an explosive combination. Never had it before, but there you go, first time for everything.
Last edited by apwrigs on Mon May 21, 2018 2:36 pm, edited 1 time in total.
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Gary66
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Re: screaming engine

Post by Gary66 »

I had this on an X7 just after i had "restored" (made better) it :lol: Had to do the same by wacking it in gear to stall the engine, never done it since in 5 years of ownership :?:
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canaletto5
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Re: screaming engine

Post by canaletto5 »

It sounds like an extreme case of sellf-detonation. Unburnt fuel build up eventually ignites under compression even without a spark. Frightening. Could be coke build up soaking up fuel or too rich a mix.
bod750
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Re: screaming engine

Post by bod750 »

I had this happen to me while touring Switzerland on an RD400, the throttle
jammed open and exactly the same thing happened got so hot it it just
kept on going again as you did stalled the engine.

The aftermath a few months after was when I kicked it over the engine
was solid after stripping it down it had loosened a flywheel weight
and had jammed the crankshaft, lucky it did not happen on the move!

Steve
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BAZ
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Re: screaming engine

Post by BAZ »

Hard to see how an engine can over rev with no fuel supply. even with the carbon glowing..
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