compression

[lee125]

hi if a can keep my thumb over the sparkplug hole while turning the engine over does this mean that there is low compression as i can keep it on and the bike wont start and by the way the bike is a 1993 honda nsr125r cheers

[puremagic72]

if you can keep your thumb on the hole, then yes you have poor compression.

But first warm the engine up for about 5-10 minutes(go round for a spin).

Stop the engine, take ht lead off and plug, and make sure the kill switch is on.

Then kick it over.

The bike wont start without a plug!!!

Baz.
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Make; cbr929cc blade Year; 2001
Gsxr 750 2000, alstare Corona, Current bike 1999 R6
(1) Kids in the back seat cause accidents; accidents in the back seat cause kids.

[lee125]

thanks mate but i cant warm the engine up as i cant get it to start

[shager]

if there is low compresion try bump starting the bike if that does not work check ur piston and get new rings

[mr jamez]

Get a compression test done for confirmation, your thumb is not very accurate for compression testing

If you have fuel and a fat blue spark then it probably needs a new top end.
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NSR 125F > BROS 400 > NC30 > BROS 400 > Trumpet S4 > '97 VFR 750

[shager]

just thort has the engine got fuel going to it and has it got a spark?

[lee125]

yes the bike has a nice big bright spark and fuel is geeting to the engine fine i will get my local dealer to check the compression tomorrow with a gauge cheers

[lee125]

yes the bike has got a nice big bright spark and fuel is gettin to the engine fine i will get my local mechanic to check the compression 2moro with a gauge cheers