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Discussion Starter · #1 ·
My bike has a real tough time starting. I’ve tried changing spark plugs, air filters, batteries, voltage regulators and cleaned the petrol.
The bike will turn over but spurt and struggle to start. Sometimes you can’t even hear the combustion.

I’ve included a video of me trying to start it so hopefully that will help.

Wont start
 

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2008 YZF-R125 (180cc)
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well done on doing the steps you've taken - they are all sensible thigns to have checked first :)

does it run ok once it is going or is it sluggish/slower than you'd expect. If it's also slower than it should be when it IS running, then could be a compression issue. E.g. what's the top speed? That's a reasonably good indicator of the state of the motor.

If you have compression issues chances are it would be sluggish and top speed wouldn't be quite what it ought to be. I think mine used to do about 82/83mph on the clock flat out while she was 125cc in case that helps as a reference.
 

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It is a fact that you need to check the valves, maybe they let go. And it's hard to start the engine. I had poor compression, the motorcycle rode max 110 km / h.
 
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