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Beta Evo 300 4t backfire

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Hi Guys

My bike has started backfiring almost every time I give it more than a blip on the throttle, does anyone have any ideas where to look first?

 

Regards

 

Andy

  • Author

Sorry should have said I have fitted a new plug

Does it pop on the overrun? Air leak in the exhaust?

Edited by spen

The rubber inlet manifold is not great. Inspect for any cracks or poor fitting. 

Mine had a poor connection between the carb and intake boot, I also fitted a air screw adjuster makes all the difference.

  • Author
On 22/01/2017 at 10:24 PM, spen said:

Does it pop on the overrun? Air leak in the exhaust?

Yes only on the overun, should you use exhaust sealer where the front pipe meets the back box?

Generally an air leak on the inlet will cause the revs to 'hang' when you shut off, a leak in the exhaust can cause popping. Doesn't hurt to seal it.

Slacken off all the mounting bolts before snugging down the joint to the cylinder head (assuming gasket there is okay).  It could also be a leak at the pipe/silencer join - sometimes exhaust clamps can become "bound" and need relieved with a hacksaw to allow full pressure on the pipe.

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