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  #1  
Old 07-20-2012, 10:13 AM
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Default Lean Bog?

     

Right, i've put a new and correct spark plug in my derbi senda 70 and it still isnt running right.
It makes a "Boooooooooooooooaaaaaaaaahhhhhhhhhh" sound in gears; 1, 2, 3 and 4
And it makes a lower pitched "Booooooooowwwwwww" sound in gears; 5 and 6 with no acceleration.

Is this a lean bog? Any ideas welcomed.

Cheers

Sheffy.
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Old 07-20-2012, 10:30 AM
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Default Yes

Yes it could be, but more info needed.
How old is the top end on the engine?
Have you checked the compression?
Is the air filter clean?
Have you checked the fuel flow?

Paw Paw
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Old 07-20-2012, 11:33 AM
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Cheers for the reply, its got : Brand new top end; Good compression; Good fuel flow and a brand new air filter.
I've ordered a new carb to engine inlet rubber as the other one is split. Could this be causing it?

Cheers.

Sheffy
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Old 07-20-2012, 12:11 PM
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Default Yes

Yes, but it could also give you some idle issues as well, but not always.

Paw Paw
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Old 07-21-2012, 09:07 AM
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When warm the bike doesn't idle, I have to rev it up to keep it going. It also hesitates when you crack the throttle from cruising to accelerate. It ran a lot more responsive when I took the air filter off to check. Your opinion?

Cheers.

Sheffy
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  #6  
Old 07-21-2012, 10:19 AM
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Default OK

Ok, what was your compression reading?
Did you instal the new carb boot?
Don't run it without the air filter!
Is the air filter overoiled?
It sounds like your may be running rich, but until the new boot is on and you check the compress it will be hard to tell.

Paw Paw
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Old 07-22-2012, 04:43 AM
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I will get the compression reading tomorrow, when i go to the garage.
I just started it without the air filter.... Don't panic. But it seemed to me as if the idle was more consistant and the throttle response was sharper. So maybe when i put the new 'carb boot' in it will get the correct ammount of air/fuel.
Also the air filter after taking it the the garage, the head mechanic said it may be a little small.

Cheers for the help Paw Paw.

Sheffy.
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Old 07-23-2012, 12:23 AM
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if it runs badly warmed up it is usually a rich condition. if it improves with the air cleaner of, it is more convincing that it is rich. summer time requires leaner jetting to achieve similar performance characteristics to winter, though you likely will always get more power with the colder air of winter, particularly if it is dryer.
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