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Motorcycle Repair/79 cb 650 honda


bike has no power when cold I have to pullthechoketo keep it running and when hot bike is hesitant
In taking off . I have brought my bike to several mechanics and no good result came I hope you can help me
Thank you

Hello Peter,

I can't see how several mechanics couldn't diagnose the problem, but my first guess would be, low cylinder compression.
This could be due to cylinder-wall/pistons/piston-rings, or, simply to low valve clearance.

As I mentioned, this would be a "guess" and my first measurement, but if you provide me feedback to the following questions, I could be more accurate.

a)Did this happen after a long "sitting" period, or from one day to the other?
b)After a carburettor overhaul?
c)After valve clearance adjustment?
d)Have cylinder compression been measured and if yes, what were the results?
e)Have ignition system been checked, spark plugs replaced?
f)Have you tried emptying the fuel tank end fill with fresh gas?
g)Have you checked engine oil level? Is it by any chance overfilled and/or strongly smells like gasoline?

Take the time to answer these questions and bear in mind that most of the time, the biggest problems hide behind the smallest details.
Experience taught me, before searching on the moon, check under my nose...

Looking forward for your reply and will be a pleasure to sort this out.

Best Regards,

Motorcycle Repair

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Lazaros Ampatzidis


I can help you on EVERY issue involving POST-1980 Japanese Motorcycles plus KTM and Husaberg. My field of expertise includes Engine, Transmission, Fuel system (carburation & EFI),Electrics and Electronics. Maintenance, repair and tuning. Road and off-road suspension tuning. Please don't ask me about non-Japanese Motorcycle, especially American built on which I have low to zero experience.


I'm a rider and hobbyist since childhood. 25 years motorcycle workshop mechanic.15 years motorcycle racing mechanic. In order of experience high to low:Kawasaki,Suzuki,Honda,Yamaha,KTM,Husaberg.

Hellenic (Greek) Technical School.Internal Combustion Engines Engineer. Automotive Electronics.

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