[Ilmari]

Hi folks,

I have been spending my holidays on my girlfriend's poorly running bike, and starting to run out of ideas (and holidays). The bike is an injected XL700VA with 95,000 kms (57,000 mi) on it.

Symptoms:

• Misfiring and jolting at 1,500-2,000, when throttle opened smoothly.
• After 3,000 rpm, the engine sometimes accelerates on its own without a visible change in throttle position.
• Engine idles well and does not stall at any rpm range.
• When riding, the bike suffers from lack of power at higher rmps and jumps forward at certain rpm thresholds (4,000-4,500).
• Shows no diagnostic trouble codes (checked through the MIL light not blinking).

Checks already done:

• Air filter cleaned & air box checked for foreign objects, leaky gaskets.
• Fuel tank breather & overflow hoses cleaned
• Sparkplugs & caps replaced
• Front spark plug cable replaced (rear cable would require exhaust removal, not easy with old bikes)
• Fueled with new fuel and added injector cleaner
• ECM/ECU connectors & terminals checked (visual, cleaner spray)
• Throttle operation checked and cables tightened to spec.
• Throttle position sensor checked (visual, mechanical operation OK)
• Camshaft position sensor checked (voltage, resistance OK).

I thought you wizards might have good advice on what to do next!

-Ilmari

 

[Bardley]

Fuel pump? Check the pressure and make sure it's not intermittently running.
Also, it maybe controlled by a relay that only feeds the pump with engine cranking/running. Check it's getting the 12v and again not intermittent through the relay working when it feels like it. (Bad connection or internal contacts). Check the earth points.

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