I am stumped... Suzuki FA50 problems please help

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Wheelman-111
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Re: I am stumped... Suzuki FA50 problems please help

Post by Wheelman-111 »

Greetings:

Yes, there's likely an oily mess if a seal is weak at high RPM. By no means is this the only possibility. Obstructions to high flow that don't affect idle and low-speed operation can include intake, carb fuel obstructions - even a fuel filter - and exhaust crud. Another hunch based on personal experience; if there's a vacuum-operated fuel valve of any sort, make sure it doesn't close when throttle is wide open. Good luck.
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Re: I am stumped... Suzuki FA50 problems please help

Post by kingdele »

Wheelman-111 wrote:Greetings:

Yes, there's likely an oily mess if a seal is weak at high RPM. By no means is this the only possibility. Obstructions to high flow that don't affect idle and low-speed operation can include intake, carb fuel obstructions - even a fuel filter - and exhaust crud. Another hunch based on personal experience; if there's a vacuum-operated fuel valve of any sort, make sure it doesn't close when throttle is wide open. Good luck.
There is no leakage of any kind coming from the engine, I have a new and extremely clean carb and the exhaust is unclogged. The fuel valve is one that only flows when engine is running but does have a ÔÇ£primeÔÇØ position which lets the gas flow when it isnÔÇÖt running and that position doesnÔÇÖt change the problem.
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Re: I am stumped... Suzuki FA50 problems please help

Post by noiseguy »

So we're back to electrical issue and main jetting.

- Did you check the plug wire and cap? On some caps, the underside of cap (that attaches to plug) has a metal part that unscrews... contains a resistor, and can corrode. Again, quick to check. Any sort of corrosion on these parts can create a sort of low-pass filter that keeps the engine from running at higher RPMs while not impacting idle.

- Do you have a larger main jet you can install to see if this clears up issue? Something 5 - 10 pts higher than current? Or an extra jet you can drill out to next size up? What you describe sounds like extreme lean bog at higher RPMs.

- You have the factory airbox and element... right? B/c that will cause lean bog as well. Just looked at the factory filter box... looks like a foam insert. Did you check it for rot?

Past that, agree carb is probably clean or it wouldn't idle. Reed valves would impact idle / mid-range, likewise air leaks. I'll take your word for clean exhaust, and assume you checked the exhaust port for plugging.
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