Newly acquired NC30 running issues

[Vfr400/tbird]

I've just got a 89 NC30, it fires up but seems to splutter and finds it a struggle to rev up cleanly past 6k.
So far I've, cleaned the carbs (carb cleaner, air compressor).
Bench sync'd the carb butterfly valves.
Checked all plugs (all between 4.8 to 5.5k resistance).

There is a leak on the exhaust at the connection between front and rear ( left seal).
The battery won't hold charge however I have ran the bike using a booster.
Choke operates effectively.

Where do I go next?
Thanks for any suggestions :)

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[st22041967]

I've just got a 89 NC30, it fires up but seems to splutter and finds it a struggle to rev up cleanly past 6k.
So far I've, cleaned the carbs (carb cleaner, air compressor).
Bench sync'd the carb butterfly valves.
Checked all plugs (all between 4.8 to 5.5k resistance).

There is a leak on the exhaust at the connection between front and rear ( left seal).
The battery won't hold charge however I have ran the bike using a booster.
Choke operates effectively.

Where do I go next?
Thanks for any suggestions :)

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The carbs are really fussy. Carb cleaner and compressed air are probably not going to do it. If your getting a good spark I think a proper carb strip and clean is the way to go.

Let us all know how you get on

Good luck



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[magg]

The engine will not run without the booster connected? If it needs the booster connected to run, what type of booster, just another 12v battery.

[Vfr400/tbird]

The engine will not run without the booster connected? If it needs the booster connected to run, what type of booster, just another 12v battery.

Not quite, it's actually a crypton auto booster ( a massive wheeled charge/booster).
I've not tried it without it on the battery though.


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[magg]

You may want to measure the output voltage of your battery booster, a massive wheeled charger/booster may produce significantly more than 14 volts when connected to an NC30 with a dud battery. Excessive supply voltage can have a detrimental affect on the performance of the ignition control unit.

[Vfr400/tbird]

You may want to measure the output voltage of your battery booster, a massive wheeled charger/booster may produce significantly more than 14 volts when connected to an NC30 with a dud battery. Excessive supply voltage can have a detrimental affect on the performance of the ignition control unit.

This would cause erratic running due to overheating of the charging system and possibly the components within the CDI?
The voltage is regulated at 13.8v but!
It maybe kicking out a great volume of amps than the bikes charging system.
So what your saying is try a new fully charged battery

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[magg]

Provided your charger/booster output voltage does not exceed 15 volts it should not be an issue. If it runs clean up to 5500rpm you may have an issue with the over speed limiter located in the speedo unit. Is the OEM speedo fitted and the 3-pin plug connected to the loom.

[Vfr400/tbird]

That I do not know :/
Does the over speed unit effect running in neutral?


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[magg]

If speed limiter is not detected by ignition unit when ignition turned on, system will misfire on rear cylinders when engine rpm exceeds 5500rpm. Gear selection is not factor.

[Vfr400/tbird]

If speed limiter is not detected by ignition unit when ignition turned on, system will misfire on rear cylinders when engine rpm exceeds 5500rpm. Gear selection is not factor.

Ok so if mines missing that's likely the cause, thanks.
I'll take a good look tommorow.

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