Overheating and Electrics Issue NC30

[DavieBob]

Hi there

I bought a NC 30, Japan import, 2 weeks ago, I started to notice a few things that I need advice with. The engine has overheated once going well into the red and since then has a habit of running very warm, also, my electrics seem to have a life of their own with the speedo light sometimes working and sometimes not. I wondered whether the fan may also have a bit of issue with consistency on coming on.

Any ideas?

A bit of a side issue, the bike has a 'race can', the seller advised that the link pipe was cut so it could be fit on, I am looking to replace it as the bike has been dropped a few times and the can has seen better days, is there anything I should be aware of when buying a replacement. (Also any recommendations on fairing restorers and repainters appreciated around the Scotland area)

Cheers
Davie

[Cammo]

I bought a NC 30, Japan import, 2 weeks ago, I started to notice a few things that I need advice with. The engine has overheated once going well into the red and since then has a habit of running very warm, also, my electrics seem to have a life of their own with the speedo light sometimes working and sometimes not. I wondered whether the fan may also have a bit of issue with consistency on coming on.

These bikes do run hot, but it shouldn't get into the red. Is this when you're riding the bike or when it's stationary?

Easiest way to sort it is to flush the radiators out with plenty of water (drain bolt on water pump cover), fill it up from cold when the bike's running to prevent air locks, squeezing the water hoses as it fills.

You could also check that the thermostat is operating properly by removing it and dropping in a pot of boiling water, but I'd see how it goes after a radiator flush first. The fan doesn't make much of a difference unless the bike is very hot and statinary (e.g. sitting in traffic). I've removed mine and have no probs in the hot Aussie summer.

Regarding dash globes, they can sometimes be a bit finnicky making electrical contact in their holders. Pull them out from behind the instruments and see that the're seated properly in the rubber holders.

[Dynamohum]

As well as doing what cammo has advised it's worth checking both radiators are flowing air through them as they tend to get clogged with road debris flies etc through time and a lot of the fins get flattened The lower in particular takes a fair bit of punishment due to the proximity of the front wheel . Drain the coolant remove the rads and hold them up to the light and you will see if the airflow is restricted.
There was a place in Fife that did repairs repainting bikepaints in Cupar muir I think

[Neosophist]

Yes.. 25 years of neglect can soon be sorted with an afternoon.

Full check of cooling sytem wont take you more than a couple of hours.

Points to check.

1. As Cammo has said.. remove the hose from the lower rad that connects to the water pump.. flush the bike through with lots of water from hose pipe.. both ways.. from the bottom of the rad and from the filler cap to clean the rads out. remove the drainbolts from under the front headers too.

2. take the water pump cover off and inspect the fins of the water pump, dont remove the waterpump from the engine without draining the oil though else it will leak everywhere..

3. take the thermostat out and throw it in a pan of boiling water to make sure it opens, while its out blast a load of water in there to flow through the engine and out the water pump end.

if you have lots of corrosion in the system holts do a 2 part chemical / neutraliser cleaner for about 8 quid thats really good

Once youve cleaned your pipes check the rads themselves.

the fan only works on the lower rad so you need to make sure as above that the fins are not filled with road shit, if they are take it off the bike and soak it overnight in a hot bucket of degreaser / washing powder or something water and rinse with hose pipe.. should coem up nice, be sure to rinse throughly.

next check the fan actually works and the fanswitch is ok and you should be good to go.

Japan regularly has long hot summers... high 30s with lots of humidity and these bikes work fine there, same as Aus.

The fan does come on quite late but unless the needle is in the red you shouldnt have issues after clening it.