Just wondering what you have done with radiator layout.
After a few minuits in slow moving traffic (i know you will say go round it) the temp shoots up and does not drop, even if the fan cuts in, until up to 40mph+
I took the radiators off today and the bottom is caked up so that is being cleaned and the top is very mis-shaped i know this will make a difference but i dont think enough...the radiator are connected in parallel which seams strange as they would surely flow half the coolant where as if they were in series thay would both flow all the coolant....
so would it be a good idea to modify the set up to flow round the top rad then the bottom or leave it as is?
i will also add fans to the top rad but i still think it will get to hot....

(if you understood that then im impressed and please help!)

cheers

Matt

Its just what happens dude. The NC30's get very hot and there isn't much you can do about it. Some on here have spent £500+ on new rads from Rick Oliver that are supposed to be much better but if you can't afford that all you can do is keep moving. Surely on a bike its not very often that you are stopped for long periods of time is it?

well its my first proper motorbike and i not been on it long but i dont do the whole "aim for oncoming traffic to make up a few second thing" im happy waiting but not with the temp....

All bikes get very hot in traffic. Trouble is with the NC is the lower rad gets clogged very easily due to its location and thats the only one with a fan so when it's blocked the fan does virtually nothing.

When its in fully working order it shouldn't overheat but it will still get very hot.

Druid

Clean the rads mate. The lower rad, if blocked or mucky, is useless...

There is a "HRC" mod where they did block some of the outlets, on kit rads, to make the flow go in series rather than parallel.

I have the pic/gif at work and will post it tomorrow. EDIT >>



These bikes do run bloody hot - I do not use a fan anywas and I have 2 lower rads I swap fairly regularly so I can keep one clean and sorted at all times.

I also only use water as it is the best coolant available.

I've changed my rad setup just the way you described at the top. Will also be using an electric pump, controlled to always aim for a set temp (not starting at all 'till the ideal temp is reached, and then varying its speed to keep the coolant always at the set temp). Should let the engine warm up pretty fast, and never, ever over heat, I guess.

/Lasse

I have seen this 'HRC' mod before, but I can't see why this should be better, and I miss some proper testing of this issue.

The standard routing connects the rads in parallel which make the flow rate in the rads 'slow' since the rads are sharing the amount of cooleant delivered by the waterpump. This gives more time in the rad for the cooleant, but only in 1 rad.

The 'HRC' setup will connect the rads in serie which will make the flow rate 'high' since both rads will handle all the cooleant deliveresd by the waterpump. This will give less time in the rad for the cooleant, but it will have to pass 2 rads.

I'm pretty sure the reason for couple the rads in seriel is fewer hoses = less maintainence time which is important on a racebike.

By just blocking off the in/outlets as suggested it will be impossible to have all the air removed from the system.

I see it that the coolant has to flow through the cores and by doing so will dissipate more heat due to the exposure to both rad central cores on the way through the system.

Agreed about ease of maintenance too - good call.

That HRC setup was what i was considering but i see what you mean about the slower flow through both rads.
I have tried to clean the bottom rad by soaking it over night in a penetrant spray then blowing it out with compressed air but it has really made no difference. i think i will leave the top one as is (but with fans) because after looking at the "Excelent Condition" eBay ones mine must be "Brand New Never Used"

So how do i go about cleaning the radiators?

Have you flushed out the system too?

If you have the rad off the bike and have soaked it overnight, Gunk is good to use as its' made for removing gunge, grime etc, hose the dirt off the fins (with a hosepipe not a pressure washer or it's bye bye fins.)

I also use an old paintbrush to really rub the gunk / degreaser into the rad while i'm cleaning it.

After you've cleaned the gunk off it stick the end of the hose into the rad and flush it through with loads of running water until no crap comes out, do this from both ends of the rad, flush the engine too.

If loads of crap comes out you can get chemical treatments you run in the system to descale them.

While you have the rads off, whip the cover off the waterpump and make sure its ok, and test the thermostat by dropping it in freshly boiled water and making sure it opens.

As druid said, if the bottom rad (with the fan on) is clogged up air will not pass, so the fan comming on will not cool the coolant down when your idling.

If you have lots of bent fins you can get a 'radiator comb' which will help you straighten most of them up.