How hot does the NC24 get? I've just got back from a 30mile ride on the motorway, was doing about 95 all the way back and the temperature gauge was hovering around the very top of the white gauge just underneath the red.

Slowing down to say 70mph and it goes back down even further towards the middle of the dial. The expansion bottle was lukewarm when i got home.

Do they always get this hot or do I have a problem? I've noticed quite a few bent fins on the radiator.

The Coolant (50/50 distilled / antifreeze ) is new and as far as me and 3 others can tell has been bled properly.

Also had a new rad cap arrive as the old one was buggard, it's stamped 1.1 on the top (same as the old one) and David Silver assure me its correct.

Had the rad flushed out with 3 part chemical rad flush stuff (not that sandy stuff) as the old coolant was rust coloured, the new stuff is still blue.

Any comments / suggestions etc are welcome.

Many thanks,

Martin.

could be the bent fins on the rad, or much in there
give it a clean, gently, and ensure theres no air in there
i had a similar problem, and it was trapped air in the rad itself

2nd the trapped air........when the coolant is flowing faster the air pocket can cause the temp to be a bit funny for a little bit then it tends to go back to normal.which in your case sounds about right........ :D

I'll try bleedin the fecker some more and see what happens.

Any tips for bleeding it?

From what I gather running it with the cap off till the stat opens and lets the water circulate and the air bubbles come out, snap the throttle a few times too?

Sound about right?

yeah,the manual says just to blip the throttle a few times and that should be enough to see bubbles at the top rad....
hope all is well :D :D

also try squeezing the 2 hoses on the bottom. This should release any air pockets thats trapped.

right, squeezed the hoses etc, 99% sure their is no more air trapped in the system.

after about 35 mins of A road driving, say a steady 50 - 60mph, the temp gauge is sitting at the very top of the white line.

I'm gonna dig my old rad cap out and try that as the water in the expansion bottle level didnt' change and was freezin cold.

It's a brand new cap from dave silvers but before I flushed out the old manky coolant and changed the cap as part of a service, the temp used to stay mid-way unless it was idling for a long time.

Any other suggestions?

update!

I put the old cap on last night to rule out the brand new cap having problems as after about 50 attempts at bleeding the system i'm pretty sure there is no air in there and lo and behold it seems to have fixed the problem!

I'm gonna give it some stick today and if all is well email Silvers back and see whats going on.

Moral of the story ...never trust new companants!

y i
i had a similar problem, sorted itself out
(mine doesnt run any more btw )

Sounds more to me like the thermostat has died.

All the cap does is open at a certain pressure so when the bike gets hot the coolant expands into the expansion tank, then when it cools down again it sucks coolant back into the rad. While a malfunctioning cap will allow the rad to over pressurise that shouldn't affect the temp.

The expansion bottle shouldn't be warm, there should only be a dribble of (warm) water from the rad to get into it and that'll only happen once when it gets up to temp and then shouldn't change.

What it sounds like to me is the thermostat has stuck, the thermostat is a temperature operated flow valve, when the coolant is cool it redirects the coolant back into the engine rather than into the radiator to try and warm the engine up faster. When the coolant warms up it lets the coolant flow into the radiator.

If it's jammed shut (or part shut) then the coolant will miss out the radiator (a small amount will still pass into it even when closed), the temp gauge will read hot as it reads from the thermostat housing (on the NC30 and NC35 anyway). The fan will not come on however as it is driven off a switch in the radiator.

You can quite safely remove the thermostat and run without it in summer but in winter you'd need to tape up some of the radiator.

I've never had an issue with air in the system on the NC35 or RC24, just fill it up, start it up, squeeze hoses a few times, blip throttle. Top up as required until the level starts to rise, fit cap, kill engine and top up coolent bottle to the line. Go for a short ride, let it cool right down then check coolent level in expansion bottle and rad, topping up as required.

Druid