Overheating help needed!!!

Helen · Guest

Hi
I bought a second-hand NSR125RK 1990 twin headlight model in October.
But now the warm weather is here it overheats like hell!!!!
My boyfriend (he rides a Firelade) has taken off the the radiator, cleaned out the fins, run water through the radiator, replaced the rad cap with a new one. OK we bought it from Halfords for £4 - it has 15 psi printed on the top - because I can't afford £23 for the Honda cap, what a rip-off.
What a pain to refill the rad!!!!
But is still boils over when I go for a ride of more than 5 miles.
Is this usual for a 125RK?
Please, Please can anyone help me!!!

Hex · Party Boy Joined: 04 Feb 2002 Karma :

not familier with the system sorry but basics to check:

thermostat is opening
water pump is working

brakes aint binding!!

hope these help a bit

Gav

spencer · Guest

Hi
1 Did u bleed the system after filling rad with coolent.
2 Take the thermostate out and take the bike for a run if it dont overheat it is that, if it dose it could be head gasket or as hex said waterpump.
3 Sounds to me like the thermosate . hope this helps good luck

Milo · World Chat Champion Joined: 08 Feb 2002 Karma :

to me it sounds like the water pump. check everything though. or take it to a garage and get a quote for repairs, ask what's wrong and do it yourself Smile

____________________
Shaft drives rule. Razz

Dylan · Trackday Trickster Joined: 03 Feb 2002 Karma :

That aint normal, my bike only started to overheat once in thick traffic in the summer and a quick blast up to 50mph and it cooled down again. Could be a
Faulty temp gauge or gauge sensor
Thermostat syuck closed
Passages blocked in radiator, hoses or water jacket
Faulty water pump
Air in system
Hope this helps
Dylan

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Only had 2 strokes overheat a few time. First off was the MBX125 which blew its head gasket (then ate its piston rings!). The Gilera we have is a TOTAL pig to bleed the cooling system on, and will easily overheat. Get the systsem bled through and it works fine though (just takes about a dozen attempts). On the RS125 I have had overheating once, and this was due to using too strong a mix of antifreeze. Antifreeze is quite thick and difficult to pump, so the not much got moved round the engine and the engine would run hot (but the radiator would be cold). Draining off some of the antifreeze and adding some water fixed this

All the best

Keith