Don't even need to fire it up just turn it over.

Druid

surprise surprise, removed the pump to discover the back of the pump had sheared off where it slotted to the pin.
So new pump fitted and yes it flows and warms as it should.

however - its now a game of hunt the bits of metal. removed the sump and no sign.
Hmmm i can only hope it was ground to powder and caught in the filter. engine ran good, good pressure and gearbox was lovely.

UPDATE - found them. they were playing a game of hide and seek, lodged nicely in the strainer between the gauze and the plate.
Fished out both parts, matched up perfectly so confident nothing crushed around the motor.
result, sump gasket came off in one piece too, cleaned, sealed with a smear of grease, and tourqed.
jobs a goodun

Lucky you. I'm still trying to work out what the feck is wrong with mine. Fan check, thermostat remove as was tits, waiting for themometer to check switchon side of rad, new plugs to replace just in case and after all that may only be the rad cap which i shall borrow off the other bike. On tickover seems fine but under load the temp flies up.

scotjell wrote:Fan check, thermostat remove as was tits, waiting for themometer to check switchon side of rad ... and after all that may only be the rad cap which i shall borrow off the other bike. On tickover seems fine but under load the temp flies up.

At tickover is when most NC's get hottest because of the lack of airflow (e.g. stuck in traffic on a warm day). Under load as you're moving the airflow will cool the water.

The fan is designed to cool the rads slightly when the bike is not moving, it won't make any difference to cooling performance otherwise (and reduces cooling performance when you're on the move by obstructing air out the back of the rad).

I would say either your pump is shagged (like CRM's) or your rads are gunked up badly.

i would also say it is proberley your rads could do with a clean if it stays at good temp on idle

mine does the same, my road one on idle its not bad but on a ride it goes about 90 never got to red yet i would worrie if it did but i suspect its my lower rad full of shit or thermastat playing up

Well I will find out today as have had the lower rad off and give it a good blast in the shower and it is definately surprising how much crap is in there. Water Pp is fine as level goes up and down whilst revved. Today lower rad will be fitted with a good temp switch for the fan, washed out lower rad and wil be putting a proven rad cap. Lets see what the outcome is this evening.

CRM wrote:surprise surprise, removed the pump to discover the back of the pump had sheared off where it slotted to the pin.
So new pump fitted and yes it flows and warms as it should.

however - its now a game of hunt the bits of metal. removed the sump and no sign.
Hmmm i can only hope it was ground to powder and caught in the filter. engine ran good, good pressure and gearbox was lovely.

UPDATE - found them. they were playing a game of hide and seek, lodged nicely in the strainer between the gauze and the plate.
Fished out both parts, matched up perfectly so confident nothing crushed around the motor.
result, sump gasket came off in one piece too, cleaned, sealed with a smear of grease, and tourqed.
jobs a goodun

Damn you updated it... I was going to say you'll find them in the strainer :D

Same place mine were I guess your waterpump must of gone and eventually siezed.. causing the bike to snap the shaft.



I managed to pick up one like that (mint!) for £20.00 to replace mine!

What did your impeller blades look like though? I havn't seen one as bad as the one of mine that was snapped!

scotjell wrote:Well I will find out today as have had the lower rad off and give it a good blast in the shower and it is definately surprising how much crap is in there.

Have you cleaned the top radas well?

While you have them off run a hose through the engine water jacket. If you leave any crud in there it will eventually block stuff up again.

Well everything has proved itself fan cuts in and out, pump works, etc. But and this is a big but I'm not happy with the way the engine sounds. Its no where near as smooth as my other engine. The only thing that could be wrong is one of the con rods is incorrect. When I rebuilt the engine after the crank was pooped i replaced it checked with Rick regarding the cranks shells all were good. The only problem was he had 3 pistons and rods and some spares in a box. The markings were not visible for balancing out the crank. Tickover fine bang the throttle open sounds like a bag of nails. Didn't ride it as it started snowing!!!!! Engine now removed had a spare lower half ready to go built up with pistons etc swapped the heads. Work to be done over the weekend. I wouldn't mind but only doing this one to sell it!!!

Neosophist wrote:

CRM wrote:surprise surprise, removed the pump to discover the back of the pump had sheared off where it slotted to the pin.
So new pump fitted and yes it flows and warms as it should.

however - its now a game of hunt the bits of metal. removed the sump and no sign.
Hmmm i can only hope it was ground to powder and caught in the filter. engine ran good, good pressure and gearbox was lovely.

UPDATE - found them. they were playing a game of hide and seek, lodged nicely in the strainer between the gauze and the plate.
Fished out both parts, matched up perfectly so confident nothing crushed around the motor.
result, sump gasket came off in one piece too, cleaned, sealed with a smear of grease, and tourqed.
jobs a goodun

Damn you updated it... I was going to say you'll find them in the strainer :D

Same place mine were I guess your waterpump must of gone and eventually siezed.. causing the bike to snap the shaft.



I managed to pick up one like that (mint!) for £20.00 to replace mine!

What did your impeller blades look like though? I havn't seen one as bad as the one of mine that was snapped!

I had an nsr250 pump in my nc30 that looked the same. Replaced it and the lower rad too but Its still overheating. Can it be that the broken blade is stuck somewhere in the system limiting the flow?