radiator earth issues?

[Oberon Kenobi]

Hi guys, I'm having some problems and need some help if poss please

I recently had my left hand radiator repaired, and having reattached everything and changed coolant etc, the cooling fan does not kick in as it should, and there are a couple of strange symptoms.

The fan motor is fine as the fan operates when I earth it manually.
Both radiators get hot.
Coolant does not flow out when I take the rad cap off and run the engine up to temp and blip throttle (ie it looks like it is not flowing around the system)
Fan does cool engine as it should, when manually operated (so coolant must be geting round the engine?)
Airflow does cool engine - motorway test ride drops high temp to 76-79 (so thermostat must be ok too?)

I gave in and took it to local garage. They are a bit stumped. They are saying the coolant should pulse out if it flowing correctly, but if it was not then the fan would not bring the temp down. And there would probably be a cold patch n one radiator. They suggested a manual fan switch but I declined, cos it doesn't really fix / find the problem and would look rubbish.

Their other suggestion was a poor earth on the radiator. This could be due to the new paint on it since repair, but considering it is monunted with rubber washers I'm not sure - I guess I should check the mounting point with no rubber grommit. They suggested my first port of call is to determine this earth problem. But this doesn't explain the still looking coolant..?

Do you guys have any ideas? I've almost put it away now for a few weeks but hate to leave it not working properly.

Thanks in advance!

Dave

[Sppete]

Oberon said

The fan motor is fine as the fan operates when I earth it manually.

Haven't looked at the manual so I don't know if the return side of the fan is earth or not but from what you are describing here it looks like it may well be. If that is the case, why don't you just run an extra earth lead back to the engine directly from the fan? It seams a shame to have to start scratching paint off, especially if you aren't sure that is the cause. Also, check your plugs and sockets and where possible I would meter the fan loom for continuity just in-case you have a broken wire.

Pete

[Oberon Kenobi]

Cheers Pete - any ideas on the coolant level thing?
Is it normal for it to pretty much remin static with the engine running? Or should t spew out in waves as it circulates?
If I can limit the problem to just the fan I'd be happy, as the bike operates fine except for that.
Thanks

[5parkyuk]

cant quote on the sp , but my 929 never did when I redid its fluids.
Fill radiators first then bottle, start her up give her some revs ups for a minute and redo levels,I left the lid off the rad and none gushed out.

[Sppete]

I was under the impression it only circulates out to the rads when the engine warms up. Again I'd have to check the manual for the temperature but Once the temp reaches a certain level a thermionic valve opens and the fluid stops circulating around the engine only and flows out to the whole system. It's possible the valve is stuck or maybe a problem with the water pump but if you can drop the engine temp by manually operating the fan I would think they were both working and concentrate on the fans for the moment.
Just a thought. Have a good look at the big electrical connector by the left hand rad. It's notorious for corroding and giving spurious faults. It catches all the wet when the bikes on the side stand. pull it apart and give it a good clean and then pack it with some vasaline before putting it together.
Also give all the pipes a good squeeze you might just have a bit of an air lock somewhere

Pete

[5parkyuk]

http://img502.imageshack.us/slideshow/w ... dpage1.jpg

[Oberon Kenobi]

thanks chaps will check it all out again with this in mind