OK, so i'm about to get ridiculed but here goes...

I'm about to plonk a whole new cooling system in place and I'm wondering how important the thermostat is? (mine is a 1000cc Fazer setup)

The way I see it, if I take the thermostat out of the equation the coolant will simply flow in a simple circuit through the radiator and back to the engine.

In the case of a BEC there's also the added bonus of saving weight?

I remember speaking to AP Racing on this matter some months back (a little blurred about the exact details) and they sometimes re-jig / de-activate the thermostat so flow goes to the radiator BUT they keep it in the system to slow the coolant flow down.

Question 1:
Has anyone done this

Question 2:
What are peoples views on this?

Question 3:
What purpose do the two wires plays leading to the thermostat? I guess one is an earth but is the other one (i) sending a signal to allow the fan to come on, (ii) supplying juice to the thermostat for an electro-mechanical action (I thought it was simply a bi-metallic strip?) or (iii) other?

I keep telling you I'm a beginner!!!

Kyle

The thermostat wire are so the ecu know what's going on or to activate the fan relay, at a guess, as I don't know the set up.
What you remember is right about the thermostat removal. Yes, you can remove the working parts, but don't remove the entire thing, as it'll screw up the flows through the engine. Same thing as on minis. You can remove the 'stat, but you have to add a dummy outer part to maintain the cooling.
Why would you weant to remove the 'stat anyways? It may not get up to temp, and this is a bad thing with things like bike engines, as cold running can be harmful to the engine.

You are talking about two different thermostats?
The mech temp one and the fan/ecu one?
If you remove the temp one your ecu will think that the engine is cold and your engine will be permenantly rich, plus your cooling fans won't work.
I would leave the mech one in too, it regulates the water through your engine from the rad ensuring that the returning water is neither too hot or too cold.
Cold running will also enrich your fuel.

[Edited on 23/8/2007 by nitram38]

It's a carbed model so I figured it doesn't effect any sort of ECU?

I would leave the stat in the system. It will give faster heat up which is a good thing.

If you do insist on removing the stat then replace it with a restricting plate otherwise the flow around the head will be different to designed. This can lead to hot spots in the head.

John

Hi Kyle

Why?

Ive spoke to you before about your cooling and told you what to do

you shouldnt have to take the thermostat out

ta chris

This post suggests that you're still having cooling issues, but have you plumbed it all in correctly now because as I mentioned in a previous thread (here) you had a hose into the bottom hose rather than the top which will very likely cause the type of cooling problems you're having.

If you've now rectified this and are still having problems, there's something else awry because if correctly plumbed in you shouldnt be having cooling problems with the Polo rad with the engine you have.

cheers
Chris

[Edited on 23/8/07 by ChrisGamlin]

I assumed "filler" in the diagram also included an expansion tank but if not then yep that wont help either.

Don't remove the thermostat, it's there for a very good reason. Without it the engine will be running cold all the time, especiely in cooler weather which is going to cause power loss and more wear on the engine.

If you are getting overheating problems and the thermostat is working (have you tested it?) then your problems lie elsewhere.

Ive just had a look at my logs from a Spa trackday on Monday, and with the same radiator as you and a 2003 R1 engine with a similar (same?) thermostat, the maximum water temperature I recorded was 80c, and that includes about 40-50 seconds of the lap above 100mph / 10k rpm, so if you're seeing 100c or above just tootling around on the road then there's something wrong in the system that taking the stat out won't fix.

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(Late) evenin' all.

Thanks for the advice and input from all.

Just to cover the point that I've spoken to some peeps before... Yes, but I then got a job in London and didn't have much time on the car back up in Leeds.

Basically during my time back in Leeds (weekends) I've done the following:

- Re-designed the dash
- Installed a doomsday starter switch
- Changed the steering rack
- changed the lower steering column arm
- Had my RaceTech 'Slug' welded to my steering column
- Changed the diff
- Changed oil and filter
- Modified the rear arches
- Fitted a choke cable
- Overhauled the brakes
- Mounted the radiator further forward
- Flushed the cooling system out thoroughly
- Replaced grill with competition stuff
- Bought & Installed an expansion tank
- Bought £90's worth of samco hosing
- Bought an air release valve for the upper hose

All I have to do now is fit the cooling system back in as described in my query about 2 months ago. As I said it has been a slow process and the car's not been driven.

Was just curious about the thermostat before cutting the expensive hosing.

Really looking forward to Elvington this Saturday!!!! Going to take the GPS to determine the top speed with my new diff.

[Edited on 23/8/07 by The Great Fandango]

So are you planning on plumbing it back in as in your diagram in the previous thread, or with the hose coming out of the oil cooler going into the top hose instead?

All plumbed in tonight...

Small hose from engine block (guess that's the oil cooler?) goes to the main hose (highest in the engine bay).

The CBS temp sensor housing works a treat as an air release valve.

Cheers for all the help.

The oil cooler is the circular shaped protrusion with the big shiny bolt on the end next to the oil filter, as seen on the left of this pic of my R1


Bottom Hose plumbing

To all those who helped you'll be pleased to hear the temp maintained a steady 80-90 degrees celsius today at Elvington for 3 short (but energetic) sessions...

Then the clutch went!