www.zxrworld.co.uk

noelb wrote: On the rad taping - is it not easier to just leave the thermo stat in - if you're taping the rad then the cooling system is well fit to cool it with the 'stat still in and there's going to be so little power lost I doubt is it could ever be measured.

with the stat in place you run the risk of it closing and re-opening .. under racing conditions if it closes for too long, when it re-opens (dumping cold coolant into a hot engine) the temperature difference can be enough to cause a (partial) seizure.. apparently

my bike has no oil cooler (blanking plates), no thermostat, an H2 radiator and lots of tape to keep it warm... seems fine.

Can't argue with that logic! I was alway nervous of it after a road racing buddy of mine over here (running Tony Scott engines) was told to leave it in his GSXR 1000 (can't remember which model) after a few had wrecked themselves from running under temp. On one particular model (K7 I think) the cooling system is hugely effective and removing the 'stat allowed it to overcool and the lads on the roads weren't watching it enough or taping the rads. I'm always nervous of any advice that applies to "all race bikes" without having a sound basis for it. I do see some weird variations in temperature on mine (nothing sacry though) that might be explained by opening and closing of the thermostat. Its probably as old as the bike (OLD.......) so may not be as analogue as it couild be.

Got me thinking about it now - cheers!

Noel B.

Another variable is the exact location of your temp probe thingy

On the subject of temp probing, where does the scitsu temp gauge probe into!?
does it screw into the rad?

I've discovered the true function of the oil cooler it keeps all the crap off the front of yer engine during a wet race...............

My bike was a bit flithy after just 3 wet races...................

Very interesting subject, a bit long to read but very interesting...
Sure that if outside Tº remains low the oil should not overheat even in traffic, but bikes are developped for every country so they are fitted with this device.
I am currently living in Spain, near Barcelona, and if you use such bike here without its oil cooler you might fry the oil.

One good hint is that the coolant radiator of the zxr4 seems to be quite oversized, even while racing the bike, so why not using it to cool down the oil instead of using a separate radiator?
Since the engine has an external oil filter, it should not be difficult to adapt an oil-coolant intercooler from such bike as the zx6r
I think theese are called "modine", you just need to get one with the part where the filter does screw in (I don't know how it is called), this part should be of the same diameter than zxr4 one (standard), but larger to acomodate the intercooler.

This requires to check if the exhaust allows the oil filter to be moved around 2 inches, eliminate the oil radiator + tap the holes and connect a couple of coolant hoses to the coolant radiator.

With this kind of intercooler you will heat-up a little the coolant Tº while cooling down the oil, and it eliminates all the risks of a leaking oil radiator.
Oil and coolant heat up is more homogeneous, since it helps the oil to heat up faster, and the oil's heat exchange is regulated through the coolant thermostatic valve + fan.

Off the top of my head.........................not enough room

I measured up the one from my 04 ZX6R as well and it wouldn't clear the headers on the H - Pity 'cos it would be a very good solution as well - water to oil exchangers seem to be the way most japanese manufacturers have gone.......

Noel B.

Yeah just looked at mine and it's too big as you say pity...................


Ready for the Bush ? ?

You're still thinking of mister Boyd I'd say.......

I don't think I'll even make it up to spectate, a few of the buddies have entries alright though. All the complaining about the long break in the calender in June 'cos of Bishopscourt - did a hare and hound last weekend in the rain and will need another month to recover....... Is the forecast any good?

Noel B. (#34 LWSS)

There is still a solution, but then the system is heavier:
On the ZXR750 H1, the oil filter is separated from the engine block. It is not too difficult to replace the zxr4 filter by a plate with a couple of hoses to adapt the 750 oil filter system + an intercooler. Then it should be possible to locate the whole thing much easier
A second solution might be to let the oil filter to its actual position and replace the standard oil radiator by the 750 (H1) oil filter system, on which the filter is replaced by a closed intercooler, the same as the one fitted on ZXR750 (J...) and ZX-7R.

Damn and blast.................... wrong Noel

Im not 100% on the no oil cooler yet.
Second meeting without it fitted.. Most races when i come back in the water is boiling away in the overflow. After its sucked that back in, the water level is low enough to be a slight worry. Can i lose lots though steam in 10 minute races?
Ive sat under my bike for 10 minutes watching for leaks, and nowt. I dont really look at the temp gauge in the race, but when i come back in its between 80 and 100 on the scitsu

The rad is not the best, so im gonna try a better one if i can find one, then if no joy, oil cooler is back on.
Having said this, in the holding area, the temp shoots up so fast. any more than 5 odd minutes and ive got to knock it off.

jake wrote:Im not 100% on the no oil cooler yet.
Second meeting without it fitted.. Most races when i come back in the water is boiling away in the overflow. After its sucked that back in, the water level is low enough to be a slight worry. Can i lose lots though steam in 10 minute races?
Ive sat under my bike for 10 minutes watching for leaks, and nowt. I dont really look at the temp gauge in the race, but when i come back in its between 80 and 100 on the scitsu

The rad is not the best, so im gonna try a better one if i can find one, then if no joy, oil cooler is back on.
Having said this, in the holding area, the temp shoots up so fast. any more than 5 odd minutes and ive got to knock it off.

Normally the coolant shouldn't go out of the radiator with Tº below 100ºC, you may have a problem with the pressure limiter cap. If this cap is leaking the pressure won't go up so coolant will boil sooner (pressure allow coolant to boil at a much higher Tº). This cap fails frequently, also check its seat for dirt, oxidation or damage...
I don't know exactly where is the Tº sensor on the 400, but once the radiator has lost coolant it is possible that the sensor measures only steam and not coolant anymore, thus your conservative Tº while the coolant is boiling away.
Anyway, a failing cap wouldn't heat up your coolant (just let it boil sooner) so if Tº rise too much you should better check the head gasket.

Agree completely with the regular checking of the rad cap - changed mine last year and solved a host of weird water loss issues - one thing though - water starts to expand as soon as it gets warm so if you manage to fill the rad really thoroughly you need to expect a small amount to appear in the overflow from expansion rather than boiling. Same reason old central heating systems have expansion tanks. My KTM enduro has no expansion bottle so they recommend you only fill to the top of the cores in the rad and it rarely (not yet anyway) loses any water. The air gap allows enough room for the expansion.

Cheers
Noel B.