expansion tank and rad coolant not mixing

[madrevs]

So is this normal for the dt as some saying yes others saying no.might take the stat out and double check it again as was in a rush Afyer riding home tonight 13 miles last 5 on dual carriageway way at 70temp gauge was still the same left bike standing for 15 mins took rad cap off and using a digital thermometer it read 43 degrees does this mean its not heating up properly. ThanksAlso would this be the thermostat or something more serious

[slice]

Sounds ok to me, if the engine gets hot and then the rad gets hot as well then it's doing it's job, can't see anything wrong with it running a little cool as that will help the engine run efficiently. The only thing I can think off that might be a problem is if the water pump is not working ok but as your getting hot water around the system then all is cushty.

[dt502001]

Ok sounds like the t stat is not closing fully,the temp gauge if working properly should stay in the middle.As the coolant heats up in the cylinder t stat should open and alow it to flow to the rad to be cooled ,but when the temp of the coolant drop below 180f the stat should start closing to keep the coolant hot/even temp in the cylinder.The temp of the rad is not important,the temp of the cylinders is.

Think of it this way if it were a car and you had the heat on,if the stat dosent close to keep the coolant hot you would have no heat .If the cylinder is forced to flux in temp,due to the stat not closing,then your running around on a cold motor,this causes different problems.

A I.C.E. needs to get to a temp of 180f to be efficent in burning the fuel,all the parts expanded to the same degree from cold,the piston takes very little from the effect of the coolant,so it will expand at it's normal rate,the cylinder however will expand and contract depending on the temp of the coolant and this is typicaly when a 4 corrner seizure happens .The piston expands faster than the cylinder,if every time you pull away the cylinder drops it temp then you run the risk of a 4 corrner.

For the cost of a new t stat you should just put a new one in.But a easy way to check is to block off the rad with card board and go for a short ride with the bike warmed up(temp gauge in the middle) if you dont see the sudden drop in temp then the t stat is not closing.

The water pump must be workin or you would be over heating all the time.

[2 Wheels]

What DT50 is saying is right,,,,,,,, but if you have the thermostat in and its working and the temp guage is in and working then your bike is fine. That's the way these bikes are.

[Cynic]

Wow. The expaansion tank doesent have any flow to it. If it gets hot you have problems.

Its connected to the overpressure side of the rad cap. Overpressure causes fluid to pass into the tank, if an extreem event occurs causing v high temos like summer traffic the system can let off steam.

The reverse happens when it cools and the excess will be drawn back by vacume.

If the exp tank is cold its fine. The coolant level MUST be checked at the rad. The level on the exp tank is just for the tank.

Worrying about nothing....

[madrevs]

Ok thanks for all the info starting to understand how it works a bit better still havent got round to takimg thermostat out again as been a bit busy but haven't used the bike since my last post.might kust change the thermostat anyway if there not too expensive from yamaha.saying that though everything I have got from them so far has been silly money