Water Temp Too Low?

Simon Masters · Jan 6, 2018

Hi all,

I’ve just finished my project (previous post) which was a Sprint 900 cafe racer conversion.

I’m running an Acewell clock and the water temp, even when riding hard never gets above 78 degrees.

I appreciate the engine is a bit more exposed as all fairing is gone but is that right? What should it run at?

I blocked off about a third of the rad with some card and it barely moved the temp up at all?

I know the thermostat works because if I turn it off the temp soon runs up near 100 and the fan turns on if it goes past that.....

Has anyone had a similar issue?

Thanks, Simon.

Callumity · Jan 6, 2018

Thermostats are cheap and quite commonly out of spec. If you are over cooled it will 99 times out a hundred be down to an open stat or one operating below its spec temp range. Blocking the rad is normally useful in cars to get the heater temp up but will likely make limited difference on a bike because it is not sheltered inside a steel box.
Have you independently verified the accuracy of the temp guage?

stevethegoolie · Jan 6, 2018

In terms of actual degrees I know not what they run at ..... but on the standard temp gauge the needle does not normally get more than half way between cold and vertical when in motion. In traffic the gauge will often get to vertical and possibly beyond at which point the fan kicks in. Yours, young Simon, seems to be about right(ish). Perhaps!
(All the above is as per the behaviour of the particular example of the very fine 900cc - or 885cc for the pedants - engine provided for my delectation when out and about on my Trident).