On the 100 mile journey yesterday on the cbr the temp gauge was sat on cold the whole way and only rose when stuck in traffic.

Is that what these bikes are like, or is my thermostat stuck open?

 

If your talking about the temp gauge reading about 1/4 scale while ridding and then climbing to 3/4 scale (almost into the red zone) while in traffic, Yep, normal.

If you replace the thermostat, nothing will change.

 

No, its sitting on Cold when on the motorway, about 2 mm above the stop.

I assume that 1/4 scale is normal operating temp, so I will change the stat.

 

This LINK may be helpful then.

 

Ambient temperature and humidity must *first* be factored in when discussing what the "normal operating temp" should be.

In the crazy roller-coaster weather we have in the Houston (TX, USA) metro area, my temp gauge will register a different "normal" steady-state when on the freeway (or in stop-light traffic) dependent upon the weather conditions.

For example, last Saturday, we had 65*F (50% humidity) temps at mid-day and the gauge ran about the 1/4+ on freeway, 1/3+ in traffic. This AM, it's ~30*F (40% hum) and is under 1/4 freeway. A couple months ago, when we had close to 100*F (95% hum), the gauge will run no less than the 1/2 way mark on freeway, 3/4 in traffic.

Sidenote: it'll only be around 40*F for a high today (mid-20*F Tue AM) ... this coming Thur\Fri, the high will be in the low-mid 70's

 

Thank you very much indeed!

I cant find the cheaper equivalent in the UK. If I buy a thermostat element for a 1983 honda accord that should be ok?

 

The temp rises when you're going slow and stuck in traffic because the airflow across the engine is reduced and the cooling is less. This is normal for an air/water cooled engine.

The temp on my bike is around 172-173*F while I'm out riding on the open road with nothing ahead of me blocking the airflow. It tends to climb over 220*F when I exit the highway and am stopped for a red light. Even when riding at a slower pace in traffic it generally stays above 200*F. It probably wouldn't be that high today but right now outside my door the temp is 4*F below zero.

 

I know that!

Im sure the bike is being overcooled, the ride on the motorway yesterday was 10 deg C at 70 mph and the needle basically didnt move

 

I commute into London from Surbiton, down the A3 for the first 6 or 7 miles at 50-70mph. In this weather my temp gauge is like yours, reading just above the cold mark. Been like that as far back as I can remember. When stuck in the traffic it warms up real fast and the fan cuts in continuously.

 

Same as mine then. On my cars the thermostat life seems to be 2-3 years before they get stuck open.

I would be surprised If our 20 year old stats aren't stuck open too!