VF1000RE running very hot in town

In the Shed
1

Just back from a 50 mile run and noticed the bike was running very hot in town, right up to the top mark on the temp guage, also when in traffic. Both are with ambient temperature around 20 degrees. Is this normal?
Notes: the fans do come on, although only when the guage is right near top of dial.
I also changed the coolant over winter and flushed through the hoses and radiators, but I think the bike ran hot before this too.

The bike is a 1984 VF1000RE

Thanks in advance for any insights.

2

Make sure the radiator cap is in good condition and is tightened fully to keep pressure and coolant in. The fan sensor is located right at the top of the top radiator so if coolant is low then this sensor will not operate until very hot.
I put a lower (80°C from memory) temp sensor and fans come on sooner as temp rises.
You can also check your thermostat to make sure it is opening fully when warm. A thermostat that opens at a lower temp might be a good option along with a manual fan switch.

1 Like
3

Thanks for your feedback, do you remember where you got the fan sensor switch with the lower temperature from or the part number?

4

I bought it off Ebay. See link below. The thermo switch is on at 93° and my old one was on at 100°. When my temp gauge gets halfway up the dial the fans come on. The seller originally sent an 80° switch but sent the correct one when I pointed out the error.
The switch on my bike was the 2 wire one with a plastic clip that holds the wiring connector securely on. With some fiddling and time I got everything to fit as the original switch.
Check that your thread size is the same.

5

Thanks that is very helpful

6

A few other Honda models use an 85 degree on switch,part numbers 37760-KS4-880, 37760-KE7-003, 37760-MB4-770 all have two terminals and an M16 thread.The original items are prohibitively priced but an ebay search using the part numbers will throw up some reasonably priced options.
I use an 85 on my RF with no issues

7

Thanks Bif very helpful.
Another question; on an earlier post you suggested an alternative thermostat (Genuine Blue Print Thermostat - ADK89202) does this fit straight into the housing as it looks quite different to the Honda thermostat?

8

It was recommended on a vf500 forum,the 1k uses the same thermostat so will drop right in

9

Thanks for this info Bif I think I will go with this option as its £38 + delivery from David Silver.
The temp sensor part numbers above are all for 93 degrees C rather than 85, is that what you went for? The standard sensor is for 107 - 113 degrees C from my handbook.

10

If you check the offered replacements on eBay they are listed as 85
Try item no. 254541079782
dropping to 93 is still a good step tho

11

My RF has the switch mounted on the lower rad rather than the top one,I don’t know the temperature difference between the top and the lower rad so opted to try the fans coming on earlier rather than later using an 85 switch.

12

Thanks Bif, as my sensor is in the top radiator and that is likely to be the hotter of the 2, I think I will go with the 93 degrees sensor as Downunder did.

13

It sounds like your 1984 VF1000RE is running quite hot, especially in traffic and at lower speeds. Here are a few insights and possible causes to consider:

  1. Cooling System Check: Since you recently changed the coolant and flushed the system, ensure there are no air pockets trapped in the cooling system. Air pockets can prevent the coolant from circulating properly, leading to overheating. Bleed the cooling system to remove any trapped air.
  2. Thermostat: The thermostat could be malfunctioning. If it’s not opening fully, it can restrict coolant flow and cause overheating. Consider testing or replacing the thermostat.
  3. Radiator Condition: Ensure the radiator is clean and not clogged with dirt or debris. A clogged radiator can significantly reduce cooling efficiency.f the problem persists after checking these aspects, it may be worth consulting a professional mechanic for a thorough inspection.