Bimota Forum

[Falcolion]

Recently I got myself a complete spare radiator from 97 Yamaha Thunderace. Obviously radiators are an exact match with a tiny exception.

A temperature sender is of different shape. The one on Bimota is wider on the thread side and much wider on the top. Top has kind of stepped flat surface. The one from Yamaha has a much smaller thread diameter and of a plug on type.

How important is it to have one from Bimota or can I just swap connectors and everything would work fine?

3LN-82560-01-00 THERMO SWITCH ASSY (on Yamaha Fiche Electrical 1, pos 14 and on Bimota - Electrical page/section 31, position 35) - these are identical.

But THERMO UNIT are different. Yamaha is 11H-83591-00-00 - pos 15, and Bimota - position 34 part number 215000849. Its a Bimota part number. Does anyone have any idea on the specs for these 2 parts?

http://fiche.worldofpowersports.com/wps_dealer_orders/showmodel.asp?Type=13&make=yamahamc&a=216&b=48&c=0&d=-ELECTRICAL-1
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2016 Suzuki GSXR750 TRACK BIKE
2011 KTM RC8R
2010 Husaberg FE390
2008 BMW HP2 Sport
2007 Aprilia RSVR Bol D'Or
2006 Bimota SB8K Santamonica
2005 Benelli Tornado Tre
2002 Mondial Piega

[Bud977]

The temp sensor is a temperature sensitive resistor. As long as the resistance changes at the right values, it will be OK. If not, it will read incorrectly.

However, it looks like the YB11 has different clocks to the Yamaha, so it might need different calibration.

It's worth trying the Thunderace one.

[Falcolion]

Thanks. That is what I thought. Thunderace one is definitely different. I managed to get a new one from Bimota Classic at a pretty decent price. I will just re-thread the Thunderace radiator and install Bimota one. This way no headache.
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2016 Suzuki GSXR750 TRACK BIKE
2011 KTM RC8R
2010 Husaberg FE390
2008 BMW HP2 Sport
2007 Aprilia RSVR Bol D'Or
2006 Bimota SB8K Santamonica
2005 Benelli Tornado Tre
2002 Mondial Piega

[bimotabob]

Quite often the manufacturers continue using sensors with the same temperature vs resistance collation nearly always a cheap NTC type.

To verify you could use cold water in a small jug and run a jumper of the sensor to the frame (ground) and connect the sensor wire to the loom and place in the water and watch the gauge with key on. Then heat water in your jug and test again, ideally a ohm gauge and temp probe make it really easy as you can do a few checks of resistance vs temp with both sensors.

You cant really damage the gauge by using other bike sensors so don't be too scared.

One last point, Yamaha in their infinite wisdom placed the sensors including radiator fan switch in a most inappropriate location - the radiator (often not even at the top)
Ideally move it to inside the thermostat system.

I have done this already and can tell you its quite a big difference.
1) it will show instant readings as soon as the bike is started even when thermostat is closed.
2) you get a higher reading, the true engine temp at the hottest part, in the engine not outside by the front of the bike.

Also if its a similar system to the earlier series like mine change the fan switch type as Yamaha also stuffed up, leave it in the radiator if you must but change to a Honda car 85°C on type.
No point in having your fan work nearly 40°C beyond your thermostat opening - bearing in mind its also located in a cold area of the coolant circuit.

Thermostat opening : 67°C
Radiator fan switch setting 105°C

Sometimes i wonder if the R & D guys were sleeping or on powerful drugs.

I have done the R & D over the last few years so happy to help
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YB8EI

[Falcolion]

[bimotabob]

Without you posting any photo's i have no idea what Bimota done to the fan switch, my YB8 was left alone in that regard.

Seems odd but theres a reason they replaced with their own.
The standard Yamaha item the Thunderace came with is best throwing away for its 105°C turn on point.
Maybe Bimota swapped because of that - the turn on point is normally written on the fan switch so let us know.

Photos are good...

Basic info:


A fan switch is easy enough, its just joining the two wires together when the radiator is hot enough so ideally find a thermo switch with the same thread so you dont have to modify stuff then select the right switch on point temp and then just a case of connectors to match as it will no doubt be different.
Look for turn on range between 80-90, don't go higher if possible.
The part number fits many many bikes over 20 years - its super common and cheapish.

The temp gauge sensor looks like they have a standard they stick too - good work Yamaha.
This part is super common and fits bikes over 25 years and cheapish.

So cross references on both parts list them being the same part for thunderace and fzr1000, YZF750 etc.

Thanks to Boats.net for information.
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YB8EI