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Discussion Starter #1
Hi guys,

As stated on my introduction topic, I´m racing a 675. I´m used to race big twins and this triple is a little toy when compared with my Aprilia RSV 1000.

This bike is not a new bike (it was raced before) but it´s new to me and I came across some issues that I´d like to see explained/solved.

1) Overheating : The bike overheats very easily and spits quite a large amont of coolant. I took the cap off and it´s deffective. But on top of that, the fan doesn´t kick in when it should. I actually never seen it working!

2) The gear linkage seems to need some alignment. I made a couple of pics so you can help me with this.

3) I took a look at the manual and set-up the bike for track but I think I can take a lot more from it. In the dash menu I used the "S" mode because I had no idea how to fine-tune the custom set-up mode. Can you guys help me here with tuning the "Gas sensitivity", "Max engine torque" and "Engine brake".

Thanks in advance, guys!!!
 

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The coolant can be a simple fix to fill the small plastic container only up to MIN level, and not any higher when bike is cold.
Since your fan isnt working, it might be topped to MIN level but bequase of so much heat it poors out.
 

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Discussion Starter #4
The coolant can be a simple fix to fill the small plastic container only up to MIN level, and not any higher when bike is cold.
Since your fan isnt working, it might be topped to MIN level but bequase of so much heat it poors out.
That´s a good tip! Thanks!!!
 

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do you have a race ecu. Maybe it does not have a program for a fan since most race bikes don't have fans
I´m running the stock ECU. It must be something else that causes the fan not to work.

What´s the best way to test the fan? (without take the bike for a ride :grin2: )
 

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the temp sensor on the radiator may be bad. Make sure the connections are good. Not exactly sure how the circuit works. Don't know if the sensor opens or closes when the temp is too hot. You may try shorting the 2 leads together.
 

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Regarding the cooling issue, some members here have had success swapping out the OEM radiator cap with one from KTM, with a slightly higher pressure rating. Do a quick search here for the part numbers you need.
 

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Never ran fans on any of our race bikes, although haven’t raced my 800. One thing I’ve found is that the fan doesn’t always kick on, on my bike. My suggestion is ditch the fans. Search for any kinks in the cooling system. Switch to a lower temp thermostat and run a longer cool down in the pit area.

I’d also check emissions equipment. Charcoal canisters and vent tubes.
 

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The single best thing that you can do for your F3 is a kit radiator, they are expensive but very effective, we saw a temperature drop from 119C to 85C in our F3 Supersport bike, just because it isnt boiling doesnt mean that it is not overheating.
 

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?

You don't need a bigger, heavier radiator...... you need to fix your ignition and fuel maps and radiator ducting
A 1st Gen MV F4 has 41% more radiator core volume than a Ducati making more horsepower.......but the MV
overheats and the Ducati doesn't
THINK......

Strega makes 30 times the horsepower of your Cripple ......and look at the size of the radiator inlet......
Research it, it's all in SAE papers from the '30s and '40s
Astronaut "Hoot" Gibson flying "the witch"

https://goo.gl/images/G4493D
 

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Seems everyone has an opinion about this subject. There are a few things that are well known with the 3 cylinders. They tend to run hot. They tend to trap a bit of air inside the water jackets. The bigger radiator isn't the end all be all for overheating. There is more to it. Noel is not wrong about the inlet issue either, in fact inlet and exit must be kept clear and open as much as possible. It is a problem.

My F3 race bike has a much larger H2O racing radiator and oil cooler but still had heat issues. I made plastic sections to better direct air to the radiator, that helped a little. I took the thermostat out, that didn't help, made it worse (more about that later). I trimmed the fairing out to expose all the cooling fins for the radiator and oil cooler to air flow, that helped. Clear as much as you can from behind the radiator to allow the hot air to get out of the way. I carefully bled the coolant, that helped. There is no easy sure fire way to get all the air out of the water jackets, running the engine, squeezing the hoses and moving the bike around a bit releases some of the trapped air pockets.

Finally to keep the engine temps under control I had to make a restrictor plate to insert into the thermostat housing area. Turns out that since on track the F3 revs like mad and that in turn creates very fast water flow through the radiator because the water pump turns like mad as well. For track use it is too fast to allow for proper exchange of heat from the coolant to the radiator surfaces. Restricting the flow into the radiator helps allow the coolant adequate time to cool off. This works and the engine stays cooler. A thermostat would probably be restrictive enough, but I don't want one in the system, so a plate was the solution.

Street bikes in traffic face the same challenges, but for different reasons. How to keep air flowing through the radiator? Same things I've recommended plus some robust fans and possibly a switch to turn them on in slow heavy traffic. There are bigger and better fans than what the MV's come with in standard trim. One can generally source them on eBay for a low cost. If you want a street triple to run cool, these are options that can make things cooler for your engine. Cheers
 

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So, you didn't change the fueling or ignition mapping?
 

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No, not magic...it's science, but if you are where you should be with ignition advance and A/F ratio, it does reduce heat load.
 
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