Engine Temperature

[Bobatvracer]

I recently had some engine work done to my 400ex. My mechanic bore it out to be a 426 with a Hot II cam and all new hardware. After break in I took quad to a Hare scramble race. The track was extremely mudding, there were several steep hills etc…. During the race my quad started getting very hot; at some point my engine started losing power. I found myself downshifting a lot to overcome small hills etc…

1. When a 400ex engine gets extremely hot is there usually a noticeable power loss???

2. If so will synthetic oil assist with reducing engine temps??

3. I understand there is a fan that can be mounted on the engine oil cooler?? If so does the fan make a huge difference?

4. Does anyone know about adding a second oil cooler?

[honda400ex2003]

1. yes there is a noticeable loss
your issue was an over heating issue not just a hot issue. they loose alot of power when overheated.

2. full syn is not recommended for the wet clutches in these machines but would probably help out a little bit. blend would be better if you insist on running any syn in it. imo it is not enough to waste the money on oil.

3. the fan will help quite a bit. it is a great mod along with the bigger oil cooler mod. check out the stickies for both subjects.

out of curiousity, what kind of temps are you regularly seeing? regular is 190-220 oil temps but over 250 would be an issue area along with anything higher than that.

steve

[honda400ex2003]

1. yes there is a noticeable loss
your issue was an over heating issue not just a hot issue. they loose alot of power when overheated.

2. full syn is not recommended for the wet clutches in these machines but would probably help out a little bit. blend would be better if you insist on running any syn in it. imo it is not enough to waste the money on oil.

3. the fan will help quite a bit. it is a great mod along with the bigger oil cooler mod. check out the stickies for both subjects.

out of curiousity, what kind of temps are you regularly seeing? regular is 190-220 oil temps but over 250 would be an issue area along with anything higher than that.

steve

[CJM]

See the 400ex FAQ about adding an extra/larger engine cooler. It will help quite a bit. You can also add the spal fan (helps alot) and a bigger oil tank.

Might also want to check the jetting to make sure your not to lean as well as that will cause the engine to run hotter.