Running Hot or not a problem?

We'll, I gave up on the CR250 and bought on to a new '99 YZ400F recently. When I first started the bike, I thought how nice it was to have a bike that will sit and idle on it's own. After a few practice starts and a few sessions of idling, it started to lose radiator fluid(boiling over)through the overflow (about 85 Degrees outside). My question is, is this normal, does this thing need alot of airflow through the rad's to keep cool? Or am I seeing a future problem coming to light. I take it out Saturday for my first real ride and would hate to have cooling problems. I'm bringing a quart of coolant to be safe. The bike is brand new, 1999. Caught a great deal here in Japan. 390,000 Yen, or $3900.00. I had to jump on it.

The YZF does not like to sit and idle for any length of time. I'd say that the radiator overflowing after idleing for a while is normal and you have nothing to worry about. If it continues during normal riding then I would suspect a problem. So just keep it moving :) .

The wr400 has a overflow bottle in the back

behind the left side cover. They must have anticipated that the bike would need this for trail riding or for sitting at idle for extended periods of time.


So Cal Erik

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The first time I raced my '26F it was about 95 out and at the gate my bike smelled like my wood stove when it gets too hot. I swear the pipe was glowing red! I'm told this is common with these bikes, they really need to stay moving but that's cool, I like to be moving too...


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