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2002YZ426

Spewing Coolant

10 posts in this topic

I had an issue with my newly acquired yz426 not revving out. I did some checking and the neutral switch was already disconnected. So I increased the jet size from the 162 that was in it to a 165 then a 168 with good results for each fatter jet. The bike has an aftermarket pipe & muffler but I don't know what brand. So far so good but now I notice after only a few minutes of riding the coolant is spewing out as if it's overheating. Does anyone know if this is likely to be an overheating problem, or maybe just a bad radiator cap

? Has anyone experienced a bad cap? I just got the bike a month ago and haven't had time to work on it till now and planning a new years trip to Ocotillo Wells. Time to get busy huh? Thanks for any input you might have.

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the yzf's will overheat if rode slow or left to idle not moving. Mine had some grung on the cap when I got it, so I replaced it. Could not find a non oem one and the yamaha is about 30.00. I put engine ice coolant and a new cap and mine has yet to spew again. All I have read on the yzf's says not to ride them slow, or let them idle with no air flow.

my .02

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the yzf's will overheat if rode slow or left to idle not moving. Mine had some grung on the cap when I got it, so I replaced it. Could not find a non oem one and the yamaha is about 30.00. I put engine ice coolant and a new cap and mine has yet to spew again. All I have read on the yzf's says not to ride them slow, or let them idle with no air flow.

my .02

where is the coolant coming from? The cap or the overflow hose?

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Coolant is coming from the overflow hose and the cap tests out good with a pressure tester. I was thinking maybe head gasket but with the cap off it doesn't blast out like I have seen in the past on other vehicles from a bad head gasket, and it seems to be circulating really well. Maybe it's just worse with the fact that I am trouble shooting another issue and riding slow through the neighborhood then idling for a few seconds when I get back to the house. Thanks to all for your replies.

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I think they all puke out the overflow if you putt around or idle for any length of time-just like the headpipe glowing red. does it do the same thing when you ride at speed? if not, then just go faster!!

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Blown head gasket wont show up as bad when bike is sitting idol with Rad. cap on or off even when reving engine. When bike is moving (engine under pressure/tourque) you will blow fluid out the overflow as you shift through the first couple of gears. After you have blown out about half of your fluid there is not enough pressure to blow the rest out. Replace head gasket, possibly new piston & rings since you in there and forsure use Engine Ice. ... nothings better.

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