2007 te 250 athena 310 overheating

HI,
I've got an 07 TE 250 with the Athena big bore kit fitted. It rides brilliantly but have recently been having some minor overheating issues.

Even if I take it out for a short ride the cooling fan comes on. This rarely came on before, only in the gnarliest conditions. If you look really hard you can see a very small amount of steam coming from the right hand rad. So minor you can't see exactly where it's coming from but looks like the bottom of the rad. Anyhow more alarmingly the expansion tank seems to be spewing coolant out.

Any ideas. I heard somewhere it's possible to fit the head gasket upside down. Could this be the culprit or would that have a different effect. The oil is clean, no signs of water. I'm off for a big ride in a week and desperate to find the problem. There are no off road bike shops on the Isle of Wight.

make sure you have about a quater to a third of the overflow tank ful of fluid. Use a top quality fluid and also go up to a 1.4 psi rediator cap.

Noticed the expansion tank was about three quaters full so drained it down to just over quater. Ran it on idle for ten minutes and the fan didn't come on. Took it for a quick ride and got the fan on after about ten minutes. Let it cool down and noticed that after 10 minutes cooling the expansion tank was now three quaters full. I believe that this should flow back into the rad when it cools. If it's not is that down to the radiator cap or could it be something else.

A local rider had overheating issues after installing Athena kit on brand new '09 TXC250. I believe the ultimate culprit was incorrect gasket installation or not torqued correctly.

Would head gasket problems not cause other symptons. i.e milky oil. Not ruling it out, just don't wan't to strip it down unnecessarily. I'm thinking if the coolant's not going back to the rad either the caps not working or the systems pulling air in from somewhere else and not creating the vacuum to pull the fluid back through. There is a tiny amount of steam coming from the right hand rad when hot. Is this normal or could it be a tiny pinhole causing problems.

I would check your headgasket. The Athena gasket is not that good. Use a Husq gaskey from a TE310. Even though the 310 uses an Athena jug, it uses a different head gasket that lasts longer.

Sounds like i'm going to have to try a new head gasket. Cheers for the advice on the husky part rather than the athena one.

Impeller nut OK and impeller turns when bike kicked over. Rad probably a culprit, would be nice if it wasn't head gasket. Spoke to Husky sport the UK importer and their mechanic thought it would be rare for the head gasket to have gone with little use.

Just been checking a few other things before I bight the bullet and order radiator/ head gasket today. Removed expansion tank and all seems good, no cracks etc but if I blow though the inlet I can get fluid to spit out of the cap. Is this normal or a faulty cap. Also whils removing it I noticed the pipe that goes from the rocker cover to the airbox has a thick yoghurty goo in it. As previously mentioned the oil and cooland are both clean. Is the goo in this pipe a sympton of head gasket failure. Also if the head gasket has failed with probably only 8 hours on it since fitting the athena kit has it failed due to poor installation or could their be something else causing it. I let it idle for 10 mins and the fan did not cut in and no fluid passed to the expansion bottle. The i took it for a short ride, 5 mins gentle on road no high revs and about 3 mins on a gentle gravel lane (a few more revs here naturally). When I got back the fan was going and the expansion bottle had filled. After letting it cool there was fluid around the bottle where it had spat out the cap. None had returned to the rad. My point is the type of riding I did would not have got the fan running normally. Could this be a timing issue.

A friend's TE 310, (Athena kit), had the same symptoms. Turned out to be the head gasket. Coolant did not leak into the crankcase, just out the overflow and radiator cap.
Good luck...

Find and fix the radiator leak and see if that rectifies the issue. You are going to have to do this any way. if not as all the sages here are indicating, a new head gasket for you.

Old thread, but I am having the same symptoms as described in post #10 other than no steam leaks from the radiator. What was the culprit? I hope not head gasket because I stopped at the dealer today and they said head gaskets are 4-6 weeks out...I can't wait that long. If it matters I have an 08 te250 with the Athena 300 kit in it as well. I haven't done a leak down test yet due to I work out of town during the week and I discovered bubbles in the coolant late Sunday afternoon.

Do you know which 310 head gasket it uses? There are 3 part numbers for three different thicknesses.

In case someone else is looking for this same information in the future as I was I'll post the answers here and how i fixed it. I had the same symptoms and the original person in this thread. It was the head gasket. Head gaskets don't normally just go so I suggest you figure out why it went. For me it was a combination of 2 things. The Previous owner had drained the coolant and was running water, just regular old water. The other and probably the real cause was the inside of the water pump impeller was stripped. It would feel fine if you checked it with your hand but once the coolant heated up it would slip. As for the gaskets to use, after more searching and some thought on my own I came to the conclusion using the Athena gasket kit was the right thing to do. The OEM 310 gasket is slightly bigger meaning the gap between where the cylinder ends and the gasket begins will create a void and thus a gas wedge when the engine is running and more likely to leak than the properly sized Athena gasket. The next big thing is don't be intimidated by removing the head. It really is pretty easy and everything is marked. If you can find Top dead center and don't mind getting a little oily it isn't all that hard of a job. I also used gasket tack when I assembled everything. do you need it? No prob nut but using it won't hurt anything either. Hopefully this information will come in handy to someone in the future.

Having seen both the stock Husky and Athena branded gaskets side by side, they are similar enough that they are most likely made by the same manufacturer. Based on that I doubt that pure gasket failure alone is the problem detailed in this thread. It's more likely improper installation and/or improper torque procedures/levels. These are 3 layer metal crush gaskets & installed properly will long outlast the engine- ie. they will literally last for 10,000-20,000 hours or more.

They are both made by Athena according to several Husky places I talked to including Ferracci who originally built my engine.

update: about 500 trail miles later in the heat of summer still no leaks or overheat issues. Bike runs like a dream.

Double check the torque settings in the manual

Sometimes these can be a bit ambiguous with a setting of say xx ft lbs +90

In plain Engish, this means to torque the bolts up to the stated torque setting then turn another 90 degrees. Some people miss the extra quarter of a turn.