2008 TE 250 (Athena 300) MPG

Hey guys. I recently picked up an '08 TE 250 with the Athena 300cc big bore kit. (under 3k miles on odo) The previous owner had Uptite install the Athena kit and also did related "power up" stuff to soup it up.

After installing new CA Cycleworks fuel pump, It runs great but it's getting what I believe to be poor gas mileage and it sputters when cruising. The last time I checked, I was getting about 25 mpg. Is that normal?

Here are some other symptoms which leads me to believe it may be running really rich:

• When I get on the power it fucking goes.
• When I'm just cruising in 5th gear (any gear really) at any speed range (not accelerating) it will maintain speed but kind of sputter like daaaaaaaadadaaaaaadadaaaaaadaaa.

Could it be heat-related? I've checked all the connections and wires and they all seem to be good and secure with no frays.

Any suggestions???

for a race bike at race speeds... that's normal (a tiny-tiny bit low). But I get the sense you're not at race speeds ("daaaaaa....") so no.

Clean the injector; or it least check it. I suppose it could be heat-related but I'm thinking a fuel delivery problem. Maybe a bad regulator (too much fuel psi?). I'm not a FI expert by a long shot.

good luck.

I asked my mechanic today about how to clean the injector and he suggested hooking up to a 9v (like in many toys) and use carb cleaner. When it's hooked up, it keeps the injector in an open state so I can spray it up.

I didn't even think to check the spark plug so I'm going to take it out to see what it looks like too.

If I have any level of success, I'll put it back up here.

You will probably find a dark spark plug, my 450 was always dark, the mapping done by the dealer was very rich and my mileage ranged from 25-32 mpg.

Yeah. Spark plug was just completely black. The original spark plug part is the NGK CR8EB. I'm going to pick up a CR7EB to see if that helps. Would that be too hot?

Stay with the 8 heat range. You could go iridium though for better performance.

Its about 800 degrees in the combustion chamber, and your bike is jetted (FI mapped) way rich, one heat range will not clean up the plug.

OK. so it really sounds like I maybe leave it like it is and let it sing daaaaaaaaaaaaadaaaaadaaaadaaaaaaaaaadaaadadaaaaa since it responds fine when I'm on the gas.

My guy can change the settings with imap but I don't want to screw it up. I've never used it.

Mine is about the same

25mpg from a 4 pop thats absurd!
Stick a leaner map on it and save $$$ at the pump get that rocket ship flying like she should.

No idea about std milage infact the only fourstroke ive ridden was kenny310's 08 te310 in oz and that thing was mean awesome delivery and smooth from dead stop to the top.

I may go with a leaner map.

For the sake of experimentation, would it hurt to try the hotter plug or perhaps lower Octane gas? Not permanent... I don't want to break anything.

If I can get an extra 5 MPG, that will help us with our normal DS ride here as my round trip is about 60 miles long.

Dont try lower octane gas, it will ignite before it should it that 12.9:1 compression. You cannot solve a rich map with octane changes or hotter spark plug heat ranges.

Thanks for the advice
. I'll see what a leaner map does.

How'd the new plug work? (sheesh, been so long since I've had a plug-related problem, I didn't even think of it). A bad plug could cause the problem, OR be caused by the problem. Are you burning oil?

And you might as well ensure that the air filter is relatively clean while we're checking the simpler stuff.

Haven't tried anything yet. Work....

I bought a replacement plug and a hotter plug just to see.

As far as the simple stuff, I have new gas, new oil, new air filter. Thing doesn't burn oil or even eat oil between changes. It just runs REALLY lean but I think that's how the PO liked it setup.

I'm just trying to smooth out the cruising and stretch the mileage a few miles before taking it to the dez. 2.1 gallon tank should get me further than 50 miles.

Dont you mean running really rich? I hope so otherwise i got the wrong end of the stick.

You dont want a hotter plug on a lean engine could hole a piston.
But im more of a twostroke guy so on 4pop you may be alright.

Yes. I meant rich.

Bit of an update. I went ahead and did the home-made iBeat cable and got it up and running. It was too late to start the bike and warm it up but the Feedback Adjustment settings were 1:135, 2:110 and 3:113.

With the adjusting point 1 at 135, that explains the rich-running I think. Tomorrow I'll warm it up and adjust the TPS and play with the Feedback Adjustment.

Good luck!

135 is waaayyy rich. There is a thread on here somewhere with people listing their co's. Mine was something vaguely like 110 107 114. Cant remember the numbers but there were certainly no 135s!