temperature ? on 400ex

[skullracer34]

what temp is a 400ex suppose to run at ...mine is running at 270 degrees riding in the yard is that to hot????? and when it gets up to this temp itstarts hesitating when you touch the throttle whats causing this

[oliver1650]

where are you measuring the temperature? When I'm messing around in the yard, my temperature dipstick only shows 100-150. If I'm riding hard, I've seen near 200. 270 sounds high to me.

If I'm reading your sig right, you have 13.5:1 compression and a 6 degree timing advance key? You'd need some serious racing fuel to keep from overheating and detonating. I'd start by pulling the timing key and see if it runs cooler.

[skullracer34]

i run 110 race fuel and i check the temp with a temp gun on the head , but the valve cover reads 15-18 degrees cooler which do i go by? and when a engine gets hot does it lean out or get richer?

[oliver1650]

As far as temp reading there go, I'm not sure what is normal. I would highly recommend getting a XRs only temp dipstick. Much more reliable reading that getting the temp from the outside of the case.

[honda400ex2003]

seems a bit high but not bad on the head. the oil temps i have are around 200-250. if it is super hot it is 250. if i ever got it that hot it would be shut down. it usually runs 200-220 degrees in the tank. steve

[NacsMXer]

Originally posted by honda400ex2003
seems a bit high but not bad on the head. the oil temps i have are around 200-250. if it is super hot it is 250. if i ever got it that hot it would be shut down. it usually runs 200-220 degrees in the tank. steve

This is pretty much what they run at. Anybody that has the temp dipstick can do what I did and use some colored sharpies to mark the temp zones. Makes it easy to see if it's still warming up, in operating range, or in the DANGER ZONE :eek:

http://img831.imageshack.us/img831/9870/dsc0003xq.jpg (http://img831.imageshack.us/i/dsc0003xq.jpg/)

[erik420]

Where can I get one of these xr only dip sticks? I searched for it but couldn't find it. Thanks in advance.


Erik

[Pabst_Powered]

Originally posted by erik420
Where can I get one of these xr only dip sticks? I searched for it but couldn't find it. Thanks in advance.


Erik XR's only site,

[oliver1650]

Made it real easy for you
http://www.xrsonly.com/content/index.php?page=shop.product_details&flypage=shop.flypage&product_id=1010&category_id=104&option=com_virtuemart&Itemid=70

[erik420]

Thanks guys. That was real easy oliver1650! Thanks!I was looking on ebay for one. I did not now about xrsonly.com. Im going to look around the site to see what other goodies thay have!

Erik

[JOHNDOE83]

my 440 when extremely lean from the turbo project, had a run temp of 260 on the cylinder, I thought that was pretty high.

[skullracer34]

what about the hesitation when it heats up i mean it runs great till it gets hot does that mean its leaning out or what

[JOHNDOE83]

I would have to say deffinetly....lol.

hesitation is a lean condition, the motor does slightly lean out when warmed up, you could have secondary issues, I would try jetting first and if it cant get cleared up then I would look for other options.

[skullracer34]

well i have noticed when i first start it it will kind of spit back thru the carb till it starts warming up and what do u mean by secondary trouble

[JOHNDOE83]

popping back through the carb is DEFFINETLY a lean condition.

secondary issue would be like a air leak, or oil flow issue, but with the popping back through the carb, Id go with new jetting for sure!

[honda400ex2003]

Originally posted by JOHNDOE83


the motor does slightly lean out when warmed up

even though this part is 100% false he is correct in the rest of the info. engines richen as they get warmer since the air gets warmer inside and requires less gasoline. it just starts to show up more when warm, and as it gets warmer. same principle with when it is warm outside, jetting down is required.

these are the symptoms of a lean engine

a. Acceleration poor, surging.
b. Performance improves slightly as engine warms.
c. Better performance when choke/starter is used.
d. No color, overheated spark plug electrode (see reading plugs FAQ).
e. Removal of air cleaner makes condition worse.
f. Popping back thru carburetor.
g. Engine pings or knocks, excessive engine heat.

steve