440 big bore kit care

How would I keep my 440 big bore kit on a 400ex in good condition. I know there are head gasket problems and stuff but is there ways to prevent that and what would I do? I know one is use better feul.

I had air shrouds that directed air towards the cylinder. You can buy them, but I made them myself. I don't think I have a picture, but they are fairly cheap (for the amount of money they will save you).

 

The only problem with the 440 is how hot it runs. Like I said, air shrouds work great, but there are builds with extra oil coolers and other things of that sort.

 

I beat on my 440 for about 4 years with just the shrouds, only blew one head gasket, and that was towards the end of the 4 years.

 

Using "better fuel" (I am assuming you mean higher octane) will only make the problem worse, as that fuel burns hotter.

I have a 2000 400ex that I put a 440 big bore in.  I put the big bore probably 6 months after buying it brand new.  I've never had to tear it back down to fix anything.  I don't race, I'm just a weekend warrior.  Mainly do dune riding, trail riding and the occasional track.  I have air shrouds, added an extra oil cooler, added a larger oil tank and only run 110 octane.  I use Honda oil and change it after every 5 rides.  Its going on 13 years and it still starts and runs good, I finally had a shop do a leak down test and they said everything looked good.  Anything you can do to keep it from getting to hot is good.  I think that's why mine lasted so long.

I have the same story as above. 440, web cam, kibblwhite valve springs, white brothers full exhaust and higher revving cdi with kn. put all that on 6 months after buying brand new in 01. Been ridding the crap out of it ever since. I did put air shrouds and a fourstroke tech extra oil cooler. And no problems. I only run 92 non ethanol and sometimes av gas

Where did you guys get you 440 kit I've been looking and haven't decide what to get yet

2003 400ex

Im pretty sure that the higher the octane the cooler (and longer) fuel burns. 

Get the IMS kit from RMATV. It comes with a LA Sleeve, Wiseco piston, and Cometic gaskets; all good parts. I think it's still less than 300 bucks.

Im pretty sure that the higher the octane the cooler (and longer) fuel burns.

No, octane rating measures how much compression is needed to ignite the fuel. High octane fuels are needed with high compression motors because standard octane fuel will pre ignite and hurt performance.

Use spray copper coat on the head gasket for an improved seal

2 light coats

No, octane rating measures how much compression is needed to ignite the fuel. High octane fuels are needed with high compression motors because standard octane fuel will pre ignite and hurt performance.

 

You can ignite fuel with ZERO compression. If you dont believe me, put a pint of gasoline in a pan and touch a match to it. No compression or eyebrows. When I just checked, both Ask.Com and Wiki confirmed that higher octane fuel burns cooler. If you dont believe me or them, you could test it. Put a pint of 88 octane in the pan and hold a thermometer (or use an infrared sensor) and touch it off. Record the temperature. Then try it again (if you used an infrared sensor) and record that temperature and let us know that Ask.com, wiki and I am wrong. (I didnt ask about longer, but feel free to check it for the sake of the accuracy of what we are writing and knowing what we're talking about.)

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