My friend has a 440ex that suposedly aslo has a cam and 10.24:1 piston and a white brothers exhaust. How come it is running on the stock jetting. How come it is able to run on the stock jetting. Could the seller have been lying and it not really have a 440kit? I dont know how fast a 400ex is suposed to be but his is about the same as a stock raptor but with maybe a bit more torque and mid range. How the heck is it possible to run on stock jetting?!?!?

 

So.... What you're asking is "how can it be running on stock jetting?" I guess.

Is it running really lean??? How does the plug look??? Is there a hole burning it's way through the top of the piston? [img]i/expressions/face-icon-small-smile.gif[/img]

Check the plug and see how it's running. I would THINK those mods would require a bump up in jetting. I'm sure somebody with a similar set-up can tell you what jetting they are running.

 

The jetting stock is 38 pilot and 148 main. It should have about a 45 pilot and a 165 main. Does it have the lid on the airbox with no holes? In a straight drag race the Raptor will be a little faster or even with the 440. You take it on any kind of track and the Honda will blow the doors off of the Raptor.

 

He's talking about my quad. It was lean, had the stock filter with airbox lid on. It had a 155 main on and still did equal with the raptor I dragged. I just added a uni filter/lid off/ dynojet 170 main and runs perfect. But now the head is leaking oil and needs a new gasket [img]i/expressions/face-icon-small-sad.gif[/img]

 

Dunno about the about the pilot but the main was a 155. We replaced it with a dynojet 170 and were trying to get it right but then we noticed oil leaking around the left side of the head so now we have something else to deal with. Trying to figure out whether to buy a new gasket or just retorque the head down.

 

Hello guys and gals I was just wondering if a 440 kit comes with such a small piston 10.24:1? I thought it would be bigger than that. If im wrong please correct me so I would not make the same mistake thank you.

 

That just describes the compression ratio, can't go much higher than that (11.0:1 is about the line) and still run on pump gas.

 

I would not be surprizes that you will find out that the studs in the head have pulled out of the head. this is a common proplem with the 440 running on pump gas after talking to some builders. I use 50/50 mix of gas with my 11:1 piston. Pump gas will cause the engine to run hotter.
Like I said before a Raptor is fast in a drag race and you have the small piston(10.24:1) and running reg gas.
Don't know anything about the K&N jet kit, I use stock jets.

 

Jackalwarrior, hmm... It was suspected to be lean and now you have a head sealing issue. Could it have got hot from being lean and warped the head a little??? Just throwing out ideas since I don't have a 400ex.

 

It was lean but not all that lean, It ran fine as long as you had the air box lid on and only 6 disks in the exhaust. Put all the disks in and take off the lid though and it got bad enough where you could notice it. He never did let it get all that hot, hes about as paranoid as I am. Say the head bolts did work their way loose on one side, would it ruin the head gasket or can we just retorque it down. As for racing the raptor, I think now that it isnt bottle necked by the filter and pipe, it could probably take that raptor. Neither one was getting traction and they were very very close. Maybe 1/2 a bike length. This was before he even knew how to ride it good (his hole shots were nothign but wheel spin till 3rd gear, but I think ive taught him how to launch in first and slip the clutch), only had it a day at the time. Meet him again id say the 440 would get the hole shot and hold him off, unless he buys a pipe before then, then it would probably be even again.