I have a basically stock 400EX... I do have a K&N filter on it, I've upped the main jet a couple of sizes, I trimmed the air intake snorkel, and removed the quiet-core insert and spark-arrestor from the exhaust...

I was wondering what kind of gain I'd get from say an 11:1 piston and a stage 1 HotCam ???

would it be better than going with a full exhaust system? I want to keep the stock / sleeper look

 

ok, to make this easier, someone has a quad that youo want to know if you can beat....so post that and let us answer you....although with that you should be neck with a kfx/z400....i think im right about that

 

ok dude listen, you need a good pipe first, (sparks, hetrick) then you should get the piston and cam combo, and do not get a hot cam at all spend the extra $$$$ and buy a sparks cam, the hotcam will not last and cause more damage then good its not at all reliable, and if you run a piston get a JE or ross i run JE but those two are the best

 

and do not get a hot cam at all spend the extra $$$$ and buy a sparks cam, the hotcam will not last and cause more damage

Please qualify your claim.

I personally know several people running hotcams, and have run one myself for about a year now (all race use, both flat track and XC) without any kind of trouble what-so-ever.

Is the Sparks cam a ground OEM cam or a hardwelded & ground cam? Better consider hardened rockers if it's welded or your damage claims will be true, except for it will be the Sparks cam doing the damage, not the hotcam.

FWIW, a piston and cam combo will wake your 400 up noticibly, don't have your expectations too high and you won't be disappointed - should not have trouble outrunning stock LTZs. Stick an FCR on with that combo if you really want to wake it up.

Lose the stock silencer as well - the path thru it is the main restriction, you haven't done much but make it more noisy by removing the quiet core...

 

I recently installed a JE 10.8-1 piston, along with a Hotcams Stage II cam. I am running a Yoshimura slip on, with ground out header welds, and a K&N air filter. I don't know the gain on HP, but I do know that the quad is now a totally different animal. It pulls twice as hard through all gears, and I'm very satisfied with the end results.

The Hotcam is one of the most popular cams to install, and I've yet to hear anything negative about them. They did have a bad batch of them a couple months ago, but found the trouble, and replaced all affected cams.

I do know of a guy that ran one of Sparks' "drop in cams", and it ate his rockers alive.

 

The claims about the life of a hotcam bieng short are unverified at least! I was concerned about the cams but have used them succesfully in machines that are now really racking up the hours...the stage II cam and a piston will make that thing pull way harder than a stock Z(properly tuned of course)

 

you guys are right about the stock pipe. loose it. lol...my WB needed to have itself welded back together, so i ran the stocker for about a week. i hated how quiet it was with the stock silencer, so i unscrewed the spark arrester insert thingy. lol, it helped a bit with performance, and it made it sound like a f-ed up Harly or something when you get on the gas.lol...ill stop rambling now

 

your cam is worthless unless your motor can breate, IE. exaust and air