uhg wow....

[Chanman420q]

well today..... im riding and it sounds like my axle bearings are going, so im taking it easy, every time i gas it i hear this crunching noise, like metal rubbing on metal. So i start heading home, and on the way home my quad starts making this squeeking noise right around the front sprocket area. then it starts getting really loud. The actual engine it self, it sounded like the silencer wasnt on. And it was losing power. Then all of a sudden it just dies and my head gasket i think is blown. Or could be the base gasket, not sure which it is. when ever i hit the starter all i hear is my compression going out the engine. Then i start looking at it and i notice the plastic stuff around my wiring is all pulled up and half is melted off.

Im so sick of this quad. I suggest people start Looking in the For sale section very shortly for a lot of my after market parts. Ive had nothing but problems with this quad. Time to pass on the burdon.

also i just dropped a grand into the motor to get EVERYTHING in the top end changed. Piston, valves, valve springs, cam and rocker. the only thing that wasnt changed was the cam chain. Im gunna open it up tomarrow and if anything is wrong other than a gasket, its going up for sale, im just going to part it out and get a yfz.

so what do u think happend? i think it over heated......

[chucked]

if its a head gasket, and its a cometic, you had the old design with the design flaw. cometic just re-released the head gasket for the 416 piston that has been redesigned because of a design flaw. I wouldnt worry about it if it was a head gasket, just replace it.

[Chanman420q]

well does that sound similar to a blow gasket, i got about 15 hrs on the motor. i was using stock gaskets

[chucked]

Originally posted by Chanman420q
well does that sound similar to a blow gasket, i got about 15 hrs on the motor. i was using stock gaskets

i didnt know that the stock head gasket would fit on a 416 (87mm) piston??

[Chanman420q]

thats what i used:confused:

[TC426EX]

The stock gasket will fit a 416, and east coast atv used them on the 426 ( I dont thoug). If you are running cometic then it is probably the head gasket. I feel your pain man. After I split my cases I put a cometic head gasket in it, and after ONE race it was blown. It is actually blown right now since I bought 2 cometic gaskets and used them both hoping it was something else. When I started my quad with shorts on before I put gear on I could feel it blowing out the left side onto my leg. You can hear it too. Good thing I went to warm it up without boots on or who knows how long I would have ridden on it like that before I realized it. Probably would have burned a hole in the side of it after a while. Anyway, i hope it is just a head gasket for you chanman, and if it is, let me suggest a Tudors "no blow" head gasket. They have been working absolutley perfect for me. What I would reccomend is that instead of using a triple layer metal gasket, you get a white brothers fiber gasket for it. These gaskets have a metal ring on the inside circumference that crushes and works alot better at sealing than the triple layer if you ask me. Just my 2 cents, but I hope its just the gasket and its an easy fix for ya...

[Chanman420q]

i will 100% part it out if its more than a gasket, i just rebuilt that top end from scratch, to much money was invested in that

[440ex2001]

So are all cometic gaskets no good? I got a set for my 440 kit .Are just the ones for 416 /426 prone to blowing?

[cals400ex]

i run them in my 426, my buddies run them in their 416's and 406's and not one of us have blown one yet. but, if you reuse the gaskets, they may blow.

[Silverfox@C&DRacing]

those of you that are blowing head gaskets do you torque the head studs 4-5 more ftlbs than stock specifications and are you 100% sure the matting surfaces aren't warped.

Cometic gaskets are good. I"ve actually reused a head gasket and it's still holdin strong.

To much compression can cause blown head gaskets and uncorrect torque specs.

[TC426EX]

My head and cylinder was not warped, and I torqued the cometic down to 55 ft lbs. Stock is 44 so I think it should have covered it. I also run an oversize stud kit and the cometic still blew out with 12:1 compression... I have never blown a head gasket after I got the stud kit except the cometic so that tells me they suck. I have heard ALOT of people complain about the cometics, so I know Im not the only one...

[Chanman420q]

so what gasket should i use and what should i touge the bolts down too, i used OEM gaskets and OEM specs.

[redroost85]

Man, this sucks Chanman.:(

I think you got more gremlins in your ride than I do.:o

[hondarider2006]

I used stock gaskets on my 416 as well and its doing just fine....To many people that are having problems with the cometic head gaskets for me:o I am using there base gasket right now, and haven't had a problem. Just get a new stock one

[Chanman420q]

that one TC was talking about sounds interesting

[chucked]

Like I said earlier, cometic has redesigned their head gaskets, the new style has just been released.

[Chanman420q]

ill have to look into it..... mean while what should i tourge my head down too with 11:1 comp

[trick450r]

use cometic gaskets i like em alot!

[TC426EX]

Stock is 44 foot pounds like I said, so you want to go about 50 or so on them. Look into an 87mm tudors performance head gasket or call east coast atv and get a fiber white brothers 87mm gasket. Since you have a 416, stock size should work as well... Ive listed the URL for tudors below give em a call if you want...

www.tudorsperformance.com

Hope you get it taken care of man...

[Chanman420q]

ya well if this motor has anything else wrong with it, then its gone. no reason to keep an out dated quad that isnt reliable.

the smell of a YFZ is so close yet so far away.... id hate to part with my 400 but then theres the sweet sweet taste of yammy:p

[chucked]

Originally posted by Chanman420q
ya well if this motor has anything else wrong with it, then its gone. no reason to keep an out dated quad that isnt reliable.

the smell of a YFZ is so close yet so far away.... id hate to part with my 400 but then theres the sweet sweet taste of yammy:p

yea id love to get a 450 but you cant just save up 6 g's and I dont have enough credit yet.....

[Florida400EX]

I run Moose gaskets in my 416, and they haven't blown yet. They have the metal ring that TC426EX was talking about. I think it was $40 for a whole set of moose gaskets (whole engine). Good luck with your 400ex, I've been in and out of your situation (yfz), and I'm not really ready to step-up yet. Good luck and get it running again, once you get it running, you may change your mind (like me).