Help!!!!!! Cam Problem

[sweet t-rex 400]

Put a new cam in and wont start now. Ive tried everything and still stumped. Valves are set right and timing set right. Put cam in with lobes down and motor set at tdc. Adjusted valves and triple checked them. Everything is right but something still wrong? I'm about to burn it to the ground!!! Help would be greatly appreciated. Thanks

[sweet t-rex 400]

wanted to add that my lines on the cam dont match perfect with the top of head...can the timing chain stretch enough to where it wont fire...ran good before tear down...

[CJM]

1. When you put the cam in it should be super close when the gear is on there and of course as mentioned the lobes should be down.

2. When you adjusted the valves, did you make sure the rockers had play in them. You shoulda been able to grab them and wiggle them. If you couldnt wiggle them then you need to turn the crank again and go to the T mark and check the rockers. For me it can take a few times sometimes. works much better with the sparkplug out btw.

3. You removed the stock decompressor if your using an aftemarket cam?

[Stickman400]

MAKE SURE that you are on the "T" mark on the flywheel. I did the same thing installing my cam. I thought I was on the T and it was just a little hash mark, so I set it and they were just a hair off but I figured that it was fine too. There are 3 or 4 other marks on the flywheel besides the T. It should be dead on when you line up the T and have the cam in lobes down.

[sweet t-rex 400]

the rockers have play in them when set at tdc. Removed the decompression mech and spring and plunger out of head. It still will not fire...everything is right but wont fire...very mad and dont know what else it could be?

[NMills]

Did your new cam tell you to remove the spring adn plunger???? or does it have the decompresession mechinism on it????

[CJM]

WHat kinda cam is it? If its stock the bike wont run without the spring, plunger and decomp no matter what ya do.

[sweet t-rex 400]

its a stage two magnum cam...it didnt come with the decompression mech so i left it off and removed the spring and plunger from the head...im a very good mechanic but dont know whats happening here. getting good fire and fuel also...backfired once and thats it!!!

[Ridiculous]

do you have compression?

and i don't get your problem either. i just installed a cam in mine tonight, and when i got all done and hit the start button, she fired just fine as always.

so i'm saying, if you got fuel, spark, and check your compression, i'd tear it apart again and re-install it persay, and see what you see.

[CJM]

IDK anymore so Im gonna toss out some ideas:

-cam gear lines are parallel to head and the vertical line is facing up?
-Tensioner is good
-Cam lobes were down during install
-CDI could be bad-do we have spark?
-Your setting the piston to top dead center when installing the cam? The "T" mark on the flywheel?

[sweet t-rex 400]

Lines are parallel with head lobes down at tdc getting good blue spark and getting good fuel...it ran good before teardown and put new head gasket on and new tensioner and new cam...just wont fire now...im at a loss..did not check compression though yet. It ran great before so i dont see that being the issue...

[wildwheels22]

Did you get it running? If so, what was the problem. Post results so it can help other people!

[sweet t-rex 400]

i stopped working on it...im gonna tear the whole atv apart and re powder coat everything. I did not get it running and got mad so i stopped. It has turned into my winter project now...sorry for not posting my results...any info would still be appreciated

[dxcody]

WAIT! I did the same thing, and before you go and tear it all apart, replace the plug.

I know it sounds dumb but i was getting spark, everything was great, but the plug was just not sparking hard enough.. Just give it a try, $2 plug and you never know what it can change.

[sweet t-rex 400]

I have not touched it in like two months but decided to check it out today. I primed the cylinder by putting gas in the plug hole and blam...it fired right up and runs AWESOME!!!!!!! I dont know what it was but it runs excellent now.

[dxcody]

sweet, glad ya got goin. be careful!