help atc 500

[gasmask]

today i tryed cracking my atc 500 project bike...when i kick it over i can only get one revolution out of it...do i have to add another head gasket or another gasket at the bottom of the cylinder...it will back fire but only kicks over once...any advice is accepted...

[H.M.F.I.C.]

Those 500's are a complete biatch to start. If you are out to make sure that it runs get sombody to pull you off. I had a cr500r dirtbike and that is prettymuch the way I started it anytime it was cold. Once it was warm I could start it but even then it was stilll hard.

[ClayW]

Well, I have a XR500R Dirtbike, and it can not be started without using the compression relief valve. My bike has a small lever that mounts on the handlebars under the clutch lever. THe cable goes down to the right top side of the head. If im not mistaken it holds the exhaust valve open. Mine starts on the first kick after the compression stroke. Most of the time I get on the bike and slowly push the kickstart down until I feel resistance. Then I pull the valve open and hold it open, and kick it one time. This gets it off the compression stroke. Then I just kick it once and it fires off. It can not be cranked by a HUMAN!! unless its off the compression stroke. My wife actually tore ligaments in her ankle trying, by accident. She thought she had it off the compression stroke, but it took one more kick. She let it have it and tore ligaments. Im a big guy 6'3" and 285lbs and I cant come close to kickstarting in unless its off that compression stroke. Maybe you need to hook up a compression relief valve. Sounds like you dont have one.

CLayW

[ClayW]

It will also back fire a bit it you dont kick it over fast enough. Its more like a poping sound coming out of the muffler.

ClayW

[OldSchoolin86]

Gasmask, is this a 2 or a 4 stroke?

[ClayW]

Has to be a 4.

[OldSchoolin86]

I've been gone for awhile so I may have missed an old post but why would it have to be a 4?

[H.M.F.I.C.]

It is a two-stroke.

[coyote killer]

my yz490 just gave me the same problem....it had water in the gas.....now it starts first kick.....

[OldSchoolin86]

Thanks H.M.F.I.C., that's what I thought it was.

[ClayW]

Sorry about that. The guy I was thinking about, converted his 350x 4 stroke to a 500 4 stroke. Mine is a 4 stroke.

ClayW

[gasmask]

it is a 1985 cr 500 2 stroke engine...i cleaned the gas tank out 3 day ago & it sat in the shed until today...fresh gas & 2 cycle oil. as you already know if i remove the spark plug i get all the revolutions i need, but when i put the spark plug in i only get one...is that cause buy to much compression.i remember reading one forum saying that they used 2 head gasket to lower the compression...

[gasmask]

Gasmask, is this a 2 or a 4 stroke? 2 stroke cr 500 honda

[coyote killer]

it is a 1985 cr 500 2 stroke engine...i cleaned the gas tank out 3 day ago & it sat in the shed until today...fresh gas & 2 cycle oil. as you already know if i remove the spark plug i get all the revolutions i need, but when i put the spark plug in i only get one...is that cause buy to much compression.i remember reading one forum saying that they used 2 head gasket to lower the compression...

All that it took to make my perfect YZ backfire and not start was about 3 small drops of water in the float bowl.....I got just a couple of drops out of the tank too.....If thats not it then look for something that would cause it to be lean.....

[coyote killer]

u could also try starting fluid just to get it started the first time....

[gasmask]

ok the motor is freshly rebuilt top & bottomend, brand new 39 mm carb from ESR racing. i will try the starter fluid tomorrow...but i put about 10 drops of gas in the cylinder & 10 drops in the carb since it all new, that when it backed fired twice.so i know it getting gas & fire...how can i get it to kick over more that one revolution...lower the compression or what?????

[coyote killer]

It wont spin even with the throttle held open???It should spin a couple of times with the throttle open...

[gasmask]

It wont spin even with the throttle held open???It should spin a couple of times with the throttle open...
NOT EVEN WITH THE THROTTLE WIDE OPEN...JUST ONE REVOLUTION ALWAYS...

[coyote killer]

my 490 wont spin unless i hold the throttle open and then it doesnt spin much....But when everything is right she starts on the first kick,,,,cold or hot....

[coyote killer]

I think youre alright as far as the spinning concern....I'm guessing you have something causing a lean condition since trailprotrailpro getting a backfire....if she starts with the starting fluid then trailprotrailpro probably lean.....if she wont start with fluid then trailprotrailpro rich.....

[gasmask]

OK I WILL try the starter fluid tomorrow...i want to go try it now but it 10:18 pm here. i may try it tonight...in 1995 i had a big bore kit put in a ytz 250. in order to crank it i had to push to crank it...i sent the head back to trinity racing and when they shipprd it back i could kick it over...this bike is doing the same thing that's why i'm focused on compression...

[coyote killer]

OK,,,but before you give up on it compare it to other 500cc 2 strokes....All of them I have seen dont really spin until they fire.....Unlike a 250 thats easy to spin....

[gasmask]

i'm not going to give up just yet.it has taken me 9 month to get this far...now i won't give up until it fires up...so far that's the only hold up now.once it cranks i will have it chromed and polished, new plastic,rim & tires the works...guy around here love to drag race so that's my goal...i have someone willing to build me a wheele bar already...

[x.system]

Instead of starting fluid try WD-40, it works the same as starting fluid but has lubrication.

[200xBoy]

someone probly already said this but pull the carborator off and clean the float type thing. my 200x did that at the dunes and i was so pissed and i ripped the carb off and cleaned it and it ran fine.

[Tri-Z Pilot]

Those 500's can be very stubborn. try bump starting it maybe that will help. If you have dumped gas down the cylinder, and it still backfired, it shouldnt be lean, raw fuel in the cylinder is very rich. One more thing, have you tried a new plug?

[gasmask]

the spark plug, carb etc are brand new...the compression specs. are 7.4:1...i may have to buy a compression gauge to check me compression...if it to much i will have to put another head gasket on it...

[gasmask]

after a long night & alot of advice for you all my atc 250/500 is now running...i when a bought some starter fluid and sprayed it into the cylinder.at first it backed fired 3 times then the fourth time it sound like it wanted to crank. the compression problem is not an issue. the only thing is that when you crank it/ it's more like you have to feel the right crank stroke...after spinnig the engine over bring the kicker 3/4th of the way up the kick the sh_t out of it...that's when it cranks...thanks for all the parts, help & the advice...i will try to post pictures in a few days...

[gasmask]

see help atc 500....thanks everyone

[Tri-Z Pilot]

Oh yeah, you cant just keep kicking a cr 500, you will lose the battle every time. All you have to do is find top dead center, then kick like you have never kicked before, that should do it. Another thing I have heard riders talk about, is to lean the bike to the side a little bit, supposedly it primes it, but I dont know.

[cr500=3wheeler]

bring it up just past tdc then try to kick it thru it takes a little practice but after you figure it out no really problem still a pain but not as bad.

[cliff2302]

on tecates you gotta give it 2 slow kicks to get it primed, then put it at tdc and give it a real kick. starts first time, every time for me, maybe this might help you

[gasmask]

here are some more photo's...after i blown it up...she running again...1985 atc 250r/ 85 cr 500...

[TrikerR]

thats SWEET

[MTS]

yep that thing is gona throw some bad ass r00st :D