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Hondaforeman93

2004 Honda foreman 450 ES, won’t start

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46 minutes ago, Hondaforeman93 said:

Just wanted to say thanks for all the helps guys , it’s going to a shop, compression is to low , has to be something more internal.

 

thanks again

not sure how dealerships handle atvs/motorcycles over there where you are ?, but here in the states, most dealerships will not even touch/work on any thing 10 yrs or older !. why take it to them, and waste cash ??, that motor is really simple to fix, just ask bcs !. do the tear down, work yourself, you went and bought a compression tester, why stop there ???. you got the best atv mechanics right here at your finger tips...use it !.

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I agree ! But so far I haven’t been able to get bike running , lots of great tips and advice , but the thing has air, fuel, spark , I’ve changed everything. Set the valves and the motors in time . I don’t understand why it won’t start. 

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40 psi compression is a good place to start , need to figure out why , could be several things causing that , did you hold the throttle wide open when you tested 

 

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Battery was at full charge and throttle was wide open , 

 

when I have the plug out , and roll the engine by the pull start, I look in the hole and get it to the T, there is also an F there and two other lines that are close together.

 

when I put it to the T the piston is all the way to the top, but my exhaust valve doesn’t seem like it always wants to move. 
 

I set my intake valve to .006, I followed what shadtree sent about finding the compression stroke , and to my understanding I was at compression stroke. 
 

maybe the engine is not in time ? But I’m almost certain  I was checking that right

Edited by Hondaforeman93

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if  you take out the spark plug , hold your finger over the hole , hit the starter button , you should feel it suck in , then blow  out ---

 

you mention something about you don't see the valve move , a valve can be stuck or bent and be partially open and not closing or vice-versa ---- also the valve seat could be trashed causing a compression issue 

 

what is the history of this atv ? did you buy it used ? I asked before , do you have a service manual for it 

 

Another thing that is possible , if the  carb leaked fuel into the cylinder , then you tried to start it with fuel on top the piston , the connecting rod could get bent , if the rod is bent  then the piston doesn't achieve top dead center and  the compression is lowered , it would also throw  the timing  off ---did you ever notice a lock up when trying to spin it over 

 

if you squirt some motor oil into the spark plug hole , then do another compression test , if the compression comes up then rings/piston / jug  would be the problem , if the compression  stays the same then it is a valve , timing , blown head gasket or something else 

 

reading your story , and trying to make something fit , since it was running , then just quit makes me think that maybe what happen was that it was running , the timing chain may have jumped a tooth and the valve hit the piston and bent it 

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it does not matter what it did before you changed carbs ?, what matters now is...why wont it start NOW ?, it s very simple concept bro: IT MUST HAVE ENOUGH COMPRESSION, AND THE CORRECT TIMING TO START !. 40 psi is too low to run, now you must tear it down to find out why ?. sooo..lets dig in..and get your atv fixed !!!. remove the fuel tank, heat shield, muffler out of the head, or all the way off the atv. start taking the top end down, which means rocket box, then the head. you will need a good 1/2 drive metric socket set that has a 14mm, 10mm, and maybe even a 8mm. start taking the top end down to get the head off, we'll guide ya if ya get stumped ?..you can do this !. plan on buying a valve spring compressor tool, you will need it to put the valves back in the head. a top end gasket kit will be needed as well. dont take it to a shop !!!, we can help you step by step, wanna waste your cash ??, then paypal it to me !..lol.

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Found the issue !!!!! 
 

out of time , 

 

when I put the engine to top dead centre , the exhaust valve was a little open and the push road weren’t even , they should be even from my understanding 

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Are you sure that you were on compression stroke when checking?

There are 2 top dead centers- one on compression stroke and one on exhaust stroke

Make sure the flywheel " T"  mark is centered  in the viewing hole  and you have to have the piston on

TDC right after the intake valve closes

If you were on the exhaust stroke TDC, the exhaust valve would be open normally

You also might have your exhaust valve too tight if the rocker does not wiggle at TDC

and that would also make your compression low

Try loosening it a  bit and then check compression, it wont hurt if its a little loose for testing, it will tick a bit but

you can put it back in spec when you home in on thre problem area

Edited by AKATV
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The valve came right tight to the rocker , even after I backed the screw out all the way , it was 100% on TDC on compression stroke, and the push rods should be even when on TDC, the push road behind the exhaust valve was higher than the one behind the intake valve 

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6 minutes ago, Hondaforeman93 said:

The valve came right tight to the rocker , even after I backed the screw out all the way , it was 100% on TDC on compression stroke, and the push rods should be even when on TDC, the push road behind the exhaust valve was higher than the one behind the intake valve 

ok, now you must drain the oil, or stand it up on the back end. i find it easier to just drain the oil. pretty sure your atv is 4x4 ?, if it is ?, you will need to unbolt the front diff ( 3 main bolts, 2 small bolts on the very front of frame. yank it forward as far as you can pull the front drive line, then go to left side, reach in, and push the drive shaft forward at the coupling ( its spring loaded ), push it forward, off the output shaft of the engine. now you need to remove the front cover. all the front cover bolts are 10mm head. once they are out, pop the front clutch cover off, there are tabs spread around the cover, this is where you put a long screw driver at, and tap the cover off, try to hit all the tabs evenly !. MAKE SURE YOU REMOVED ALL THE COVER BOLTS !!!!. once the cover is off, you can see the cam chain in the top left corner when facing it straight on. with it being a 2004 ?, chances are..your cam chain is too far stretched , and needs replacing. purchase a D.I.D. cam chain !!!, you can find them all over ebay. or you can go oem from partzilla.com if they still sell them ?. in order to replace the cam chain, without tearing the top end down ?, you can just leave the cam in the engine, and remove the two 10mm bolts from the cam sprocket, its best to do this with the cam chain still attached. DO NOT PULL THE CAM OUT !!, if you pull the cam out ?, you face the task of digging the push rod followers out of the bottom of the engine !!!. in order to pull the cam out, the top end must be torn down, so you can pull the cam followers out BEFORE YOU PULL CAM OUT !, if you dont pull the cam followers out, and yank the cam out ?, they drop down into the lower engine, this will ruin your day !.

 

dont worry about removing the bolts off the cam sprocket, both the end of the cam, and the cam sprocket have a punch mark stamped on them, its impossible to mix them up as long as you pay attention to the punch marks !!!. before you even get to the cam chain, you have to pull the centrifugal clutch, oil pump, change clutch. all of this has to come out in order to replace the cam chain. there is also the cam chain slack adjuster, it will need to be screwed back inwards in order to get the cam chain back on, its bolted right in front, bottom of cylinder, you will notice there is a hole right above it ?, you can use this hole to remove the screw from the top of it. if you can get the screw out ?, you will have no choice but to tear the top end down. if you do have to pull the top end down ?, then you will need a top end gasket kit in order to put it back together.

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forgot, you may or may not need to remove the oil cooler lines ?, i can't remember right now ?, but it has two lines attached to the front cover. DONT LOOSE THE O-RINGS ON THE ENDS !.

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That is awesome thank you very very much ! Very detailed instructions :), you guys are the best ! Appreciate all your help fellas , I’ll let you know how it goes !! 🙂

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2 hours ago, Hondaforeman93 said:

That is awesome thank you very very much ! Very detailed instructions :), you guys are the best ! Appreciate all your help fellas , I’ll let you know how it goes !! 🙂

np, glad to help. be sure to keep us posted !!, we like pic's !!..lol. if ya get stumped ?, just holler at us !!, me, some one, a member will be here to guide ya !. be sure to down load the service manual from our site here, its the best tool you will ever find in your tool box !.

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OK I am remiss to not have read this post before last night.  I have a 98 450 ES and had the same symptoms as you and scratched my head til it was bare.  I also tried all the things that were listed here for fuel and ignition issues and came up blank.  The one symptom I read for you that brought back my 450 was blow back from the carb.  So with help from these guys, that time on the old forum, I pulled the front cover off and timing chain was toast.  And just like yours it had run the day before and then all it wanted to do is crank and not fire.  My chain was stretched past usable condition so it was replaced along with my cam sprocket.  Also make sure the chain tensioner is working correctly.  I had never taken apart an engine so all was new to me but with help here I did what was needed and got her running again.  Unfortunately for me not long after I got it running it started puffing smoke so again with help from retro and shadetree I was able to pull the engine, rebuild it, reinstall and get her running.  And she is purring like a champ now.  

 

Maybe missed it but how many miles and hours on the engine?  Mine had a bunch and was ready for the rebuild but maybe yours just needed a few parts like the chain and sprocket.  

 

Hang in there and ask lots of questions, you will have it running and feel good about saving many $$ by doing it by yourself....

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