plz help wont start!

[moorhous]

hello and thanks to all that trys to help me!

I took my topend off to change the head gaskit when I put it back
im dumb set the timeing wrong but it never started so I took it back apart and looked at the valves and they may have just taped the pistion. every thing looked ok but the valves had a veary small scuff mark so I put it all back set the timeing right and now it sounds like it wants to start but it wont what could it be??

when I I try to start it it wants to start almost every time but it wont!!!

[400eXr1d3rZ]

Got gas, compression, spark?

[moorhous]

spark is there gas is there comp is there I can see the valves open so there not stuck closed let me re word this its ALMOST like it starts when iam holding the starter button but when I let go shes not running!!! I hate this its nice out I want to ride!! thanks for the replay

the gas is about 2 mounths old could that do it??

[400eXr1d3rZ]

I suggest you replace the fuel and try again, make sure the gas valve is on, make sure it's actually getting fuel, make sure your spark boot is actually fitted on the spark plug and make sure your killswitch is on the ON position.

[moorhous]

thanks! I know its geting gas it was on the spark plug when I pulled it out. and the on switch is on I have a hard time tinking its the gas but worth a try! thanks I can not think of what else it could be.

[400eXr1d3rZ]

Did you recently do any new mods? Did you try cleaning out your carb?

Could it be possible that it's NOT timed correctly? Did you set it to top dead center? Did you put the cam sprocket on the correct tooth (marks on sprocket lined up with the head)?

[moorhous]

I 90% sure its right I was 100% after I did it but i am starting to think that I need to check it again! as for mods yes just put a powerboamb header on it but thats all thats new. I dont think it would stop it from starting..

whats funny is I just went out to check the valves and a guy came screeming buy on his 400ex :( jeark lol

Thanks for all the help

[BossmanEX]

I had the same problem with mine when I put it back together and it turns out that the jam nuts on the rocker arms backed off and let the adjustment screws back out of adjustment. After a quick valve adjustment and a good tightening of the jam nuts it fired and ran perfectly.

[JOEX]

Stock cam?

If so, is the decompression spring and plunger still inplace?

[moorhous]

Originally posted by BossmanEX
I had the same problem with mine when I put it back together and it turns out that the jam nuts on the rocker arms backed off and let the adjustment screws back out of adjustment. After a quick valve adjustment and a good tightening of the jam nuts it fired and ran perfectly.


Thanks ill take a look at that!

[moorhous]

Originally posted by JOEX
Stock cam?

If so, is the decompression spring and plunger still inplace? TC 926

[moorhous]

ok new gas valves are .005 .006 spark still there It still wants to start but wont its dark out now and I seen a small flame come out of the slipon what would cuse this?? thanks if any one wants to chim in plz do!

[moorhous]

oh also I took the carb off and hit the gas a few times and it was a good stream of gas.

[400eXr1d3rZ]

What color is the flame?

[moorhous]

blue mabe a little ornge

[brokenmike]

did you install a rev box on there?

[moorhous]

yes it has had a rev box on there but I put the stock one back on.

could this have some thing to do with the jeting after the header? I think theres a 148 main in it

406 11.1
tc cam 926
hmf slip on
fmf header

[the Z Man]

1 tooth off on timing?

[moorhous]

the timing has been checked and checked again. could it be geting to much gas? after it cranks a few times it dies down and smells like gas

[JOEX]

Maybe one or more valves are bent:ermm:

[the Z Man]

Automatic comperssion release on the cam.

[BossmanEX]

Originally posted by moorhous
ok new gas valves are .005 .006 spark still there It still wants to start but wont its dark out now and I seen a small flame come out of the slipon what would cuse this?? thanks if any one wants to chim in plz do!

Sounds good. that means youre getting fuel, fire and making combustion. Get another spark plug and try it with a freshn one. All that cranking and pumping the throttle with no results has very likely fuel fouled your plug. Sounds like the valves were out of adjustment. Youre close. ;)

[moorhous]

'Automatic comperssion release on the cam."

I dont think this cam uses it

[moorhous]

I am lost! new plug still no go!

[moorhous]

its more of a yellow flame!! any one

[sc400ex_rider]

you must do a compression test if the piston and vavles hit they may have very slightly bent causeing it to very slightly almost start. gl

[400eXr1d3rZ]

Originally posted by moorhous
yes it has had a rev box on there but I put the stock one back on.

could this have some thing to do with the jeting after the header? I think theres a 148 main in it

406 11.1
tc cam 926
hmf slip on
fmf header

You guys don't realise he said he's running a 148 main, I hope you mean in Dyno Jets... Here's a suggestion go to www.jetsrus.com and order a 162 165 main jet and 42 pilot.

[moorhous]

OK psi was 120 could it still be the valves?? were can I get the tool I need to get the valves out? As much as I hate to say it iam really thinking it may be the valves I have tryed every thing else

yes its a dyno jet

[400eXr1d3rZ]

Quick question, but did you try choking it when starting? You need a valve spring-decompressor, you can probably get one at your local hardware store.

[moorhous]

I have. do you mean when I was doing the comperssion test?

Dose this sound like valves to you?

If I take the caps off the top of the engine I can see the rockers pushing the valves down thats why I am blown away. wouldent they have to stick to stop it from starting?

[moorhous]

wow I just went out and looked yes the choke was on when I did the comperssion test I turnd it off and 0psi :( blows.

[moorhous]

OK I took the head off the valves look ok they open and close how much I dont know. can they be bent and still open and close but not start? why im I geting 0psi? sry for all the ? but I want to learn as much as I can! its the intake valves.

[400eXr1d3rZ]

Originally posted by moorhous
OK I took the head off the valves look ok they open and close how much I dont know. can they be bent and still open and close but not start? why im I geting 0psi? sry for all the ? but I want to learn as much as I can! its the intake valves.

You have no compression apparently, I suggest just changing piston rings and starting over, if it turns out that the valves are bent, then go ahead and buy aftermarket valves. Good luck.

[sc400ex_rider]

inthe dark shine a flashlight down the ports with the valves and springs on. you should not see any light. even a little light means a little bent. you can try lapping them back in. even with bad rings you should get some comp.

[JOEX]

I think this might work...

Pour some liquid (water ?) in the ports, let it sit for awhile then look for seepage around the valves.

[400eXr1d3rZ]

Originally posted by JOEX
I think this might work...

Pour some liquid (water ?) in the ports, let it sit for awhile then look for seepage around the valves.

Wouldn't water be bad? Why not gas or oil?

[JOEX]

Originally posted by 400eXr1d3rZ
Wouldn't water be bad? Why not gas or oil?
That's why I put a question mark there;)

I was going to say gas because it's not as 'thick' as water but there's the fire hazard for those who aren't to bright. I think oil would be too thick...