[Helixhonda]

Hey guys,

I have read all the forums regarding what could be the issue, 2007 TRX420 FM,

The bike ran fine three years ago and then sat since then.

We have replaced all fluids, drained the gas tank, replaced fuel pump and assembly, injector, fuel shut off valve, spark plug, and air filter.

The bike will not start it will continue to crank and crank. We have checked all fuses, both lights come one and you can hear the buzz and fuel pump then two of the lights go away as normal.

I am scratching my head here. As the bike is getting spark and plug does get wet meaning fuel is spraying.

What else should I check?

 

[Helixhonda]

Well we think it may be dried piston rings as we are getting no compression. Lots of pressure when plug is out. But the compression tester is saying 0. The bike ran fine before it sat. But maybe the rings dried up?

 

[retro]

Check for a stuck open valve/busted valve spring maybe. If you are flooding the cylinder with gas you can do serious damage.... squirt some motor oil in the cylinder and turn it over slowly to distribute it. You don't want to wash down the cylinder and piston/ringset, that ruins them quickly. Welcome to the forums!

 

[Helixhonda]

Check for a stuck open valve/busted valve spring maybe. If you are flooding the cylinder with gas you can do serious damage.... squirt some motor oil in the cylinder and turn it over slowly to distribute it. You don't want to wash down the cylinder and piston/ringset, that ruins them quickly. Welcome to the forums!

thank you so much, how would one check for a stuck open/ valve?

 

[misterclean59]

Low compression would indicate a stuck valve.

 

[aTVitsnot]

Seems like a good next step would be removing the head. If you find issues with the valve train, you won't need to go deeper. If they look in spec, the rings the things.

 

[retro]

You can check the valves and lash adjustments easily enough. Get a copy of the service manual, its all explained in there. Keep us posted on your progress if you can.

 

[aTVitsnot]

Some folks claim to be able to unstick rings with crazy concoctions like acetone/AT oil blends poured through the sparkplug hole. They are left to dissolve the burnt oil and combustion gasses in the lands. Seafoam is another easy fix claimed to do the job. And there are many more.

BUT...We're talking a single cylinder that has been sitting for three years. Thats why I recommend jumping right into a teardown. This will add very little time to any short cut cures that "may" work. Personally, I would have more peace of mind if I had laid eyes and hands on all the combustion components.

Oh yeah: Get a manual

 

[Helixhonda]

Thanks Guys, I read through the service manual and will tackle it this weekend. I tried the oil and seafoam trick but still 0 compression. Best take of the head and inspect everything.

 

[Helixhonda]

Some photos

 

[Helixhonda]

Last photos

 

[aTVitsnot]

 

[retro]

Its done, ehh..?

The intake valve smacked the piston too I see.

Did you just buy this bike from a storyteller?

 

[shadetree]

Last photos

intake valve is bent. I can see where it hit the piston.

 

[aTVitsnot]

Might be a good time to check the cam chain for stretch. Examine the tensioner and guide as well.

EDIT: and, of course, the cam lobes.

Another EDIT: I believe Retro, Misterclean59 and Shadetree are correct. My above advice is offered in vein of while your in there this deep, why not check theses items before you button back up.

 

[misterclean59]

The intake probably was stuck in the "full open" position. Just replace the in take valve. Clean the exhaust valve and replace the rings while you are there. Everything should be ok then. Keep us updated.

 

[Helixhonda]

Ordered new piston rings, new gaskets and new intake valve and seals. I am going to also clean everything. But seriously the bike ran fine before we parked it.

 

[aTVitsnot]

How about the guide?

 

[Helixhonda]

Cleaning all the parts tonight. I think the picture makes it look bent but in person doesn’t seem so.

 

[shadetree]

Cleaning all the parts tonight. I think the picture makes it look bent but in person doesn’t seem so.

turn the head upside down on the bench, poor some fuel into the valve area, watch to see if it seeps through ?. you can also remove the valves, run them in a cordless drill to see if the valve wobbles ?.