[Yesternow21]

I have a bad seal. Leaking just above the spark plug... My question is whether or not i have to mess with the valve covers/valve clearance. Or can i just unbolt it, take it all inside and replace the o-ring ? It's cold out here in Indiana lol...

 

[retro]

Thats easy to fix... just follow the service manual and clean those mating surfaces up good before assembly. You'll have to back off the valve adjusters before removing the rocker cover and they'll need to be readjusted after the work is done. You'll need a tube of Hondabond 2 (or Yamabond 2) to re-seal the cover. Use it sparingly, but coat both surfaces thinly using your finger. Do NOT use silicone gasket maker on it.

EDIT: Best practice is to crank the motor over to top-dead-center on the compression stroke BEFORE you begin to remove the cover. The manual explains how to do that as well, in fewer words than I can...

 

[Yesternow21]

Thanks retro!!! Going to have to get some feeler gauges i guess lol.... Appreciate the help! Got her all clean and ready. Baby wipes work great on the vent lines and whatnot ;]

 

[Yesternow21]

What will i need to adjust the valves? If you don't know off the top that's ok perhaps the manuel will specify?

 

[Yesternow21]

There's also this..... I have ordered the exhaust wrap should that hold the heat in or do i need to invest in a new one to prevent melted plastic...? Mainly going to be a hunting atv.

 

[retro]

I doubt if exhaust wrap will hold up on that muffler for long. Is there enough thickness left in the sheet metal to mig-weld a patch over the length of it? Thats what I would try first.

Valve adjustment requires a box end wrench or socket to loosen the jam nuts, then a wrench to hold the nuts still while adjusting them. I use a tiny open-end wrench on those square heads... but they turn easy so you can use needle nose pliers if you need to, or turn them using your fingers. Its all easy work... you'll see once you get into it. Read the manual 1st though... and follow it.

 

[Goober]

You’ll definitely need a heat shield to keep your fender and side cover from melting–also gets hot on ya

Consider using a quarter inch breaker bar when you’re loosening the cover bolts. Use a good six point socket, be straight over and secure on the bolt, and gradually apply torque so you don’t snap it. Might spray them with deep creep night before

 

[Yesternow21]

Good stuff guy's.... I really appreciate it! Called up the cousin and he said the only thing he can't weld is the crack of dawn and a broken heart LOL.... We shall see. ...

 

[Yesternow21]

Got the rocker box off and the valves loosened up.... Just have to battle the dowel pins and replace the o-ring

 

[fishfiles]

You mentioned a leak from the top of the rocker box , there is a sealing washer on a bolt on top of the rocker box , if that washer is not on the right bolt it will leak oil there , so even if that wasn't the problem , be sure it doesn't happen this time when you reassemble

#19 sealing washer :

 

[Yesternow21]

That bolt had a sealing washer. I'm happy you posted the schematic because i thought i had read sonewhere there was two bolts that had one on it....

 

[retro]

It looks to me like the inside cam journal (the small end) is trashed in that rocker cover. The journal in the head will look about the same as that one... the cam will starve for oil being loose and the cam will flop around inside that journal unsupported and continue to wear at an increasing rate. You'll have to replace the camshaft, head and rocker cover to fix it.

 

[fishfiles]

It looks to me like the inside cam journal (the small end) is trashed in that rocker cover. The journal in the head will look about the same as that one... the cam will starve for oil being loose and the cam will flop around inside that journal unsupported and continue to wear at an increasing rate. You'll have to replace the camshaft, head and rocker cover to fix it.

Retro , You got a good eye , when I went back , saved the pic and zoomed it , the cam journal of that head looks like it got really hot , gauled and blued up , good call ----


when you get another cam , find a 85-87 TRX3250A , 85-87 ATC250ES or a 1st gen 300 , cam and you will get a little more umph , also if you can find the same model / year span^ sprocket and a new 250 chain it would he heavier duty

 

[retro]

Maybe we'd make a decent tag-team fishfiles. Still looking for those eager beer sponsors to show up... was hoping you'd be along to recommend the hotter cam and chain/sprocket setups tho.

Happy new year ta' both of ya!

 

[Yesternow21]

I was afraid of that! It was burred up when i was wiping it down and i had a feeling that wasn't normal.... My luck lol... I have a new DID cam chain already on the shelf. I have read about that extra power from that older cam i will go that route. Now i guess i may as well pull the rest of the top end and check the cylinder and piston? It had great compression can't remember the compression range of the top of my head but it was like 15from the high end of what was listed

 

[retro]

Yeah, you'll need to replace the head so ya may as well pull it down. If you can't find a good used 300 head, you can put a 250 head on it... they are the same except the 250 doesn't have a compression release. Of course, a good 250 head might be harder to find than a good 300 head...

 

[Yesternow21]

Thanks for all the help! Can't wait to tell my wife what i have to buy next lol

 

[Yesternow21]

It's bad boys..... lol

 

[Yesternow21]

Truth be told i had a few soda pops while i was working on it the other night and was happy i didn't snap any bolts in the process and didn't even look it over good. Just remember waking up remembering the oil looked horrible but everything was pretty clean lol

 

[Goober]

Maybe we'd make a decent tag-team fishfiles. Still looking for those eager beer sponsors to show up... was hoping you'd be along to recommend the hotter cam and chain/sprocket setups tho.

Happy new year ta' both of ya!