Adjusted Valves runs and sounds poorly

[Wheeler 2,525]

Yeah I ran for a good year with a tooth off on my cam sprocket! I tried all kinds of stuff trying to figure it out.. re jetting ect.. nope.. finally figured it out &!was tooth off. I can attest that they I’ll run semi fine 1 tooth off, but once dialed back in.. night & day difference!!

Edited January 19, 2021 by Wheeler

[retro 4,048]

My .02 cents on the valve train noise (I fixed a 450 with ALL of these conditions about a year ago):

 

I am guessing that the valve lash was run excessively loose for so long that the top of the valve stems are hammered out & cupped. The lash adjuster screws are mushroomed bad too, so no way ya gonna be able to properly adjust the lash on either valve using a flat feeler gauge.

 

Also the camshaft and lifters may have become worn & hammered out on the base of the cam lobe ramps, so much that valve lash may be a lot looser at the bottom of the lobe ramps compared to the centers of the base circle (where lash adjustment is done). The cam chain & tensioner block is probably shot too, due to all the hammering shock over time.

 

So.... cam, lifters, chain, tensioner, both valves and both lash adjuster screws are probably shot. Hammering shocks may have loosened up a valve guide in the head too. A guide might be moving up & down with it's valve while its running.

 

Inspect the lash screws and valve stem tips (look for a loose guide too) to learn whether ya might have serious damages or not?

[SlammedRanger 1,556]

6 minutes ago, retro said:

My .02 cents on the valve train noise (I fixed a 450 with ALL of these conditions about a year ago):

 

I am guessing that the valve lash was run excessively loose for so long that the top of the valve stems are hammered out & cupped. The lash adjuster screws are mushroomed bad too, so no way ya gonna be able to properly adjust the lash on either valve using a flat feeler gauge.

 

Also the camshaft and lifters may have become worn & hammered out on the base of the cam lobe ramps, so much that valve lash may be a lot looser at the bottom of the lobe ramps compared to the centers of the base circle (where lash adjustment is done). The cam chain & tensioner block is probably shot too, due to all the hammering shock over time.

 

So.... cam, lifters, chain, tensioner, both valves and both lash adjuster screws are probably shot. Hammering shocks may have loosened up a valve guide in the head too. A guide might be moving up & down with it's valve while its running.

 

Inspect the lash screws and valve stem tips (look for a loose guide too) to learn whether ya might have serious damages or not?

Wouldnt his valves have been loose when he checked them? Or are you thinking someone else adjusted them way tight to stop the noise? He said when he checked before adjusting they were tight .0013

[retro 4,048]

1 minute ago, SlammedRanger said:

Wouldnt his valves have been loose when he checked them? Or are you thinking someone else adjusted them way tight to stop the noise? He said when he checked before adjusting they were tight .0013

 

I think he said the valves were loose at about .013" on the base circle (TDC)? He tightened them to .006" and the valvetrain got louder. Which leads me to suspect badly hammered out parts. I'm just guessing though... he needs to inspect parts to find out.

 

I found pics of the valve stems & lash screws I took of the 450 I fixed last year. One valve guide was found loose & flopping in the head. The cam, lifters, tensioner & chain were shot too.

 

 

 

This is an extreme case of neglect (a local tightwad farmer), yours may be fine.

[SlammedRanger 1,556]

4 minutes ago, retro said:

 

I think he said the valves were loose at about .013" on the base circle (TDC)? He tightened them to .006" and the valvetrain got louder. Which leads me to suspect badly hammered out parts. I'm just guessing though... he needs to inspect parts to find out.

 

I found pics of the valve stems & lash screws I took of the 450 I fixed last year. One valve guide was found loose & flopping in the head. The cam, lifters, tensioner & chain were shot too.

 

 

 

This is an extreme case of neglect (a local tightwad farmer), yours may be fine.

Thats a negative ghost rider! He said they were .0013. They were tight. He loosened them and now they are excessively loud and it runs like poo. LoL

[retro 4,048]

That's a typo @SlammedRanger. In his other thread he said that he could slide a .013"/.014" feeler in there.

 

 

 

[Fishfiles 20,145]

Sometimes weird stuff happens especially when the atv is purchased used and you don't know the the history of the machine 

 

There are a couple of other way an engine can be out of timing and the timing chain not be the problem , the key way can sheer or the connecting rod be bent , water ingestion could cause them , or even  over flowing carb that filled the cylinder with fuel and engine was attempted to be started against the hydro-lock ----

 

another thing happened to me one time that was hard to figure out , the valve stem was bent 

 

 

[freebo86 291]

5 hours ago, retro said:

That's a typo @SlammedRanger. In his other thread he said that he could slide a .013"/.014" feeler in there.

 

 

 

 

5 hours ago, SlammedRanger said:

Thats a negative ghost rider! He said they were .0013. They were tight. He loosened them and now they are excessively loud and it runs like poo. LoL

To clarify. They were looser. So I tightened them up. The valves had a lot more play before this all started. 
 

Well reading some of these posts up is not reassuring. So where do I begin.. set the valves back to what they were and see what’s going on? 
 

 

Edited January 19, 2021 by freebo86

[SlammedRanger 1,556]

6 hours ago, retro said:

That's a typo @SlammedRanger. In his other thread he said that he could slide a .013"/.014" feeler in there.

 

 

 

Well then......crap. Throw my theory away! LoL

[Fishfiles 20,145]

 To see it the timing chain has slack or the rod bent or key way sheered  , take out the plug , line up the T mark , take off the pull start cover , put a plastic straw thru the spark plug hole ,  put a socket on the nut under the pull start cover and turn the engine back and forth very slow and gentle  and see if the highest point of the piston is the T mark --- 

[freebo86 291]

38 minutes ago, Fishfiles said:

 To see it the timing chain has slack or the rod bent or key way sheered  , take out the plug , line up the T mark , take off the pull start cover , put a plastic straw thru the spark plug hole ,  put a socket on the nut under the pull start cover and turn the engine back and forth very slow and gentle  and see if the highest point of the piston is the T mark --- 

 

So watch the piston in the spark plug hole? I dont know how you guys do some of these, do you have more than 2 hands or 1 head lol? 

[Fishfiles 20,145]

I don't think you can see the piston thru the hole with out the use of a snake cam , and it is not a straight shot thru the hole to the piston , that's way something soft that will bend , as it you were to stick a screw driver and move the piston it would get bent up in there , so don't go that route 

[freebo86 291]

Pardon my ignorance, I'm familiar and can DIY. But engine work isn't my forte. So to better understand.

 

Whatever is going on now, my valve adjustment is too tight (even tho its set to spec) which is causing my idle to not be working. Is this the correct understanding of it?

[_Wilson_™ 6,564]

it's kind of hard to keep up with all this, with so many post ... try and put more information in one post ... multi short post on a issues  doesn't really work too good. and like mentioned a history of this bike would come in very handy, but.... so far .. steering stem bearing brake issues, dash issues .. would make me think this bike was not very well taken care of at all, mods include a winch in the front, and back, a front disk conversion, so yes, my thinking is this bike has had a rough life, but hang in there.  

[freebo86 291]

43 minutes ago, _Wilson_™ said:

it's kind of hard to keep up with all this, with so many post ... try and put more information in one post ... multi short post on a issues  doesn't really work too good. and like mentioned a history of this bike would come in very handy, but.... so far .. steering stem bearing brake issues, dash issues .. would make me think this bike was not very well taken care of at all, mods include a winch in the front, and back, a front disk conversion, so yes, my thinking is this bike has had a rough life, but hang in there.  

 

Noted. I guess part of this comes from being a 1st time ATV owner, lots of things to learn. Let me know what you want me to clarify and where and I'll be happy to do so.

 

I created this post as I figured not everyone follows the Build threads so I'd get more responses here.

Edited January 19, 2021 by freebo86

[_Wilson_™ 6,564]

my bad.... i forgot that part, I'll tell you this, I'm impressed, and your getting hands on at doing the mechanical yourself, along with tech / advise help from the guys, hang in there! yes, it's very true some dont read every thread..... but most of us do, or try to. 

[retro 4,048]

5 hours ago, freebo86 said:

Whatever is going on now, my valve adjustment is too tight (even tho its set to spec) which is causing my idle to not be working. Is this the correct understanding of it?

 

Nope. With the lash set at .006" with a feeler gauge the lash is not tight. But lash may be quite loose if the valve stem tip(s) are hammered and concave/cupped.like my photos above show.

 

If the stem tips have concave craters on them rather than flat tips your ~.014" lash may have actually been ~.020" lash because you cannot measure the depth of a crater using a flat feeler gauge..... you can only measure between the rim of the crater and the peened end of the adjuster screw So if the stem tips are indeed hammered & worn concave your new .006" lash adjustment isn't accurate, gaps will be wider. Wide gaps make a lot more noise.

 

Compounding that issue (if it exists), If the cam is badly worn & hammered too, the valve lash will be the widest right before a cam lobe begins to open a valve at the end of the base circle the lobe is ground on. Because the heel of the lobe ramp is where excessive hammering takes place when valve lash becomes grossly excessive.

 

So.... remove the lash adjuster screws and inspect the valve stem tips. They should be perfectly flat with no visible (deep) concave wear. Let us know/see what you find before reassembling & readjusting the valves.

[_Wilson_™ 6,564]

i believe he also mentioned  in the other thread this engine had never had the valves adjusted. till he 1st adjusted the valves , thens when this new issue came up ? 

[freebo86 291]

On 1/19/2021 at 1:54 PM, retro said:

 

Nope. With the lash set at .006" with a feeler gauge the lash is not tight. But lash may be quite loose if the valve stem tip(s) are hammered and concave/cupped.like my photos above show.

 

If the stem tips have concave craters on them rather than flat tips your ~.014" lash may have actually been ~.020" lash because you cannot measure the depth of a crater using a flat feeler gauge..... you can only measure between the rim of the crater and the peened end of the adjuster screw So if the stem tips are indeed hammered & worn concave your new .006" lash adjustment isn't accurate, gaps will be wider. Wide gaps make a lot more noise.

 

Compounding that issue (if it exists), If the cam is badly worn & hammered too, the valve lash will be the widest right before a cam lobe begins to open a valve at the end of the base circle the lobe is ground on. Because the heel of the lobe ramp is where excessive hammering takes place when valve lash becomes grossly excessive.

 

So.... remove the lash adjuster screws and inspect the valve stem tips. They should be perfectly flat with no visible (deep) concave wear. Let us know/see what you find before reassembling & readjusting the valves.

took them off, both are flat. Exhaust and intake, also on the lifter? The end that the screw pushes against is flat no concave or mushrooms like caps..

 

may be hard to see but they appear to be nice and even..
 

 

 

[oldmxrider 71]

23 hours ago, freebo86 said:

It wasn’t this loud, no. I’m confident it was at TDC on compression. I had my finger on the spark plug hole and felt the compression push finger and then shortly after sat the T mark on through the viewing hole. ??

Just a thought,  If it was not that load before ! Maybe Your wrong on top dead center.  Easy way for top dead center on the compression stroke ! Turn motor slowly in the proper direction, watch intake valve go down and start to come up, next T You see on the flywheel is where You adjust the valves.

Quote

 

 

Edited January 20, 2021 by oldmxrider
better directions

[retro 4,048]

2 hours ago, freebo86 said:

took them off, both are flat. Exhaust and intake, also on the lifter? The end that the screw pushes against is flat no concave or mushrooms like caps..

 

may be hard to see but they appear to be nice and even..

 

OK good! Lets check the camshaft for excessive wear!

 

Adjust both valves to .006" (Crank at TDC as normal) with the adjuster nuts tightened. Then turn the crank about 10 degrees and see if your lash is still .006" on the intake valve. Then turn the crank 10 more degrees and check the intake valve lash again. Keep checking every 10 degrees until the gap closes and the intake valve begins to open. Let us know whether the Intake valve lash measured consistently at .006", or did the lash open up?

 

Then turn the crank until you see the exhaust valve open & close completely. Turn the crank 10 degrees further & check the gap on the exhaust valve. Repeat every 10 degrees of crank rotation the same as you measured the Intake. Share that test result with us too.

[freebo86 291]

1 hour ago, oldmxrider said:

Just a thought,  If it was not that load before ! Maybe Your wrong on top dead center.  Easy way for top dead center on the compression stroke ! Turn motor slowly in the proper direction, watch intake valve go down and start to come up, next T You see on the flywheel is where You adjust the valves.

 

thanks for the info but i checked lol. I spent a good 30minutes going back and forth ensuring I’m at TDC on comp. 
 

 

5 minutes ago, retro said:

 

OK good! Lets check the camshaft for excessive wear!

 

Adjust both valves to .006" (Crank at TDC as normal) with the adjuster nuts tightened. Then turn the crank about 10 degrees and see if your lash is still .006" on the intake valve. Then turn the crank 10 more degrees and check the intake valve lash again. Keep checking every 10 degrees until the gap closes and the intake valve begins to open. Let us know whether the Intake valve lash measured consistently at .006", or did the lash open up?

 

Then turn the crank until you see the exhaust valve open & close completely. Turn the crank 10 degrees further & check the gap on the exhaust valve. Repeat every 10 degrees of crank rotation the same as you measured the Intake. Share that test result with us too.

okay, but how do I approx 10 degrees with the recoil cord? At certain points if I pull a little the flywheel spins a lot.. going to be hard to ensure the 10 degree only... 

 

so basically measure the gap consistently every ~10deg. to see if it stays at .006 or if it opens at one point?

[retro 4,048]

1 minute ago, freebo86 said:

so basically measure the gap consistently every ~10deg. to see if it stays at .006 or if it opens at one point?

 

Yes exactly. Take the spark plug out while you are working, the recoil will be a bit more cooperative. 🙂

 

[freebo86 291]

1 minute ago, retro said:

 

Yes exactly. Take the spark plug out while you are working, the recoil will be a bit more cooperative. 🙂

 

Yup, spark plug is out. But there is still parts where the flywheel just turns easier and it’s a bit hard to control, lol. I’ll give it a shot. Will report tmr evening. 
 

All input and feedback is appreciated! 

[Fishfiles 20,145]

I mentioned before to take the recoil starter cover off and use a socket , it  is worth the effort