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freebo86

Adjusted Valves runs and sounds poorly

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Well long story short, I went out this past Friday riding and ATV ran without issues. Ive had a starting issue when warm but more on that later. So, since I’ve had the ATV (Nov 2020) I found the engine is noisy and it sounded like valves I figured I should check and adjust.

 

On Saturday, I tackled that job. Adjusted the valves started the ATV started right up bud it’s ticking more than ever. I thought maybe I adjusted on the exhaust stroke and not compression. Went in tonight, it was on compression, double checked my work. ATV started up, but idle is all over the place. It will randomly increase in rpm while idle and in Neutral if I give it gas. I tried messing with the idle adjustment screw and now it just runs like crap, giving it throttle it dies out.

 

I have no idea why it’s doing this since I didnt touch anything else. As stated, it ran perfectly fine Friday, the valves were at .0013 before I started this ( now their .006) and it didn’t sound as bad as it does now or run so poorly. When I first started it and gave it throttle a ping resulted from the valve cover and can be heard every now and then. This noise doesn’t occur until the first time throttle is hit after the adjustment, did the same thing on Saturday. The engine is way noiser now than before.  
 

Here is a few videos, of what’s going on. Hoping some can chime in. Could the PO done sort sort of carb adjustments that were better suited for the valve tolerance that it was on and now with me tightening them down it all went to crapshoot? 

 

Thanks in advance! 
 

 

 

 

 

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Sounds loud for sure in the video. Are u saying it want that loud before? If that’s the case I’d say the timing wasn’t right when u set it. Make sure I have that 110% when setting the valves. IF U DID that correct only thing I’d say is cam chain is stretched...

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Just now, Wheeler said:

Sounds loud for sure in the video. Are u saying it want that loud before? If that’s the case I’d say the timing wasn’t right when u set it. Make sure I have that 110% when setting the valves. IF U DID that correct only thing I’d say is cam chain is stretched...


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. 
 

If it’s timing chain, why would it have been evident before?

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Good point.. if it wasn’t that loud before timing chain most likely out. However, agin of it wasn’t that loud  before then u weren’t at tdc when setting valves. Just can’t be... 

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Just now, Wheeler said:

Good point.. if it wasn’t that loud before timing chain most likely out. However, agin of it wasn’t that loud  before then u weren’t at tdc when setting valves. Just can’t be... 

 

So on TDC which is the T mark I lined up with the viewing port notch. On compression both my rockers had play and wiggle room - thats the the stroke I adjust on. 
 

On the exhaust stroke both intake and exhaust were tight. No wiggle room at all. I couldn’t move the rockers and they had no slack. 
 

Isn’t this correct?

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I ve only ever set the valves in my Honda 300. 1 cam & both Intake & Exhaust are loose. Never tight. So to me that doesn’t sound right if u have an exhaust valve tight. 

Edited by Wheeler

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1 minute ago, Wheeler said:

I ve only ever set the valves in my Honda 300. 1 cam & both Intake & Exhaust are loose. Never tight. So to me that doesn’t sound right if u have an exhaust valve tight. 


Not exhaust valve, on the exhaust stroke. On the exhaust stroke both valves are tight. 

Edited by freebo86

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Ahh sorry miss read that. I dunno. Sounds odd to me. No noise, prior to valves adjusted from .013 to .006 & now they sound super loud. Only thing to me is they were adjusted incorrectly, but u say they were good.. so I dunno.. wait for other to chime in...

 

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4 minutes ago, Wheeler said:

Ahh sorry miss read that. I dunno. Sounds odd to me. No noise, prior to valves adjusted from .013 to .006 & now they sound super loud. Only thing to me is they were adjusted incorrectly, but u say they were good.. so I dunno.. wait for other to chime in...

 


Well that’s why I’m at a loss. I figured it couldn’t be worse than it was but it is.. on top the idle is all wonky as you saw in the videos... 

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Single cam. 2 valve engine. Yes you adjust both on compression stroke at TDC. If you lined up the T. And adjusted them to spec. There is kinda only one option left. Not timed correctly. Which is most likely caused by a stretched timing chain. The stretch in the chain made the previous adjustment closer to correct. But now when you line up the T its actually not putting the cam at the exact right place and your adjustment is actually further off.

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1 minute ago, SlammedRanger said:

Single cam. 2 valve engine. Yes you adjust both on compression stroke at TDC. If you lined up the T. And adjusted them to spec. There is kinda only one option left. Not timed correctly. Which is most likely caused by a stretched timing chain. The stretch in the chain made the previous adjustment closer to correct. But now when you line up the T its actually not putting the cam at the exact right place and your adjustment is actually further off.


Hmm. Would that explain why the idle is all over the place and the thing sounds like a total turd? 
 

For testing purposes if I set it back to .013 it would eliminate this and sound somewhat normal again? 

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4 minutes ago, SlammedRanger said:

Single cam. 2 valve engine. Yes you adjust both on compression stroke at TDC. If you lined up the T. And adjusted them to spec. There is kinda only one option left. Not timed correctly. Which is most likely caused by a stretched timing chain. The stretch in the chain made the previous adjustment closer to correct. But now when you line up the T its actually not putting the cam at the exact right place and your adjustment is actually further off.


 

right, those were my exact thoughts as mentioned in the first post. 

Edited by Wheeler
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Oh yeah! Cuz at actual TDC on the cam your adjustment would be crazy big. Probably like .010 or something crazy like that. Being that loose your adjusters could tap the cover probably and it would run and idle horrible. Its kinda shocking it started at all honestly. Yes for testing perpose only i would go back to the .0013 and see how it runs. It would 100% confirm the cam and the crank are not in sync perfectly.

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Just now, SlammedRanger said:

Oh yeah! Cuz at actuall TDC on the cam your adjustment would be crazy big. Probably like .010 or something crazy like that. Being that loose your adjusters could tap the cover probably and it would run and idle horrible. Its kinda shocking it started at all honestly. Yes for testing perpose only i would go back to the .0013 and see how it runs. It would 100% confirm the cam and the crank are not in sync perfectly.


I’ll set it back to .013 again tmr and see. 
 

Cam chain involved job and expensive parts wise? 

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Cam chain $100, gasket $15, time= priceless lol. Not a bad job to do. 

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Involved yes. Price i have zero idea for your specific model. I do sport quads. But i would imagine its pull a side cover. Probably clutch side. Valve cover off. Cam out. Most likely remove the clutch assembly. Which on utility quads i think is kinda a chore. Not 100% sure tho. Tread very lightly with running it with close tolerances on valves. Engines have very little clearance between piston and valve. Generally around .030 or .040 at most. These making contact would be catastropic! Just fare warning. Not trying to scare you bud!

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7 minutes ago, SlammedRanger said:

Involved yes. Price i have zero idea for your specific model. I do sport quads. But i would imagine its pull a side cover. Probably clutch side. Valve cover off. Cam out. Most likely remove the clutch assembly. Which on utility quads i think is kinda a chore. Not 100% sure tho. Tread very lightly with running it with close tolerances on valves. Engines have very little clearance between piston and valve. Generally around .030 or .040 at most. These making contact would be catastropic! Just fare warning. Not trying to scare you bud!


Yah I wasn’t driving it just starting and stopping in garage for 1hr before I got frustrated i what was going on. 
 

I still don’t understand how the idle can be affected by this? Why does it sound like when I’m giving it throttle that it’s choking itself out and dying? Is this due to the idle adjustment being all off now on tandem with the cam chain and valve adjustment?

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Valves excessively loose means valves not opening all the way each revolution. Nothing is good when valves dont open fully. It should be very very angry. Idle, wide open, partial throttle and anything in between will be effected by this.

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3 minutes ago, SlammedRanger said:

Valves excessively loose means valves not opening all the way each revolution. Nothing is good when valves dont open fully. It should be very very angry. Idle, wide open, partial throttle and anything in between will be effected by this.


Interesting. Tomorrow I’ll set it to what it was and see. So, if I don’t want to replace the chain my options are basically leaving the valves at that adjustment or trying to bring them a bit but not to .006? 

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7 minutes ago, freebo86 said:


Interesting. Tomorrow I’ll set it to what it was and see. So, if I don’t want to replace the chain my options are basically leaving the valves at that adjustment or trying to bring them a bit but not to .006? 

If you dont change the timing chain you are really pushing your luck. If its that far stretched you are a ticking time bomb for it skipping a tooth in timing.(If it hasnt already). It doesnt take many teeth to do serious catastropic damage to that engine. I would really advise you change the chain. But it is your quad and your decision. 

 

More interesting stuff. If your valves are excessively loose also. Your engine is struggling to push all the exhaust out. And struggling to pull all the air in. That same air in vacuum is what is pulling the fuel from your carb or throttle body if its FI. This may explain more why your idle is screwed up. The loud rattle is a dead give away for valves being loose. Its just a matter of why. And this one was a thinker.

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One thing that baffles me @SlammedRanger is he says his motor didn’t sound like that before he adjusted his valves. I agree that it’s his valves or chain, but why would it “just” start making a noise?? I think he hasn’t set the valves correct..which would also cause the idle issue!

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3 minutes ago, SlammedRanger said:

If you dont change the timing chain you are really pushing your luck. If its that far stretched you are a ticking time bomb for it skipping a tooth in timing.(If it hasnt already). It doesnt take many teeth to do serious catastropic damage to that engine. I would really advise you change the chain. But it is your quad and your decision. 

 

More interesting stuff. If your valves are excessively loose also. Your engine is struggling to push all the exhaust out. And struggling to pull all the air in. That same air in vacuum is what is pulling the fuel from your carb or injector if its FI. This may explain more why your idle is screwed up. The loud rattle is a dead give away for valves being loose. Its just a matter of why. And this one was a thinker.


Thanks. I’ll post an update tomorrow how I make out. 

Curious if this timing chain is the culprit in some other symptoms I’ve noticed in the last bit with the machine since I’ve owned it..

 

Starting hard when warm. On Cold it starts up flawlessly. 
During riding sometimes and I come to a half, I really need to push the throttle hard for it to pick up and go again.. but this could also be the valve adjustment?

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4 minutes ago, Wheeler said:

One thing that baffles me @SlammedRanger is he says his motor didn’t sound like that before he adjusted his valves. I agree that it’s his valves or chain, but why would it “just” start making a noise?? I think he hasn’t set the valves correct..which would also cause the idle issue!

Think of it this way. Now this is a long shot of possibility. But i think at this point is the most likely option. When the chain stretches or jumps time it throws your cam to crank sync off. Now he turns the crank to the T mark. Cam is still slightly on the lobe. Which would explain is .0013 clearance. Now he sets it to .006. If the mark on the crank lined up with cam sync it would probably be perfectly at .006. But since its on the lobe and not on the opposite side of the cam completely or off the lobe its now set way way loose.

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Very well explained slammed. Makes sense. 

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11 minutes ago, freebo86 said:


Thanks. I’ll post an update tomorrow how I make out. 

Curious if this timing chain is the culprit in some other symptoms I’ve noticed in the last bit with the machine since I’ve owned it..

 

Starting hard when warm. On Cold it starts up flawlessly. 
During riding sometimes and I come to a half, I really need to push the throttle hard for it to pick up and go again.. but this could also be the valve adjustment?

No problem! Glad to help! Yeah it could 100% be the cause. You may find a whole lot of power all the sudden when its fixed. It may have skipped a tooth in timing already honestly. Ask Wheeler. They can run and ride with minimal hickups one tooth off. LoL😂😁

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