YX140 ticking after correctly adjusting valves

G

Griznant54

New Member
Hello, my yx140 is making this higher pitched, ticking noise that is synced to the speed of the engine. I was wondering what this could be? I read somewhere that it was just the valves closing properly but it didn’t do that before my first adjustment. I adjusted when the engine had around 1 hour on it if that helps. Also didn’t make the sound before. Feels like it has a little more power now though after a fresh oil change. Still makes sound. Any ideas?
 
Sort by date Sort by votes
The camshaft gear could be 180deg out.

Turn the flywheel until you see the intake valve open and close and then as the flywheel continues around stop it at the t mark.

This will ensure you are adjusting them on the correct revolution

Other than that, are you getting lots of oil up to the head?

Were the valves out of spec much when you adjusted them?
 
Upvote 0 Downvote
power6994 said:
The camshaft gear could be 180deg out.

Turn the flywheel until you see the intake valve open and close and then as the flywheel continues around stop it at the t mark.

This will ensure you are adjusting them on the correct revolution

Other than that, are you getting lots of oil up to the head?

Were the valves out of spec much when you adjusted them?
Click to expand...
It does get a lot of oil to the head as I found out by starting it with the exhaust valve cover off.

They were pretty tight when I first adjusted them.

I will try the cam gear solution first.
 
Last edited:
Upvote 0 Downvote
Make sure to adjust them cold. You didn't mention what you set them to? They like a slight drag spec. Set the intake to 0.05mm and the exhaust to a ''slightly'' loose 0.05 if it ticks the exhaust is obviously too loose. Re set tighter.
 
Upvote 0 Downvote
It is so easy to mistakenly set them on the valve overlap instead of top dead center on compression. The T will still line up but as stated the cam will be 180 from correct. and require another flywheel rotation. Just like P---6964 was mentioning
 
Upvote 0 Downvote
OLD CT said:
Make sure to adjust them cold. You didn't mention what you set them to? They like a slight drag spec. Set the intake to 0.05mm and the exhaust to a ''slightly'' loose 0.05 if it ticks the exhaust is obviously too loose. Re set tighter.
Click to expand...
I adjusted them again today to a .05 intake and .06 exhaust. I also put thicker oil in since it is warming up now and the noise stopped. Part of it may be the oil. Now my issue is the bike had severe stutter at higher rpm’s (around 50mph) in last gear. Tried adjusting all jets at least 10 times now and can’t seem to find the right balance.
 
Upvote 0 Downvote
Also, if you are running some cheap china air filter that could be your Hi RPM stutter. Buy a real K&N OR UNI foam filter! Check it out! REAL K&N! Quality parts don't cost, they PAY!
 

Attachments

  • IMG_2874.jpg
    IMG_2874.jpg
    73.1 KB · Views: 14
Upvote 0 Downvote
OLD CT said:
Cheap filter.
Click to expand...
I got it off of a site Bart moto. That’s where I got everything basically on the bike. I will run to my local dealer tmr and grab a Uni. Also it’s not oiled😐 so I’m probably destroying my engine too so I’ll grab oil and a Uni filter tmr and hopefully that fixes the high stutter. It sounds like it hits a rev limiter but it’s super inconsistent.
Also would a Uni sock filter work? I’m looking at a blue one and idk if it is foam or not otherwise I’ll just get the Uni pod.
 
Upvote 0 Downvote
Bartmoto, Matt is a good guy, but the parts are all sourced from China. Run it without and see if it changes. Oil would clog it more, don't worry about it. Let us know what the filter less run acts like. Rev limiter is a rich main jet sign but still want to know the filter less test, Before you do anything.
 
Upvote 0 Downvote
OLD CT said:
Bartmoto, Matt is a good guy, but the parts are all sourced from China. Run it without and see if it changes. Oil would clog it more, don't worry about it. Let us know what the filter less run acts like. Rev limiter is a rich main jet sign but still want to know the filter less test, Before you do anything.
Click to expand...
Okay. So I just took it out on a quick cruise down the road. Hit 50 which I wasn’t able to do before and the stuttering was very minimal. But just checked my plug and it looks like this. I adjusted the needle clip to a leaner position or pos 2 before I rode it way earlier in the day. So now it’s definitely running lean since it is becoming whiter after it was fully black. What now?
 

Attachments

  • image.jpg
    image.jpg
    1.6 MB · Views: 16
Upvote 0 Downvote
Double check the gap .028, Sounds better. I always keep the clip in the middle and tune from there. The only time you play with the clip is if you are fouling from just idling or putting around on a stock 70. That trick saved my bacon once when it was a 72cc. And then you would go up to drop the needle one notch leaner. Trying to fatten up by going down is always a fail. At least at my place. ;) The plug looks like that Star Trek episode. One side black and one side is white. And the morale of the story is we need it even chocolate. The mixture screw should now be re visited and any new filter gets a ''very light'' spray of foam filter oil. Too much, will gum up the works.
 
Last edited:
Upvote 0 Downvote
OLD CT said:
Double check the gap .028, Sounds better. I always keep the clip in the middle and tune from there. The only time you play with the clip is if you are fouling from just idling or putting around on a stock 70. That trick saved my bacon once when it was a 72cc. And then you would go up to drop the needle one notch leaner. Trying to fatten up by going down is always a fail. At least at my place. ;) The plug looks like that Star Trek episode. One side black and one side is white. And the morale of the story is we need it even chocolate.
Click to expand...
I will return the clip to the middle position the next time I get a chance. I just would rather not blow this engine by running too lean and after seeing the black plug go from black to white after just that half a mile ride I would like to figure that out for road cruising. I will
test this all out tomorrow hopefully when it’s not freezing cold. AND what do I do about the air filter because here I def need to run with one.

It’s an iridium plug also
 
Upvote 0 Downvote
I just noticed that's some Iridium plug? With a little hair on it too! Lol! Buy a standard C7HSA. Here kitty kitty.:LOL: 10 pm est, My ass is wiped, time to hit the slab.
 
Last edited:
Upvote 0 Downvote
OLD CT said:
I just noticed that's some Iridium plug? With a little hair on it too! Lol! Buy a standard C7HSA. Here kitty kitty.:LOL: 10 pm est, My ass is wiped, time to hit the
OLD CT said:
I just noticed that's some Iridium plug? With a little hair on it too! Lol! Buy a standard C7HSA. Here kitty kitty.:LOL: 10 pm est, My ass is wiped, time to hit the slab.
Click to expand...
what would you recommend doing about the air filter though? I’m already gonna move the needle clip back to the middle and hopefully richen things up but the air filter?
Click to expand...
 
Upvote 0 Downvote
Awesome, then my crystal ball still works.:cool: Measure the carb opening and report back .If you plan to get the bike muddy UNI if it's a neighborhood street bike K&N.
 
Last edited:
Upvote 0 Downvote
Back
Top