Abnormal noise
 

Broke the buggy out today for some neighborhood romping and heard an abnormal sound . So... I thought my valves needed adjusted, but that did not resolve this noise.....https://www.youtube.com/watch?v=Ge7HIKn7BrU Sounds like a clicking or winding noise. You can hear it at idle but is most prominent after reving. I fear it right be internal gears. The sounds is faint at valve cover, and sounds like it is not in the cvt but past that. it is not at the stator either but past that. that is why I think it might be gears/ tranny.


You have to listen close after reving.


Here is a similar sound last year but I fixed that with valve adjustment. https://www.youtube.com/watch?v=6WjJfU_AHeY

What do you guys think?
I even adjusted the valves a little tight too like .003 thinking that would stop noise. Nope... so I put it back to intake .003 and exhaust .005
:suspect:

Hm.... And it's not like anything else is rattling? Maybe a loose panel or something like that? If it's the engine and the valve adjustments aren't doing it I'd check for something hitting something else, coming from a 14y/o with next to no engine experience, LOOK FOR THINGS HITTING OTHER THINGS. <-- expert advice right there :biggrin:

good luck

I actually thought that too. I checked to make sure the cooling fan wasn't hitting any part if the shroud. When I get some time I will pop off cvt side cover and investigate more.

I had an internal rattle coming from my muffler last year. I discovered it by pressing my foot on the muffler while the engine was running. No rattle while pressing, but as soon as I let go it would start rattling/clicking.i

possibly slight piston slap? sure sounds like a lifter tho. i couldnt imagine a sound like that coming from the gearcase

Nah it's def. not the cvt... Especially when its at idle and nothing is moving over there (as far as I know at least)

The cooling shroud was my thought, but obviously it isn't it... Try the muffler test mustanger brought up!

What I the lifter? So I can investigate more.

That engine does not have lifters. The cam has rockers, which are in direct contact with the valve. Lifters are used to take up valve lash in larger engines where adjustments are redundant or not easily performed.

The noise is kinda hard to hear over the engine itself. I would invest in an engine stethoscope to help narrow down the location of the noise. If it is lower than the head, but not quite in the gearcase, then you may have piston slap, or a wrist pin issue. I assume you made triple sure the circlips were properly seated when you installed the piston?

Update:
I had some time today from my other projects and daily life stuff to mess around with it some more. I did do stethoscope but still feel like it the noise is coming from center of engine somewhere in final gear area; maybe...

I drained the old final gear oil and it looked like crap. Kind of looked like it had metal flakes in it (i used an old drain pan though from another engine rebuild that did have metal flakes- dumb me)

So I filled with more gear oil and drove around for ten minutes - noise still present and increases with acceleration.

Drained off the new oil and used a clean pan, but I think it still has some metallic flakes; hard to tell.

Here are some pics..
pic 1 and 2 is the newly drained gear oil in 2 different pans.
pic 3 and 4 is Left is brand new oil from out of the bottle. and right is oil that has been run for 10 minutes.

What do you guys think??

Do I have tio remove entire engine to open it up and see?

I change the gear oil every year and it looks like crap. The oil breaks down quick so I now change it twice a year so it isn't so bad. I get small crush washers from cycle gear. I recommend replacing the crush washer every time. I stripped out the gear box and had to put a time sert in to fix the threads.

As for the sound did you check your valve springs? I would imagine it wouldn't run as good as it does with a broken spring but I would still check them.

I did them and readjusted, but next I get a few minutes to work on it I will check again.

I got to agree with 5 on this. Sometimes, not all, but sometimes when I change fluids I will find just a trace of metal residue in them, and it's usually just some minor issue that needs addressed!

Well guys I was going to pull off reverse and gear assembly, but...........
I decided I think I will just pull the entire engine from the sub frame/swing arm.
That way I can put the engine on the workbench and disassemble it to find potential problem. It is such a pain to try to work on the engine at odd angles. I will start with the top end since that is what I replaced.

I have several other projects going on at the same time. I just don't want to drive it with that noise.

Time is what I don't have enough of....

best way to go at something like this.
definitely an internal contact noise, might be starter clutch ...

Ya, thanks.
You can hear it real clear at about 23 seconds- after rev( in 1st post, 1st vid )

I am a little unclear as to how it can be starter clutch, but hey once it is on bench and tore apart I will update.
Thanks again.

had a light knock/tick from the starter clutch that followed rpm when i forgot to tighten the lock ring beyond finger snug.

Ohh okay,will check it out.

Sounds are difficult to hear on video but to me it sounds like a cam chain tensioner.

I have no experience with the cct on a gy6 engine but on a lot of motorcycles the teeth on the tensioner break and allow the tensioner to bounce around.

They tend to make more noise on deceleration after a rev, sometimes they will have a certain rpm where they make a the most noise.

huh...interesting. I will look in to that since I did replace cam chain tensioner.
Thanks.

It has a been a while and I have been busy. the cold weather is here so it is time to move inside.
I decide to just take the rear swing arm off, to start assessing the source of the noise.

I will do a complete maintenance and inspection and addressing everything to insure good spring and summer riding.

Will go over the noise, recheck all the BBK upgrades, tranny, CVT, and brakes.

what happened to the other cart you were building?

Pretty much done with it. I do need to update the build.
I have to finish painting rear, upholster seat, and just took engine off to remove governer.

Today's progress:

Engine removed from swing arm.
Drained all fluids and double checked my timing.

I was off a little as seen in pic. Corrected cam and I am starting to believe that the noise could have from cam chain rubbing the tensioner guide.

I readjusted valves and closed it back up.
I decided not to check internal reverse tranny case. I don believe the sound to really be coming from there. I think the small amount of metal glitter was from grinding gears from putting in reverse.
I will check cvt too, but pretty sure that is good.

I did however find all four bolts loose on axle sprocket.

if you take a long screwdriver, hold the tip firmly against the case and put your ear to the tip of the handle it acts as a stethoscope.
By moving the tip around the case you can isolate the source of noise quickly and accurately.

or if you really want to play doctor you can buy a stethoscope at Harbor Freight tools for about $5 or so, I have one and it works good.

Thanks guys, but I am a nurse and have plenty....:D
The sound was really hard to isolate. It sounded equal on all sides. I felt like it was located in the center of engine. Oh well, if it doesn't work then try again.....:yuck:
I went ahead and put engine back in swing arm.
I will fill with fluids, start it, and listen again before I reconnect swing arm.

You were 1 tooth off on the cam timing. Hopefully it wasn't valve contact.

it did sound lick valve smack, or piston slap however u want to call it with the valve hitting the piston lol. hopefully if didn't damage anything and u have ur timing correct now

Update:
Everything put back together, engine runs great,and that sound still exists.

I still have it isolated to the cam area. I am starting to wonder if maybe it IS just cam chain on the guides making that noise (noise after acceleration ). I will probably readjust valves again just for the heck of it later.

but I think I might just be making something out of nothing with that noise.
quick vid to listen to here... I think the mic adjusted so sound wouldn't be so loud
https://www.youtube.com/watch?v=BY1f...ature=youtu.be

still sounds like u have some valve binding.

I know....maybe I should tighten them up a little.... I did the last time adjust intake at 0.002"and exhaust 0.005"
On the valve noise it is coming from lower valve/exhaust. Maybe I should adjust .003 - .004 to eliminate that sound at least. Because I don't think I can get rid of the the after rev sound you hear distinctly after 45 sec in vid

Like I mentioned before, I don't have any experience with a 150 cct. But I do know that on lets say a Kawasaki 636 cct it is possible to install it incorrectly. This would put way too much tension on the cam chain.

Is the cct automatic or manually adjusted?

It is automatic.
Maybe by chance chain has stretched. It is a new cct. I am confident in my assembly of the guides.

You are confident of the guides but what of the tensioner? I suspect it has some type of spring and a mechanism to keep it from loosening? If it is installed with the plunger too far out it will put too much tension on the guide and the chain.

All you got to do is screw the chain tensioner in about a half turn and release it. Also what if the tensioner is bad and not keeping the chain tight? What cam are you running and are your valve springs stock?

The cct does just extended and I believe does not retract like a shock under pressure. You have to do what johnny5 said and turn it to wind up then release. I checked twice when installing that the cct does keep the chain tight. I am running the A12.
My valve springs are stock.

The a 12 cam compared to a stock cam you can see how steep the lobe ramp is. The valve spring may not be keeping up. I may be wrong but just to be on the safe side I put stiffer valve springs on both our buggies. The down side of stiffer springs is the valve and seat wears faster.
You can also get titanium valve spring retainers.

Holy crap where have u been johnny 5

I will readjust valves and see where I am at. Maybe just have to live with that sound until somethings goes wrong and I then will know for sure what it is.....

I changed jobs and have been low on cash so we haven't been out much. We did go to the desert mid November and me and my son rode off a 4 foot wash sideways landed on the passenger side and bent the frame. Safety belts and helmets saved the day.

I set my valves intake .003 exhaust .004. I did notice the A12 cam on both our buggies is louder than normal.

Did the noise start after the cam was installed? You could put the stock cam back to eliminate the valve springs.

Do you still have kick starter gears in cvt area..when the gear hangs up it can make that clicking noise....

Johnny glad you and ( was it Tyler?) are okay.
I did the whole BBK and cam all at the same time. I will just change oil more regularly and often to keep a look out for any break down of material.

This buggy did not come with kick starter gears - Mike

Sounds like a interference problem. some part striking another with each rotation of the crank.
You know two things: A-it's a abnormal noise. B- something isn't correctly positioned.
I would want to protect my investment. Go back into that motor and discover the problem before it possibly does permanent damage.

You could check for coil bind in the valve spring.

Coil bind is when the new cam has way more lift than the stock cam. It can compress the valve spring so far that it actually makes all the coils in the spring touch.

It would only make that noise if the spring was fully compressed. If only a few coils touch it wouldn't make any noise and probably wouldn't be a problem.

remove/delete that junk its useless

Kind of sounds like a rod knock, or piston slap to me.

1. Are you sure your oil gallery is clear on the cylinder leading up to the head? Did you use any gasket sealer on the cyl base?

2. Do you have oil present in the valve cover?

3. Did you check piston to cyl and piston ring gap when you installed the BBK?