CA95 Ticking, Knocking? Noise when increasing the throttle.

joehadams

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Joined
Apr 20, 2026
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Location
Connecticut
I picked up this 1965 CA95 project a little while ago. The previous owner put some money into it having it sandblasted, chrome polished, new tires, cables, NOS 6V battery... But said he didn't touch the the engine since he got it.

Here it is when the previous owner got it:
119717832_1038259273271105_6070594037575917238_n.JPEG


Here it is when I acquired it:
IMG_3478.jpg



Now, I've been putting it back together with the pieces he's given me. I cleaned out the tank, rebuilt the fuel-shut off, rebuilt the carburetor, replaced the cylinder head breather gasket set the points gap, and installed the engine. I was able to get it fired up and running, but its got a horrible ticking, or knocking sound when you introduce some RPM's. So, after that I checked the cam chain tension (I believe its doing its job) and set the valve lash. Unfortunately the sound still persists. This video is pre-tune up, when I first got the engine installed and running. In the video below, you can hear the sound when the RPM's increase.


You will also notice an exhaust leak. I fixed that after this video was taken. I appear to be getting some oil out of the exhaust port on the left cylinder as well.

I also noticed that the exhaust on the right side is cooler than the exhaust on the left side, but I'm not sure thats an indication of anything. See video below.



I started to diagnose this issue by pulling the left side cover off, but I ran into a snag when I didn't have the right puller for AC Dynamo. I did notice, that when I use the kick starter, the electric starter motor chain spins as well - just a little bit. This chain is very loose, and I'm wondering if the sound could be this chain slapping the side cover because its staying slightly engaged.

Looking for other suggestions to point me in the right direction towards figuring out this problem.

Thank you in advance!
 
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Is there a pad of rubber on the bottom side of left exhaust to keep the center stand from rap-clunking the muffler on these bikes ?
 
Boosted said:
Is there a pad of rubber on the bottom side of left exhaust to keep the center stand from rap-clunking the muffler on these bikes ?
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There is, for the center stand, yes. Not one on the kickstand. I'm not sure if that touches the exhaust. Ill have to look.
 
Finally got my rotor puller delivered, and found some time to tear into it. Didn't see anything abnormal, except for the fact that someone had been in here before as evidenced by the scratching and scraping. Cam chain tensioner appears to be working fine, I adjusted it visibly. One thing I noticed is that the clutch pushrod wasnt adjusted properly, and allowed for movement. If I moved it back and forth it makes a tapping/ticking sound on the adjuster and the clutch itself. Could this be the noise I was hearing? Is it possible for the rod to vibrate back and forth between the two parts to cause this issue?

I also removed the electric starter chain. At rest it is sitting on the case, so my thought is that could be slapping the case as well. Any idea how to add tension to this chain?

Any other suggestions while I've got it apart?

IMG_4753.jpg
 
Not likely the starter chain is making any noise as it sits still when the engine is running because of the sprag starter clutch design, and the clutch rod isn't likely the source of the noise either.
 
Remove both spark plugs. Put the key in the crankshaft and place the flywheel back on just enough to catch the keyway. Turn the flywheel by hand back and forth advancing a full 360 degrees and listen for any tapping or metallic sound.
 
ancientdad said:
Not likely the starter chain is making any noise as it sits still when the engine is running because of the sprag starter clutch design, and the clutch rod isn't likely the source of the noise either.
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I would agree with you, but when I operate the kick starter with the side cover off I have observed the starter motor chain rotating slightly. So I was wondering if the starter clutch was sticking, but it appears fine.
 
Spokes said:
Remove both spark plugs. Put the key in the crankshaft and place the flywheel back on just enough to catch the keyway. Turn the flywheel by hand back and forth advancing a full 360 degrees and listen for any tapping or metallic sound.
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Will do, thank you!
 
joehadams said:
I would agree with you, but when I operate the kick starter with the side cover off I have observed the starter motor chain rotating slightly. So I was wondering if the starter clutch was sticking, but it appears fine.
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The chain is only reacting to slight movements backwards as the engine comes to a stop. It's the same as hearing the starter kick in just slightly after turning the engine off, sometimes the engine bumps into TDC on compression stroke and when the key is off and it doesn't fire, it recoils slightly which is what causes that movement.
 
Hopefully one of the guys that knows this engine better than I will hop in, but something looks off with the cam chain and tensioner. There's an awful lot of deflection for a cam chain and the tensioner should have a hard rubber "pad" pressing on the adjustment pivot.
 
ancientdad said:
The chain is only reacting to slight movements backwards as the engine comes to a stop. It's the same as hearing the starter kick in just slightly after turning the engine off, sometimes the engine bumps into TDC on compression stroke and when the key is off and it doesn't fire, it recoils slightly which is what causes that movement.
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Got it, guess I’ll put it back on
 
EzPete said:
Hopefully one of the guys that knows this engine better than I will hop in, but something looks off with the cam chain and tensioner. There's an awful lot of deflection for a cam chain and the tensioner should have a hard rubber "pad" pressing on the adjustment pivot.
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The pad is there on the elbow of the tensioner. Just can’t see it in the pic.
 
Been slow to get back to the this, but finally pulled the right side cover. Was having clutch issues so had do it anyway. Plates and discs were stuck to eachother real good.

Anyway, everything else looked fine except for this…

IMG_4879.jpeg

Going to try and look around with the borescope before I dive into potentially splitting the case
 
Looks like aluminum shavings, maybe from the cam chain rubbing on the head? Can you pick those pieces up with a magnet, knowing if they are ferrous or not might pinpoint the area to look at.
 
boddy said:
Looks like aluminum shavings, maybe from the cam chain rubbing on the head? Can you pick those pieces up with a magnet, knowing if they are ferrous or not might pinpoint the area to look at.
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They are not magnetic metal shavings
 
That aluminum looks pretty chunky, not fine shavings, maybe just the picture. Right side is not cam chain but clutch basket and oil pump rod is. I'd pull the clutch outer basket off and have a good look at it and especially the pump rod and pump. Generally have to remove the clutch basket and oil pump together. look at the circlip that holds the pump rod to the clutch basket. Probably have to make or get a new oil pump gasket out of thin gasket paper.
Thanks for the pic showing yet another unexpected problem on these 60+ year old bikes. Also possible someone put the pump rod on backwards, rod should curve clockwise when looking at back of clutch basket.

As long as the left side is apart, I'd clean and inspect the cam chain tensioner, making sure the spring well is sludge/grit free and the spring is whole. It is easier to set that tensioner while observing it to get the chain tension just right.
 
ballbearian said:
That aluminum looks pretty chunky, not fine shavings, maybe just the picture. Right side is not cam chain but clutch basket and oil pump rod is. I'd pull the clutch outer basket off and have a good look at it and especially the pump rod and pump. Generally have to remove the clutch basket and oil pump together. look at the circlip that holds the pump rod to the clutch basket. Probably have to make or get a new oil pump gasket out of thin gasket paper.
Thanks for the pic showing yet another unexpected problem on these 60+ year old bikes. Also possible someone put the pump rod on backwards, rod should curve clockwise when looking at back of clutch basket.

As long as the left side is apart, I'd clean and inspect the cam chain tensioner, making sure the spring well is sludge/grit free and the spring is whole. It is easier to set that tensioner while observing it to get the chain tension just right.
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It was pretty chunky. I did pull the clutch components apart and other than the discs being stuck together everything looks very good. I will have to look at the oil pump rod to be sure it is in the correct orientation.

I also inserted a pencil into the spark plug hole, effectively stopping the piston from rising all the way to the top, and i jiggled the rotor back and forth by hand, and did not hear any knocking or noises that would indicate loose internal parts.
 
Here's a pic of the upper engine case showing the transmission and kick start assembly for reference. Gears against aluminum will give you aluminum grinds. Fortunately, you can invert the engine and pull the bottom off without disturbing the top end for inspection.
 

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Nevermind. I looked at some diagrams and it appears to be correct and not the source of the noise.

Noise seems to be at the head, most noticeable when the right side piston is at the top of its stroke. I didn’t have enough hands to hold the camera, light and spin the engine to get a definitive answer, but this seems to be the most likely time of the cycle that it makes the noise.
 
My scope is not great, and these are photos of the screen…but I found some areas of concern.

First is this area inside the case, from the right side looking in above the transmission gears. Seems like an out of round hole that isn’t supposed to be there.


IMG_4906.jpeg


Next is the area above the cam chain tensioner. Could be nothing but also could be where the chain may have contacted the case.

IMG_4908.jpeg


Finally, this valve rocker side to side movement seems excessive. What do you all think?

 
A loose or sloppy rocker will sound. My concern is the rough grinds as found. Something is being eaten away.
Here is another pic of the area you are referring to about the oblong hole. I'm not sure if the oblong hole means anything.
Maybe just adjust the valves, flush the bottom of the crankcase, clean the clutch plates and friction discs then put her back together. Just keep in mind that something is being eaten away internally.
 

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Spokes said:
A loose or sloppy rocker will sound. My concern is the rough grinds as found. Something is being eaten away.
Here is another pic of the area you are referring to about the oblong hole. I'm not sure if the oblong hole means anything.
Maybe just adjust the valves, flush the bottom of the crankcase, clean the clutch plates and friction discs then put her back together. Just keep in mind that something is being eaten away internally.
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Thank you for the photo that is helpful. I think you are right. I will likely just make any adjustments I can to try and mitigate future damage then save a full tear down until next winter.
This is my first bike over 50cc so I’m still just getting my feet wet.
 
The arm does look good, on the correct way. I was just thinking what could grind chunks on the right side. That odd hole may likely be part of the issue. I like spokes suggestion of opening the bottom to have look. If it is in the head then you’ll need another head gasket at least. It may not make it through the season with the problem it has and just destroy more parts. I’d keep looking to find and fix the problem.
 
So, I've been riding it even with the ticking and I've discovered that after the engine warms up a bit it stops ticking completely. It makes me think that it might be ticking until it builds decent oil pressure in the valve train.

While riding I've found that it has very poor mid range throttle response. it will eventually rev up and take off if I stay on the throttle. I think I need to adjust my needle height - richening the mixture by moving the clip downward, correct?
 
Who would have thought that there are 2 that color. FWIW, mine ticks too. Figured that was just what they sounded like.
1000004209.jpg
 
EzPete said:
Hopefully one of the guys that knows this engine better than I will hop in, but something looks off with the cam chain and tensioner. There's an awful lot of deflection for a cam chain and the tensioner should have a hard rubber "pad" pressing on the adjustment pivot.
Click to expand...
Looks just like mine
 
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