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Convert factory cam chain tensioner to manual - For $4

17K views 43 replies 11 participants last post by  DannoXYZ 
#1 · (Edited)
So after going through 2 brand new factory tensioners in less than 1000 miles (original made it 28k), I decided that I wasn't going to buy another factory one to destroy my engine, and I also wasn't going to pay $50 for a bolt and nut shoved through a tensioner housing. Here is the original post with a video showing the symptoms and details of what I was experiencing: Cam chain tensioner dying

So, since I had an extra (bad) tensioner laying around, I decided to do some surgery, find the underlying culprit, and solve this once and for all. So here goes. $4 in Lowes hardware and half an hour later, and no more ticking.

Supplies needed:
1 package of M6x1.00 40mm stainless steel bolts (need 1 bolt)
1 package of M6x1.00 stainless steel nuts (need 1 nut)
1 package of M6x1.00 stainless steel nylon lock nuts (need 1 lock nut)
1 package of stainless steel washers (need 1 washer)
Total cost: $3.96, and enough leftover to do 3 more tensioners!

Remove the hex cap bolt on the back of the tensioner and remove the small black o-ring. Do not lose this!

44553


Remove the tensioner from the back of the motor with the two 8mm bolts on each side. Hold it in towards the motor when removing to prevent stripping the other bolt.

Remove the snapring from around the base of the plunger using a small, thin, flat head screwdriver and working around the housing a little at a time. Be careful to not warp/bend the snapring out of shape, as you'll be re-using this later. (Sorry, no pics of this. Needed two hands and didn't want anything flying out in my face.)

Once you have the snapring off, you can remove the plunger and all the guts of the tensioner. BE CAREFUL! There is a spring inside under tension, and it can slice you if it pops out.

Here are the parts in their glory. We'll only be using a couple going forward: 1. The housing 2. The snapring 3. The plunger. The spring, plastic sleeve, wormgear, and washer will not be used. Here, you can also see the end of my spring is also quite knarled. This thing was ready to let go.

44555


And this brings us to the crux of the tensioner debacle. The spring tension does both duties: Providing outward tension, and preventing the wormgear from backing off; there is no lock on the wormgear. Unfortunately, once the spring weakens to a point where it is no longer providing adequate pressure outwards, it is also unable to prevent the wormgear from backing off under vibration, allowing the cam chain to rattle around and make that cringe-worthy noise at idle.

Ok, now is when the magic happens. Take your stainless bolt, then place 1 regular stainless nut on the bolt, followed by 1 stainless washer, followed by the black sealing o-ring from earlier. Begin threading the bolt into the tensioner housing from the back side. Here you can see the order and the orientation.

44557


You will want to move the nut to the head of the bolt so that you can bottom the bolt out on the housing as far as it will go. Make sure your o-ring is in the recession on the housing so it doesn't get pinched or torn.

44558


Now grab your stainless nylon lock washer and place it on the end of the bolt that is now pushed through the housing. Use a 10mm wrench on the bolt head, and a 10mm socket on the nylon lock nut to tighten the nut until it is flush with the end of the bolt. If you feel paranoid, you may place some locktite on the threads before doing this.

44559


Now back the newly completed bolt apparatus out of the housing until it hits the lock nut. Place the plunger back over the housing and lock nut, then reinstall the snapring.

44560


44561


Place the gasket back on the tensioner housing and reinstall in the bike.

Now make sure the o-ring is in its recession, and the washer is laying against it (this will keep oil from weeping out around the bolt). Turn the main bolt in finger tight until you hit resistance. I turned it one-half turn further, then held the bolt head with a wrench to keep it from moving while I snugged down the nut with another wrench to lock it in place.

Here is the completed install:

44562


This may take a little adjustment. If you hear rattling after this, loosen the nut and turn the bolt head another half turn in. If you hear a whining sound on deceleration, then it may be a tad too tight and you should back off a smidge.

No rattles, no more failures, and no overpriced custom manual tensioners. Bling, blang, blao. :smile2:
 
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#4 ·
I have been informed by another member that my photos for this thread are no longer active because of Photobucket's updated 3rd party hosting policy, in which the host of the forum must pay Photobucket for the images to be hosted. Hogwash.

Anyways, here's a link to the album with the pictures. They aren't necessarily in order, but they're basically in reverse order for the process.

Cbr250r Cam Chain Tensioner Fix | Photobucket
 
#5 ·
'please update your account to enable 3rd party hosting'
with a tacho image with 100% over it, and 'go to photobucket' etc..

at first your images came up then replaced with a 'photobucket'
image,, but just repeated and the images stayed up..
[remember manual adjusters on earlier hondas
never having any problem with them
incl sohc 750/4's]
 
#16 ·
Mechanic replaced my cct and timing-chain 1500km ago and the sound is back again so I am going to go manual. You didn't mentioned it but reading the manual its says to put the piston in TDC compression stroke, is there a way to know/feel the compression stroke without opening the valves cover?
 
#17 · (Edited)
Mechanic replaced my cct and timing-chain 1500km ago and the sound is back again
I would try to test more options before I state that the problem is in the tensioner.
You claim that mechanic replace your CCTensioner.
You should have warranty for that repair, yes?

... so I am going to go manual. You didn't mentioned it but reading the manual its says to put the piston in TDC compression stroke, is there a way to know/feel the compression stroke without opening the valves cover?
Yes it is possible. To do this you need to remove the plug, look through the hole of the plug into the combustion chamber and see the piston when it reaches the top. If the fuel tank is not removed, a mirror can be useful. Also you can push a rod (plastic rod? One that will not damage the cylinder) into the plug hole and know TDC by the height of the rod. It is also possible to pinpoint the TDC if you look at the T-Mark.
Automotive tire Motor vehicle Automotive lighting Rim Bumper


Tire Wheel Automotive tire Automotive lighting Tread
 
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#19 ·
CCT wearing out quickly is only symptom or effects/side-effect. Real problem causing this is still unresolved.
...Find real problem and fix it before wasting another CCT
The problem is not anywhere else, it's just the The CCT that requires replacement earlier than expected according to the manufacturer's instructions.

Doesn't matter if you replace with factory or manual CCT.
You are right. In the years that there was a manual tensioner, the adjustment in any case would have been done at a frequency of every 5000 Km. Not that something was broken, because that's the maintenance schedule for manual tensioner. At cbr250r the automatic tensioner needs to be replaced every 20,000 Km, which is indeed earlier than expected, but not a dramatic matter (Because it requires very short working time to replace it, also because the access is very convenient).

Note that the matter is not longevity of the CCTensioner, the matter is 30USD Vs 4USD.

Considering the fact that our motorcycle is a budget motorcycle, the offer to go for a D.I.Y cheap manual CCTensioner is in the spirit of the model.
 
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#24 ·
Hmm, I wonder where oil-pick up is in oil-pan? Is it in front or rear of pan? With or without baffles?

I've seen lots of bikes that are used for stunting and wheelies have premature bearing-wear because oil pick-up tube sucks in air instead of oil. Might be case with going uphill for long time?

Have you measured cam-chain stretch amount?
 
#26 ·
Hmm, I wonder where oil-pick up is in oil-pan? Is it in front or rear of pan? With or without baffles?
You are made me to curiosity. Now we both have no "wonder" anymore. Thanks!
Wheel Tire Automotive tire Motorcycle Motor vehicle
Automotive tire Crankset Light Motor vehicle Vehicle brake


Motor vehicle Automotive tire Crankset Vehicle brake Rim
Automotive tire Motor vehicle Bumper Rim Gas


I've seen lots of bikes that are used for stunting and wheelies have premature bearing-wear because oil pick-up tube sucks in air instead of oil. Might be case with going uphill for long time?
YES: It's need really crazy angles, like situations that stunt riders get into.
No: There is no road in the world that the motorcycle can climb on in terms of slope, and the fuel pump will not get oil.
 
#27 ·
So after going through 2 brand new factory tensioners in less than 1000 miles (original made it 28k), I decided that I wasn't going to buy another factory one to destroy my engine, and I also wasn't going to pay $50 for a bolt and nut shoved through a tensioner housing. Here is the original post with a video showing the symptoms and details of what I was experiencing: Cam chain tensioner dying

So, since I had an extra (bad) tensioner laying around, I decided to do some surgery, find the underlying culprit, and solve this once and for all. So here goes. $4 in Lowes hardware and half an hour later, and no more ticking.

Supplies needed:
1 package of M6x1.00 40mm stainless steel bolts (need 1 bolt)
1 package of M6x1.00 stainless steel nuts (need 1 nut)
1 package of M6x1.00 stainless steel nylon lock nuts (need 1 lock nut)
1 package of stainless steel washers (need 1 washer)
Total cost: $3.96, and enough leftover to do 3 more tensioners!

Remove the hex cap bolt on the back of the tensioner and remove the small black o-ring. Do not lose this!

View attachment 44553

Remove the tensioner from the back of the motor with the two 8mm bolts on each side. Hold it in towards the motor when removing to prevent stripping the other bolt.

Remove the snapring from around the base of the plunger using a small, thin, flat head screwdriver and working around the housing a little at a time. Be careful to not warp/bend the snapring out of shape, as you'll be re-using this later. (Sorry, no pics of this. Needed two hands and didn't want anything flying out in my face.)

Once you have the snapring off, you can remove the plunger and all the guts of the tensioner. BE CAREFUL! There is a spring inside under tension, and it can slice you if it pops out.

Here are the parts in their glory. We'll only be using a couple going forward: 1. The housing 2. The snapring 3. The plunger. The spring, plastic sleeve, wormgear, and washer will not be used. Here, you can also see the end of my spring is also quite knarled. This thing was ready to let go.

View attachment 44555

And this brings us to the crux of the tensioner debacle. The spring tension does both duties: Providing outward tension, and preventing the wormgear from backing off; there is no lock on the wormgear. Unfortunately, once the spring weakens to a point where it is no longer providing adequate pressure outwards, it is also unable to prevent the wormgear from backing off under vibration, allowing the cam chain to rattle around and make that cringe-worthy noise at idle.

Ok, now is when the magic happens. Take your stainless bolt, then place 1 regular stainless nut on the bolt, followed by 1 stainless washer, followed by the black sealing o-ring from earlier. Begin threading the bolt into the tensioner housing from the back side. Here you can see the order and the orientation.

View attachment 44557

You will want to move the nut to the head of the bolt so that you can bottom the bolt out on the housing as far as it will go. Make sure your o-ring is in the recession on the housing so it doesn't get pinched or torn.

View attachment 44558

Now grab your stainless nylon lock washer and place it on the end of the bolt that is now pushed through the housing. Use a 10mm wrench on the bolt head, and a 10mm socket on the nylon lock nut to tighten the nut until it is flush with the end of the bolt. If you feel paranoid, you may place some locktite on the threads before doing this.

View attachment 44559

Now back the newly completed bolt apparatus out of the housing until it hits the lock nut. Place the plunger back over the housing and lock nut, then reinstall the snapring.

View attachment 44560

View attachment 44561

Place the gasket back on the tensioner housing and reinstall in the bike.

Now make sure the o-ring is in its recession, and the washer is laying against it (this will keep oil from weeping out around the bolt). Turn the main bolt in finger tight until you hit resistance. I turned it one-half turn further, then held the bolt head with a wrench to keep it from moving while I snugged down the nut with another wrench to lock it in place.

Here is the completed install:

View attachment 44562

This may take a little adjustment. If you hear rattling after this, loosen the nut and turn the bolt head another half turn in. If you hear a whining sound on deceleration, then it may be a tad too tight and you should back off a smidge.

No rattles, no more failures, and no overpriced custom manual tensioners. Bling, blang, blao. :smile2:
Thank you so much for posting this. I tried it and it's working absolutely perfect. No more rattles. I wish i knew this 5 years ago...i would've saved 20k. I wish to thank you personally...please contact me on 9915746406
 
#28 · (Edited)
No one who destroyed an engine are here to tell us they destroyed an engine because of this nonsense: That the manual is better than the automatic.

I disassembled the automatic mechanism, and studied it in depth, there is nothing that can broken in it, it is very reliable, and bulletproof.
LINK TO MY STUIEDS (My YT Channel)
Even though, it is customary to change the automatic tensioner every 20 to 25 thousand kilometers, it is not clear why, but the legend says to change it, and I change it too, because it is an easy to replace and relatively cheap (LINK to Partzilla).
Product Font Screenshot Line Parallel

The characteristic vibrations of our engine, The Rattling Issues, come from the exhaust gas valve(One-way relief) that located at the top of the valve cover. It's frequencies are amplified by the valve cover, and that's the noise we all hear. It's a noise you get used to it, and it doesn't cause any harm.
Map Font Parallel Auto part Slope

On the other hand, a timing chain that is too tight is immediate causes an Heavy Damage!
If you have a reduction in the normal CBE250R engine vibrations, such that the independent frequencies are now more restrained, I would advise you to be concerned about an overstretched timing chain.
 
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#37 · (Edited)
Sure, wedge prevents mechanism from retracting, but there's not enough spring force after 1/2-way to push it further out to add more tension on chain. Measure actual spring tension at various lengths. A spring that's fully extended exerts zero force. Fully compressed tensioner exerts maximum force that decreases as it extends.

I suspect there's also some fatigue involved as well. We should measure spring-rate of old worn-out tensioner and compare to new one.

That's why on more high-end bikes and autos, hydraulic tensioner is used. This design exerts identical tension force along entire length of travel.
 
#39 · (Edited)
Measure actual spring tension at various lengths. A spring that's fully extended exerts zero force.
NO
Danno. Inside the engine the plunger never reaches the end of its stroke, and always at the end of its stroke (when it is outside the engine) the spring have to enough force to take it out (to his end- till stop).
That is way:
  • there is no problem of the kind of spring that gets weak,
  • and there is no problem of the kind that the spring reaches to zero force.

You are describing something that never happens in this mechanism.
The Brilliant Automatic Tensioner Is A Bulletproof Mechanism.
 
#38 ·
Without blaming the Brilliant Automatic Tensioner
Anyone who wants to arrange a new tensioner for himself for free, takes an M6 screw and arranges one of these for himself exactly as the thread opener explains Very nicely(y)(y)(y)

And of course with the manual tensioner you have to be careful:
  1. not to tighten it too much,
  2. and adjust it every 5k km,
Because otherwise
the savings can come at the cost of destroying the entire engine
💀☠☠💀
 
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