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Discussion Starter · #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!

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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.

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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.

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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.

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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.

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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.

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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:

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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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Discussion Starter · #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
 

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'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]
 

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Discussion Starter · #6 ·
'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]
The new link in my previous post should go directly to the album; Photobucket hates embedding pictures on blogs, etc now if they aren't paid for hosting. Money grubbers.
 
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thank guy...worked perfect...the only change I made was a 45mm long bolt and threaded the inside lock nut onto bolt until about 1/4 of bolt stuck out past nut and that went inside plunger to help support it like original setup


thanks again...easy, quick and no noise anymore
 

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Discussion Starter · #8 ·
thank guy...worked perfect...the only change I made was a 45mm long bolt and threaded the inside lock nut onto bolt until about 1/4 of bolt stuck out past nut and that went inside plunger to help support it like original setup


thanks again...easy, quick and no noise anymore
No problem; glad it helped. :) There's nothing like saving money and fixing a problem Honda has yet to rectify yourself.
 

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No problem; glad it helped. :) There's nothing like saving money and fixing a problem Honda has yet to rectify yourself.

yup...thanks again for the idea, I love when someone figures out a way to fix something instead of throwing new parts on it...maybe cause I am cheap ..lol



my wife`s cbr has about 10k around town miles on it before it started to go bad, she is happy now which is good..:laugh:. she also has a red 2004 Aprilia tuono and a blue 2008 aprilia tuono but still enjoys cruising around on the cbr250r
 

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Wow. seems like this bike tensioner stuff is kinda weak.

I remembered my friend told me that he needs to replace the CCT and the timing chain around 4-5 times.

And his bike mileage is barely touching 20k miles.

I already replaced mine 2 times.
 

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Discussion Starter · #12 ·
Wow, so that did the job for the that rattle everyone (including myself) can't figure out!? Thanks man... I'll have to try it.
It did for me, but my shims are also adjusted in spec. Many still have the 6k rattle even with a properly working/adjusted CCT and proper valve shim clearance. Some engines just have that rattle no matter what you do.
 

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Discussion Starter · #13 ·
Original post has been updated with new pictures for reference and Photo-suck-et links have been removed.
 
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Discussion Starter · #15 ·
Dude thank you for still being here and answering questions and updating pictures after so many years. Gonna try this this weekend hopefully if i find the parts in my hardware store. Will update when done.
No problem; glad to help. Still have the bike, still having fun, and still have no desire to get rid of her. After all these years, in fact, this is our 10-year anniversary. :)
 
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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?
 

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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.
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CCT wearing out quickly is only symptom or effects/side-effect. Real problem causing this is still unresolved. Doesn't matter if you replace with factory or manual CCT, it too will wear out quickly. Find real problem and fix it before wasting another CCT.
 

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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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CCT wearing out quickly is only symptom or effects/side-effect. Real problem causing this is still unresolved. Doesn't matter if you replace with factory or manual CCT, it too will wear out quickly. Find real problem and fix it before wasting another CCT.
I already thought if it’s a side effect however it looks like it’s a known issue for the cbr300r, cfr250 and cbr250r. One curious thing it’s I am almost sure it appeared both times after doing the same route. This route is to a volcano with an altitude around 3000m. The road is almost a incline all the way up. For most of the way I kept the bike around 7000rpm at second gear and I didnt felt any lack of power. Maybe the abruptly change of altitude and temperature and something that’s not right in bike make it fail ?
 
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