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Discussion Starter · #1 ·
Some time ago my bike was serviced since the top end was a little noisy, mechanic identified the issue and recommended to replace the chain and the CCT. After the service the noise was gone. Today the noise is back and is exactly the same, the service was 1500 km ago which is not a lot I would think. After some investigation in the web it seems the cbr 250r cct lack of tension is not that uncommon.
So I have a couple of questions, first is should I be worried about the chain? 1500km seems extremely low for a timing chain. And the second is what is the opinion on replacing it with a manual tensioner, I already talked with my mechanic and he is against it, but I think its more related to his work ethic of only replacing with what the service manual specifies.
Also I read that the cbr300r uses a more expensive part(maybe better?) and that it should be compatible with the 250r, has someone tried this?

Additional information:
Bike year: 2013 (India made)
Oil: Motul 7100 10-40w(replaced same time as the chain and cct)
Odo: 29700km (Service was at 28150km)
 

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Honda: INNOVA125i(2010); CBR250R(2013)
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replace the chain and the CCT. After the service the noise was gone. Today the noise is back and is exactly the same, the service was 1500 km ago
I do not know why the mechanic replaced your chain? I would recommend also to replace the (CCT)slider and the small sprocket (it does not require further disassembly).
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It is possible that the noise you hear could be because the chain is now "digging" a new place in the OLD slaider, and when it finishes adjusting to the groove created by the previous chain then the noises will stop. I think this is not problematic, and the plastic chips are caught in the strainer.

1500km seems extremely low for a timing chain.
YES

replacing it with a manual tensioner,
The manual CCT should be checked and maybe adjusting every 5000Km. The automatic CCT, with the problem typical for the model, is replaced every 20-25 Km (it is advisable to replace it every 20Km and not wait for the typical noises). Automatic OR Manual, the access to CCT is very convenient, and it takes a bit of work to replace OR adjusting it. And of course the price issue: DIY manual at 4USD Vs OEM automatic at 30USD.
Convert factory cam chain tensioner to manual - For $4

Service was at 28150km
Maybe the CCT replacement was done a little late, so the mechanic thought it was right to replace the chain for you as well.
 

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Discussion Starter · #4 · (Edited)
Yesterday I changed the cct to a manual one, the steps I did was:
Place crankshaft in T.
Remove ACCT.
Place manual CCT.
Move crankshaft while doing hand pressure on the bolt, I felt how the slack was being removed.
Back the bolt 1/6 of a turn.
Close eveything and let the bike run to get the temperature up.
Now in this step is where I find problems, most guides I read online said you shouldnt need to tight it that much when the bike is hot since the chain should get shorter when hot, however I tightened it around 1/6 turn and the sound was still there so I backed it half of that and leave it there by the moment too avoid getting it too tigh.

Should I try to tight it further?
 

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Yesterday I changed the cct to a manual one, the steps I did was:
Hi. The Steps are (I have no experience with the process, and that's how I know it):
1. Let the engine reach normal working temperature and normal idle RPM.
2. When the engine on idle, turn the tensioner screw in by hand until you feel a slight resistance and stop there.
3. Hold the adjusting screw so that it does not rotate, and tighten the locking nut.
4. Next maintenance either when there are noises, or after 5000Km.

when the bike is hot since the chain should get shorter when hot,
YES - The adjustment (The process that I know) is done with a hot working engine [ A strict Safety Rules must be observed!!!].
NO - When the chain gets hot the metal expands and the chain becomes longer.

Should I try to tight it further?
NO - Additional tightening does not reduce noise and only causes rapid wear of the chain and sprockets.
 

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For the cam chain the correct term will be tighter when hot*, not shorter. I will try to record the sound again and upload it.
And if you only replaced the timing chain and did not replace the "Railed", then there is this NOISES issue:
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NOISES issue:
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