CCT (Cam Chain Tensioner) Fail Safe Mod. (aka Stopper Mod)

[AMCQ46]

The stopper mod is ok & it works,but you will need to change the auto,s after the failure the best thing is fit mauls, job done.just need to adjust a very few thousand miles.

no bias there Ade?

I would say that the stopper is the optimal solution,

1) it still provides the self adjustment that Honda planned when they designed the engine and that will continue to compensate for wear and differential thermal expansion through life of the engine.

2) they cant unwind due to vibration/heat.... leading to failure if not set with Loctite to the main body

3) they cant be set too tight leading to metal on metal damage on the cam journals when starting the engine.

4) it cost nothing and so far it has lasted me 13yrs

[StuartWags]

The stopper mod is ok & it works,but you will need to change the auto,s after the failure the best thing is fit mauls, job done.just need to adjust a very few thousand miles.

no bias there Ade?

I would say that the stopper is the optimal solution,

1) it still provides the self adjustment that Honda planned when they designed the engine and that will continue to compensate for wear and differential thermal expansion through life of the engine.

2) they cant unwind due to vibration/heat.... leading to failure if not set with Loctite to the main body

3) they cant be set too tight leading to metal on metal damage on the cam journals when starting the engine.

4) it cost nothing and so far it has lasted me 13yrs

i would agree with that....yes they fail prematurely but some little people put lots and lots of time in to make sure they perform the primary function. The fact they are not durable is just how development / validation can sometime fail to find issues during test and then they pop up in service ... it happens from time to time.

[KermitLeFrog]

Just completed the stopper mod without using a locking key. Just used a modified jewelers screwdriver. Drilled it for a clevis pin which makes it easier to turn and count the turns.



The rear was a bit of a bugger but the front was easy. Used the shank of an 8mm steel bolt, 10mm long at the front, 9mm long at the rear.

To get the length turn the "key" clockwise until it reaches full retraction. Count the number of turns and fractions of a turn. The worm thread is quite coarse and one whole turn is 5mm of movement. With the CCT now removed and the roll pin and plunger head removed clamp it in a vice. With one hand turn the key to fully retract and then let it out the counted number of turns. With the other hand drop some dial calipers down the hollow plunger rod and note the distance. Take 5mm off that (the distance the plunger head goes into the plunger rod) and you have the nominal length of the stopper rod. Then take a 1/4 or 1/2 turn (1.25mm or 2.5mm) off that and cut your stopper rod.

You have to screw in the plunger rod (clockwise turns of the "key") to get the plunger rod to retract and the CCT body to seat before you tighten up the bolts. Easy on the front, a bugger on the rear. Job done.

The Honda manual calls for 17 ftlbs on these allen screws. I couldn't bring myself to give them that much but hopefully they wont back out.

Toodle pip
Ian

[sirch345]

Just completed the stopper mod without using a locking key. Just used a modified jewelers screwdriver. Drilled it for a clevis pin which makes it easier to turn and count the turns.



The rear was a bit of a bugger but the front was easy. Used the shank of an 8mm steel bolt, 10mm long at the front, 9mm long at the rear.

To get the length turn the "key" clockwise until it reaches full retraction. Count the number of turns and fractions of a turn. The worm thread is quite coarse and one whole turn is 5mm of movement. With the CCT now removed and the roll pin and plunger head removed clamp it in a vice. With one hand turn the key to fully retract and then let it out the counted number of turns. With the other hand drop some dial calipers down the hollow plunger rod and note the distance. Take 5mm off that (the distance the plunger head goes into the plunger rod) and you have the nominal length of the stopper rod. Then take a 1/4 or 1/2 turn (1.25mm or 2.5mm) off that and cut your stopper rod.

You have to screw in the plunger rod (clockwise turns of the "key") to get the plunger rod to retract and the CCT body to seat before you tighten up the bolts. Easy on the front, a bugger on the rear. Job done.

The Honda manual calls for 17 ftlbs on these allen screws. I couldn't bring myself to give them that much but hopefully they wont back out.

Toodle pip
Ian

Good on you Ian for trying something different that worked, and taking the time to explain how you did that

The only real downside for me is the bit about fully retracting the CCT plunger, as that creates more tension on the CCT spring. So for me I would rather stick with using a CCT locking key for that reason, and they are not really that hard to make,

Chris.

[KermitLeFrog]

The only real downside for me is the bit about fully retracting the CCT plunger, as that creates more tension on the CCT spring. So for me I would rather stick with using a CCT locking key for that reason, and they are not really that hard to make,

Chris.

I agree. The locking key would have made it much easier and will def use one the next time. One possible advantage of fully retracting the plunger is that, if the spring does have a weak point, a crack or such like, that's when it's most likely to break. If the spring is in good shape it should be unaffected by a full retraction as that would be within the design limits.

[lloydie]

Thank sirch for the guide , I did the stopper mod today following your instructions .
Thank you .

[sirch345]

Good man Lloydie, another one saved

Chris.

[Stepkevh]

I did this stopper mod a few weeks back but couldn't test the bike until yesterday.
9mm in the back and 10 in the front, 1/4 turn on the back and 1/2 turn on front as suggested.
Manually turned it around and all ok, no valves hitting
So yesterday happily pushed it out of the garage to the street, fired it up, all running fine, no unpleasant noses

Drove it a bit around to heat it up...
Then when warm it pulled it open and when releasing throttle and letting it come down in revs i hear the rattle
Tried it again and everytime when it comes down in revs i heard the rattle.

Was a bit shocked and pushed it back to the garage.
Thought there was little bit to much slack on the front chain allthough i respected the 1/2 turn as suggested.
In the garage took of tank / airbox, set TDC first offcourse and pulled the cct out.
Plunger spring still ok, so added another mm to the stopper, from 10 to 11mm = a quarter turn as well just like on the back cct.
Put everything back together and back to the street.

Now while warming up in idle i heard nothing, when driving it always rattled slightly and once the engine was on temperature it was gone.

Is this ok what i did ?
Or was i reasoning wrong and does the front cct need a quarter more slack => 3/4 instead of 1/2 turn ?
Without the stoppers it didnt have that rattle, so there must be something
As this is all my first time i'm not 100% sure

[KermitLeFrog]

Seems strange. The stoppers should have no effect at all in a working auto tensioner. They are only there if the tensioner fails.

[Stepkevh]

Seems strange. The stoppers should have no effect at all in a working auto tensioner. They are only there if the tensioner fails.

I know, that's why i don't understand it either.

[sirch345]

I did this stopper mod a few weeks back but couldn't test the bike until yesterday.
9mm in the back and 10 in the front, 1/4 turn on the back and 1/2 turn on front as suggested.
Manually turned it around and all ok, no valves hitting
So yesterday happily pushed it out of the garage to the street, fired it up, all running fine, no unpleasant noses

Drove it a bit around to heat it up...
Then when warm it pulled it open and when releasing throttle and letting it come down in revs i hear the rattle
Tried it again and everytime when it comes down in revs i heard the rattle.

Was a bit shocked and pushed it back to the garage.
Thought there was little bit to much slack on the front chain allthough i respected the 1/2 turn as suggested.
In the garage took of tank / airbox, set TDC first offcourse and pulled the cct out.
Plunger spring still ok, so added another mm to the stopper, from 10 to 11mm = a quarter turn as well just like on the back cct.
Put everything back together and back to the street.

Now while warming up in idle i heard nothing, when driving it always rattled slightly and once the engine was on temperature it was gone.

Is this ok what i did ?
Or was i reasoning wrong and does the front cct need a quarter more slack => 3/4 instead of 1/2 turn ?
Without the stoppers it didnt have that rattle, so there must be something
As this is all my first time i'm not 100% sure

Personally would have stuck to the original measurements I came up with. These figures I put in this topic were from considerable time spent in R&D. By lengthening the front stopper you could possible be running the front cam chain tighter than it would have been using the standard CCT without the modification. How much if any would depend entirely on the expansion of the different metals that are in the engine when it gets hot. An extra quarter of a turn gives some leeway to help here in my opinion, now you've lost that leeway.

Possibilities of why you had a rattle from the front CCT after the Stopper Mod was carried out:-

(1) The spacer you cut to the required length is jumping around inside of the CCT due to it being considerably smaller in diameter than the internal diameter of the CCT plunger shaft.

(2) The front CCT spring could be getting weak and struggled to keep the required tension on the cam chain. If that was the case, if you ran the bike a few more miles the rattle may have disappeared. I have know a CCT plunger to stick when a CCT spring is getting weak causing them to give a rattle then for it to disappear again.

Chris.

[Stepkevh]

The spacer i used is 8 mm stainless steel as suggested

I have no problem to put back the previous rod length of 10 mm to get the half turn again, it's only 45 mins work.
Maybe even 30 mins as i'm getting used to pulling out the cct's

Just thought it was wrong when i heard the rattle after coming down in revs

[sirch345]

I agree you shouldn't have a rattle after carrying out this mod.
May be as I said the CCT spring is getting a little on the weak side, even so if it did break you're safe with this mod.

Your call on if you want to put the rod back to the size you had it the first time

Chris.

[Stepkevh]

There's one thing i dont understand...
I was reading up on Kriegers website last night that for setting MCCT's tension, you turn them by hand until all slack in the chain is gone and then lock it off.
While with this stopper mod, we should have slack.
Is this just because we still use the original CCT's and they rod must be able to move ?

[Wicky]

There's one thing i dont understand...
I was reading up on Kriegers website last night that for setting MCCT's tension, you turn them by hand until all slack in the chain is gone and then lock it off.
While with this stopper mod, we should have slack.
Is this just because we still use the original CCT's and they rod must be able to move ?

Mark Krieger's Firestorm instructions are based on manual tensioner installation procedure written here in the Workshop Knowledgebase, and cleary states finger tight then back it out 1/8 turn before locking it up. Not sure how you missed this.

http://www.clems-garage.com/CCT/VTR1000 ... ctions.htm

13) Then continue turning while still finger tightening the cam chain tensioner to make sure all play is out, then back the thru bolt 1/8 turn and tighten lock nut. (static setting)