The Grambo Trick - Version 2.0 (ACCT Adjustment)

400 Views 31 Replies 5 Participants Last post by O' Darkness, 19 d ago

O' Darkness

Before committing to replacing or repairing my ACCT's, or making the conversion to MCCT's (be it DIY or pre-made) I decided today to completely remove both of them and have a peek.

With the ACCT out and in my hands, I tightened the (front cylinder) tensioner screw all the way in, fully retracting the plunger. While doing this VERY slowly, I could feel just the tiniest bit of resistance about halfway through. Almost as if there was a little friction point that the spring might have bound upon. The rear cylinder ACCT also had this almost imperceptible bit of resistance about halfway.

So I submerged both ACCT's in clean motor oil inside of a clean tupperware container. (Don't worry, I wiped it out afterwards with a paper towel before I ate my Campbell's Cream-Of-Mushroom soup out of it. It DID taste a little funny, though...)

I flipped the container gently, so as not to create bubbles; a few times about every ten minutes for an hour. Giving the oil the opportunity to seep into every crevice.

Additionally, I turned the tension screw all the way in a few times while they were submerged.

When I replaced them onto the bike, I observed how far I could install them back onto the bolts before I was stopped by the compression guide. Slightly more than 1/4 inch. I simply turned that tension screw until I could slip one of the nuts on. It went much easier than I thought.

I should have taken pictures, but I'm pretty sure everyone here is rather familiar with how this went.

I hope this is useful and possibly helps someone in the future!

EDIT: Problem solved! No more clacking.

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O' Darkness

Discussion Starter · #21 · 19 d ago (Edited)

dirtrack650 said:
Please clarify why the ACCT can't back out? Heat+vibration+wear+weak spring= opportunity to back up. I'm not saying it stays retracted, even a millimeter or two would cause engine noise.

Maybe I should have clarified: Buddy stated: "I don't understand how it can back out by itself."

The literal answer to that question is : It can't. Although possibly weakened by heat , vibration and wear, that screw section is not going to back out of the plunger at all. How could it? The spring -even if completely unwound, no pre-tension- physically prevents that from happening. I suppose if you want to think of that spring as a solid barrel, that's what I'm trying to convey.

Of course, a reduction in that tension would limit how far forward the plunger would move, but I cannot see how it could be forced backwards? That would require lateral compression of the spring. If that's true, then the spring is fine and working as it should. I think the problem that everyone has been experiencing is the spring is BINDING. I don't think it has anything to do with the physical pressure capabilities of the spring...

Maybe I've got it wrong, but it looks rather straightforward to me.

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Buddy

· #22 · 19 d ago

dirtrack650 said:
Please clarify why the ACCT can't back out? Heat+vibration+wear+weak spring= opportunity to back up. I'm not saying it stays retracted, even a millimeter or two would cause engine noise.

I had originally bought the springs from TOC when I was installing the new springs I had to remove a circlip after spring was installed I put circlip back in place then I was testing to make sure I had properly got the preload correct. I was using a screwdriver to manipulate the ACCT once I was satisfied it was good I put a lot of pressure with my thumb on the head of the ACCT trying to push it back it would not budge I pressed really hard and the circlip popped out and the assembly wound up in my hand . No matter what I did I was unable to retract the plunger the only way I was able to retract it was to turn the slotted end counter clockwise that loaded spring tension and retracted the plunger

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O' Darkness

Discussion Starter · #23 · 19 d ago

Buddy said:
I had originally bought the springs from TOC when I was installing the new springs I had to remove a circlip after spring was installed I put circlip back in place then I was testing to make sure I had properly got the preload correct. I was using a screwdriver to manipulate the ACCT once I was satisfied it was good I put a lot of pressure with my thumb on the head of the ACCT trying to push it back it would not budge I pressed really hard and the circlip popped out and the assembly wound up in my hand . No matter what I did I was unable to retract the plunger the only way I was able to retract it was to turn the slotted end counter clockwise that loaded spring tension and retracted the plunger

Exactly, that plunger can't be forced backwards any further than the spring will physically allow.

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dirtrack650

· #24 · 19 d ago

Then explain why the set screw idea works? I haven't adjusted it in years, many thousands of miles.

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O' Darkness

Discussion Starter · #25 · 19 d ago

dirtrack650 said:
Then explain why the set screw idea works? I haven't adjusted it in years, many thousands of miles.

I'm not sure how it works. You just toss a set screw in there and it keeps that plunger screw from moving? Do I have that right?

Admittedly, what I've been saying is no more than my own theories and I've said repeatedly I could have this entirely wrong.

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Buddy

· #26 · 19 d ago

So the setscrew locks the plunger from going in, and if you potentially have the ability to back off, it no longer has that because the set screw locks in place. So if you have any wear of the cam chain then the ACCT will no longer function because it’s locked in place. So I have this theory correct? since you have not had the need to readjust the set screw and you’re not getting any noise caused by chain wear so we assume the setscrew has resolved yes

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Thorn

· #27 · 19 d ago

If a spring weakened, it is absolutely possible for the plunger to work it's way backwards. In the other thread I used the 'hammer vs wrench' description as to why the spring is able to hold the plunger forward against the chain. If you remove the torque of the spring from being a constant 'forward' force on the plunger, then the constant vibrations of the chain/motor and pressure backwards against the screw would cause the screw to turn clockwise (as seen from the outside) in the direction of compressing the spring. It would be slow, but it could definitely move. You couldn't put it in a press and push it backwards, but if you put a pneumatic hammer on it it would spin ever so slightly with each tap. There's nothing 'hard' backing it up, so it could potentially travel to it's furthest most compressed position if the spring isn't resisting that spin. The set screw 100% stops the spinning, but also prevents the spring from pushing forward, so it is effectively an MCCT at that point.

O' Darkness said:
I cannot see how it could be forced backwards? That would require lateral compression of the spring.

I'm really not sure what you mean by this. The spring never laterally compresses or expands, other than a very very slight amount as the coils turn, compared with the plunger travel. It is never laterally pushing on, nor can be pushed on, by anything.

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Buddy

· #28 · 19 d ago

Thorn said:
The grambo trick as I understand it is to turn the screw so that you're pushing WITH the spring instead of compressing it, forcibly extending the plunger further than the spring had naturally pushed it, and taking up the slack in the chain. This would help a weak spring or overcome unwanted resistance between the spring coils as mentioned. Interesting that there isn't enough oil seeping/creeping around in there to keep things fairly well coated. My MCCTs drip oil at an annoyingly constant rate (installed by PO, and I'm sure loctite would help, but I'm lazy).

If you would wrap the screw where the oil is leaking with plumbers, Teflon tape doing several layers where the oil is leaking it might stop the leaks

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O' Darkness

Discussion Starter · #29 · 19 d ago (Edited)

Thorn said:
If a spring weakened, it is absolutely possible for the plunger to work it's way backwards. In the other thread I used the 'hammer vs wrench' description as to why the spring is able to hold the plunger forward against the chain. If you remove the torque of the spring from being a constant 'forward' force on the plunger, then the constant vibrations of the chain/motor and pressure backwards against the screw would cause the screw to turn clockwise (as seen from the outside) in the direction of compressing the spring. It would be slow, but it could definitely move. You couldn't put it in a press and push it backwards, but if you put a pneumatic hammer on it it would spin ever so slightly with each tap. There's nothing 'hard' backing it up, so it could potentially travel to it's furthest most compressed position if the spring isn't resisting that spin. The set screw 100% stops the spinning, but also prevents the spring from pushing forward, so it is effectively an MCCT at that point.

I'm really not sure what you mean by this. The spring never laterally compresses or expands, other than a very very slight amount as the coils turn, compared with the plunger travel. It is never laterally pushing on, nor can be pushed on, by anything.

Maybe I used the wrong word?

The spring would have to be squeezed tightly into itself.

I dunno, like I've pointed out several times already, this is just my own observations. But what you're saying makes no sense from a mechanical standpoint at all.

You would literally have to remove the spring completely for that screw to move backwards. It can't. I don't care how "weak" the spring is. It takes up space, just like a spacer. If that spring is completely, 100% compressed, that screw still could not unscrew at all. None.

EDIT: UNLESS there's something about the functionality of that ACCT I'm not seeing?

Regardless, I've ordered MCCT's and f**k those ACCT's. Shoulda done that sooner.

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Thorn

· #30 · 19 d ago

O' Darkness said:
If that spring is completely, 100% compressed, that screw still could not unscrew at all. None.

You're right, but it doesn't ever get to 100% compressed. Using the screwdriver, you retracted the plunger all the way. The cam chain would never b able to do that so long as the spring is still on this physical plane of existence. I've never really been sure why the question was being asked about whether the plunger can 'go backwards'. A tiny bit of extra play in the chain, or a slight weakening of the spring can cause enough slop to have pretty bad rattle in the chain I think Dirttrack has already pointed that out. There's not a ratcheting or cam mechanism, to provide a strictly one-directional movement.

O' Darkness said:
Maybe I should have clarified: Buddy stated: "I don't understand how it can back out by itself."

The literal answer to that question is : It can't. Although possibly weakened by heat , vibration and wear, that screw section is not going to back out of the plunger at all. How could it? The spring -even if completely unwound, no pre-tension- physically prevents that from happening. I suppose if you want to think of that spring as a solid barrel, that's what I'm trying to convey.

I feel like we both see the same components, but are drawing very different conclusions about how they behave. All that would have to happen is for the spring to have a reverse force put against it's natural inclination to uncoil. With no pre-tension, and a weakened torque from heat cycles/whatever, it would be absolutely possible for the cam chains guide to push against the plunger, forcing the screw to thread into the plunger, causing slight coiling of the spring. This would look much like those yankee 'push' screwdrivers, but with a much tighter thread pitch.

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Buddy

· #31 · 19 d ago

I’m sitting here and I keep saying cam chain, tensioner, cam chain, tensioner, manual, cam, chain, tensioner, automatic, ham, chain tensioner I think I’ve lost my mind and I said ham sandwich. I’ve lost my mind. Hey CCTMCCT I’m going to bed. Good night off tonight

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O' Darkness

Discussion Starter · #32 · 19 d ago

Thorn said:
You're right, but it doesn't ever get to 100% compressed. Using the screwdriver, you retracted the plunger all the way. The cam chain would never b able to do that so long as the spring is still on this physical plane of existence. I've never really been sure why the question was being asked about whether the plunger can 'go backwards'. A tiny bit of extra play in the chain, or a slight weakening of the spring can cause enough slop to have pretty bad rattle in the chain I think Dirttrack has already pointed that out. There's not a ratcheting or cam mechanism, to provide a strictly one-directional movement.

I feel like we both see the same components, but are drawing very different conclusions about how they behave. All that would have to happen is for the spring to have a reverse force put against it's natural inclination to uncoil. With no pre-tension, and a weakened torque from heat cycles/whatever, it would be absolutely possible for the cam chains guide to push against the plunger, forcing the screw to thread into the plunger, causing slight coiling of the spring. This would look much like those yankee 'push' screwdrivers, but with a much tighter thread pitch.

I would normally be inclined to agree with you, but it seems as if the "plane"(?) of the screws threads would make that rather difficult, would it not? This topic is starting it irritate me!!! I suppose it's one of those things we could discuss for pages, but at the end of the day, I'm satisfied that the steps I took -my variation of the Grambo trick- were not only effective, but also revealed some interesting things I hadn't seen mentioned elsewhere; specifically, that binding that occurred at identical points of the plunger's manual compression. Seemed quite odd to me, so I'm forced to attempt to draw logical conclusions that may or may not be flawed.

Either way, I think the overwhelming consensus agrees that the ACCT's are a PITA and IDGAF what I have to do to prevent that clacking, as long as it stops. MCCT's are going to be my next step. I'll keep the current ACCT's and dissect them in a mechanical autopsy to see what I can learn.

Thanks for your input, Thorn!

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