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Balancer chain adjustment confusion CM450E

Randall

Veteran Member
Joined
Jun 26, 2021
Total Posts
609
Total likes
7
Location
Cape Coral, FL, USA
I pulled the right cover to have a go at my clutch, and wanted to assess the balancer chain adjustment, because I am a little confused by it. First, the adjustment nuts in both the Honda FSM and the Clymer call for 8 and 10mm, but they are 12 and 14mm. When I loosened the left nut, the bracket barely moved from the almost top of the groove in the bracket.I worked it back and forth a bit to make sure it was moving freely, and when I let it go from the full clockwise position, it lands about 1 mm from the full cc position. From here I don't know what to do or think.

One thing that does concern me is when I loosen the left nut, the threaded stud comes with it, ie they move as one. This doesn't look right according to the manuals which talk about an adjusting nut only.

What should I be doing here? And what exactly does this adjustment do? Is the balancer chain the one to the left of the adjustment nuts? because it seems loose to me.

002.jpg
 
You need to tighten the 12mm nut, remove the 14mm nut then remove the 12mm nut.
When both are removed pull quadrant off splines.
You turn the shaft as far counter clockwise as you can,with your fingers (it should be very easy/free turning)
Re-fit the quadrant as high as possible in the slot then re-fit the nuts.( the splnied shaft isn't 'clocked' so can be fitted in any position)
Most of the 3 valve motors needed it done around 300~500 miles from new as they were made for fast engine building but not service requirements ( and why Honda had dealer workshops)
After quadrant is moved up you should be good for 20~30,000 miles
I had forgotten about the stud coming out, it was very common. You can either ignore it or use soft jaws in a vice, remove nut from stud then screw stud back into crankcase with a spot of Loctite.
If I remember right, the shaft with 14mm nut has an eccentric on the other side and physically moves shaft counterweight to tighten balance chain. Running it loose is a real bad idea because it only runs on a couple of teeth on crank and could 'jump' timing (although I only ever saw that happen once)
 
Tighten the 12mm nut, remove the 14mm nut followed by the 12mm. Now pull the bracket off and reset it so the slot is exposed at the top. This will allow for more adjustment, no worries there as the dimple on the end of the shaft is @1:30 and chain replacement is when it gets to the 9 o'clock position. You've got at least another 50,000 miles on that chain.
If the 12mm and stud come out that's really not much of an issue but I would separate them and reinstall the stud with Red LocTite.
The other chain you see is the oil pump drive and it's always loose, no problem there.
 
You need to tighten the 12mm nut

Tighten the 12mm nut

Thank you both for this; I’ve only done mine once, but it was a bit confusing to me also. I’ll use this info to verify its set correctly.

Randall; the balancer chain is in the crankcase, look in the crankcase section of the FSM if you want to see more.
 
Thank you guys for your stereo explanations, in simul-cast no less!

I understand the procedure now, but am still unsure of how this adjustment is made with regards to the spring. I cannot visualize how it works. If by moving the bracket or 'quadrant' clockwise, does this allow the spring to take up more slack? If so, how far can the spring keep adjusting in the future, if I am making sense here? The part about removing the round cover and loosening the left nut, 12mm in this case, does this still work? If so, should I do this now after moving the bracket with the cover off?
 
The shaft is spring loaded to make the proper adjustment and chain tension. The shaft is eccentric ground so as it turns it pushes the front balancer.
Resetting the quadrant is a normal thing to do when the adjustment slot bottoms out. The dimple mark in the end of the shaft starts life new at the @2:30 o'clock position and as the chain gets adjusted thru it's lifespan it moves counter clockwise until the 9 o'clock position when it needs replacement.
For the next 5=10 adjustments it's simply remove the plug in the right cover and loosen the 12mm nut, then tighten. You can peer inside each time and when you no longer see the slot open at the top you know that the next time will require resetting the quadrant again.
 
^^^
Looks correct to me, based on their descriptions, and FSM photos. Not sure about torque values, or tightening order, since the manual shows the M8 and M10 sizes. IIRC I tightened mine as specified assuming they meant small nut and large nut in the manual. I’m waiting to hear LDR’s and/or crazypj’s answer.
 
As am I, this is a foreign country as far as I'm concerned. I'll take the crazy complex DOHC 450 vibration machine any day.
 
Perfect. Tighten the 12mm nut first then the 14mm. Next oil change pop the access plug out, loosen the 12mm then tighten and put the plug back in.
The shock adjust spanner wrench is used to remove/install the plug.
 
That's because most of the pictures are upside down.

I did notice that looking through the crankshaft section to find the initial setup for the chain adjuster… the engine case is upside down in the photo.
Any idea why it mentions 8 and 10mm instead of the 12 and 14mm… I first thought it was possibly the stud/bolt size, but that doesn’t match up either?
 
OK, good. Except I am still having a hard time grasping something. I have looked hard at the FSM exploded drawing, but some of it is lost on me. The thing I am having a hard time with is this:

I see what I think is the spring that reduces the slack. And I have been told the shaft at the other end of the gear that the bracket meshes with is ground to an eccentric shape so as it turns, I assume it cogs something to compensate for the extra length of the chain due to wear over time. Right so far?

And as the chain wears, and we release the 12mm nut, the spring keeps taking up the slack until the bracket tops off again, in which case we remove both bolts and reposition the bracket for another period of wear and adjustment. Correct?

Now, put my poor mind at ease and tell me this. Does the spring have enough energy due to it's static wind tension to be able to bring the 14mm shaft from 2:30 o'clock position to the 9:00 position in a CCW rotation over the useful life of the chain, with no changes to the spring? It just can do that by design? This is why simply moving the bracket allows for continued slack uptake, if that is even the right word?

Put this straight for me and my OCD, and I promise I will stop pestering you guys about it!
 
There's an explanation of the balancer system in section 18 of the 400 FSM. Look at the picture of the shaft and you'll see the eccentric grind on it.
So instead of the balancer running on a perfectly straight shaft it is offset some. As the shaft rotates during adjustment the balancer is moved further from the rear balancer which in turn tightens the chain. The offset starts as close to the rear balancer and eventually 180 degrees later, half turn, is the furthest away it can get. This corresponds to the 3 o'clock starting position new to the 9 o'clock position when the chain is due for replacement.
Yes, that spring will make the full half turn since the spring is pre-wound on the shaft @3/4 turns
 
Yes, that spring will make the full half turn since the spring is pre-wound on the shaft @3/4 turns


That is what was dogging me. Thank you for your succinct explanation, I get it now. (y)
 
That's because most of the pictures are upside down.

Yet another thing poorly done by the FSM authors back then. Book people trying to assemble technical info on something they've probably never worked on without an engineer's oversight most likely. As historically good as Honda was about so much, it's hard to understand stuff like this.
 
I'm pretty sure the 8 and 10 are just normal as that is the thread size and not the nut size.
To make life easier, 'we' tend to tell you what socket or spanner size you need.
In the Honda General manual it will give standard torque specs for the bolt diameter as the head size can vary (you can have 12, 13, 14 on a 10mm bolt)
As for the other questions, the video is 'perfect'
The tension spring aids the weight of quadrant, you can also push gently on top of quadrant.
If you ever need to re-adjust quadrant again, you probably have about 100,000 miles on bike and chain should be changed (although cam chain will probably run out of adjustment or fail before 100,000 miles?)
 
"In the Honda General manual it will give standard torque specs for the bolt diameter as the head size can vary (you can have 12, 13, 14 on a 10mm bolt)"

Well, this is some very important information. And it explains why I broke one of the 4 bolts with 10mm head size in my clutch basket, and why I felt just before it broke that this didn't seem right. Fortunately, it came out easily, and I was able to get an exact replacement at my local Lowe's home center for $2, so I got off real cheap on that one.

Now I know. I am going to make an annotation in my Clymer to remind me.
 
In the Honda General manual it will give standard torque specs for the bolt diameter as the head size can vary (you can have 12, 13, 14 on a 10mm bolt)

That explains it! Thanks.
(I had assumed 8 and 10mm actual thread size until I looked up the “standard” head/nut sizes and it didn’t match up.)
 
That explains it! Thanks.
(I had assumed 8 and 10mm actual thread size until I looked up the “standard” head/nut sizes and it didn’t match up.)

Yeah, it's really no different than a 1/4" bolt American (regardless of 20 or 24 thread pitch) having a 7/16" head. It's still a 1/4" bolt and has to be tightened like one.
 
Got it, thanks. The varying head size is what threw me off. Those Honda engineers again, such tricksters! [emoji6]

But it isn't really them, it's an industry standard - which is why I mentioned the American version, all bolts and nuts are that way, thread size is always different than the nut or bolt size.
 
thread size is always different than the nut or bolt size.

Right, I understand this part. Here’s what confused me:
47e583d2eb75a94b644ab2865e969867.jpg

I never knew there was a JIS standard for head/wrench size!
The FSM says loosen the 8mm and 10mm, which is the bolt/stud diameter, which take a 12mm and 14mm wrench size (head/nut size). I was confused because I was expecting the ANSI size, which of course, doesn’t apply in this case.

(Pardon all of this, back to programming! Although, someone did mention OCD earlier… I think… if I’m in the correct thread?)
 
Right, I understand this part. Here’s what confused me:

I never knew there was a JIS standard for head/wrench size!
The FSM says loosen the 8mm and 10mm, which is the bolt/stud diameter, which take a 12mm and 14mm wrench size (head/nut size). I was confused because I was expecting the ANSI size, which of course, doesn’t apply in this case.

(Pardon all of this, back to programming! Although, someone did mention OCD earlier… I think… if I’m in the correct thread?)

True, but I'm surprised it caught you simply because of the first word in the acronym... "American". It's like replacement metric bolts made in America (or FOR America) where the thread is 8mm but the head is 13mm... and you can always tell when you look at a bike that has been restored with locally available hardware.
 
^^^
I got lucky to find a chart with the JIS standard listed, I’d assumed one bolt size (whether fine or coarse thread) had one wrench size. Now I know!
(I worked for Fastenal for 7 years and whether I learned it there or not, I guess it didn’t stick.)
 
Dang, I'm back at this balancer chain adjustment again. I think I am hearing chain take up noise coming from the right side during start from first. I popped the round over and loosened the 12mm nut, but the adjuster piece doesn't move. I backed off the nut some more, still doesn't move. I can move it with a small amount of pressure with a little screwdriver. If I push it all the way up it stays there. Last year when I had the case open the adjuster was sitting right in the middle, so I pulled it and rotated it one cog, leaving it with a full open slot on the top. Figured I was good to go for a while. That was about 5K miles ago, and now I have it in the middle somewhere with more open top slot than lower. But I want to know if the chain is banging due to it not adjusting correctly.

So what would cause it to not be moved by the spring when loosened? Is it okay to just coax it with a little screwdriver what would seem like enough tension?
 
That's weird, never had one 'stick'.
It was moving fine after you adjusted quadrant?
You'll probably have to remove clutch cover to check for condensation causing corrosion inside making things stick?
(unless LDR has a better explanation?)
 
I doubt condensation is the issue. The bike is very well cared for, it has never spent a night outside. And it doesn't get cold here in SWFL much.
 
I'm in Central Fl, 90% humidity is pretty 'normal' outside.
You do also get more than a gallon of water produced for every gallon of gas you burn
A hot engine cooling down will 'suck' air in through breather so even low humidity can build up over time.(if you use Castrol you will see oil emulsify as water builds up)
Short trips on a regular basis are the worst for engines as they don't get hot enough to 'boil' condensation out of the oil.(I try not to do less than 10~15 miles at a time)
I would just use screwdriver to adjust things, if it quiets down ignore it until next year.
 
Dang, I'm back at this balancer chain adjustment again. I think I am hearing chain take up noise coming from the right side during start from first. I popped the round over and loosened the 12mm nut, but the adjuster piece doesn't move. I backed off the nut some more, still doesn't move. I can move it with a small amount of pressure with a little screwdriver. If I push it all the way up it stays there. Last year when I had the case open the adjuster was sitting right in the middle, so I pulled it and rotated it one cog, leaving it with a full open slot on the top. Figured I was good to go for a while. That was about 5K miles ago, and now I have it in the middle somewhere with more open top slot than lower. But I want to know if the chain is banging due to it not adjusting correctly.

So what would cause it to not be moved by the spring when loosened? Is it okay to just coax it with a little screwdriver what would seem like enough tension?
The only thing I've seen affecting the spring action on the shaft has been old oil buildup. You can spray the shaft where it enters the case with a little penetrating oil, not much because of oil dilution. Then work the shaft back and forth to loosen it up. You don't want much tension on the chain so a manual adjustment would be done with your little finger.
 
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Oil buildup? I have been good at keeping good oil in her. In a little over a year since riding I have changed it several times. 1,400 miles ago, 2,400 before that, 250 before that, 1000 before that, and 450 before that. Filters every other time. Oil that's in it now still looks pretty good.

I am not really in a good place to take the side cover off and inspect. My other bike is up on a jack with it's rear wheel in pieces, so I cant move it. And my shop is so small, I'd have to do it outside, but it is just too damn hot right now where I am, and no shade. I'd perish.

The spring has worked to some extent, given that the slotted piece was left at full open top slot when I put it together, and has now moved some. I just don't like that it is sticky. I want to correct the chain slop I am experiencing.

See video in post #7
 
Do you mean sticking a little finger in the opening, or taking off the side cover?

How big of a job is it to replace the spring? I'm thinking it is 40 years old after all, and sat for many of those years.
 
Finger thru the hole.
Spring inspection/replacement means splitting the cases. Here's the spring at the other end of the shaft and how that sits in the upper case half
201_4360.jpg 201_4364.jpg
 
When he says to use your "little pinkie finger" that's so that you don't rotate the adjustment "quadrant" counter-clockwise too much or so much that the balancer chain becomes too tight.

Also, in post #29 you say that you think you are experiencing slop but then in #34, as if 100% sure, you say that you are experiencing slop = a contradiction. Disregarding that, if you are hearing an abnormal noise or what you think is abnormal, do as LDR said with the little assistance of your pinky in helping the spring tighten the chain because there are only 2 scenarios here : too tight or slight free-play, with the slight free-play being THE CHOICE.

As to whether or not one can hear an abnormal sound when it's correctly adjusted with slight free-play, I'd be checking other other possible noise makers on that right side, like the clutch, etc..

Also, I'm not intending to be a smart-arse here, sincerely trying to help... ..abnormal noises will always be the hardest things for us forum-ites to help each other diagnose because, as you know, we are all acting here thru computers from far away. AND, I may be riding in a similar "boat" in that I think I may have an abnormal sound eminating from the left side of one of my 2 twins. But I'm only guessing because the other bike doesn't seem to have it, but I'm still in the "Uncertain if there's even an abnormal noise stage". I've thought that if indeed there is one and I cannot figure it out, I'm going to seek out some Honda-experienced ears, starting with the nearby Honda dealership, and one of their long-time techs who is retired but I can track him down because I've met him years ago and remember his name.
And, EUREKA ! I just remembered Ancient Dad Tom is in FL - if he's too far from you, he might know someone close enough who you could meet up with and could listen to your bike in person with you...
 
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