Author Topic: cb400 cam chain adjuster thread gone. Suggestions please!!  (Read 16231 times)

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Offline hoodellyhoo

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #25 on: March 25, 2011, 01:35:53 pm »
Thanks Jamie. I was wondering how much pressure was needed while pushing down.
I sure could use some advice here as I am stumped as to why I can't get any "play" in the adjuster...

I shared a Guiness or two with you last week!! How was your St Patricks Day Celbration?

If the bike is run for too long with a maladjusted cam chain then the chain rubs on the pivot point causing it to get stuck. I had to give a pretty good shove to unstick mine and get it to move but it now works fine. Might be a good idea to do this while the bike isn't running?
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Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #26 on: March 25, 2011, 02:22:26 pm »
If the bike is run for too long with a maladjusted cam chain then the chain rubs on the pivot point causing it to get stuck. I had to give a pretty good shove to unstick mine and get it to move but it now works fine. Might be a good idea to do this while the bike isn't running?
[/quote]

Did you give the top of the adjuster a good shove? I think this is what you mean...

How did you give it the shove? I am thinking to give it some assertive (but friendly) attention with a screw driver/punch and hammer... say 6" swing with a claw hammer as opposed to a full swing 3lb sledge hammer... lol

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Offline kyre

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #27 on: March 25, 2011, 03:06:59 pm »

Well I'm pretty sure the nut is SS anyway. The bolt definitely is and I'm 99% sure the nut is. I don't know the first thing about welding so I wouldn't know how to do it. It's definitely welded though. The engine is back in the bike so it's a bit hard to get closer pics but here's what I got.


From your photos the nut almost looks J-B "welded" to the case.
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Offline hoodellyhoo

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #28 on: March 25, 2011, 03:28:26 pm »

Did you give the top of the adjuster a good shove? I think this is what you mean...

How did you give it the shove? I am thinking to give it some assertive (but friendly) attention with a screw driver/punch and hammer... say 6" swing with a claw hammer as opposed to a full swing 3lb sledge hammer... lol



Yeah, I'm talking about the top of the adjuster. I was just leaning over it with a screwdriver and gave a good heave (as opposed to just pressing and gently applying more force), although I did use a light blow with a hammer to free the one on my 750.
1972 CB350F (Back from the Dead!)- http://forums.sohc4.net/index.php?topic=20822.0
1965? S65 - Coming Eventually!
1972 CB750K2 (father-son project)
1976 CB750K6- (sold) http://forums.sohc4.net/index.php?topic=96859.0
1976 CB750K6 (sold)- http://forums.sohc4.net/index.php?topic=62569.0

Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #29 on: March 25, 2011, 03:44:59 pm »
No bother. I don't know can't remember Paddy's Day ;D nah only joking I was a good boy, only 6 or 7 pints + some vodkas. It was pretty good here, hit the town about 2pm after the parade and stayed out til about 10 or 11, pubs were jointed though as they usually are for Paddy's Day here. Is there much interest for it in Canada?

Are you kidding? We Canadians love to celebrate anything that involves drinkin'! especially St Patricks Day... we skip the parade and go straight to the pub!
1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
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2007 HD Road King

Offline -CB-Jamie-

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #30 on: March 26, 2011, 02:29:24 am »

Well I'm pretty sure the nut is SS anyway. The bolt definitely is and I'm 99% sure the nut is. I don't know the first thing about welding so I wouldn't know how to do it. It's definitely welded though. The engine is back in the bike so it's a bit hard to get closer pics but here's what I got.


From your photos the nut almost looks J-B "welded" to the case.

Could be, I don't even know what J-B weld is. It works a charm anyway if the threads in the crankcase are completely stripped.

No bother. I don't know can't remember Paddy's Day ;D nah only joking I was a good boy, only 6 or 7 pints + some vodkas. It was pretty good here, hit the town about 2pm after the parade and stayed out til about 10 or 11, pubs were jointed though as they usually are for Paddy's Day here. Is there much interest for it in Canada?
Are you kidding? We Canadians love to celebrate anything that involves drinkin'! especially St Patricks Day... we skip the parade and go straight to the pub!

That's what I like to hear :D
72 CB350/4
76 CB400/4 CB400f "Project Resurrection"
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Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #31 on: March 26, 2011, 06:08:26 am »
I removed the top bolt, removed the cam chain tensioner bolt, started the bike, gently pushed down with an allen wrench through the top bolt hole... nothing moved... nothing! I tried a gentle push through the tensioner bolt hole... again nothing moved. Gave the bottom hole a long very skinny screw driver and with the engine running, and someone pushing through the top hole, gently tapped the screw driver... still nothing.
In the end, I could not get any movement what so ever in the adjuster to quiet the chain.

Becasue the bike has been sitting and not running for 10 years, could it be that the tensioner is stuck?

What do I do now??

I believe some time ago, Bodi posted a very good description of adjusting the cam chain tension.  Essentially you go about it as you describe, using some additional pressure for the springs, by inserting a small screwdriver or rod into the top hole with its plug removed. Bodi's post described how you may have to gently tap or hammer the rod/screwdriver end to free a stuck mechanism, but this has to be gentle and not too forceful since if the mechanism is stuck and something "frozen", you could knock it too far.  That would over-tension the chain and cause excessive wear or worse.

I was able to adjust mine as described, without resorting to excessive pushing and certainly without hammering on the screwdriver end that I inserted into the top hole.  Mine wasn't stuck and seemed to move readily.  I just added enough pressure to quieten the chain noise to an acceptable level and then, holding the pressure with the screwdriver, tightened and locked-down the adjusting screw.  All that was tricky with a hot, running engine, in-and-around the exhaust headers.  Then I saw someone else post a description of replacing the upper plug with a longer stainless bolt of the same thread pitch, and grinding down the end to allow it to go trough the hole and press down onto the end of the adjuster rod (instead of the small screwdriver).  The other end of this bolt was a slotted hex head (rather than a regular bolt head) that allowed easy access and careful turning/adjustment around the hot headers, so that you could adjust the additional pressure and hold it there while tightening the locking bolt below.  Similarly, this new stainless bolt has a nut to lock it in place.  I replaced my upper plug bolt with just such an item, as I fortuitously found a stainless, hex-head bolt in my toolbox that was just the right length and pitch.  (Don't know now what that was, but when you work on it you can easily figure it out...)  If the mechanism was "stuck" as yours sounds to be, then I would expect that rather than a risky whacking on the end of the rod through the upper hole, this stainless bolt (it really doesn't have to be SS) would make it easier to apply greater controlled force to free and adjust the mechanism.

Either way, you just want to go easy and not over-tighten the mechanism.  Just enough to quiet it some.  And, this is done with the motor running slightly above idle speed so that it doesn't surge or hunt.

Offline -CB-Jamie-

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #32 on: March 26, 2011, 06:45:54 am »
Hey HondanutRider, I had to do same as you describe here i.e. pushing a screwdriver through the top hole to quiet the camchain with gentle enough pressure and then lock it in place. I also came across that post about the bolt method before while searching and wanted to do it that way to make it easier. So I tried this before I used the screwdriver method but it didn't work for me. I threaded in the bolt a little way and then started the engine and started tightening in the bolt slowly, there was a bit of pressure on the bolt and I tightened it in a good bit but it was making absolutely no difference so I started worrying that I might be putting pressure on the spring without the mechanism working and that it might eventually give way and overtighten the camchain so I stopped and tried the screwdriver and that seemed to work ok.

I would prefer to do it using the bolt method as it's a bit easier and more accurate so could you tell me in a small bit more detail what you did? I didn't grind the end of the bolt or anything I just threaded it straight in as I thought the hole was the same size the whole way through and then it got bigger in further to act as a kind of stop for the spring but maybe I'm wrong so any advice appreciated.

Jamie
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Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #33 on: March 26, 2011, 10:54:27 am »
Jamie:

Sorry I don't have more info or even a picture of what I fabricated.  It's on the bike now and in the garage.  Besides, I never really tried to adjust the chain using this, at least not yet.  I had successfully adjusted it the other way so wanted to leave it alone rather than mess with it further.  I just found the adjustment tedious and saw what appeared would be a much simpler method - that and finding the correct SS bolt to use.  I do remember that I ground down the end of it somewhat to round off the threads, but to what extent I can't remember.  If I go trying to adjust using it now, it may work as you found - not at all.  In theory it should work fine if indeed the end presses onto the shaft as does a screwdriver inserted into the hole.  Perhaps it would be a good idea to actually measure the diameter of the hole at its bottom and compare to the threaded section.

Offline -CB-Jamie-

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #34 on: March 26, 2011, 11:42:29 am »
Ya that's no preblem, I'll have a better look at it when I have some ttime to spare.
72 CB350/4
76 CB400/4 CB400f "Project Resurrection"
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Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #35 on: March 26, 2011, 11:53:33 am »
Just had a chance in the cold garage to pull the bolt and have a look.  (Not easy to re-insert in the cold and all. :P)  It appears that I didn't grind the end down very much at all, and inserting various diameters of screwdrivers didn't give me a feel for the shape or diameter of the hole at the bottom.  So, perhaps mine will need some more shaping/grinding. :-\ :-\

Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #36 on: March 26, 2011, 01:44:06 pm »
Well guys, I gave it another attempt today!
I still can't get any movement in the adjuster.
I sprayed Sea Foam pentrating fluid - Deep Creep in the top hole and let it soak in. I placed a small long machine screw (#8x3") in the hole for a very loose fit and put an extension with a 10mm socket over the screw head and smacked it a couple of times with a hammer to see if I could jar it loose... nothing moves...
So then I put a nice long 8mm bolt in the top hole and tightened it down to 5 +/- ft lbs.

I am going to put some miles on it now and pray that it loosens up.

The chain rattles at idle but quietens down nicely with 1800 rpm or more.

Is there anything else I could do guys? Any suggestions are welcome!


1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
1999 XR400R
2006 CR230F
2007 HD Road King

Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #37 on: March 26, 2011, 02:46:36 pm »
I assume with all your attempts to "knock" the mechanism loose through the top hole, that the front-facing lock bolt was free?  If so, from what you describe it really does seem to be frozen, and I don't have anything else to suggest.

Looking again at your above post, I see that you say: "The chain rattles at idle but quietens down nicely with 1800 rpm or more."  You actually want to have it up at about 1800rpm to smooth it out and do the chain adjustment, looking for the rattle to quiet as the tension on the chain is tightened.  There is some noise anyways at low idle, as the chain rattles with the motor lurching at that lower rpm.  Perhaps your chain adjustment is good for now.
« Last Edit: March 26, 2011, 02:56:48 pm by HondanutRider »

Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #38 on: March 26, 2011, 03:45:20 pm »
I did have the adjustment lock bolt removed when working on it today. (I did almost forget to remove it when I started working on it though.) ;D

Perhaps it is adjusted pretty good now. I didn't know the rpm had to be that high... hhmm... the chain sure is noisy at 1200 though. "lurching" is a great description!
1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
1999 XR400R
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Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #39 on: March 31, 2011, 06:35:39 am »
Update-
I finally synced my carbs yesterday and I couldn't believe how important this is when chasing the cam chain rattle!! Even while synching I could get the chain to rattle more or less depending on how the balancing was progressing.

On the same topic, I was able to get some movement (I think) in the adjuster. Someone here (sorry but can't find it right now to quote) posted a process where you take an 8 x 35 bolt and grind down about the first 7 threads to about a 5mm diameter and use it in the top hole to push on the adjuster. I did this and was able to change the noise coming from the chain. What I am not sure about now is if the adjuster will "return" if I remove this bolt. I am going to remove it, insert a small screwdriver and then while watching it, remove the cam chain locking bolt and see if it rises up. I may even be able to push it down with my screwdriver now that I think I have some movement in the adjuster.

One thing for sure is that I am not too tight as there is a small amount of chain rattle at 1200 rpm after I synced my carbs. Not very much rattle at all, hardly detectable. It totally disappears when the rpm get up over 1800 or so.
« Last Edit: March 31, 2011, 06:37:15 am by DarcyCB400F »
1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
1999 XR400R
2006 CR230F
2007 HD Road King

Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #40 on: April 02, 2011, 02:23:05 pm »
Just had a chance in the cold garage to pull the bolt and have a look.  (Not easy to re-insert in the cold and all. :P)  It appears that I didn't grind the end down very much at all, and inserting various diameters of screwdrivers didn't give me a feel for the shape or diameter of the hole at the bottom.  So, perhaps mine will need some more shaping/grinding. :-\ :-\

I had an opportunity to reshape my "special" bolt and grind down the end according to some information posted by others.   It's now installed but I haven't done any further adjusting, as the current cam tension seems about right.  Here's a picture of what it looks like.   Perhaps someone can comment if this shape seems about right and similar to what they may have found works.

Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #41 on: April 02, 2011, 03:36:27 pm »
If that is an 8mm thread size, you have it the same as mine. I didn't use a socket head bolt; just a regular 8mm (12mm wrench).
Why do I see a gap in threads below the lock nut?
« Last Edit: April 02, 2011, 03:39:11 pm by DarcyCB400F »
1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
1999 XR400R
2006 CR230F
2007 HD Road King

Offline HondanutRider

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #42 on: April 03, 2011, 05:35:41 am »
There actually isn't any gap in the thread.  It's maybe just an illusion from the lighting or the grease I had put on it to "stick" the sealing washer onto it while installing.  I also put a dab in the socket hole so that the whole works would stay attached to the wrench while I guided it home.

Offline DarcyCB400F

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #43 on: April 03, 2011, 08:24:30 am »
Then I think you have it then.
My chain is quiet now so I hesistate to fiddle with my bolt but will anyway. I want to see if my special bolt is actually doing the job as I posted here earlier... I will remove it, and then loosen the locking bolt to see if the adjuster returns to the top of the blanking hole by inserting a screw driver and watching it.
« Last Edit: April 03, 2011, 08:27:12 am by DarcyCB400F »
1977 CJ360T
1977 CB400F
1980 CB900 Custom
1981 GS550L
1989 DR200R
1998 VT1100C2 ACE
1999 XR400R
2006 CR230F
2007 HD Road King

Offline fasturd

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #44 on: April 04, 2011, 03:53:16 am »
What you did with your bolt is pretty much what I did with mine. I ground mine to a slight dull point. I don't think I ground as much as you did but better safe than sorry. I used a SS allen and nut. I used the allen because it is easier to tighten especially if you have bondus headed allens. Remember you don't need to strong arm them just snug is correct. Obviously this trick will work with stripped threads too you will just have to re-thread in the next available size.

Good luck.

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Offline 77Pinto

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #45 on: April 21, 2013, 03:43:04 pm »
I found this thread, and my issue leads me to think there is a reason why that hole gets damaged....

The adjuster nut/bolt on mine is doing nothing but plugging the hole.  If I back off the locknut I can turn the bolt into the engine all the way to the collar to where the nut threads start.  I verified this by inserting a small torx screwdriver, and pressing into the lower hole with it while the bike is running made no noise difference.  As of right now I have not attempted to remove the upper bolt or press down on anything there, but I did attempt to press in the lower hole; no movement.

I can see why people have the lower engine holes stripped out, as people might just crank down on the bolt thinking if they twist it 'just a little more' the chain will stop making noise.


Bill
« Last Edit: April 21, 2013, 04:13:26 pm by 77Pinto »

Offline stevej

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Re: cb400 cam chain adjuster thread gone. Suggestions please!!
« Reply #46 on: May 26, 2013, 02:41:51 pm »
Hi all, ive recently purchased  an American import cb350f that hasnt run any distance for proberably 20 years it was sold to me as a non runner but with fresh petrol clean carbs tappets set and a full service  its running great but sounds like a tractor compared to my 550k. I have tried the cam chain tensioning statically also with engine running and eventually using pushing the "rod" method  during which I can feel the chain vibrating through my rod but no change in engine clatter.Any ideas  please steve
1974 cb350f,   1980cb550,  1990 Zephyr750