Author Topic: '77 CB400F - it runs!  (Read 550 times)

Offline SeanFD

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Re: '77 CB400F - it runs!
« Reply #15 on: September 03, 2020, 03:25:38 PM »
I’m jealous; you are where I want to be, without the cam chain problem of course. Well done.

I read somewhere that it is possible to “fix” a non-functioning adjuster by, essentially, doing just what you said.

You plug off the adjuster bolt and use a longer bolt with a locknut in the oil cap channel to push down on top of the adjuster rod until the noise goes away. The tighten up the locknut.

So I guess it wold be safe enough to try. It won’t work if the horseshoe is seized or if the chain is over-stretched, as Julie says, I suppose, but it might work if the horseshoe is just a bit sticky.

Oh and no, I didn’t try it. I fixed the adjuster bolt etc.
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Online taysidedragon

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Re: '77 CB400F - it runs!
« Reply #16 on: September 03, 2020, 03:49:23 PM »
Gareth,
Looks familiar!!!
When I finally got the 400 running the other week I was so keen to just sit on it I forgot that wearing shorts isn't a great idea near a piping hot exhaust - nice burn to remind me next time!
Cheers,
Andy

Ouchy! Stings doesn't it. 😯
Gareth

2010 Street TripleR
1977 CB400F

Offline mattsz

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Re: '77 CB400F - it runs!
« Reply #17 on: September 03, 2020, 04:06:21 PM »
I’m jealous; you are where I want to be, without the cam chain problem of course. Well done.

I read somewhere that it is possible to “fix” a non-functioning adjuster by, essentially, doing just what you said.

You plug off the adjuster bolt and use a longer bolt with a locknut in the oil cap channel to push down on top of the adjuster rod until the noise goes away. The tighten up the locknut.

So I guess it wold be safe enough to try. It won’t work if the horseshoe is seized or if the chain is over-stretched, as Julie says, I suppose, but it might work if the horseshoe is just a bit sticky.

Oh and no, I didn’t try it. I fixed the adjuster bolt etc.

Certainly worth a try... to that end, I took a chance and ordered this "manual cam chain adjuster" bolt, made by our friend Kevin from TTR400.  It basically does the job you describe above, and is much more controllable than just inserting some kind of rod down into the opening and just pushing by hand.  As long as I can maneuver my tools in between the header pipes and frame openings...

Worst that can happen, I guess, is that it won't work and I'm out $20.  Or is it?  ;)  At least it will help me diagnose the issue...

Offline Johnny4428

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Re: '77 CB400F - it runs!
« Reply #18 on: September 03, 2020, 04:37:30 PM »
That is not good! OUCH!
1952 Cymoto on Triumph bicycle.
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Offline mattsz

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Re: '77 CB400F - it runs!
« Reply #19 on: September 04, 2020, 08:35:29 PM »
Update - the manual adjustment bolt came last night.  It was a bit fiddly, but today I was able to get it installed and found a way to get some tools on it without burning myself.  It seems to have worked quite well - I slowly tightened down on the adjustment screw and the rattle slowly quieted down:

https://youtu.be/GEFcueAWPXM

I'm not sure if this is where it really wants to be, but it's so much quieter after tightening just a bit that I'm going to ride it a few miles and see what happens...

Offline Macabethiele

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Re: '77 CB400F - it runs!
« Reply #20 on: September 06, 2020, 09:55:05 AM »
So pleased for you that its running.  :) :)

I plan to be where you are by the end of this month.
I know I bought mine with a declared cam chain rattle - I just don't want any other nasty sounds.
When the frame is being powder coated I will then sort out the cam rattle, take the head off, check piston tops etc.
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Offline mattsz

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Re: '77 CB400F - it runs!
« Reply #21 on: September 06, 2020, 11:35:13 AM »
So pleased for you that its running.  :) :)

I plan to be where you are by the end of this month.
I know I bought mine with a declared cam chain rattle - I just don't want any other nasty sounds.
When the frame is being powder coated I will then sort out the cam rattle, take the head off, check piston tops etc.

Thanks Macabethiele!  And, sorry for cluttering up your shiny new project thread with all that petcock talk, we really should have moved it somewhere else!  :-[

My time-frame has been a bit longer than yours... I got the bike almost 2 years ago!  And I haven't done any major work on the engine, it's just been puttering with many, many odds and ends just to get the bike road-worthy to see if the engine works...

 

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