Camchain adjuster

[Sprocket]

Hi - silly question, perhaps. Is the camchain adjuster bolt at the front of the engine supposed to be completely perpendicular to the front of the crankcases? Mine was definitely a little skewiff, and when I looked inside I can see the original drilling is at a bit of an angle. So I can see the merit in either being correct.

[Nurse Julie]

You may be able to see from this picture what angle the adjuster bolt should sit at [ Guests cannot view attachments ]

And another pic side on [ Guests cannot view attachments ]

And another
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[Athame57]

If the upper angled bolt is the camchain adjuster what is the other one below it? Confusing.

[Nurse Julie]

If the upper angled bolt is the camchain adjuster what is the other one below it? Confusing.

The locking device for the adjuster.
No's 12, 16,17,18. If you don't lock it in place, the bar will not push on and tension the horse shoe and in turn will not tension the blade against the chain.
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[Athame57]

OK..so with engine ticking over...I slacken that, then slacken the camchain adjuster...tighten the former again and tighten camchain adjuster?

[Sprocket]

I'd be interested to know the proper process too. But as I see it, the top bolt just holds the end of the adjuster in place, it's the one on the front of the engine that you would be slackening, allowing to take the slack then re-tightening?

[Nurse Julie]

It is only the tensioner adjusting bolt (with lock nut) No.12, that you loosen and re tighten. You do t touch No.11 at all. For this procedure No.11 is of no consequence. If the horse shoe is jammed or the cam chain is knackered and at its maximum, some people remove bolt No.11 and push something down the hole to try and get more tension but, it achieves nothing if the horse shoes is seized (which is a very common problem on these engines) or the cam chain is beyond service limit. The only way to resolve these problems is to take engine out and renew everything.

This is from the shop manual.
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[Clem2112]

The only real fault with the design of this engine is that mickey-mouse tensioner.
Why they didn't put it at the rear of the block like all other fours only Honda know.
Possibly, the designers thought it was a too tight a squeeze to access the thing beneath the carbs?

 I think the owners' handbook describes that to tension the chain, the engine should not be not running but rotated to TDC on one pair of cylinders, before loosening then re-tightening the adjuster bolt. Might work on a newish engine but I was shown how to do it with the motor idling and applying gentle firce down the top with a small screwdriver to help it as the springs apparently lost tension after a while.

[Athame57]

Sounds like a bodge, for those without the means just now to do the whole job, can a new camchain be threaded through by splitting and joining links?

[Nurse Julie]

Yes, you buy a 'soft link' chain as a replacement (one with a join) but you still have to cut the old one to link in the new one. (Edit....assuming you don't have a soft link fitted already. Standard chain solid, not split)  It also does nothing to sort out a seized horse shoe if you have that problem also. Horse shoe, =engine apart job.

[Greg65]

An example of a jammed horseshoe. Cam chain has made contact!

[Bryanj]

Greg, that was the way most 400 and the 250 G5 cam out back in the late70's mate

[Greg65]

Ooooh I’m normal, ish. 

[PatM]

Yes, you buy a 'soft link' chain as a replacement (one with a join) but you still have to cut the old one to link in the new one. (Edit....assuming you don't have a soft link fitted already. Standard chain solid, not split)  It also does nothing to sort out a seized horse shoe if you have that problem also. Horse shoe, =engine apart job.

Julie- I know we spoke about this last year and your post/advise fills me with sorrow! Im sure mines jammed.
I had the engine out 9 years ago but only had the sump off- noting lots of ally-filings, but after 30 years, I wasnt surprised...

[Nurse Julie]

TBH Pat, by the sounds of it there aren't many horse shoes that aren't jammed at the pivot. I suppose its a case of if its not rattling too much, live with it but the rattle will get worse as the chain stretches even more through use. Mine was jammed on my 400/4 when I stripped the engine (not the reason for the overhaul) but I only had a very quiet rattle but it would have got worse, not any better in the long run.