Timing of cam chain correct? (solved)

[deltarider]

Honda didn't offer much help as far as the do's and don't's. In Holland in those years Honda dealer mecs were invited once a year at Honda The Netherlands for instruction. No doubt they have had additional instruction on how to treat the camchain tensioner. For us, amateurs, Honda left a puzzle. Honda never made clear whether adjustment was best done with the engine cold or warm. Also the instruction varies. Compare p.48 of the Owner's Manual CB500K1 https://www.honda4fun.com/dwnload/Owners-Manual/CB500-K1-Owners-Manual.pdf,
p.12/13 of the Shop Manual Honda CB500-550, http://manuals.sohc4.net/cb500/service_manual/HSM500550_1.pdf
p.68 in the CB550K3 Owner's Manual https://www.honda4fun.com/dwnload/Owners-Manual/CB500K-CB550K-Owners-Manual.pdf and
p.3-7  in the manual for the CB650 https://cosky0.tripod.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=https://cosky0.tripod.com/sitebuildercontent/sitebuilderpictures/page03-07-cam-chain.jpg&target=tlx_new.
Four different methods...
Oh... and I do have an opinion on the design. It's poor. I've never managed to do more than 45.000-50.000 km with one.

[Oddjob]

I'm on the same camchain tensioner from new, blades been replaced more than a few times along with the damper rubbers at either end. It's done around 147000 miles at present and it will be refitted once the engine comes apart this summer. It's a matter of how you use it IMO. Do it right and it seems to last forever. I do seem to recall replacing the spring once but that might be the K reg bike not the L reg.

[deltarider]

Well... I certainly can learn from you. IMO the whole thing lacks robustness and a mistake is just too easy to happen. If even the mere replacement of the locknut by a new one, is a risky affair... I sure hope there will be an aftermarket one that's more robust. Pro mecs have also struggled with it. Honda The Netherlands gave them extra instruction, but left us amateurs the puzzle of four different methods.
I suppose the method in the CB650 manual is best. What would be best: engine warm or cold?

[Bryanj]

Dont matter just do it the right way and dont force the sxcrew and there is no problem, only problem with nut is if s~mebody has forced the screw and splayef the end open which is again bad operation by an idiot owner and nothing to do with Honda

[deltarider]

Thanks for the compliment, but mecs here were of a different opinion. They also told me the 5000km interval of adjusting the tensioner (as in the maintenance scedule) is a joke. It needs to be done much more frequently. In my 100.000 km experience at least every 1500km. They also strongly advised not to do it the way described in the K3 Owner's Manual. Two of the mecs had a CB500 themselves.
A screwdriver can be needed to keep the bolt in position while tightening the lock nut. Even the slightest and unnoticed widening of that gap may later - when you have completely forgotten about it -  hinder replacement of the nut by a new one. When you then start to wonder, why the nut doesn't come further of, it's already too late and the damage is done. If that can happen, in spite of warnings, I'm sorry, but then the design is poor. Yes, lesson learned, but at what cost...
Never damaged a tensioner yourself, Bryan?

[Bryanj]

Ive fixed a few but never damaged one, i found the 3,000 mile service ok if you made surr the front run was tight so all the slack in rear and that was advised by the UK travelling Honda techs, we didnt get annual training

[deltarider]

IMO the design is too close to the racers our models derived from. The CB350F tensioner was even worse. Before models came to the market, they were thoroughly tested ofcourse. But what Honda never was able to test is, how things would be after six months of inactivity. If you try to adjust a CB350F tensioner, after six months of hibernating, well, good luck!
The method you was told, was also the instruction Dutch mecs received from Honda The Netherlands. The public was never informed though. That method is good, be it that the mec I've learned it from, always asked a collegue to assist for a second. Amateurs like myself I'd advice to do it with plugs removed, for a good feel, because the compression could fool you. Or do it as described in the CB650 manual, turning the crank extremely slowly, so you are sure.

[peterengland]

Why are you not supposed to turn the engine with the big nut at the points? I know it's been mentioned before but can't find anything relating as to why not.

[deltarider]

Peter, I've been using that nut to turn the crank for the last 42 years. What you refer to is the usual mass hysteria in the international forum, once one high in the pecking order has warned against it. That will be echoed by the others. Ofcourse you can do it wrongly, but if you use a T-handle like shown below, you can even do it when the engine is red hot.

[Bryanj]

The reason why is that with plugs in you can easily break the "ears" off the cam and elongated the hole the locating pin fits in. I have seen both but never done it myself.

With no compression (plugs out) it ought to be safe to use BUT putting that caveat in an explanation people either dont read, dont understand or dont care.

How many owners of cars with broken cam belts have ignored the OR FIVE YEARS bit

[McCabe-Thiele (Ted)]

The reason why is that with plugs in you can easily break the "ears" off the cam and elongated the hole the locating pin fits in. I have seen both but never done it myself.

With no compression (plugs out) it ought to be safe to use BUT putting that caveat in an explanation people either dont read, dont understand or dont care.

How many owners of cars with broken cam belts have ignored the OR FIVE YEARS bit

What do you mean by "breaking the ears off the cam" please Bryan?

[Oddjob]

There are 2 ears on the advance/retard mechanism Ted, these are so the nut locates properly and allows the nut to turn the mechanism if required, if you force the nut there is a chance these will shear off.

I regularly used to use the nut to turn the crank, hard not to when your watching the points for opening/closing etc but I always removed the plugs first so the effort required was much less.

I ditched the bike one night coming down a steep hill with a 90 degree bend at the bottom, the council had tarmaced over cobble stones and they was an area where they were exposed, I didn't see it in time and being cranked over to the max the bike just went away under me, skipped up a kerb island, through a bus shelter, luckily one of those sheet metal types, scattering the waiting queue who were luckily watching me rag the 500 down the hill (I was young and an idiot), fell off the kerb island into the bus stop and stopped. I was already walking toward it before it stopped, picked the bike up and the points cover was mashed flat, removed that and spotted the advance/retard mechanism was bent to hell and back, removed the bolt, smashed it flattish and reassembled everything whilst bleeding all over the floor, bike started on 2 cylinders but got me home. Second hand mechanism later and good as new, really built these bikes to take punishment. The ears were still ok though so it takes some force to break them off.

[deltarider]

The steel of the ears is much harder than that of the WASHER,SPECIAL (Hondaspeak for that nut, PN:30233-300-000). I've learned about risks turning that nut on the CB750, but the CB500/550, mwah, if you do it with care...

[Bryanj]

Its is harder, but they still break off seen quite a few after owner maintainance done wrong.