Timing- / cam-alignment, new CCT's, valves...

[vivec]

Meh... same thing. It turns around (smoother than in 6th), but it still just 'stops' at a certain point. Then I can turn it around the other way round just fine, but that stops too again. Not rough, but just from moment to moment no further turning motion possible...

[gabi81]

Check tension on chain when it stops if too tight loosen cct and try turning again. If it would be me id start doing ccts again and check timing at tdc

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[vivec]

no no, there are NO CCT's in. The cam lobes are loose (or even out, on the front) and the cam chain is loose on both cylinders!

In other words; the valves are up all the time, and the cams aren't even turning round. The chain is, because I'm turning the crank.

I'm trying to crank the engine full revolutions and that 'stops' at a certain point.

Both camchains do move, so they have to be 'around' the crankshaft cog... right?!

situation:
- neutral gear
- cams are loose or even out (front cylinder)
- camchains are lying loose
- CCT's are out (physically... out of the engine / bike)
- sparkplugs are out
- alternator cover is off (that way I can crank engine, alternater cover nut is fixed shut)
- oil is out

I can turn the engine like 270 degrees both ways, and then it just stops.
Engine turns gently too, no force needed, no strange sounds, no grinding, nothing... until it simply suddenly stops turning.

I started thinking the rear cylinder valves might be bent (fronts have been replaced), but that's actually impossible since the camlobe clearance is right into spec. So valves should be seated quite well (and not touching piston).

[sirch345]

no no, there are NO CCT's in. The cam lobes are loose (or even out, on the front) and the cam chain is loose on both cylinders!

In other words; the valves are up all the time, and the cams aren't even turning round. The chain is, because I'm turning the crank.

I'm trying to crank the engine full revolutions and that 'stops' at a certain point.

Both camchains do move, so they have to be 'around' the crankshaft cog... right?!

situation:
- neutral gear
- cams are loose or even out (front cylinder)
- camchains are lying loose
- CCT's are out (physically... out of the engine / bike)
- sparkplugs are out
- alternator cover is off (that way I can crank engine, alternater cover nut is fixed shut)
- oil is out

I can turn the engine like 270 degrees both ways, and then it just stops.
Engine turns gently too, no force needed, no strange sounds, no grinding, nothing... until it simply suddenly stops turning.

I started thinking the rear cylinder valves might be bent (fronts have been replaced), but that's actually impossible since the camlobe clearance is right into spec. So valves should be seated quite well (and not touching piston).

Unless I have misunderstood you, it sounds to me the cam chain or both even are jamming up around the crank sprocket. You should have both CCT's fitted to take the slack out of the cam chains first before trying to turn the engine over,

Chris.

[vivec]

I'm thinking this too...
I just had the front head off to fit new intake valves. I now wanted to place all cams at their correct timing (starting with rear) and so turned the engine, alle chains loose, all CCT's out, just wanted the correct 'RT_' mark on the flywheel to come by .

Since there can't (never say never...) be anything jamming up top, it has to be at the lower part of the engine.

Gawd... I have to remove the flywheel, don't I ?! ;)

[gabi81]

Lifting the chains with something to put a bit of tension on them is gona allow u to turn the engine over. That being u should refit all back before turning the engine

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[vivec]

@gabi81, you think? Will they magically refit well around the crank cog / sprocket ;)? I do hope so, so I'll at least give that at try.

Lesson learned anyway; don't turn engine while chain has too much slack...

[sirch345]

I'm not sure why you removed both CCT's when the rear valve timing had not been changed by the front CCT failure. If you had left the rear cylinder CCT where it was you should have been able to keep the front cam chain taught while you turned the engine over,

Chris.

[vivec]

Well, it went like this:

- Front head was off, valves replaced. Of course all cams off, chain off, CCT out. Rear was untouched and in order!

- Refitted front head, tried to turn engine over... didn't work... sooo... well... rear cylinder chain looks quite tense... Let's see if I can turn over engine if I also loosen that one...

You see ;). It's not that I just removed everything because I like removing things. It's 'a path I am on' these days .

Also, CCT's where the original Honda ones, so they're being replaced by manuals too. Had to come out anyway.
I just didn't realise the consequence of slacking those chains too much...

[gabi81]

Its not a major problem...refit rear and front using autos and restart procedure to fit manuals...nxt time do them one by one always start with rear even if not damaged or untouched.

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[Pete.L]

I had the same thing happen to mine.
The chain slipped and went slack when I had the cams out.
It jammed on the crank sprocket. I managed to free it off by turning the engine over backwards whilst pulling like hell on the chain.
Might be worth a go before you strip everything

Pete.l


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[sirch345]

Well, it went like this:

- Front head was off, valves replaced. Of course all cams off, chain off, CCT out. Rear was untouched and in order!

- Refitted front head, tried to turn engine over... didn't work... sooo... well... rear cylinder chain looks quite tense... Let's see if I can turn over engine if I also loosen that one...

You see ;). It's not that I just removed everything because I like removing things. It's 'a path I am on' these days .

Also, CCT's where the original Honda ones, so they're being replaced by manuals too. Had to come out anyway.
I just didn't realise the consequence of slacking those chains too much...

Ah I see

Now you know where you've been going wrong, hopefully you'll be able to start getting it back together successfully,

Good luck, I hope it all goes well,

Chris.

[vivec]

@gabi81 and Pete.l and Chris you hero's you! Simply pulling the top end of the chain did the trick.

I did have to rotate the crank clockwise for a bit, but I'm just hoping it won't pose too much of a problem.

I then refitted cams, chains, cam-clamps... whats the name and of course the MCCT's. Tightenend them and then tried to rotate the engine.

AND IT DOES!!! IT REALLY DOES!!! . Pretty very really well too!

I can tell that the (new) front intake valves need different shims. Putting them in, I could already 'feel' that they where 'up higher' than their sisters at other valves. This resulted in the engine having a bit of difficulty while the camlobe passed that 'bucket'. Not much more, but noticable when cranking slowly by hand.

Anyway, that's a worry for further up this week (shimming all valves / buckets).

Thanks already for all your help. Simple things like 'just pull the chain' are invaluable for someone who's not that technical and sometimes affraid to put force on things while the private parts of the engine are exposed .

[Pete.L]

Good man. Hopefully it's all plain sailing from here

Pete.l

[sirch345]

Unless I have misunderstood you, it sounds to me the cam chain or both even are jamming up around the crank sprocket. You should have both CCT's fitted to take the slack out of the cam chains first before trying to turn the engine over,

Chris.

And there's me thinking it was I who pointed out the error of your ways

Glad to hear you've got it sorted now

Chris.