Cam chain gets loose when rotate crankshaft

[vaggmak]

I put cylinder head back on the engine and timing the engine as manual says but when i rotate crankshaft the cam chain gets loose(watch video) ... Do you know hwy this happens?its gs550

https://youtu.be/SaDfiTnlISw

[Gorminrider]

It is very hard to turn the engine smoothly by hand... Removing the spark plugs will help. Also, a longer wrench will help turn the engine slowly....sometimes, you can slip a piece of pipe over the wrench to make it longer, or some other way to "gain leverage".

[vaggmak]

Thanks for reply but my question is why the cam chain gets loose...

[Rich82GS750TZ]

What, if anything, have you done with the automatic cam chain tensioner? Also, what bike year and model? Please put this info in a signature.

[tom203]

I’d suspect the tensioner too....do understand how to reset and reinstall it? Seems to confuse lots of people

http://members.dslextreme.com/users/storagecliff/images/engine_odds-n-ends.html#A06

[vaggmak]

Should chain tensioner move back without turn the knob?https://youtu.be/7NsE9C8ArMw

[Gorminrider]

No. In operation The chain tensioner moves out to apply MORE tension as the chain wears but does not move back unless you turn the large knurled nut... The chain tensioner is only really "locked" to remove it.
That said, the blade that contacts the chain is a bit flexible and springy. Turning the crank forwards and backwards a little will show a little slack across the cam sprockets. That is why I told you to turn it smoothly ( forward).

Still, if you think it's too much,
There are many threads here about the chain tensioner AND it is explained quite well in the shop manuals some of which are here:BikeCliff's Website

The best are the real "Suzuki" manuals. Clymer and Haynes may not explain it as clearly. If you can't find the exact manual, look for one with a similar engine because the tensioner is the same on many.

[vaggmak]

Thanks a lot👍👍👍👍👍

[Gorminrider]

further note:just because it comes up here the odd time: You want to be careful if you get diverted into "manual adjustment"...too tight might burn off or break the plastic face of the tensioner blade and they are $$ and difficult to replace on some bikes...tensioner just keeps the chain on the sprockets as the engine runs but not so loose as to rattle or whip at the engine case. That's why the self adjusting ones are nice to have, when they are working right.

Really, it's A very similar principle to the drive chain that spins the rear wheel...