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Hello all. I'm posting in the Daytona sub thread because the ST thread was for the new 765.

I'm about to replace the hydraulic cam chain tensioner on a high mileage 2015 ST3 R. I have the workshop manual (see clip below). The manual says that when installing a new tensioner "do not release the plunger" before install. It goes on to say to remove the wedge and the pin, rotate the engine 1/4 turn anti-clockwise, then rotate two full revolutions clockwise. This apparently engages the plunger on the hydraulic tensioner.

However, the manual also says in bold that the tensioner will be empty of oil on start up and that the blade/chain may be noisy for the first 5 seconds or so until the plunger feels oil pressure.

Here is my concern, there is a probability that the chain is already stretched. What is there to keep the chain from jumping a tooth while I hand rotate the engine with the tensioner not yet engaged? Also, assuming the hand rotation sequence releases the retaining clip and the tensioner goes under some spring tension, isn't there a chance of the chain jumping time in the 5 or so seconds it takes to build up oil pressure in the tensioner?

I would be less concerned if I were taking out the cams and installing new chain and blades but I was thinking of just changing the tensioner and tension blade first. If the chain is stretched on this 70K mile bike there seems to be a good chance that I could slip a tooth before the new tensioner self adjusts. Does anyone have any experience with this?

Thanks

719103
 

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I've got experience from setting the valve clearances on my 675 Daytona which will be the same tensioner I imagine.
You should keep your wedge in against the tensioner blade after fitting the cct to maintain the tension on the chain until you've rotated the engine and heard the tensioner click, only then do you remove the wedge.
I turned mine over on the starter with the fuel line disconnected until the oil pressure built up, mainly to get oil around the cams but you could do that if you are worried about the hydraulic tensioner, I doubt very much the chain could jump though.
I used these videos from muddysump, an ex-Triumph mechanic, made it seem easier than the manual.
Resetting the tensioner
Skip to near the end of the second video where he refits the tensioner.
 
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