Cam Chain Rattle.

[Our Gee]

Having recently returned to the RT owner's fold and having previously owned an 1150 Twin Spark, a couple of Hexheads a Twin Cam, I am all to familiar with Cam Chain "Rattle" when starting from cold, especially after the bike has been standing for a while. As my "new to me" very low mileage Twin Cam also displays this trait I have been trying to gain more info on this apparently "harmless" but annoying BMW noise. The general feeling seems to be that when the bike is left for some time oil drains from the Tensioner and after start-up it takes some time for pressure to be re-instated which in turn applies pressure to the chain / guide. However, looking at the various pictures and videos of Tensioner replacement I notice that the Tensioner is a pretty simple affair consisting of a plunger / piston with integral spring which is housed in a screwed sleeve. My question is as follows, Is the tension applied purely by mechanical spring pressure or indeed by oil pressure as suggested by the oil draining away during prolonged non running.
Thanks.

[Beagle]

The right tensioner seems totally different to the left, no obvious spring as in the left one.
Maybe its the right one that relies on hydraulic pressure.

[Beagle]

Looking on the net its claimed its the left side that rattles and this is claimed to help,


https://www.euromotoelectrics.com/product-p/camtensioner797.htm

[Our Gee]

The right tensioner seems totally different to the left, no obvious spring as in the left one.
Maybe its the right one that relies on hydraulic pressure.

Looks like those sketches are for the W.C. engine with both Tensioners positioned underneath the cylinders ?.

[David.]

Looking at the Haynes manual (2.21),  the LH and RH cam chain tensioners are different. The LH being spring loaded whereas, the RH "appears" to be of a hydraulic design, similar to this found in an 1150.

https://www.youtube.com/watch?v=jBgO_Fbn02A

What viscosity is the engine oil, this MCN article recommends 20w-50 or 10w-50, https://www.motorcyclenews.com/new-ride ... t-rattle-/

[Beagle]

Looking at the Haynes manual (2.21), the LH and RH cam chain tensioners are different. The LH being spring loaded whereas, the RH "appears" to be of a hydraulic design, similar to this found in an 1150.

Thats what I said in my above thread.

[David.]

The OP has a Camhead not a Wethead or a Hexhead, they are all different.

[Our Gee]

Dear me, this is confusing. If the Left side Tensioner is indeed a purely mechanical device as looks to be the case following David's "Haynes" link info then the initial "Rattle" can't be down to a delayed "Oil Pressure" build up as this device looks to work on Spring pressure only which one would think would be constant. If this is the case why does the rattle noise fade away after a short period of time.

[Beagle]

The OP has a Camhead not a Wethead or a Hexhead, they are all different.

Does the Camhead have a spring loaded tensioner on the left and a hydraulic on the right?

[David.]

The RH tensioner is hydraulic and appears to require engine oil pressure to be fully functional.

[Beagle]

The RH tensioner is hydraulic and appears to require engine oil pressure to be fully functional.

Isnt that what my thread informed?

[David.]

Please can you post some details of the LH & RH cam chain tensioners for a 2011 Camhead.

An explanation of why there is a rattle on start up which disappears shortly afterwards would be helpful too, thank you.

[Beagle]

Does this pertain to the OP,s engine




[size=x-small]the LH and RH cam chain tensioners are different. The LH being spring loaded whereas, the RH [/size]"appears"[size=x-small] to be of a hydraulic design, similar to this found in an 1150.[/size]

[Our Gee]

Managed to find a link to a series of pictures showing Tensioner (both sides) replacement on what looks like an R1200 Twin Cam Engine of the 2010 / 2013 vintage. (Like Mine). CORRECTION. The engine shown in the pictures is a Hex Head, not a Twin Cam.
These pics clearly show the Right Side (underneath the cylinder location) to be the Spring type and the Left Side (top of cylinder location) to be the Hyd. Type.
All of which is going against the present understanding of just what we actually have. Sorry if this only goes to ad further confusion as it does look the opposite to the Haynes set-up.




http://viethorse.com/site/en_US/2017/02/11/tensioner/


Incidently, note how the chap in the pictures changed his Tensioners just after a River crossing with Muddy water and Grit all over the engine !!.

[David.]

This photo is of the LHS cylinder on a Hexhead.



The Haynes manual for a Hexhead also confirms that the tensioners are opposite to those fitted to a Camhead.