Cam chain tensioner – Part 3 ….. Judgment Day!

Aprilia Caponord ETV1000 Rally-Raid cam timing chain tensioner AP0236252 AP0236253A few days ago the two new cam (timing) chain tensioners (AP0236253) arrived ……. and as if she knew, the Capo started to rattle the rear cylinder for a second or two at almost every start-up! So as soon as we got home yesterday, it was off with the bike kit and into the workshop-wear and time to seriously twiddle some spanners.

Thankfully the rear tensioner is nice and easy. Fuel tank up, pop out a couple of spark plugs to make rotating the rear cylinder to top-dead-center nice and easy, then rummage under the wiring on the right hand side and find the cap requiring a 6mm hex-key.. Remove the cap and the copper washer underneath and then use something pointy to hook the tensioner out enough to get a grip with podgy fingers.

Aprilia Caponord ETV1000 Rally-Raid AP0236252 cam timing chain tensioner INA F-46807The tensioner shows definite signs of movement and rotation and the plunger could be pushed in about 1/2 its travel ….. I think FUBAR best describes it! The new tensioner was oiled up and before it was dropped into the motor I did a little experiment. Both old and new parts were flushed and filled with new 15w/50 and gently pinched in a vice. The new tensioner remained snug for a long time, only a small amount of oil could be seen coming out ….. next up the old one. This remained snug for no more than 1-2 minutes and oil could be seen leaking from it the second it was compressed. So all in all a major difference in performance between old and new.

Aprilia Caponord ETV1000 Rally-Raid cam timing chain tensioner AP0236252 AP0236253After a few more jobs were carried out, it was buttoned together and warmed up …. no rattles and in fact the idle was smoother than it has been in a while.

The tensioner that came out is an original Mk1 (AP0236252) that was superseded by the new version a good few years back. From what year they were fitted as standard I don’t know. Looking closely at the old one I found ‘INA F-46807’ printed around the edge. I can’t find much about it unfortunately. However ……..

……. I did find something that might be of interest. It looks like the tensioner fitted to the BMW 650 (late models) and F700/800 bikes could well be the same. Now this can only be corroborated by direct comparison, so I might tout the other new Aprilia one around a few BMW dealers to see if I can find out if they match. If they do fit, then they are available for substantialy less than the £68 each from Aprilia.

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