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Discussion Starter #1
2013 F4 RR regularly maintained 12km was done have been having issues with the timeing chain tensioner has it fixed once now 500km later it sound like it backed out again its the ratchet style and the last one would not go past a cretin point , not putting pressure on chain now a new one was installed and sounds like its done it again !! I do not race the bike or over rev bike I am a conservative rider and love the bike but its becoming a real pain in the ass never mind the cost !!
 

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That's an unusual problem since the early F4 bikes...... Normally, when a cam chain tensioner fails it will allow the cams to jump time with catastrophic results. It is a very simple mechanism.

Is it just making rattling sounds at idle or decel? Are you doing the work yourself? You can take the central bolt and spring out and use a drift punch to force the tensioner forward.
To inspect it, first set the crank at TDC #1 and tie the chain to the cam sprockets with zip ties or safety wire so they can't jump time and remove the center bolt and spring. Then remove the unloaded tensioner from the head. You will see just how far out it has moved, and can see what may have happened if it is not holding.
 

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the first one I had that failed had gotten stuck and would not extend out any further upon inspection by my mechanic we found that the chain had slack causing it to jump a bit ! but not so much that the chain would jump a tooth , we then inspected the tenisioner and found it to be the issue . bike sounded like a ducati dry clutch but still ran fine

this one in my bike now is the new style black casing ones from proitalia same as stock one just a revised one this was installed in my bike no issues for 300km then got home and heard the dreaded rattle again I am sure its the tensioner again ! i even think i was hearing it clicking back while rideing ?? anyways this is a pain in the ass too fix so back to the shop !
i am seriously thinking of taking my old one to a machine shop and have a look at making it a manual type tensioner !
still using the mv parts just eliminating the spring and push rod held in by center bolt ,maybe have a bolt threded into that area with a manual adjustment bolt this will work for sure
other than that i am not monkeying around with these tensioners any more there has to be a reason thay are backing off or not extending and we cant figure out why ??
 

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That's an unusual problem since the early F4 bikes...... Normally, when a cam chain tensioner fails it will allow the cams to jump time with catastrophic results. It is a very simple mechanism.

Is it just making rattling sounds at idle or decel? ...
this one in my bike now is the new style black casing ones from proitalia same as stock one just a revised one this was installed in my bike no issues for 300km then got home and heard the dreaded rattle again I am sure its the tensioner again ! i even think i was hearing it clicking back while rideing ??...
Not sure how to interpret this ^^^, I get a rattle when idle but when the clutch is pulled in the rattle stop, everyone that I have spoken to said this is normal on an MV...
 

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Discussion Starter #6
mv

Not sure how to interpret this ^^^, I get a rattle when idle but when the clutch is pulled in the rattle stop, everyone that I have spoken to said this is normal on an MV...


I am going to try to drift the ratchet in one more tooth if I can its very tight with the rad in the way maybe a longer spring rod and stronger spring would help ?? I am puzzled by all this cant wrap my head around how it would back off ? it was fine when I picked it up from the shop 300 km later it was a ducati dry clutch sound same as before with bad tensioner , my last tensioner was stuck no going out far enough


any suggestions how to get a drift pin the there without removing the rad ?
I amsure its not going to take much force to push it out one tooth or 2 I am very handy with tools but I am older now and want to enjoy my toys not fix them \lol
 

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Not sure how to interpret this ^^^, I get a rattle when idle but when the clutch is pulled in the rattle stop, everyone that I have spoken to said this is normal on an MV...
If the sound goes away with the clutch in it is NOT the cam chain tensioner. You are hearing the straight cut gears on the primary drive. With transmission gear drag to take out the lash the sound goes away. When the clutch basket is freewheeling without the drag of the transmission (clutch lever pulled in, clutch disengaged) the primary gear lash creates a rattle sound...NORMAL !! Ride on and stop worrying.
 
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@rulookin What model bike do you have?
Don't just force the tensioner to extend. You shouldn't need to drive the tensioner out with force, just gentle pressure. A drift punch just gives you a hand tool to push it with. A screwdriver could work just as well.
But I would recommend to actually remove and inspect it. !
Yes, you will need to remove the radiator. You should also take off the valve cover and tie the chain to the sprockets...and you need to remove the left crankcase cover to access the bolt on the end of the crankshaft so you can rotate the engine, as well as apply slight rotational pressure while pushing on the tensioner (to put s much chain sack as possible on the tensioner side).

But are you sure it is the cam chain??? MV motors are not quiet sewing machines like, say, a new Honda. They have a lot of mechanical sounds that are normal.
 

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Discussion Starter #9
mv

2013 mv f4rr is what I have .
I am going to try to manually push the tensioner forward one tooth by removing center bolt, spring and push rod , By the way the push rod does nothing at all but support the spring ! I have my old tensioner here at home and I held back the toe and retracted the tensioner push foot all the way back , without the spring I put the center rod back in and hand tightened the center bolt , it did not move the foot at all !! with spring in it does , leading me to believe the rod does nothing buy support the spring !
in theory a longer center rod is all it needs , slowly tingeing the bolt ( with longer rod ) and wait to hear a CLICK ! now the ratchet mechanism has moved forward on tooth , then take it out center bolt and re install OEM part (spring and shorter rod ) tighten all up start bike and see how she sound !maybe have to do this once or twice but this eliminates having to pull the bike apart ! the cams will not move as there is pressure just not enough, by doing my suggestion it will now push the ratchet one tooth forward putting just a bit more tension !
I am convinced that the stock tensioners and the spring is not pushing the foot out far enough ! and as soon as the foot feels a bit of resistance it locks in ! by adding a bit of force (going one tooth past ) this should rectify things I hope !!


Love my MV and will fix her even if it means making a manual tensioner out of the parts I have !
@mv.Duane instagram
 

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Search within mvagusta.net for manual tensioner and you may just be surprised by what other people have discovered.
 

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If you are removing the tensioner, as well as tying the chain to the sprockets, you should maintain the tension on the chain with a length of wire wrapped around the chain and tensioner blade and secured to somewhere solid (the frame or the engine) otherwise the chain may loop off the bottom sprocket and you could loose the cam timing.

Can you post a photo of the failed tensioner showing the particular issue? I've never heard of a later black tensioner failing.

My previous (fortunately) local MV dealer was also a Triumph dealer and talked about sometimes needing to manually extend Triumph camchain tensioners an extra notch to quieten the engine. Apparently the spring sometimes doesn't have enough oomph to take up that last notch. Maybe MV's have enough other noises to hide the fact that the chain could use a little more tension but if you overdo it????

Tony
 
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