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Discussion Starter #1
I've just done a valve adjust on my '08 312R for the first time. After much reading on the forum, countless efforts trying to line the cams up with the mark on the phonic wheel using all the suggestions provided on the forum I got it as close as I could and left it at that concluding that my cam chain had a little stretch in it at 24000Klm.
I turned the bike over manually via the phonic wheel to check for any catching etc and all was good. I assembled the bike etc and started it and she fired up pretty much straight away once the fuel got through it HOWEVER!! there was a hell of a rattle noise. I turned it off quickly and thought maybe the cam chain tensioner needed to adjust so I started it again and let it run a bit longer but the rattle would not go away so I stopped it again. I gave it one more try but nothing changed. I have begun to strip it back down and pull the valve cover off again.
Question- When positioning the mark on the phonic wheel with the notch on the casing and piston 1 at top dead centre at 'Burst Phase', how many rotations a required to get to Burst Phase again?
I am hoping that I haven't missed a rotation (if required) when lining the cams up. The piston was at top dead centre when I set them.
I am praying that it's a sloppy cam chain and the tensioner is faulty.
Thanks in advance
Steve
 

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Discussion Starter #3
Thanks For that and yep the cams were removed and new shims put in. If by chance I missed a rotation could I have done valve damage.....would the bike even start??
 

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Discussion Starter #4
If the cams are out and you are rotating the phonic wheel, and every time the timing mark is on the casing notch with the piston at top dead centre, is this Burst Phase?
 

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I don't think the bike would start if you were 180 out on timing.

Pull your cam chain tensioner and check that it isn't jammed.
 

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Discussion Starter #7
I thought that might be the case. I'll pull the tensioner out tomorrow and take a look. I'm starting to think I may need to replace the Cam Chain but it was not making the noise before I pulled it down for a valve check.
Getting the cam marks lined up with the casing and then lined up with the phonic wheel was an absolute pain in the rear. It took me hours and they still weren't exact. Some are saying that it is critical some are not. I'm thinking that if your Chain is stretched then an exact setting would be near impossible to achieve.
My biggest fear is that the valves have hit the pistons. I've now have also rounded the the phonic wheel nut (I've given it so much attention these last two days) so I'm going to have to get that sorted before I can go further:banghead:
 

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I know when Ed and I did mine. We had to tighten everything about half way. Hand turn the cams with the phonic wheel. Then tighten everything more. When we would try to just tighten everything down. It would rotate the cams out of alignment just a little and when we went to turn the cams you could feel one touching.
 

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Cam timing is pretty critical with the high lift and long overlap MVs use. Even with a stretched chain you should have the intake cam mark just about perfectly aligned with the cylinder head surface.
I was coaching Randrew on his cam replacement project, and every time he would put it together it would be off. It was tricky getting the cam caps all tightened down without slipping. so we manually held tension on the chain and rotated the crank to move the cams and take pressure off the lobes on the cap we were tightening, going in repeated steps until all were snug, then installing tensioner and rechecking timing before torquing the caps.

The ECM uses the cam position sensor to determine which cylinder is at TDC compression, so you only need set the phonic wheel pointer at the mark to start. But to check cam timing after installation you must rotate the crank 2 full turns.
 

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Discussion Starter #10
OK that's good to hear. I'm thinking now that the rattle is the CCT not doing it's job. To get it right I think I may have to use Noel's suggestion and lock the crank, set the intake cam up turning anticlockwise to take up tension between crank and cam and lock that down(3 pieces paper between 1 cam cap and cam shaft) then set the exhaust cam at the 24th link and then install the tensioner.
I've tried similar to what you and Randrew did but the crank would move way passed the mark when the tensioner was put in.(I am working alone)
Any suggestions on how to lock the crank?
 

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?

Cam timing is pretty critical with the high lift and long overlap MVs use......

The ECM uses the cam position sensor to determine which cylinder is at TDC compression, so you only need set the phonic wheel pointer at the mark to start. But to check cam timing after installation you must rotate the crank 2 full turns.
High lift and long duration?
2010 F4 valve timing
Intake
Open BTDC 16°
Close ABDC 60°
Duration 256°
Exhaust
Open BTDC 48°
Close ABDC 18°
Duration 246°
Measured @ 1.0mm lift.....the Industry Standard is 0.050" sorry
Lift
Intake 10.3mm
Exhaust 9.0mm

Isky #396831 Roller cam for Big Block Chevy 500 cuin 5,600-9,600 RPM
Duration
Intake
288°
Exhaust
310°
Measured at 0.050"
Lift
Intake 0.831"
Exhaust 0.805"

Ed listen to the motor..... there's no lope, it has mild cams


Cams jumping around.......
Been doing this for professionally off and on for 58 years.......lock the crank and remove the spark plugs
Point the intake cam mark at the edge of the head....... SAFETY WIRE THE CHAIN TO THE SPROCKET
Count pins, SAFETY WIRE THE CHAIN TO THE SPROCKET
With the cam chain tensioner out....reach in with​ safety wire and make a loop hook a bungie cord through the loop and hook it to something
Nothing can move.....if with the bearing blocks torqued the marks don't align......undo them and adjust the chain on BOTH sprockets and rewire them

Now install the cam chain tensioner

Simple!......and the crank is still locked on TDC ON #1.....unlock crank and rotate 720° check marks

:wink2:
 

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Discussion Starter #12
Thanks Noel,
How will I lock the crank?
Do I still use your bits of paper method to hold the cam? Also do I do this procedure with the cam blocks done up firm?
 

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Thanks Noel....I knew you would have better information than I.....although my Brutale has a lot of camy lope sound when idle is set just a tad low.

Yeah, Randrew and I weren't tying the cams to sprockets like we should have. My bad...but we had fun !!!
 

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Discussion Starter #14
I've pulled the valve cover off, re engineered the phonic wheel nut and positioned the crank on the casing notch. The intake cam mark is slightly lower than the casing (about 2-3mm) and the exhaust cam mark is above the casing 2-3mm. I've pulled out the cam tensioner and it appeared to be functioning OK.
Have I bent the valves!:eek:
 

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Thanks Noel,
How will I lock the crank?
Do I still use your bits of paper method to hold the cam? Also do I do this procedure with the cam blocks done up firm?
the paper method doesn't work on this because the bearing blocks span both cams

I'd use a junk box end wrench 12 point..... you're trying to lock the crankshaft nut to one of the 5 bolts of the F4 cover
you can weld or epoxy​ large washer to the handle of the wrench and then use a thick large 6mm to clamp the welded/epoxied to the case

if the fit of the wrench is loose put some tape on the nut.....and tap the wrench on with a mallet

hell, you can use safety wire to keep the wrench from moving...... or RTV Silicone ( but you must wait for it to set up)

you just need to keep the crankshaft from moving

Safety wire is probably the easiest.....you can use a good wrench it won't be damaged
 

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Discussion Starter #17
Ok, briefly as I have gone off to work for a week now.
I set the cams as per Noel's advice and tightened everything down and the marks were out when I unlocked the crank. Everything was good untill that moment. I rotated crank 720 degrees and no change (I heard the cct click once). The intake was about 2 mm above casing, exhaust 2mm below. So I locked the crank again and went through the process again but moved the the cams 1 link clockwise. Tightened everything down and now the intake is 2mm below casing and exhaust is 2mm above. This time though there is a point on crank rotation where its difficult to turn without a bit of force. This was evident in the initial assembly where when I started the bike, it was noisy. So I've moved the cams anticlockwise one link back to where it was (intake 2mm above casing). The crank turns freely now. I would say say I'm dealing with chain stretch and possible guide wear. The bike was running fine prior to the valve service and unfortunately I didn't take note of the cam marks prior to pulling them out. The outcome will be evident when I get back home, get it back together and start it up.:|:flat:
 

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Discussion Starter #18
Good news!!:grin2:
Started her up today and all is good. Once the fuel was through she started immediately with a nice crisp throttle response and no nasty rattle. It will be interesting to see how she goes on track, performance wise, revealing weather any valve damage has occurred.
I didn't recheck the clearances as I had assembled the valve cover etc. before I read (Vector - If you have bent the valves your clearances (cam - bucket) will be large as the valve cannot return to its seat properly) so hoping that luck is on my side with this one.
On reviewing this whole process to this point...
- Crank must be locked when installing the cams
- I partially installed the cct with it extended at the point when I removed it (without the centre bolt and spring) and gradually tightened it up as I tightened the cam caps down to keep tension on the cam chain preventing it from jumping teeth.
- Ideally, the cams should line up perfectly but if not the intake must be above the casing and not below(with the exhaust cam mark between the 24th and 25th link from the intake mark)
In time, I will replace cam chain, guides and tensioner when budget permits.

One Question.... Can the ECU make allowances for the changes in timing due to stretch in cam chain and wear in guides? Or is it fixed and there is a margin of error before performance is noticeably affected?

Steve
 
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