'08 Cam Problem? & Valve Lash Specs

[ETN550]

Hi All,

I have about 1200 miles on my '08 SXV 550, engine s/n #5300 something. I decided to check my rear cylinder valve lash (seemed to be the quickest to get to without draining anything). Anyway this is what I found! It looks like a very fine layer of the cam lobe surface is eroded away or peeled off. Hard to tell. I'm referring to the "crack looking thing on the nose of the lobe. It can be felt by fingernail, it is not just visual. Only on that one lobe. I have not opened up the front cylinder, but now will do so as well. I am thinking of running it some more and showing the dealer the pics as I have 4 yr warranty. Something tells me they may not be interested in it until it blows up. Maybe check it again in 500 - 1000 miles. What do you all think??






Next question. The inlet lash was fine. The exaust lash is .003 and .004 which is a little tight. Should I leave it for now? If not, can I slide out the pivot shaft and reset the lash without taking everything else apart?

Thanks for any help with these items. Cal or Amauri, I would appreciate your comments if you read this. Thanks.

Doug

[amauri]

.003/.004" for the exhaust is very tight, should be .007/,008"

Did you check EX clearance with the decompressor lever removed?

[ETN550]

Amauri,

No did not remove the decompressor lever, but positioned the roller on the rocker to where it was almost but not touching decompressor pin on cam lobe. If it makes a difference I'll remove the decompressor and pin the cam in position. (Actually I think I can just rotate it by hand and tape it in position while I check lash). Maybe that's my problem. It's well off of the lift area though. If it turns out to be .003 and 004 after I check it pinned and w/ decompressor removed can I slide the pivot shaft out to remove the fork and shim the ex valves without removing everything else?

What do you think about that inlet cam lobe??? I don't like it one bit but I don't think it will outright fail anytime soon.

[waxxer]

It looks like the mark you are talking is a one time event from some particulate matter that may have passed through. I don't know how the cams are surfaced--meaning will it begin to delaminate or the hard surface seperate from the cam. Ducatis had an issue like this.

The only other thing I noticed is you stated you have a 4 year warrantee. If I were you I would put it back together. I would state that a mechanical inspection was done by yourself and you touched nothing.

You may have created grounds to void the warrantee if you do this work yourself. Fine print is nasty stuff. That is why my bike is box stock. No one can claim that I put anything out of spec. during the warrantee period.

[amauri]

If your EX clearance is truly at .003-.004" something is wrong.
Most likely, the valve retainer has stretched and the shim is no longer touching the tip of the valve stem. Instead, it is now resting on the valve retainer itself.
Also possible that the valve face has worn and sunk in the seat.
Inspect with a magnifier.

The cam lobe will deteriorate rapidly now that the hard surface has worn off.
The spring bucket should also show excess wear to match the cam lobe.
What is the intake clearance?

[cal550b]

i have seen this a lot on the cams ,it is caused by badly set shimming and slaps the buckets chipping them and in turn then files at the harder cam lobe ,as amauri has said the exhausts are too tight ,i would reset, a clean up cam and new buckets asap .

[ETN550]

Thanks very much for insight and for info. I am going to pull the motor and check the front cylinder as well. I talked to the dealer and they said they would approach Aprilia after I take some high quality pictures and ask for help. Either way it will get fixed. If I have to fix it myself Imay ask some more questions. For now I will disassemble some more and continue inspection. Thanks again.

[cmoss]

Hi All also currently having issues with my cams, could someone tell me if there are major differences between the stock sxv 550 and the VDB cams. Just trying to suss if its worth putting these in.

[cal550b]

[QUOTE=cmoss;2116365]Hi All also currently having issues with my cams, could someone tell me if there are major differences between the stock sxv 550 and the VDB cams. Just trying to suss if its worth putting these in.[/QUOTE
450 /550 /550vdb are standard cams 450 vdb are different.

[john boy]

Hi All also currently having issues with my cams, could someone tell me if there are major differences between the stock sxv 550 and the VDB cams. Just trying to suss if its worth putting these in.

if its rear you need i have a good second hand 550 rear one front is to worn to refit to any thing pm me if interested

[cmoss]

Cheers John boy, I can get hold of a nearly new set of OE cams, but just interested to see if its worth the extra for the VDB cams.

[Alice Racing]

Not worth it for a 550 no.

[ETN550]

Someone on here said that the VDB cams were slightly different mainly at the high end.

I have my cams out. The front looks ok but the inlet and exhaust are both off. It actually seems like they were set backwards Inlet is loose and exhaust tight. I'm going to replace the rear cam and re-lash all.

Are the sxv cams the same from '07 - '08? I might have a line on an '07 and mine is '08.

[Alice Racing]

All cams are the same yes, VDB has slightly more inlet lift and slightly less exhaust lift, but open around 10 degrees earlier.the map makes more difference than the cams.........you would need to be a very good rider to tell two bikes apart both running the same maps , one with VDB cams one with stock.

[Markee]

I run the VDB map in my std 450 and it makes a huge difference in the the way the power comes on.