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Reply #25
by Barocca on 20 Oct, 2020 15:20
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Reading tea leaves? After doing essential work on other bikes, I've eventually started a strip down to attempt to identify and remedy the source of my "mystery" noise. The bike has only done about 150km since the rebuild, all of this for the purpose of testing and seeking an informed diagnosis.
Today I drained the sump and removed the oil filter and I found that I had some black material in the filter and the bottom of the drained oil (see photos). The material has no metallic lustre and doesn't feel granular. I'm hoping that this material might be from initial wear-in of the new cam chain on the black (hard rubber?) guides. Has anyone experience of this?
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Reply #26
by Seagrass on 20 Oct, 2020 15:53
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I am now wondering if one of the camchain guides has broken/failed, that might explain the black particles in the oil (I do not believe it is normal wear)
Seagrass
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Reply #27
by CX PHREAK on 20 Oct, 2020 16:12
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what Seagrass said.
Most likely to be chain guide material.
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Reply #28
by 308GTSi on 20 Oct, 2020 23:47
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Is your taco running smoothly ? I have received second hand camshafts with pieces chipped / broken out the worm drive and teeth broken off the drive gear. That would certainly cause a sound like this , no need to rebuild whole thing if this taco drive is at fault.
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Reply #29
by Barocca on 21 Oct, 2020 09:05
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Interesting thought. It seemed to be working normally, but I'll look there before digging any deeper.
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Reply #30
by Barocca on 03 Nov, 2020 16:18
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Possibly a Eureka moment(s):
Pulled off rear cover and found camchain guides appear in good condition.
Saw that I'd trapped a gasket against the starter idler - possible cause of black residue in oil?
Removed tacho-drive/cam-holder and found that the worm gear has experienced a failure and "teeth" are broken. Could this be the source of the noise that I experienced? It would be consistent with the sudden onset of the noise.
Lastly, despite what I thought were best endeavours, I managed to stretch the gear change spring and believe it may need replacement.
I'll continue with camshaft removal and inspect the cam and followers in case the failed worm gear is not the true or only cause of the noise.
In the meantime I'll be looking to buy a good usable camshaft. Can anyone help?
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Reply #31
by Barocca on 06 Nov, 2020 20:49
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I removed the cam followers and examined them and the cam today. Now I think I've finally identified the true cause of my mystery noise. See pics of exhaust cam lobe and RH follower.
I guess I'm looking at sourcing a usable camshaft and followers, or perhaps having them rebuilt/reconditioned by someone with a proven track record. Does anyone have a camshaft and followers for sale? Or know of an accomplished affordable reconditioner of these parts?
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Reply #32
by Seagrass on 07 Nov, 2020 08:01
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I had a camshaft repaired/reground by Waggot Cams in NSW some years ago. They did a great job and from memory were not that expensive.
I am sure they could do the work for you but I would think there would also be someone much closer to you that could do the work.
Seagrass
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Reply #33
by Onetrack on 07 Nov, 2020 17:33
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Reply #34
by Barocca on 08 Nov, 2020 20:34
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Thanks Les, I agree with your replacement advice. I have found affordable cam lower rocker arms of the later design available (see pic). Do you know whether these can be used on the earlier engines? and with the existing earlier pushrods?
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Reply #35
by Onetrack on 09 Nov, 2020 06:49
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My experience is limited to the 650 engine - CX Phreak (Mark) will know better.
"Young" Les F
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Reply #36
by CX PHREAK on 09 Nov, 2020 18:06
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I just select subrockers based on condition heedless of type or type of cam fitted.
It doesn't seem to matter.
The rockers with the added pad appears to be an upgrade maybe based on the hardfacing of the originals being a litle suspect.
I don't know, but changes aren't generally made for no reason.
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Reply #37
by Barocca on 19 Jan, 2021 10:11
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A, hopefully, closing post to this topic.
I've fitted the replacement camshaft and lower cam followers, and the bike seems now to be running without the clatter that prompted the start of this topic.
Thanks to all members who've helped me on this journey.