Author Topic: Intake Cam Question  (Read 1031 times)

Offline bigdt73

  • Newbie
  • *
  • Posts: 9
  • Country: us
Intake Cam Question
« on: November 20, 2018, 01:34:58 pm »
I bought two ZG1000 project bikes for $300 last year. I have the first one (1994) nearly completed and I started working on the second one (1993). I was in the process of checking and adjusting the valve clearances when I noticed some damage to the intake cam lobes. It's present on all four lobes with varying degrees of damage. All four of them seem pitted at the tips of the lobes, yet the exhaust cam lobes look perfect.

So, what would cause the damage to the intake cam lobes but not the exhaust cam lobes? Can I replace just the intake cams or do I need to replace them as a set?

Thank you in advance.
Demian

Offline works4me

  • Full Member
  • ***
  • Posts: 104
Re: Intake Cam Question
« Reply #1 on: November 20, 2018, 01:57:12 pm »
From another thread:

I have a C10 with pitted cams. It's a non-issue as long as the pitting does not extend across the entire wear surface. Basically, as long as the follower rides on at least some shiny metal all the way around the lobe, it'll be OK. It does bear watching, though, to make sure it's not getting substantially worse over time.

Offline DC Concours

  • Full Member
  • ***
  • Posts: 228
  • Country: us
  • 2001 Concours, ~19K miles
Re: Intake Cam Question
« Reply #2 on: November 20, 2018, 02:01:39 pm »
This seems to be a common issue with our bikes. Mine had pitting at 10k miles!

Steve in sunny fla does cam upgrades. contact him if interested.

Offline bigdt73

  • Newbie
  • *
  • Posts: 9
  • Country: us
Re: Intake Cam Question
« Reply #3 on: November 21, 2018, 11:04:53 am »
That's what is worrying me. The pitting is extensive on two of the lobes to the point that there is little to no smooth, shiny surfaces left.

From another thread:

I have a C10 with pitted cams. It's a non-issue as long as the pitting does not extend across the entire wear surface. Basically, as long as the follower rides on at least some shiny metal all the way around the lobe, it'll be OK. It does bear watching, though, to make sure it's not getting substantially worse over time.

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2493
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: Intake Cam Question
« Reply #4 on: November 21, 2018, 03:59:14 pm »
post up clear photos, for us to see. Enough of us here have experience to tell you whether to be worried, or not... It was a common problem in the metalurgy of the cams, but most times it isn't as bad as you may think..
let us be your judge as we have seen a jillion of them in various states.

30 YEARS OF KAW.....

Offline bigdt73

  • Newbie
  • *
  • Posts: 9
  • Country: us
Re: Intake Cam Question
« Reply #5 on: November 25, 2018, 01:52:57 pm »
Pics

Offline bigdt73

  • Newbie
  • *
  • Posts: 9
  • Country: us
Re: Intake Cam Question
« Reply #6 on: November 25, 2018, 01:56:30 pm »
More pics

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2493
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: Intake Cam Question
« Reply #7 on: November 25, 2018, 03:10:22 pm »
seen a lot of pitted cams, but I agree... those are about as bad as I've seen, and I'd consider replacing it...
also, examine the followers that cam rides against, for extreme wear, and scoring (dishing/grooves/etc.,)...

contact SISF at sholdabeen, he has cams, and even stock ones I think.

so yes... those are fugly and in bad shape.

30 YEARS OF KAW.....

Offline bigdt73

  • Newbie
  • *
  • Posts: 9
  • Country: us
Re: Intake Cam Question
« Reply #8 on: November 25, 2018, 03:32:17 pm »
Thank you, MOB. I appreciate the feedback even though it means more work...lol That's what I was afraid of but better safe than sorry. Thanks again.

Offline DC Concours

  • Full Member
  • ***
  • Posts: 228
  • Country: us
  • 2001 Concours, ~19K miles
Re: Intake Cam Question
« Reply #9 on: November 25, 2018, 06:46:14 pm »
MOB, what happens of you keep running on those lobes? Does the whole lobe disintegrate? And does the type of motor oil have anything to do with it?


Offline qman

  • Jr. Member
  • **
  • Posts: 52
  • Country: ca
    • Autobahn Motors
Re: Intake Cam Question
« Reply #10 on: November 27, 2018, 12:23:34 pm »
check the rocker arms too! mine were toast.

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2493
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: Intake Cam Question
« Reply #11 on: November 27, 2018, 07:13:15 pm »
MOB, what happens of you keep running on those lobes? Does the whole lobe disintegrate? And does the type of motor oil have anything to do with it?

Lobe wear stabilizes at that point, that wear was from poor metalurgy in the forging process... but at that point it becomes stable..

BUT, the cam surface does accelerate the wear on the follower's surfaces, the followers are also a forged metal, with a "hard" surface coat, and a chrome "hard plating", which when it begins to wear, will continue, and eventually wear a "groove" in the fash, and 'dish' out and continue to, until some point it creates adjustment issues, and then further wear of the remaining cam's 'crater edges'...

check the followers, if they are worn, replace if you are replacing that cam.. if not replacing the cam, run them as long as they work...

 also I'll give you a tip... the followers are the same part on the 500 Ninja engines of the same era, just they had only 2 sets... I have a couple as backups, and also in case I have an adjuster screw/nut strip.

30 YEARS OF KAW.....

Offline DC Concours

  • Full Member
  • ***
  • Posts: 228
  • Country: us
  • 2001 Concours, ~19K miles
Re: Intake Cam Question
« Reply #12 on: November 27, 2018, 09:27:46 pm »
Thanks for the info. I was wondering what would happen if I keep running... because I had some pitting and I am leaving it alone for now. Mine had this happen at only 10K miles!!!! Unbelievable. That is why I was wondering whether it had to do with motor oil.

Thanks for that other tip. Does it also mean that a 2000 era ninja 500 will have followers with the same metal flaws?

Offline connie_rider

  • Full Member
  • ***
  • Posts: 1107
Re: Intake Cam Question
« Reply #13 on: November 28, 2018, 07:26:22 am »
I've been seeing these over the years, and didn't notice,,
Did it happen during a particular year/period, or over the entire production span?

Ride safe, Ted

Offline MAN OF BLUES

  • Arena
  • Sr. Member
  • ****
  • Posts: 2493
  • Country: 00
  • WHISKEY.Tango.Foxtrot.
Re: Intake Cam Question
« Reply #14 on: November 28, 2018, 02:35:40 pm »
Thanks for the info. I was wondering what would happen if I keep running... because I had some pitting and I am leaving it alone for now. Mine had this happen at only 10K miles!!!! Unbelievable. That is why I was wondering whether it had to do with motor oil.

Thanks for that other tip. Does it also mean that a 2000 era ninja 500 will have followers with the same metal flaws?

the flaw was in thee cam metalurgy, not the followers...
as for frequency and year of mfg, it really didn't surface till about '93, and varied for a couple years, most of the odd cams were depleted prior to 2000...

30 YEARS OF KAW.....