110 Web cam question

I've got a 76 900 (1015) with 110 web cams on it. When I went to check the clearance they varies quite a bit when you rotate them long before they begin to open or close. Makes it hard to decide what shims to use. Go by the smallest gap?? A couple of the lobes seem to vary by over the .05 gap between shims. I've never run into any cams that were ground that "unround" on the back of the lobes. Any one else run into this? Maybe I just got some poorly ground cams?? Most factory cams I've worked with were spot on.

110 cams???:huh:

LarryC has mentioned them before. He'll know for sure...

Julio, Safe reply.. Contact Webcam. One factor for prolonged valve life is is the time valve spends closed.(allowing heat transfer) Many cam manufacturer's use stock/core cams, building up stock lobes and machining. In order to maintain smooth ramps origional base circle is diminshed. Hope this is not too cryptic. Luck g

The place to check the gap is 180 from lobe center +/-. The 110 is a very good grind. one of their most popular. The set I have is quite consistent. i wonder if the set that you have in the bike were not adjusted properly to begin with and just wore unevenly. The gap at 90/180/270 from lobe center should be almost identical. These just may be badly warn cams. This is a pretty hefty cam for a motor that vintage.

Hey, thanks. I'll try and give Webcam a call. The only thing I can think of is maybe the valve springs were not up to the needs of the cam and/or the valve timing was so far off that maybe the valves were bouncing or something on the seats so the followers were rubbing on the back of the lobes?? The gaps are all either OK or a bit too big. The largest was .23 mm ant the rest varied from about .06 up to .2 or so. I don't think the gaps would cause any problems other than running a little uneven. The cam grind doesn't exactly look nice and clean, but the bikes been sitting for probably close to 10 years or without being run very much.

Their site says you need high compression pistons and performacne valve springs with that cam. I don't know exactly what the previous owner had done to it other than it supposedly had a 1015 kit (not sure about compression) so I'm trying figure it out by "back engineering" his build. It'd kind of annoying. Wish he would have documented it a little better.

Thanks for the advice.

Julio, Pic's would help, But, ramps of cam lobes should be smooth,. any "waving" indicates wear/poor "hardening" of lobe. cams utilizing rocker arms are a much easier "read". as lips form away from wear area, If you have doubts, they're probly founded. luck g

Call Web and ask to speak with Debby. They're customer service is exceptional.

There's no way of knowing how old the cams are or the history of the oil changes in the bike, etc. All can add up to wear out a set of cams.

Pull the cams and measure them up. See how much difference you have between the lobes. Have that information available when you speak to Web on the phone.

I've seen cams from pretty much every manufacturer that are like that. Occasionally, a core gets ground poorly. I even had a set last winter, brand new, that should never have been ground at all. They were replaced for free.

Q.C. ain't what it used to be in America....that's for darn sure.

PS - for a small motor like that, you might like their #483 grind better. Same lift, less duration.

Larry C