Japan Meets Britain

Vince Lupo · Post by **Vince Lupo** » Thu Jun 30, 2016 7:46 am

Here are two photos of the profile -- does this help?

teazer · Post by **teazer** » Fri Jul 15, 2016 8:16 pm

That split cam looks like it started as a CL unit and the tacho drive looks like it was machined off a CB to make it work. Alternatively it might have been supplied that way as a billet cam suitable for CL (no tacho) or Cb (with tacho).

I have a full race cam here without tacho drive so that I could use a CA or CL end tower and an electronic tacho with electronic (dyna S or motoplat) ignition.

That is s lumpy cam. How much lift at the cam on both profiles and I'll see if I can match it to anything in my lists. If you measure the base circle and maximum height I'll see if I have any specs anywhere close.

Vince Lupo · Post by **Vince Lupo** » Sat Jul 16, 2016 6:59 am

teazer wrote:That split cam looks like it started as a CL unit and the tacho drive looks like it was machined off a CB to make it work. Alternatively it might have been supplied that way as a billet cam suitable for CL (no tacho) or Cb (with tacho).

I have a full race cam here without tacho drive so that I could use a CA or CL end tower and an electronic tacho with electronic (dyna S or motoplat) ignition.

That is s lumpy cam. How much lift at the cam on both profiles and I'll see if I can match it to anything in my lists. If you measure the base circle and maximum height I'll see if I have any specs anywhere close.

Teazer, many thanks for your thoughts. I've taken four photos - hopefully I'm showing the things you requested!

So now when you say that the cam is 'lumpy', is that going to be a problem for road use? The type of riding I do is typical weekend-warrior stuff (backroads etc), with the occasional long trip. Do you think this cam is okay for that, or am I going to have issues with it?

teazer · Post by **teazer** » Sat Jul 16, 2016 10:35 pm

Thanks Vince. Do you have a digital caliper? Or a micrometer or dial caliper? It's too hard for me to try to scale the pictures with any degree of accuracy.

A reasonably accurate measurement across those 4 points would be wonderful.

Vince Lupo · Post by **Vince Lupo** » Mon Jul 18, 2016 12:01 pm

Hi again Teazer -- I had to go to my car mechanic's place around the corner from my house to borrow his micrometer (see why I pay people to do all my mechanical work?). Anyhow, here are the new and hopefully improved measurements! Let me know what you think.

Thanks!

teazer · Post by **teazer** » Tue Jul 19, 2016 12:13 am

Vince, that's much better. I did print out the original pictures and scaled them but these numbers are way better.

That's a lot of lift. What do we know about the cams? Are there any small numbers stamped into the end of the cam shafts or more probably engraved into the ends or perhaps into the shaft?

A stock cam has a difference in measurements of around 5.5mm inlet and 4.5mm exhaust and this one is 6.7mm inlet and 5.9mm exhaust- very different. We can see that it has been built up with weld and ground to new profiles. The question is who ground them.

The inlets are a perfect match to a Norris 1354S cam and exhaust is somewhere between 1354S and 1354SS "lift". Megacycle 121-20 has slightly less lift and the drag race cam I use has more lift on both sides.

The old Norris SS cam was sold for racing with high compression and strong valve springs and pockets in the pistons to clear the valves. I ran both Norris profiles but the valve acceleration and jerk were too harsh and caused rapid tip failure but they would work with hardened valve stem caps. I may still have an old Norris catalog hiding here somewhere.

Norris used to engrave the cam number into the shaft IIRC. It was decades ago since I used to buy cams from Norris Barumian and his sons Bruce and Brian. megacycle bought all of Norris's cam masters when they closed down and that was a loooong time ago.

Vince Lupo · Post by **Vince Lupo** » Tue Jul 19, 2016 4:26 am

Hi again Teazer -- thanks ever so much for this great info. No, there aren't any numbers or markings on the shafts at all.

So my question is -- are these cams too much for the street? What I have in the bike now are racing valve springs with APE titanium caps, so hopefully they'd be okay to use with these cams. The other alternative that I have is to send a pair of stock cams that I have, along with the rockers, to Megacycle to have a 'Scrambler' profile applied to them. That would run about $700, I think, but might be more 'streetable' than these ones. Not sure, you'd likely have more insight into that than I would.

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Japan Meets Britain