Topic: Norris camshaft RX2 AJ #56

[KirkBurner]

Does anyone have any information on such a camshaft....

If the cam is too mild, then sorry for going to the wrong forum. None at the other could help me much when I asked there.

It was installed in the bike when I bought it ..
Im trying to work out if I need to rejet the carbs or not.. after I put on the Carpy 4-1 exhaust.

or what other adjustmest I should be doing with this setup..


thanks up front for feedback

[johno]

Hi Kirk,
There are a few threads relating to Norris cams, just google norris cams info  in the google search option. It will take you to a few !
johno

[KirkBurner]

I have created most of the entries when I search for that spesific cam..

then I will view this as lost information...

[Old Scrambler]

Talk to Jim or Barbara at MEGACYCLE CAMS...........415-472-3195.  They purchased the Norris business and still produce a Norris profile for mild performance (125-NR) and the 125-N-T3 grind for boosted motors.

[KirkBurner]

Thanks alot Scrambler... I will shoot them an email since I live in Europe

[PeWe]

If you get the cam data, please publish here.
I have only seen questions about this cam, no answers with data. You never know, one day a cam like that is available...

[KirkBurner]

This is what I have found, I have no idea of how to read these figures..

anyone able to help me out abit..?

[PeWe]

Nice! The language look familiar too

Cam: H750RX2   
Hot Street/ Roadrace. Ideal for 836cc
Lift
IN: 0.381"  (9,68mm)
EX: 0.357"  (9,07mm)

Duration:
IN: 290 degrees
EX: 280 degrees

*********************************************
Cam: H750RR   
Cafe/ Roadrace. Ideal for 900c or high-revving 836cc
Lift
IN: 0.380"  (9,65mm)
EX: 0.357"  (9,07mm)

Duration:
IN: 290 degrees
EX: 280 degrees

One question is if the durations are measured at 1mm (0.004") lift or when start to lift until it close completely (total duration). I guess that the numbers here are total duration.
Many cams spec have the duration measured from 1mm lift until it is 1mm to be completely closed. some have  at 1.25mm (0.005").
You'll see when timing the cam. Equal lobe centers are generally a good start. This is explained in some threads here
http://forums.sohc4.net/index.php?topic=56168.msg606141#msg606141
http://www.muzzys.com/articles/lobe_centers.html

I guess that you will find less duration if you measure at 1mm lift.

Verify the Top Dead Center for 1:4 is important. T mark should be aligned with case mark when piston is at top. The crank will move a few degrees while piston is at top (TDC). You must find the center.

My T mark on the adv unit show different depending on the play it has. Correct when it's mounted max counter clockwise in its play area. Max clockwise is 3 degrees.
I mount it max clockwise, 0 degree wheel here (pistons at TDC) and remember that the T mark is slightly on the right of the case marking when timing the ignition.
Too early ignition (advanced) will foul your plugs (possible to get holes in the pistons too). I know since I have fouled some sets of plugs. Had to jet carbs really lean to avoid that.  Got hole in my old RC 836 back in the days too

Now better ignition timing, finally possible to find proper jets for the carbs... Will test my latest jetting today.

[KirkBurner]

I am not well versed when it comes to cams

are there any fairly similar to these specs that I could adopt the valve gaps from as a starter?

[PeWe]

You mean valve lash..?
0.15mm  IN and EX. 
IN 0.10mm might be possible too.

[KirkBurner]

Alright... I guess thats what its called...  I will try those measurements... What does an increase or decrease do the effect of the engine?

[PeWe]

The lash must not be too small. It must close completely. Exhaust will have time for cooling
You can check other cams recommended lash.  Very often 0.004/0.005" (0.1/0.125mm)
http://www.satanicmechanic.org/megacyclecam.shtml
http://www.dynomanperformance.com/engine/cams/webcams_honda.html#sohc

The old Russ Collins profiles have  lash..! DPxxx instead of RCxxx
http://www.dynomanperformance.com/tech-sheets.html

I attach Action Fours cam data and how to install a cam. Documents I got with my cam I bought 30 years ago. I knew that the paper copies should be useful.

This forum is full of cam installation guides and helpful members knowing a lot.