camshafts for 750 Commando

ILLF8ED · Nov 14, 2011

Hobot,

You mentioned Mrs Peel has a PW3 cam. Mrs Peel is a combat, right? Why the change from double S cam? Just picked up a Norris RX for my combat....remember it had a standard cam installed.

Others that have run a Norris RX, would like to hear your input. I have all the specs, but more interested in how the engine works.

JimC · Nov 14, 2011

Others that have run a Norris RX, would like to hear your input.

I don't recall a Norris RX grind, but I had a Norris R in a 69 Commando. It ran like a thief in the night.

jseng1 · Nov 15, 2011

THe Norris RX is one of the wilder cams you can fit into a Nort. Lots of duration. This is a full race cam and wilder than the Norris R or the PW3 (possibly wilder than the Combat 2s cam) . I used to race with it and it was enough cam for a (ported) 850.
Its about in line with our stage 2 cam.

See RX cam comparisons at:

http://www.jsmotorsport.com/technical_CamLifters.asp

beng · Nov 15, 2011

If anyone wants a Norris Rx, which is apparently a great cam for road racing or insane street racers, I have an original brand new one with it's original spring kit, timing card and all installation instructions that I really do not need.....only thing is it is for the Dominator or early Commando with the tach drive on the timing cover. It is ex-T.C. Christenson stock.

ILLF8ED · Nov 15, 2011

jseng1 said:
THe Norris RX is one of the wilder cams you can fit into a Nort. Lots of duration. This is a full race cam and wilder than the Norris R or the PW3 (possibly wilder than the Combat 2s cam) . I used to race with it and it was enough cam for a (ported) 850.
Its about in line with our stage 2 cam.

See RX cam comparisons at:

http://www.jsmotorsport.com/technical_CamLifters.asp

I looked at the comparison Norris RX to double S (combat). Specs don't really tell me much about performance. I'm familiar with performance of the combat cam which has a steep and tall lift on the intake. The Norris isn't as tall and has a more gradual openning. Sounds better for the valve train, but again doesn't give me any feel for performance. I'm going to plug the Norris in and maybe get back with my findings by mid summer 2012.

Hobot · Nov 15, 2011

Correction: There was prior accidental expedient Peak Peel Power which was mainy a small port head low compression head on a factory Combat with lightened smaller steel flywheel and 34 mm single carb. I hunted down and out squirted into corners over 100 hp sports bike till 7500 in 2nd - then liter size bikes could out accelerate longer, but only in the wide opens. 2S cam was plenty and about perfect to me, not too jumpy on the loose stuff yet kicked in another piston power @ 6800. No PW3. Old Peel also weighed under 360 lb which definitely could be felt in better leap response.

Next New big block blown Peel has a Norris D+ drag only cam from Jim Schimdt.
I'm skee'd of the 9000+ JIm S. runs his twins too and Peel valve train already testing over 8000+, so didn't get Jim's light BSA lifters. Ken Canaga is doing a mass lose mod on factory lifter slugs. Cam will be rifle drilled by Comstock and pressure fed oil, plus nitrided polished by Geoff Collins in Canada. There's recent post [snakehips??] on green cdo with Norris D logo above the Norton tank logo, who mentioned the roll on wheelies finishing up gears yet started and idled just fine. Time=Money=Motion=Life. hobot

ILLF8ED · Nov 15, 2011

hobot said:
Correction: There was prior accidental expedient Peak Peel Power which was mainy a small port head low compression head on a factory Combat with lightened smaller steel flywheel and 34 mm single carb. I hunted down and out squirted into corners over 100 hp sports bike till 7500 in 2nd - then liter size bikes could out accelerate longer, but only in the wide opens. 2S cam was plenty and about perfect to me, not too jumpy on the loose stuff yet kicked in another piston power @ 6800. No PW3. Old Peel also weighed under 360 lb which definitely could be felt in better leap response.

Next New big block blown Peel has a Norris D+ drag only cam from Jim Schimdt.
I'm skee'd of the 9000+ JIm S. runs his twins too and Peel valve train already testing over 8000+, so didn't get Jim's light BSA lifters. Ken Canaga is doing a mass lose mod on factory lifter slugs. Cam will be rifle drilled by Comstock and pressure fed oil, plus nitrided polished by Geoff Collins in Canada. There's recent post [snakehips??] on green cdo with Norris D logo above the Norton tank logo, who mentioned the roll on wheelies finishing up gears yet started and idled just fine. Time=Money=Motion=Life. hobot

This is good news. The Norrid D is supposed to be the next more radical grind compared to Norris RX. Again will plug in the Norris RX and report back sometime next summer with what I think of it. It's a used camshaft so will probably get someone to put it in a lathe, check to see if it's straight and measure the maximum lift per lobe, just to be sure of what I have.

Hobot · Nov 15, 2011

D is more aggressive than RX huh, cool. In new Peels case main reason to get such over lap + late intake closing profile was to lower the 920 kick over and low speed detonation compression on skinny leg and low octane gasoline. Her static CR is 10:5 other wise. Gotta bump up the CR to get much real life use of a big bad bang stick. I want Peel to run pretty good w/o the blower belt on too so your feed back will help appreciated. Will run er' in on a 34mm Miki carb to start off. I don't expect to top out over what sports bikes can nowadays but do want to out squirt them up to 'realistic' speeds in real world and small track conditions no one can get to their top speeds before time to turn in again. Builders assured me 150 will be easy to do.

I know what happens with excess power response applied while leaned a bit so be careful and be restless about decreasing sweepers till a rump rod and two helpers fitted. Then the real joy ride of excess power response can be tapped into, making any and every turn funner by turning em all into faster decreasing radius flings. Ahh.

bwolfie · Nov 15, 2011

Just a FYI, I make and sell quick change cam bearings and LH needle bearing conversions. Thread here...

norris-cam-quick-change-kit-t9167.html?hilit= norris

Makes changing the cam quick and possible without spplitting the cases. I don't have any done right now, but can in a week or two.

There is one insise Mrs. Peel....

Hobot · Nov 15, 2011

Yep sir Brent I snagged one of your cam doors already.

JimC · Nov 16, 2011

Makes changing the cam quick and possible without splitting the cases. I don't have any done right now, but can in a week or two.

Am I the only one that installs new or reground lifters with a new cam?

johnm · Nov 16, 2011

[/quote]

Am I the only one that installs new or reground lifters with a new cam?[/quote]

No

ILLF8ED · Nov 16, 2011

JimC said:
Makes changing the cam quick and possible without splitting the cases. I don't have any done right now, but can in a week or two.

Click to expand...

Am I the only one that installs new or reground lifters with a new cam?

Tell me more...why I need to regrind the lifters. I'm putting a used camshaft in soon.

Thanks

RennieK · Nov 16, 2011

Any hi stress parts that contact other hi stress parts in precision applications will eventually become "matched sets" after any significant run in period. The wheel bearings on your car, the outer race, the inner race and the roller or ball bearing cage will become a "set" after sufficient milage. This is because no 2 things are alike (when you get picky). The hub and the axle the bearing set interfaces with will have a different proximity to the hub and axle on the other side. The 3 piece bearings are a perfect fit to each other when new but once you mount the inner race on the axle and the outer race in the hub and sandwich the bearing cage in-between they no longer contact each other so perfectly. Looking closely at the wear patterns on the contact surfaces will reveal the distinct wear patterns. The bearing set when new was extremely tightly manufactured to exacting tolerances and all the inner, outer races and the ball or rollers cages are interchangable until they have been run in and formed wear patterns. After that, installing a single new component in the "set" will result in faster wear on the new component and other components until the 3 parts wear in together again.

Some parts on a Norton that become sets are:
rocker spindles - rocker arms
lifter - cam lobe
any 2 or 3 piece bearings (one piece bearings always remain as a set)

Components like quick change cam fixtures are designed for race bikes because these components are replaced before wear patterns form. If you start with new or reground lifters and cams and only run a dozen races and change to another new or reground cam there won't be much of any wear pattern started yet. Racers frequently access these parts and can change or repair when needed so they have no need to concern themselves on the longevity so much as benefits of the quick changeability. On a road bike if you change cams after a season where you've logged 5000 miles or so, wear patterns will have formed and will be visible on the parts. Mixing other parts with different wear patterns will always result in quicker wearing of those parts however nothing catastrophic is going to occur, just faster wear of the parts and more frequent adjustments of rocker clearances etc.

ILLF8ED · Nov 16, 2011

RennieK said:
Any hi stress parts that contact other hi stress parts in precision applications will eventually become "matched sets" after any significant run in period. The wheel bearings on your car, the outer race, the inner race and the roller or ball bearing cage will become a "set" after sufficient milage. This is because no 2 things are alike (when you get picky). The hub and the axle the bearing set interfaces with will have a different proximity to the hub and axle on the other side. The 3 piece bearings are a perfect fit to each other when new but once you mount the inner race on the axle and the outer race in the hub and sandwich the bearing cage in-between they no longer contact each other so perfectly. Looking closely at the wear patterns on the contact surfaces will reveal the distinct wear patterns. The bearing set when new was extremely tightly manufactured to exacting tolerances and all the inner, outer races and the ball or rollers cages are interchangable until they have been run in and formed wear patterns. After that, installing a single new component in the "set" will result in faster wear on the new component and other components until the 3 parts wear in together again.

Some parts on a Norton that become sets are:
rocker spindles - rocker arms
lifter - cam lobe
any 2 or 3 piece bearings (one piece bearings always remain as a set)

Components like quick change cam fixtures are designed for race bikes because these components are replaced before wear patterns form. If you start with new or reground lifters and cams and only run a dozen races and change to another new or reground cam there won't be much of any wear pattern started yet. Racers frequently access these parts and can change or repair when needed so they have no need to concern themselves on the longevity so much as benefits of the quick changeability. On a road bike if you change cams after a season where you've logged 5000 miles or so, wear patterns will have formed and will be visible on the parts. Mixing other parts with different wear patterns will always result in quicker wearing of those parts however nothing catastrophic is going to occur, just faster wear of the parts and more frequent adjustments of rocker clearances etc.

By this are you saying a used camshaft should also be resurfaced before being used...so both cam follower surface and cam lobe need to be ground?

RennieK · Nov 17, 2011

illf8ed said:
By this are you saying a used camshaft should also be resurfaced before being used...so both cam follower surface and cam lobe need to be ground?

The key word is "need". Maybe we should use the word "should" instead. If all the parts were new you could swap them around at will. Used components should be reground to square again. A lot of worn cams display wear more to one side than the other. It is important to always return each lifter to it's original tunnel on reassembly. Think of the tunnel geometry as the 3rd. part of the "lifter - cam lobe set". If there is not significant wear on your cam or present lifters and all you want to do is try the cam you won't do much damage running it for 50 to 100 miles to determine that this is the cam for you. If you already know you definitely want to get rid of the stock cam and we wouldn't hold that against you, then maybe grind your current lifters with the new cam. It sounds like this cam may require stronger springs which is another case for the resurface.

debby · Nov 17, 2011

illf8ed said:
By this are you saying a used camshaft should also be resurfaced before being used...so both cam follower surface and cam lobe need to be ground?

lifters should be resurfaced, but do NOT grind the cam lobes. You would cut through the surface hardening and very quickly have a "shark fin" cam.

Hobot · Nov 17, 2011

Yes that is what I did with Trixie Combat a rod bolt let go nicked the cam surface but scored the lifers bottoms, so had lifters resurfaced and filed proudness off cam lobe and let er rev over 2000 for some long minutes on first start up to let cam make the lifters fit it. So far 5000ish miles so goodie. A further step on a hot rod cam might be to have Geoff Collins nitirde and polish it. Remember that initial cam start up is vital to bedding in way more than mere ring sealing which happens in a few seconds if dry installed. I had to shut down in 1 min to nip up a rocker leak then gave er hell for like 12 min knowing after measuring temps there ain't much temp w/o much fuel w/o much load on engine. A small fan can help ease your concern as oil vaporizes off what ever.

ILLF8ED · Nov 24, 2011

beng said:
If anyone wants a Norris Rx, which is apparently a great cam for road racing or insane street racers, I have an original brand new one with it's original spring kit, timing card and all installation instructions that I really do not need.....only thing is it is for the Dominator or early Commando with the tach drive on the timing cover. It is ex-T.C. Christenson stock.

Hi Beng,

What does your timing card say for intake and exhaust openning and closing for the Norris RX camshaft? I've got mine in and want to make sure it's timed correctly.

beng · Nov 26, 2011

Some of the literature supplied with the Norris Rx cam and springs:

camshafts for 750 Commando

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