Lightweight BSA style cam followers

Gents,
I know it's an old mod this one, and well catered for by JS, and I know JS describes the stock followers as 'lumps of iron' but today I looked at the weights and was amazed.
I only have Triumph followers 'in stock' in the shed, I assume they're similar to BSA items?
The Triumph follower is 32g.
The Norton follower is 78g!
Considering that total load on the system is x 4... that is a staggering difference. It's probably the difference between requiring upgraded valve springs in a given situation, and not doing.
So, a couple of questions:
To those who have done this mod, is the difference actually noticeable?
Are Triumph followers suitable for this mod? I've got a box full, so it would be nice if they were!
Rgds,
FE.

Hi Nigel

SRM do this conversion I believe.
I am sure you could use the Triumph followers but you would have to make a holder for them.
I think I have previously posted a link to the Mez porting site ( He was superb) I will try & find the link. I think he had a photo of his conversion.

all the best Chris

Hi Nigel

Just looked at the site again. mez.co.uk/mezporting/page6.html#Norton
It isn't shown! I am sure he did them.
I know they were in a Norvil Catalogue they were developed by Pete Lovell (you can still contact him) He was a very fast man on a Commando.
I will have a butchers at the SRM site.

Chris

I have used BSA lifters for many years- both street and race.

A normal long stroke motor is not rpm limited by it's valvetrain, so installing them in a normal street motor will not be "noticed" in how it performs.
They do seem to have a little better wear characteristics. They don't launch the valve train over the lobe peak as much so they don't wear the line across the center of the lifter as much as a flat lifter does.
Cam wear seems to be about the same and I have never been able to hear any difference in the noise level.

On a race motor with a big cam there is an improvement in high rpm valve control. If you are running a short-stroke motor in the 9000 rpm range you will need lightweight lifters and rocker arms.

You can use the Triumph or the BSA lifters. They have a different radius so they will need different cam grinds. The BSA lifters are a little heavier than the Triumph lifters.
The Triumph lifters are not as durable - they have a 5/16 instead of a 3/8 shaft [and ball] and the face is not as long so there is less area for wear. I much prefer the BSA type lifter over the Triumph. Jim

I have the BSA lifters and the JS stage 1 cam to match. I will not say that it is cheap insurance but it is good insurance when running something other than a standard grind cam.

This was an upgrade from a stock cam and lifters and although the performance increase is profound, I cannot compare it to a stage 1 with flat lifters. As Jim sort of said, it's just nice to know it's there. With good springs I feel comfortable taking it to redline but am a bit squeamish to go further. With good crank bearings, a fresh gearbox and lube wheel bearing, I may go for a buck 10 or even 20 this next season.

FWIW
I do not know if it is normal to the Axtel 3 grind, of which the stage one is based on, or if it is just happenstance with the radius system, but I needed to advance the cam timing 10 degrees to get it to run perfect.

FWIW
I do not know if it is normal to the Axtel 3 grind, of which the stage one is based on, or if it is just happenstance with the radius system, but I needed to advance the cam timing 10 degrees to get it to run perfect.
To get any cam right -it needs to be checked with a degree wheel. There is a lot of variation in the timing as the Norton motor comes from the factory. I have seen 10 degrees difference between two motors using the same cam and installing it on the timing marks.
A lot of the change comes from the difference in the distance from the intermediate pinion gear to the cam. "In the area" seemed to be close enough when they were building them.
When building the cam chain tensioners I have noticed that I can install a chain and gear set on one motor and the chain will be almost tight, then I can move the same gears and chain to another motor and the chain will be sloppy loose.
Installing the cam "strait up" is usually a good starting place but for maximum performance you need to advance or retard the cam to find the sweet spot.
The sweet spot is going to be determined by the resonances produced in the exhaust system and/or intake tract and will vary from motor to motor. It seems advancing a cam 6 to 10 degrees from "straight up" is pretty common on a Norton to find the sweet spot. Jim

Good info, thanks guys.
Chris, I wouldn't be buying anything this important from Norvil! And I can't find any info on the SRM site.
Jim, it sounds like BSA lifters are clearly the best option here, thanks for that info.
Pete, I too had my eye on the stage 1 JS cam, you sound pretty impressed with it, could you describe it's performance characteristics a little more?
I'm thinking of using one along with 34mm JS carbs and 9.7:1 CR.
Rgds,
FE.

comnoz said:

I have used BSA lifters for many years- both street and race.

A normal long stroke motor is not rpm limited by it's valvetrain, so installing them in a normal street motor will not be "noticed" in how it performs.
They do seem to have a little better wear characteristics. They don't launch the valve train over the lobe peak as much so they don't wear the line across the center of the lifter as much as a flat lifter does.
Cam wear seems to be about the same and I have never been able to hear any difference in the noise level.

On a race motor with a big cam there is an improvement in high rpm valve control. If you are running a short-stroke motor in the 9000 rpm range you will need lightweight lifters and rocker arms.

Click to expand...

Jim, as you know cam wear and valve float are indissoluble related to valve spring pressure. Too low spring pressure the valves will float but the higher the spring pressure the more wear of the cam and lifters. For racing (reving to max 8500 rpm) using standard lifters (slightly lightened) I had to shim the valve spring pressure to approx 100 pound (seated valve) and 210 pound (full lift) to prevent valve float.
I am curious what max spring pressure do you need using the lightweight BSA type lifters ??

Fast Eddie said:

I'm thinking of using one along with 34mm JS carbs and 9.7:1 CR.
Rgds,
FE.

Click to expand...

I feel that 9.7:1 CR would compliment this cam quite well. Performance wise, I have tried many different carb scenarios and ignition units so the characteristic I mention should apply to the cam in particular.

The low end torque is great but that is consistent with any Commando. I would say that there is a slight improvement there which is saying something.

The real boost is at around 3500rpm to 3750 rpm where I here the pipes start singing a different tune and the increased pull becomes evident. In first, second and third gear it simply continues to pull to 7000. When cruising at 80mph (4500rpm with my gearing) a simple twist and all the sudden I'm doing 90 (5000rpm).

Make no mistake, the idle will be a little lumpy even with a single carb. I find it very appealing and any motor head near by will understand. With the slightest hint off idle and it's as smooth as glass all the way.

To say the least, I really like ( love might not be applicable here) this cam. I have a RGM belt drive so 20 tooth sprocket is a good all around function, although a little high for city driving. I will change to the 19 for this spring. I think I could race it with an 18 but would be just too much for the gearbox and may require a beefier unit. In this regard, primary, gearbox and any items related to power output needs to be at their best.
As mentioned earlier, I feel comfortable going to redline but going well beyond that is not out of the question, particularly after the installation of the beehive springs.

Hope this helps.
Pete

pete.v said:

Fast Eddie said:

I'm thinking of using one along with 34mm JS carbs and 9.7:1 CR.
Rgds,
FE.

Click to expand...

I feel that 9.7:1 CR would compliment this cam quite well. Performance wise, I have tried many different carb scenarios and ignition units so the characteristic I mention should apply to the cam in particular.

The low end torque is great but that is consistent with any Commando. I would say that there is a slight improvement there which is saying something.

The real boost is at around 3500rpm to 3750 rpm where I here the pipes start singing a different tune and the increased pull becomes evident. In first, second and third gear it simply continues to pull to 7000. When cruising at 80mph (4500rpm with my gearing) a simple twist and all the sudden I'm doing 90 (5000rpm).

Make no mistake, the idle will be a little lumpy even with a single carb. I find it very appealing and any motor head near by will understand. With the slightest hint off idle and it's as smooth as glass all the way.

To say the least, I really like ( love might not be applicable here) this cam. I have a RGM belt drive so 20 tooth sprocket is a good all around function, although a little high for city driving. I will change to the 19 for this spring. I think I could race it with an 18 but would be just too much for the gearbox and may require a beefier unit. In this regard, primary, gearbox and any items related to power output needs to be at their best.
As mentioned earlier, I feel comfortable going to redline but going well beyond that is not out of the question, particularly after the installation of the beehive springs.

Hope this helps.
Pete

Click to expand...

Hi Pete, yes that helps a lot! Almost exactly what I had in mind ie increased pull from 3-7k. I'm not interested in going over 7.
Thanks.
FE.

I've paid good attention to the various famous-fastest-tested Norton powered history and builders to find they did it on slightly modified-lightened Norton lifters, so it'd take a hell of a hi rpm over cammed engine to appreciate power gain/control in WOT race conditions with lighter valve train. Peel's 2S cam had Dreer valve/spring kit and a 1/2" hole out lifters when her throttle stuck on a cold start up that more than pegged tach needle but bounced it invisible for a hand full of seconds and another handful of seconds seen over red zone on shut throttle sucking pistons to bend crank, but there was no valve clash no piston hits and Ken Canaga said head like new to run in next Peel. So though there is no downsides to lighten up with BSA radius lifters and cam, just don't expect much form the extra cost but longer cam life and slight power gain by less spring pressure needed. One of the most IMPRESSIVE POWER SONGS I ever heard was the complete lack of mis fires on750 Peel into 11 grand unloaded inside a big tin shed with open megaphone. Checking 2S cam showed it'd lost most of the RH exht lobe though, so cam seems to be the weak item in really hi rpm Norton, I hope never to hear at home again.

[/quote]
Jim, as you know cam wear and valve float are indissoluble related to valve spring pressure. Too low spring pressure the valves will float but the higher the spring pressure the more wear of the cam and lifters. For racing (reving to max 8500 rpm) using standard lifters (slightly lightened) I had to shim the valve spring pressure to approx 100 pound (seated valve) and 210 pound (full lift) to prevent valve float.
I am curious what max spring pressure do you need using the lightweight BSA type lifters ??[/quote]

I really have not seen much difference in the needed spring pressure with the lighter followers.

Where I see a need for more spring is when the opening and closing ramps on the cam are fast. Not enough spring pressure shows up as valve bounce on the seat and valve and seat failure. That also depends on the RPM range you are running.

Mild cams -JS stage 1, web 12a - Megacycle 560-00- I usually shoot for around 90 lbs at seat and 205 at .400 lift.

Stronger cams - Norton 2s and 4s or the Web 86c need a little more. I like 110 on the seat and 210 at .400 lift

Big cams like a Norris D+ or Megacycle cams 560-NSS or larger - I go up to about 140 on the seat and 225 at .400 lift.

Stock springs give around 70 lbs on the seat and 195 at .400 lift.

The springs that have been on my streetbike were Kibblewhites at 130 and 220. They were probably stiffer than needed but I didn't have any wear problems. Jim

Jim, as you know cam wear and valve float are indissoluble related to valve spring pressure. Too low spring pressure the valves will float but the higher the spring pressure the more wear of the cam and lifters. For racing (reving to max 8500 rpm) using standard lifters (slightly lightened) I had to shim the valve spring pressure to approx 100 pound (seated valve) and 210 pound (full lift) to prevent valve float.
I am curious what max spring pressure do you need using the lightweight BSA type lifters ??[/quote]

I really have not seen much difference in the needed spring pressure with the lighter followers.

Where I see a need for more spring is when the opening and closing ramps on the cam are fast. Not enough spring pressure shows up as valve bounce on the seat and valve and seat failure. That also depends on the RPM range you are running.

Mild cams -JS stage 1, web 12a - Megacycle 560-00- I usually shoot for around 90 lbs at seat and 205 at .400 lift.

Stronger cams - Norton 2s and 4s or the Web 86c need a little more. I like 110 on the seat and 210 at .400 lift

Big cams like a Norris D+ or Megacycle cams 560-NSS or larger - I go up to about 140 on the seat and 225 at .400 lift.

Stock springs give around 70 lbs on the seat and 195 at .400 lift.

The springs that have been on my streetbike were Kibblewhites at 130 and 220. They were probably stiffer than needed but I didn't have any wear problems. Jim[/quote]


Thanks for sharing Jim. I also use Kibblewhite springs (and valves) and for steet use I shim them down to approx 100 and 190 by grinding off the steel bottom spring seats.
I have used valve springs from different manufacturers and their spring pressure can differ a lot. That's why I always shim every head race or street!

I started at 230 lb over the nose on my 500 with a PW3 cam but have been coming down ever since. Im now at around 215 lbs and no valve contol issues at 8500. (The 500 has a smaller inlet valve than the Commando so maybe I can come down more ). My valve train has standard followers and pushrods but I spend a lot of time on the valve spring set up.

Its very important to inspect the standard followers very carefully. In older engines I have inspected more than half the followers have the stellite pads cracked or only partially attached. If you warm them a little you can see oil coming out from under the sellite pad where the weld (or braizing??) has failed. There was a period around 10 plus years ago where all spares were badly made and the pads fell off.


Because of the difference in rod stroke ratio I actually retard the cam in the 500 about 5 degrees. Advancing makes sense for the Commando. The 4 S cams I have measured have big diferences (5 plus degrees) between cam timing using the standard key ways. Two PW 3 cams measured up within 2 degrees.

The Triumph lifter stems are smaller diameter and can break (especially when raced with hot cams) - the BSA lifters do not break.

Some early JS cams did not have the keyway perfectly located and needed the cam timing checked and adjusted (needed to be advanced). I spent some time & money getting the cam grinder to fix this.

Hi Jim, you wrote "I really have not seen much difference in the needed spring pressure with the lighter followers".

Have you actually compared back-to-back, with stock lifters and light ones, to see if you can reduce valve spring pressure? It would be a good test to do.
The reason I ask is thus: I'm new to Nortons, but not old Brits. I raced Triumphs of various configurations in BHR, and rode for Dresda for a while. Dave Degans of Dresda is obsessed with lightweight valve train and springs.
We would put in 6mm stem valves (4mm on Nourish motors) and do all the usual lightening. But all of this was done simply to allow the lightest possible spring for a targeted red line.
Motors in which this was done were noticeably different, not necessarily on the dyno, but in the way they picked up revs when the throttle was blipped and in reduced vibration.
I once raced a 500cc Nourish engine with stock valves and it would get valve float at 6250rpm. When discussing with Dave Nourish, he said I shouldn't be going over 6250! But advised fitting K springs, which are heavier, if I wanted to.
With the K springs fitted, the motor simply would not rev above 6200!! Not due to float, simply due to the fact that this was the max rev ceiling with these springs.
Dave Degans 500cc Nourish based Triumph engine, with 4mm stem valves etc, would rev to over 11,000.
I realise that none of the above is conclusive proof of anything, but it does seem to strongly hint that reducing spring pressure will lead to improved performance.

Chris said:

Hi Nigel

SRM do this conversion I believe.
I am sure you could use the Triumph followers but you would have to make a holder for them.
I think I have previously posted a link to the Mez porting site ( He was superb) I will try & find the link. I think he had a photo of his conversion.

all the best Chris

Click to expand...

Chris,

I have been in touch with SRM several times during the year on this one. They do not currently have any A65 followers, nor am I aware they have done a conversion.

They are in teh process of trying to develop a suitable A65 follower, but not ready to market anything.

Notice that Jim Schmitt only lists them as part of a cam kit, and I know from contact with him that he would like a source of more followers.

But...as JimC says, not really an issue unless you expect to run at up to 9000 in a short stroke, I am expecting to run mine up to 8000!

I am a bit concerned however that the stellite feet of standard followers do occasionally drop off.....

There is already a comment about this above, anymore anyone?

Oh! and when discussing lightening the standard follower, where do you safely take weight from?

extremely lightened racer risky

Fast Eddie said:

Hi Jim, you wrote "I really have not seen much difference in the needed spring pressure with the lighter followers".

Have you actually compared back-to-back, with stock lifters and light ones, to see if you can reduce valve spring pressure? It would be a good test to do.
The reason I ask is thus: I'm new to Nortons, but not old Brits. I raced Triumphs of various configurations in BHR, and rode for Dresda for a while. Dave Degans of Dresda is obsessed with lightweight valve train and springs.
We would put in 6mm stem valves (4mm on Nourish motors) and do all the usual lightening. But all of this was done simply to allow the lightest possible spring for a targeted red line.
Motors in which this was done were noticeably different, not necessarily on the dyno, but in the way they picked up revs when the throttle was blipped and in reduced vibration.
I once raced a 500cc Nourish engine with stock valves and it would get valve float at 6250rpm. When discussing with Dave Nourish, he said I shouldn't be going over 6250! But advised fitting K springs, which are heavier, if I wanted to.
With the K springs fitted, the motor simply would not rev above 6200!! Not due to float, simply due to the fact that this was the max rev ceiling with these springs.
Dave Degans 500cc Nourish based Triumph engine, with 4mm stem valves etc, would rev to over 11,000.
I realise that none of the above is conclusive proof of anything, but it does seem to strongly hint that reducing spring pressure will lead to improved performance.

Click to expand...

I would have to agree with your reasoning. I can not say I have done comprehensive testing between the stock lifters and BSA followers but I have played with spring pressures both with stock lifters and BSA lifters and generally found the same springs seemed to work best with either lifter on my racebike. It's very possible that the reason was simply that the choice of springs I had available was not good enough to dial it in exactly to what it needed.

The last experience I had with springs was on my streetbike. A few years back when I was working on my fuel injection system I had noticed my bike would seem to hit a wall at around 7000 rpm. It would go flat before it hit the rev limiter which was set at 7500. I removed the R&D springs which were set at about 100 lbs on the seat and installed Kibblwhites at 130 on the seat. The bike immediately reved to the limiter easily and made a few more horses doing it. The bike has BSA lifters and lightened rockers but it has a cam with steep ramps. Jim

SteveA said:

Chris said:

Hi Nigel


Oh! and when discussing lightening the standard follower, where do you safely take weight from?

Click to expand...

Click to expand...

I will not lighten stock followers. The only time I tried it I ended up with a two piece follower. Luckily it stayed in the hole. Jim