1972 750 Interstate Resurrection

[CanukNortonNut]

I am sorry TJBaker.
My first post was too sharp in tone.
I would like to give you a good piece of advice with the 1972+ M/C
They were 5/8 bore and feel like your pressing two pieces of wood together on the disk to stop you. That is my experience with the operation. Not good for rapid stopping power.
Change it to 13mm bore for today's type of driving with vehicles that have 4 wheel disk brakes and ABS... That is if you want to ride it in today's traffic.
IMHO.

 

[marshg246]

Great - you can count on it being right. In case Matt didn't impress it enough - be damned sure it gets there in September! Consider sending your oil tank at the same time. I use that service on every Commando build that has a side mounted tank.

Colorado Norton Works Norton Commando modifications by Colorado Norton Works Custom Norton Motorcycles

Norton Commando modifications by colorado norton works

coloradonortonworks.net

Good news! I've been talking to Matt and he has decided to offer crank turning four times a year so much better now for winter rebuild projects. The service can be found here now: https://coloradonortonworks.net/cnw-machining-services

As most know, cNw does quality work - let's support them!

 

[TJBaker57]

I am sorry TJBaker.
My first post was too sharp in tone.

Seemed fine to me. I am a sometimes fan of brevity.

Change it to 13mm bore for today's type of driving with vehicles that have 4 wheel disk brakes and ABS... That is if you want to ride it in today's traffic

Noted. Though I haven't ridden since like 1982 I drive with great caution always. I am that annoying old fart that does the speed limits and nothing more. No doubt pisses off a lot of folks behind me. I leave an abundance of space in front of me as well, generally gauged by the speed I am travelling.

That said, one cannot predict when a deer will dash out in front of you.

As I go through this bike my current notion is to skip or postpone the items that would be an easy repair/upgrade after the rebuild is done. If the part or system will work with a little rebuild I'm good with it, "for now".

Things like this crank regrind etc. are another matter. Anything deep in the engine I will do.

Greg suggested I let Matt do the oil tank upgrade. That seems like a good idea given that it would be a pain to get the oil tank out later.

I won't know my level of interest in riding until after the bike is back on the road. I can consider simple upgrades then.

 

[CanukNortonNut]

Noted. Though I haven't ridden since like 1982 I drive with great caution always. I am that annoying old fart that does the speed limits and nothing more. No doubt pisses off a lot of folks behind me. I leave an abundance of space in front of me as well, generally gauged by the speed I am travelling.

That said, one cannot predict when a deer will dash out in front of you.

As I go through this bike my current notion is to skip or postpone the items that would be an easy repair/upgrade after the rebuild is done. If the part or system will work with a little rebuild I'm good with it, "for now".

I would priorities safety items first. Brakes are #1 on my list.
But that's just my opinion.

 

[marshg246]

I would priorities safety items first. Brakes are #1 on my list.
But that's just my opinion.

I know the 13mm M/C is a popular "upgrade". If I need a new M/C, then I buy one. Otherwise, there are WAY less expensive ways to improve braking. IMHO, the 13mm M/C moves less fluid for a given lever pressure. To me, the stock Norton front brake sucks and the difference in stopping has much more to do with the condition of the rotor, how well the caliper is bled, the hoses, and the strength of your right hand.

 

[CanukNortonNut]

I know the 13mm M/C is a popular "upgrade". If I need a new M/C, then I buy one. Otherwise, there are WAY less expensive ways to improve braking. IMHO, the 13mm M/C moves less fluid for a given lever pressure. To me, the stock Norton front brake sucks and the difference in stopping has much more to do with the condition of the rotor, how well the caliper is bled, the hoses, and the strength of your right hand.

Greg,
I totally agree that the Stock Front Norton brake system sucks! You need the arms of a Silver back to try and stop the bike. There is a kit from RGM that convert the existing M/C to 13mm but requires machining and a Metric tap and a drill to complete. Some have had issues trying to bleed the system with this kit so I guess it's not for everyone.
The 13mm ratio for M/C to caliper is closer to the ideal 27:1 ....not perfect, but good enough for today's traffic.
https://vintagebrake.com/mastercylinder.htm
There is also a stripped down version that Andover sells which require you to use your existing M/C components. So at a slight reduced price.
https://andover-norton.co.uk/en/shop-details-2/15702
nice if your want it to stay looking stock with the switch gear.
What I have on my ride is the 13mm conversion from RGM.
Ferodo Platinum Pads, A stainless steel braided brake line (Russell), and I Blanchard ground the contact surface of my disk and lightened the disk with a hole pattern.
EBC pads are also a good choice.
It keeps the bike looking relatively stock but with much better braking.
Then there is cNw from Matt or Madass140, Don in the Philippines have some great brake kits.
A more modern brake system and the price that goes with it.

 

[marshg246]

Greg,
I totally agree that the Stock Front Norton brake system sucks! You need the arms of a Silver back to try and stop the bike. There is a kit from RGM that convert the existing M/C to 13mm but requires machining and a Metric tap and a drill to complete. Some have had issues trying to bleed the system with this kit so I guess it's not for everyone.
The 13mm ratio for M/C to caliper is closer to the ideal 27:1 ....not perfect, but good enough for today's traffic.
https://vintagebrake.com/mastercylinder.htm
There is also a stripped down version that Andover sells which require you to use your existing M/C components. So at a slight reduced price.
https://andover-norton.co.uk/en/shop-details-2/15702
nice if your want it to stay looking stock with the switch gear.
What I have on my ride is the 13mm conversion from RGM.
Ferodo Platinum Pads, A stainless steel braided brake line (Russell), and I Blanchard ground the contact surface of my disk and lightened the disk with a hole pattern.
EBC pads are also a good choice.
It keeps the bike looking relatively stock but with much better braking.
Then there is cNw from Matt or Madass140, Don in the Philippines have some great brake kits.
A more modern brake system and the price that goes with it.

Yes, every bike I build has the rotor sent to TrueDisk (https://truedisk.net) or it is replaced.

I have used the AN 13mm when requested or when I need to buy a M/C.

I've installed cNw's and Don's brakes - they actually work.

I generally use Ferodo pads but the AP pads that AN sells work fine too. My rider currently has a completely stock setup with EMGO pads and it works almost as well.

I'm not a fan of the RGM 13mm upgrade. I have also installed the Triumph M/C on a Norton - quite a bit better and still uses the console.

Most Commandos I take in for repair or I buy to rebuild have a partial bleed on the caliper. The Norton caliper is simply stupid engineering with the inner chamber air having to come out the hole the fluid is going in. On top of that many calipers don't have that hole fully drilled so it's nearly impossible to bleed the inside chamber unless you finish the drilling. So, I go the messy route and fill the chambers on the bench so there is no air in the inside or outside chamber when I mount the caliper and I fill the M/C and line so when I connect the line there is almost nothing to bleed and certainly no air in the inside chamber. There is a BIG difference when there is no air in the system!

 

[grandpaul]

Greg,
I totally agree that the Stock Front Norton brake system sucks! You need the arms of a Silver back to try and stop the bike. There is a kit from RGM that convert the existing M/C to 13mm but requires machining and a Metric tap and a drill to complete. Some have had issues trying to bleed the system with this kit so I guess it's not for everyone.
The 13mm ratio for M/C to caliper is closer to the ideal 27:1 ....not perfect, but good enough for today's traffic.
https://vintagebrake.com/mastercylinder.htm
There is also a stripped down version that Andover sells which require you to use your existing M/C components. So at a slight reduced price.
https://andover-norton.co.uk/en/shop-details-2/15702
nice if your want it to stay looking stock with the switch gear.
What I have on my ride is the 13mm conversion from RGM.
Ferodo Platinum Pads, A stainless steel braided brake line (Russell), and I Blanchard ground the contact surface of my disk and lightened the disk with a hole pattern.
EBC pads are also a good choice.
It keeps the bike looking relatively stock but with much better braking.
Then there is cNw from Matt or Madass140, Don in the Philippines have some great brake kits.
A more modern brake system and the price that goes with it.

I hear this point of view often. More and more, I'm wondering if it has to do with a critical rider weight.

I weigh 145 now, but most of my Commando-owning years, I weighed closer to 125. I never found the stock brake, if properly sorted, to be inadequate, even in a panic stopping situation. Even at 145, it seems OK, though I never ride my Commandos at any "high" speeds, so never felt short of brakes.

I wonder if most of the complaints with a PROPERLY SORTED stock front disc setup are riders at 150# or higher?

Again, "just wondering"...

 

[marshg246]

I hear this point of view often. More and more, I'm wondering if it has to do with a critical rider weight.

I weigh 145 now, but most of my Commando-owning years, I weighed closer to 125. I never found the stock brake, if properly sorted, to be inadequate, even in a panic stopping situation. Even at 145, it seems OK, though I never ride my Commandos at any "high" speeds, so never felt short of brakes.

I wonder if most of the complaints with a PROPERLY SORTED stock front disc setup are riders at 150# or higher?

Again, "just wondering"...

Could be - the lowest I've been as an adult is 230 and that's a dream these days. There is no doubt that any bike will stop faster with you onboard rather than me.

On the other hand, my Trident stops much better than my Norton - better caliper and better M/C so Lockheed was able to do better.

 

[concours]

 

[acotrel]

I appreciate what you are doing and I wish you well, however I would not do it. The 850cc Commando engine is excellent. And the bikes look lovely, but some things give me nightmares.

 

[TJBaker57]

Some tasks are no doubt easier without 'helpers'.

 

[marshg246]

Some tasks are no doubt easier without 'helpers'.

View attachment 121652

He/she has the look of "what the hell is wrong with you?" Funny how cats want to "own" anything new.

 

[armadefuego]

He/she has the look of "what the hell is wrong with you?" Funny how cats want to "own" anything new.

any thing "New"? anything that takes your attention away from the most important thing in the world... them... unless, of course they don't want attention.
Then they want you to give you some, so they can spurn you.

 

[TJBaker57]

Cannot really get any sort of measurement of what clearance I have now but I'm hopeful it is adequate. With no gasket and all surfaces clean the cam now rotates freely.

That said, when it's time to put this engine together with a replacement 2S cam I will again check the clearances in the same fashion. If I need to further adjust the clearance I can go at it again.

Got a new 2S profile cam (Hepolite) from @marshg246 and rechecked clearances to the bottoms of the cam followers bore skirts. Back in contact again so more grinding is in order. And I'll be revisiting this once again after new cam bushes are installed at cNw.

This time to get an idea of how much material has to come off I shimmed the barrel to crankcase with a few sets of feeler gauges to see how far I needed to raise the barrels to allow cam rotation. No base gasket in place.

I began at .010" and increased by .004" increments.

.010" not enough
.014" not enough
.018 not enough, but got a little improvement, contact being made closer to full lift.
.022 achieved free rotation of the cam.

So I think this gives me an idea of how much to go though I have no way to accurately measure it as I go.

The exhaust lobes never contact the bore skirts, not now and not previously.

I find the whole business rather bizarre.

 

[marshg246]

Got a new 2S profile cam (Hepolite) from @marshg246 and rechecked clearances to the bottoms of the cam followers bore skirts. Back in contact again so more grinding is in order. And I'll be revisiting this once again after new cam bushes are installed at cNw.

This time to get an idea of how much material has to come off I shimmed the barrel to crankcase with a few sets of feeler gauges to see how far I needed to raise the barrels to allow cam rotation. No base gasket in place.

I began at .010" and increased by .004" increments.

.010" not enough
.014" not enough
.018 not enough, but got a little improvement, contact being made closer to full lift.
.022 achieved free rotation of the cam.

So I think this gives me an idea of how much to go though I have no way to accurately measure it as I go.

The exhaust lobes never contact the bore skirts, not now and not previously.

I find the whole business rather bizarre.

View attachment 121878View attachment 121879

I'm sure you already did, but say again the engine serial. I just put together 205578 with a 2S cam and there are no clearance issues. Most of the bikes I build are Combats and I've never had an issue.

 

[TJBaker57]

I'm sure you already did, but say again the engine serial. I just put together 205578 with a 2S cam and there are no clearance issues. Most of the bikes I build are Combats and I've never had an issue.

Mine is 208482. Am I right in thinking that in Combat models they machine the bottom of these follower bores differently for clearance for the 2S cams??

If so I would suspect they forgot that step for mine !!

I just finished relieving the timing side and checking the clearance. No base gasket.

Here's what I am doing this time around. With the case halves and camshaft assembled I read the depth from the crankcase deck down to the intake lobe at its highest point. I got 15.28 mm.

I then checked the tunnel bore height from the barrel deck at the same location using the center front stud hole as a reference. This has already been ground down once and reads like 15.75 mm.

The exhaust side has not been touched and it reads about 16.20 mm. There has not been any clearance issues on the exhausts.

I took the intake side of the bore skirt down to 15.00 mm.

The first time I did this I used a small barrel sander bit and a Dremel. I recently discovered I have a larger barrel sanding bit that fits nicely. Just needed to proceed cautiously as the drum I have is coarse grit and that is some soft metal there.

My first test fit revealed I still had the tiniest little high spot at the most forward spot so I addressed that and retested. Am good now on the timing side and will repeat for the drive side.

 

[marshg246]

Mine is 208482. Am I right in thinking that in Combat models they machine the bottom of these follower bores differently for clearance for the 2S cams??

If so I would suspect they forgot that step for mine !!

Very unlikely, especially if it left the factory as a Combat! Do you know the history? Is there any evidence that the cases have been decked?

I have 208558 listed for sale. If it doesn't sell, I'm going to take it apart and put it in bins. It definitely has always been a Combat. So, if I do take it apart, I'll check.

 

[TJBaker57]

Do you know the history?

It was first sold in March 1973. I bought it in November 1975. I have registrations from 2 previous owners, however,,, there are large gaps in time between these registrations. So it is hard to say with certainty what may have transpired before I acquired the bike.

I have reciepts for parts when the owner prior to me had replaced the main bearings and rod bearings etc. and had a Kawasaki shop do the final assembly. I suspect the Kawasaki shop also sold Nortons which seemed common then.

In February of 1976 I recorded the odometer at 7850 miles. Would it seem odd for a bike with that mileage to have had such modifications as decking??

 

[marshg246]

It was first sold in March 1973. I bought it in November 1975. I have registrations from 2 previous owners, however,,, there are large gaps in time between these registrations. So it is hard to say with certainty what may have transpired before I acquired the bike.

I have reciepts for parts when the owner prior to me had replaced the main bearings and rod bearings etc. and had a Kawasaki shop do the final assembly. I suspect the Kawasaki shop also sold Nortons which seemed common then.

In February of 1976 I recorded the odometer at 7850 miles. Would it seem odd for a bike with that mileage to have had such modifications as decking??

So, you owned the bike in 1976? Was it running? If both are true, how is there a clearance issue now? Feel free to call me!