72 750 Combat Roadster project

Richard Tool

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Hi all - new member here . Here are a couple of shots of my current project .

I owned this bike for a few years and started a rebuild of it shortly before Superstorm Sandy hit us . At that time I had built new wheels in stainless, drilled the rotor and had it Blanchard ground and sleeved the master cylinder.
I only had one lift at the time and so the ES 2 went on it and had to make do with an ATV jack to lift the Commando. We had to evacuate and on our return I found the ES 2 fine but the Commando got wet up to the axles / mid timing chest. Fortunately the new wheels were safe in our bedroom ( I have a very understanding wife ) - to make a long story a little shorter , life got in the way for a bit and the Commando moved to the back of the line . Five years to the day after the storm I was able to return to working on it. Total tear down , new main frame as seawater had found its way in to the tubing and worked it’s magic over five years . Media blast and refinish of remaining chassis components . All new bushings , bearings everywhere- gearbox rebuilt , cylinder head rebuilt , and now into the bottom end . Thanks for looking !

Cheers- Richard

Oops ! Sorry- looks like I don’t know how to post images here - have to get url code - pics to follow
 

NPeteN

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Hey Richard,
Here is how you can post photos.
Upload your photos on a hosting site like this one https://postimages.org/
Then copy the "hotlinks for forum" link found below your uploaded photo then paste it in the body of your post.
Or, you can become a VIP member and upload photos directly.
 

Richard Tool

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Thanks NPeteN - I have an Imageshack account so I will try that tomorrow- what is the cost of VIP membership ? I have only just joined today .
 

NPeteN

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40$ a year. Lump sum or 10$ quarterly.

There are great people here willing to help with whatever you need. Genuine Norton freaks who will gladly go out of their way to help you with the minutia of your project.

$$ is by no means expected but a great way to support the forum.
 

Fast Eddie

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Lookin’ good Richard...

Are you keeping this Combat as a full blooded Combat?

Or are you castrating it with soft cam, soft pistons, single carb, etc as seems to be the fashion these days?!
 

Richard Tool

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Lookin’ good Richard...

Are you keeping this Combat as a full blooded Combat?

Or are you castrating it with soft cam, soft pistons, single carb, etc as seems to be the fashion these days?!
Hi Eddie - slow Richard here -

Full Combat - low mileage so original cam , cam bushes , crank journals good so just disassembly ,cleaning and new bolts for crank, new big end shells & rings - new super blend mains - original hepolite pistons were fine - new oil pump as the original had sadly developed an appetite for munching on bits of piston ring that found their way into the sump sometime in the long ago. I have purchase a pair of the new Amal’s with the supposed hard anodized slides and modern fuel compatibility- nothing really wrong with the originals other than idle issues when hot so hopefully the new ones with the more durable slides will cure that . I fitted new guides, valves , springs, etc. in the head - rockers and shafts were fine but the valves and guides had considerable wear - likely due to lubrication issues from the dodgy pump . Thanks for looking in.
 

grandpaul

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What a great-looking progress shot up there on the stand. Should be quite the looker soon...
 
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Great looking bike. Quick question about Combats. Other than the C on the head is it possible they built a Combat with no C on the head? My bike vin shows built November 72 but titled as a 73. My bike came with a disc and a vent tube off the rear lower engine. Fin gap between head and barrel is very close compared to the other fins. I heard the Combats came with disc and vent in 72???
 
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NPeteN

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Proper workspace. Looks fun but don't let it keep you off the beach!
 

L.A.B.

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Quick question about Combats. Other than the C on the head is it possible they built a Combat with no C on the head? My bike vin shows built November 72 but titled as a 73.
November '72 is rather late for it to have been a Combat. If the serial number is later than 211110 then it's almost certainly not a Combat.

Is the head stamped RH5 or RH6?


My bike came with a disc and a vent tube off the rear lower engine. Fin gap between head and barrel is very close compared to the other fins. I heard the Combats came with disc and vent in 72???
The disc brake and two versions of lower compression 32mm cylinder head (RH5 & RH6) and 32mm carbs continued to be fitted after Combat production ended.

Although often referred to as a 'Combat breather' the presence of the lower rear engine beather does not conclusively identify a Combat because all '72 and '73 750 production (from eng. 200000) had that breather and all Commandos tend to have less gap between the barrel and the head fins.
 
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November '72 is rather late for it to have been a Combat. If the serial number is later than 211110 then it's almost certainly not a Combat.

Is the head stamped RH5 or RH6?




The disc brake and two versions of lower compression 32mm cylinder head (RH5 & RH6) and 32mm carbs continued to be fitted after Combat production ended.

Although often referred to as a 'Combat breather' the presence of the lower rear engine beather does not conclusively identify a Combat because all '72 and '73 750 production (from eng. 200000) had that breather and all Commandos tend to have less gap between the barrel and the head fins.
Thanks for the info. Where would the RH numbers be?
 

Richard Tool

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Great looking bike. Quick question about Combats. Other than the C on the head is it possible they built a Combat with no C on the head? My bike vin shows built November 72 but titled as a 73. My bike came with a disc and a vent tube off the rear lower engine. Fin gap between head and barrel is very close compared to the other fins. I heard the Combats came with disc and vent in 72???
Make sure you look very closely as sometimes the stamp is barely there - see photo of my cylinder head
 

grandpaul

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It is common knowledge that there are more "C" stamped heads to be found, than the actual number that the factory ever produced and stamped...
 
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I heard the Combats came with disc and vent in 72???

All 72's had the breather vent on the rear of the cases, if you ordered a disc then you got the Combat engine by default as they were linked options, but a lot can happen in 40 odd years and adding a disc front end later is not unknown.
 

Richard Tool

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I posted this a while back on NOC site - As I am tarting up my Commando with Stainless Bling I am doming all the boltheads and thought it might be of interest to others here and be useful to those who use a lathe .

I struggled making domed fasteners for my ES2 by roughing out with straight cuts using the compound tool post then finishing by hand with files , etc. A little searching around the internet found various fixtures with varying levels of quality and cost so I thought I would make my own. The cost for all the materials was under $ 150 USD.

As shown this unit will cut radii from 0" to 2 7/16" and swing through 23 degrees of arc from center - more than enough for any fasteners involved. By using countersunk flathead fasteners for hold down one can gain a full 90 degrees of arc for hemispheric facings as this will allow the radial arm to pass over the hold down. A larger base plate would benefit this as it would offer more support beyond 25 degrees or so.

Here is a list of materials -

1/4" x 6" x 6" precision ground steel - base plate (1)

1/4" x 2 1/2" x 6" precision ground steel - radial arm (1)

1/2" dia. x 12" precision ground steel - cutter handle (1)

2 1/2" x 2 1/2" x 6" aluminum block - turret (1)

5/16" x 1 1/2" Hex bolt w/ washers/ nut - pivot bolt (1)

1/4" x 20 x 1 1/2" FH screws - turret/arm fasteners (4)

1/4" x 20 x 1" socket head cap screws cutter handle clamps (2)

indexable cutter with screw (1)

Keep in mind that the combined thicknesses of base, arm and pivot bolt head and washer must clear the bottom of the lathe chuck.




 

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