Ebay combat

Hi guys this has just been listed not too far from me. Any comments or thoughts regarding the rebuild etc would be appreciated as i might be interested at the right price, for starters i had thought anything past 1970 had electric start but i cant see any , the spec sheets are a bit hard to read but i was hoping the numbers would assist in finding out its detail

sorry i dont know how to link it but if you copy and paste into a web browser it should come up

http://cgi.ebay.com.au/norton-commando- ... dZViewItem

being a performance model ( combat ) it came with a lot of extras not fitted to the standard commando which include

reinforced crankcases, err no, exact opposite, lost the guaze oil filter and oil pickup in wrong position

high lift cams Yes

larger 32mm carbs Yes
RH5 cylinder head Yes but check for a big C stamped on head to verify

higher compression ( 10 to 1 ) Yes, but ask if pushrods have been shortened which the factory for got to do
extra crankcase ventilation Yes but in wrong position, this needs to be moved up and run off the old magneto position.
front disc brake Yes

it has matching frame, motor and gearbox numbers, and has recently had the motor rebuit and gearbox inspected at a cost of over 3.500 dollars

The rebuild seems to have missed some of the important mods for a Combat, the news main bearings fitted cure the biggest fault but it would have been good to cover the rest.

It looks to me like a MkV 750 and they did have stronger crankcases around the main bearings (but still the breather /scavenge problem). If you look behind the timing case, you can see that it has no steel cover there which is the most visible difference.

With a motor in good condition and depending on useage, you may experience no problems with the rear breather set-up. Thousands of these were used for years and most of us had no idea of the deficiencies.. It does seem to be more of a problem these days but I have no idea why.

There is no mention on the spec sheet of which cam is actually fitted. It may well have a 2S (Combat) cam. The head and barrel joints look a bit further away from each other than I would expect for a skimmed-head Combat model.

It may be worth asking what the owner or his garage set the tappet clearances to.

Although the bike has had a lot of work done, it wasn't a money-no-object rebuild and the price should reflect that.

The electric tart (well mine was !) :roll: only appeared in 1975 on the Mk111 850s.

Thanks for the advice guys, I will look further into it, for the right price it seems like a nice bike, (apart from the paint and blacked out bezels and pipes) which is an individual thing of course

According to Bacon's book 'Norton Twin Restoration' the chassis number listed is from 1973. The square tail lamp would seem to reinforce this. I mention this not to be pedantic (that is merely a bonus) but because with the various well-documented problems with the combat motors Norton had more or less stopped production of them by this date. The seller claims that it has an RH5 head fitted, this is a low compression head and possibly confirms that the engine is not a Combat spec. 79X100 being a knowledgeable and observant chap has also expressed reservations about the head/barrel clearance.

dave M said:

79X100 being a knowledgeable and observant chap has also expressed reservations about the head/barrel clearance.

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Oh I'm blushing

It does seem a nice enough bike. I have no idea about Australian prices but that apart, I would have no reservations about buying it and running it as it is, just bear in mind that if it has scavenge or breather problems you know where the answer lies (plenty of threads on this forum).

Everything about it looks '73 MkV to me although they could have been changed - 'aertex' seat top rather than ribbed, square tail light, silver cylinders etc. By bezels, do you mean the long black clockholders ? They were standard for 1973 to facilitate the fitting of the deeper Vaguelia clocks to some models. They don't polish up all that well and are different. Short alloy clock holders are available new (I think) but they are over-buffed and don't have such a nice clean shape as the originals

Definitely looks like a well skimmed head to me. On std non skimmed heads the joint is visually nearly the same as fin spacing. I have a Combat and it's very close to the pic.

kommando said:

RH5 cylinder head Yes but check for a big C stamped on head to verify

higher compression ( 10 to 1 ) Yes,

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No, - the Combat head was the RH3, according to the information I have.

The (8.9:1 C/R) RH5 & RH6 (9.3 C/R) were the heads introduced on the detuned Combats and later 750s, those detuned Combats apparently could have had silver barrels as the 1973 models did.

Also, the first detuned Combat was listed as being engine number 211110, so 213264 would have been a detuned one or probably was just the standard model again by that time, originally.

79x100 said:

Everything about it looks '73 MkV to me

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I think it could be one of those 1973 (MkV) spec. MkIV models that were sent to the USA. As, according to all known records, the MkV 750 models started at engine number 220000.

dave M said:

According to Bacon's book 'Norton Twin Restoration' the chassis number listed is from 1973. The square tail lamp would seem to reinforce this.

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I think Mr. Bacon could be a little adrift with the date there, - if you were using the 212278 number as a reference for the start of 1973 750 production?
Steve Wilson lists 212278 as being from November '72 production in his Norton book , and the factory did appear to have the habit (from '72 I think?) of building batches of machines out of numerical order for whatever reason, which is probably why the Commando serial numbers don't always appear to follow on in the expected chronological order?

It would be useful to know what production date is stamped on the frame plate of this eBay Commando?

Again Thanks for the input, on the spec sheet it has compression at 170/180 is the difference a problem and within range,? it also mentions the ISO clearance and a couple of worn gears in the spec, these are not major fixes if i am correct,As a weekend social rider I doubt i could push the limits of any engine so the weekness,s of the combat may not be as relevent to me altho i am sure all the fixes and recommendations are on the forum

Rockyrob said:

on the spec sheet it has compression at 170/180 is the difference a problem and within range,?

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As the difference is less than 10% between the cylinders, - then there's no need to worry.
That level of compression does seem to indicate the compression has probably been increased over the standard RH5 ratio.

Rockyrob said:

it also mentions the ISO clearance and a couple of worn gears in the spec, these are not major fixes if i am correct,

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Those things shouldn't be too much of a problem. And I'd want to check/change the layshaft bearings anyway if it were mine?

I read somewhere years ago (was it the NOC Service notes or was it Motorcycle Mechanics 'Bargain or Banger' series in the 1970s ?) that once Norton's Warranty Department realised what a problem they had with the Wombats, quite a number of them went down the line a second time to be rebuilt to 'standard' spec which caused all sorts of build date and specification oddities.

If my rapidly deteriorating eyesight read the receipts properly, this bike has had gearbox bearings so we're only talking about tooth wear which is rarely catastrophic.

The bike looks quite nice and seems as though it has had some worthwhile work done recently, so at the right price I would buy it, however if there is some kind of premium attached to it for supposedly being a Combat model, when this appears not to be the case (as indicated by the vendors own declaration that it has an RH5 head), then I would not go above what I would pay for a standard bike.

79x100 said:

I read somewhere years ago (was it the NOC Service notes or was it Motorcycle Mechanics 'Bargain or Banger' series in the 1970s ?) that once Norton's Warranty Department realised what a problem they had with the Wombats, quite a number of them went down the line a second time to be rebuilt to 'standard' spec which caused all sorts of build date and specification oddities.

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Steve Wilson mentions in his book 'Norton Motor Cycles' about 'time travelling Combat machines'.

Quoted from Steve Wilson's 'Norton Motor Cycles':
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"[Neale] Shilton describes batches of machines going back and forwards from Wolverhampton to Andover for fitting and then removal of gaskets, and Norton management to their credit had all machines in stock fitted with the new mains, a quieter cam, and lowered gearing. This probably explains the matter of the time-travelling Combat machines mentioned earlier, [in the book] as numbers got out of sequence."
__________________________________________


And that could certainly explain why various '72 date stamped machines left the works with '73 MkV parts on them if they had only been partially assembled originally, or certain original parts were removed from them to be used on the production line, and newer MkV parts were fitted later, if those '72 machines were not fully completed until the very end of '72 or perhaps early '73?