Just bought my first Commando

Get a V4 box of plugs of normal middle of the road Cdo heat range first as may find a better one after the first round of tuning clearing coughing done. Start ups in dark may give a clue too. Pilot air screw is only thing external screwable with and worse event just stalls, which is a good thing as means floats in ballpark to be air screw responsive and most only affects starts and idle and low rpm response. They are such simple machines what could go wrong? Keep the cut off allen wrench in road tool kit.

hobot said:

Get a V4 box of plugs of normal middle of the road Cdo heat range

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I chased a bad left carb for two days. After opening the carb twice to clear the pilot jet, then moving plugs, wires, and coils back and forth, a new set of plugs brought it to life. Yes, they can be rather temperamental and illogical!

Nathan

Hi.
Please confirm 30mm carbies - should have 930 on the carby bodies.
932 if they are 32mm.

Nathen that's so classic made my wife looks so laughed as much as me. I feel so helpless so often I need constant refreshing with surprise things I never imagined. My heart sunk on where to begin with a newbie innocent inquiry. More than once having a failure mystery or re-assembly fumble - non firing kick overs or back fires or stall outs could foul a good plug even re-cleaned or new so even after ya fixed the initial source it still does same thing. Its not very common occurrence mind you so tend to forget till like Sherlock says about eliminating the possible only leaves... Peel once had handflul of issues each one doing about the same thing it took six of world famous Nortoneers hours of back firing cherry red pipes to the mufflers, till a jar of Kickapoo Joy Juice, 4 glups each let Rod sharped senses remotely sensed 8 ft away d/t lack of room with all the elbows and butts = a click behind trigger plate, then someone else found the shorting coil, then I found a failing fuse then another found broken ground then another a bad plug. Classic treasure hunt ensued over many acres of camps INOA rally to only find *one* used non R plug - that turned Peels Bulbsthatlastforever into syncopated single timing light show after dark. Then horns and hollars from acres of campsites implied time to shut show off.

One more for the newbie on scope of a Commando owner, Peel with boyah gradually developed miss fires I could not reproduce but intermitent riding. Months of this finally got very bad crossing pasture and noticed the cuts out were with bumps then it died. I already knew where I'd been too many times already so out of frustration operation on myth of nothing to loose I opened tail light to find the braided return lead had frayed and shorting on the hot parts of blub mount. Such simple machines dive right in .

Carbs are 930s

Old Scratcher said:

Carbs are 930s

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Hi again.
Some info to help identify your bike model.
1. With 30mm manifolds and carbies, the head is not likely to be a Combat version as they have 32mm inlet throats, manifolds and carbies (still could be, if someone fitted smaller carbies and manifolds but unlikely).

2. A 'C' stamped (or not) into the head under the front of the top engine mount can confirm for Combat.

3. Is the gap between the lower head fin and the upper barrel fin smaller than the other fin gaps?
The head was shaved 1mm to increase the compression for the Combat version head.

I can't see the C, but the fin gap is noticeably narrower where the head meets the barrel.
It's engine/frame no is 211412, if that helps

Old Scratcher said:

...It's engine/frame no is 211412, if that helps

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It is in the Mark IV 750 engine/frame number range when disk brake and Combat engines were options.
Could still be but the 'C' is the clincher. Good score regardless!

Old Scratcher said:

It went first prod this morning, though it's still running rough. I think it's the L/H cylinder that's the problem, as it's the one that's backfiring. I'm thinking it might be running rich. I've never worked on these kind of carbs before, so I'm loath to go fiddling with the mixture screw without taking some advice. Putting a carby kit into both, & balancing them, would cure all ills. But it could be overkill, & I'd rather spend my limited money supply for this project on things that need to be done. What do others think?

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Renew your spark plugs. That was my cause of backfiring in the last 2000 miles or so. Another cause of backfiring can be a loose or leaking head to front pipe join.
Bike looks good. Ute looks good. Nice to see another music man in the clan.

Dereck

Old Scratcher said:

Nice to see another music man in the clan.

Dereck

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I never thought to show my axe in the photo. I'll have to do that the next time she's in the den, which isn't very likely for a while as it's going to be in the 60's this weekend! At least you'll have your winter to work on yours.

And, if any of you are in the Treasure Valley area of Idaho next week, Idaho Vintage Motorcycle Club is having their annual Spring Ride and Bike Show in Caldwell on the 21-22nd.
http://www.idahovintagemotorcycleclub.org/images/posters/2015-show1.jpg
http://www.idahovintagemotorcycleclub.org/images/posters/2015-show2.jpg

Nathan

Old Scratcher said:

I can't see the C, but the fin gap is noticeably narrower where the head meets the barrel.
It's engine/frame no is 211412, if that helps

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All Commandos tend to have a narrower gap between fins at the head joint-including the 850 models, so, as noticeably narrower can be open to interpretation therefore it isn't a particularly reliable way of identifying if it is (or is not) a Combat head.
211412 would also place it outside the official Combat production series.

L.A.B. said:

Old Scratcher said:

I can't see the C, but the fin gap is noticeably narrower where the head meets the barrel.
It's engine/frame no is 211412, if that helps

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All Commandos tend to have a narrower gap between fins at the head joint-including the 850 models, so, as noticeably narrower can be open to interpretation therefore it isn't a particularly reliable way of identifying if it is (or is not) a Combat head.
211412 would also place it outside the official Combat production series.

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Thanks. It's good to know what I've got. I thought I'd have been incredibly lucky to have scored a genuine Combat, & I'm still very happy with what I've got. I'll just stop referring to it as a Combat.

Old Scratcher said:

I thought I'd have been incredibly lucky to have scored a genuine Combat,.

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Opinions vary. The realities just don't match the hype.

Combats are the Cream of the Commando Crop as best power to weight and simplest construction. The faults that blew them up were production errors that were corrected in essentially all Combats that survive today, not any innate weakness not shared with all Commandos. Was last winner of Command run as cycle of the year award and first with disc brake and IS long range tank. Only innate poor design feature is the forward sump drain that allows oil to pile up and get out playing 2S cam tunes into red danger zone but easy to fix and non issue bit for the mess. Has the best wet sump fast oil return device going to me. There's plenty of tales of Combats lifting front in lower gears so ask around if other models are more bad boy oriented than a rooting tooting Combat, especially after 90.
Main downside of Combat to me is rear tire replacing.

Good see you on the this Forum Scratcher.

Good luck with the build.

Strida

Welcome to the forum, OS.

I believe you'll want to stay away from clip-on handlebars or very low clubman bars, if you want your shoulder to last out your riding days.

As many have already said, you made a GREAT score with your black beauty. Also, as you can see, you've got significant company in your quadrant of the globe. You'll get along fine.

As to the bike-in-the-den, you are in a very small crowd!

hobot said:

Combats are the Cream of the Commando Crop as best power to weight and simplest construction. The faults that blew them up were production errors that were corrected in essentially all Combats that survive today, not any innate weakness not shared with all Commandos. Was last winner of Command run as cycle of the year award and first with disc brake and IS long range tank. Only innate poor design feature is the forward sump drain that allows oil to pile up and get out playing 2S cam tunes into red danger zone but easy to fix and non issue bit for the mess. Has the best wet sump fast oil return device going to me. There's plenty of tales of Combats lifting front in lower gears so ask around if other models are more bad boy oriented than a rooting tooting Combat, especially after 90.
Main downside of Combat to me is rear tire replacing.

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Oh for goodness sake, Steve. A cam, a shaved head, a botched port job and a front disc brake, THAT'S IT! All else is inherent to ALL 72's. Seems as though you have taken the "blue pill", Steve.

Ture enough PeteV I have taken some mulit-colored non prescription pills and powders and agree Commando are all came out of same tit so not much gap between the plain ole milk and cream layer but can make butter better with what floats on top when churned hard enough. Lack of turn signals is a big '72 feature to simpleton me. I dislike having to feather throttle on snick to 2nd on my 2 Combats d/t hesitation of tire spin and having to watch out for the fun past 6800 when the hogged out ports and 2S cam make sense.

After firing the old girl up a few times in my lounge room, much to the consternation of my dogs, I've notice that she's blotted her copy book (& my linoleum) with a little oil escaping the old mill. I think it's coming from the breather pipe though. & I'm fairly certain that all seals & gaskets are still doing the job their maker intended for them. But seeing as my bike's a 72, though probably not a Combat competition motor. Could this mean that it still needs it's oil pick-up/ breather pipe modified? Also, is there anyway to check on the bottom end, to see if it's been modified or not? Short of tearing the engine down.

A combat should not leak any more than other models until into elastic engine rpms into the red zone on 2S cam but its possible the front oil drain hole passage internally in the cases has collected a clog of debrie and can't drain out fast enough to prevent wet sump trashing violent similar to Combat's infamous red line wet sump back up. One can not have too much low pressure even a strong vaccuum so always a worth while upgrade even w/o leaks. Mere bad sealing only weeps oil out but over pressured wet sump would splash it aways. Clean well then run just a few seconds at a time till source found. I've had some leaks only took 50 yd to fin but if I went shorter didn't show up and if further too much oil to tell where it leaekd from. Part of owning a thinking man's clunker seeking state the British guys refer to as "fullly Fettered"