New member. First English bike!

danfr · Oct 22, 2012

Nortiboy said:
danfr said:

Can anyone interpret the carbs? 930's? The intake throat diameter on the engine itself looks to be 1 1/8.

Click to expand...

Amal 30mm. Look at the Amal site for "Premier" carbs and slides.

You are probably looking for new slides as they wear quickly. If the body is worn then new premiers would be my preference if you want original. If you are prepared to modify, there are a variety of carby options.

The items I always fit to commando motors are :-

1. Good Carbs are essential

2. Electronic ignition (I use Trispark, but there are a variety of good ones)

3. Breathers. Either large open breathers or reed valve type. As previously suggested there is a Comnoz unit if you search this site. Its a work of art.

Congratulations on saving another commando. By the time you have finished this and throw a leg over a well running Commando, you will either have a life long love affair, (or just go nuts)

Cheers

Mark

Thanks Mark,

Ya I just did some reading up on the Amals. Unfortunately it is a 30mm

. If I do get this bike running, I may consider getting a single 34mm Mikuni kit, but that's if I have the funds. I like the idea of the easy start up and off the line. I don't ride my bikes hard, so I don't think I'll be missing out on the little bit of extra juice near the top end.

A new in box Boyer ignition kit came with the bike. I'll be installing it next time I'm in the shop. Thankfully, that decision is already made and was included with the bike.

I'll do some reading up on breather options. Not too sure what direction to go. Simplicity (on installation and price) is key.

cheers.

danfr · Oct 22, 2012

Snorton74 said:
Those pyramidal mounts are two of the three points of attachment for the left side cover. I've got an extra primary cover, it's not great, but way better than that one. I'll dig it out next time I'm at my shop. PM me with your email and I'll send you a pic of it. If ya want it, just pay for shipping.

Rennie all yours needs is some spoked wheels.?

Oh wow, that is amazing. Thank you so so much!

danfr · Oct 22, 2012

RennieK said:
Yep, 930's not 32mm;
You can get the cover welded, it is the older style with the deep recesses and hard to find for cheap prices. The cover is held on by the one nut right beside the hole and it should be removed to clean inside and get metal bits out.;
That's the tach mount cup that's broken, no biggie;
Yep, you nailed it, condensers and the rectifier;
That is the zener diode but it looks fried probably from being mounted on steel that wouldn't pass the excess energy as heat. It should be mounted on aluminum as a heat sink to dissipate the energy as heat;
Pyramid things are the side cover locator pins, just need new rubber;
Hopefully one of those numbers will match the frame number, definitely not the only bike on the road with mismatched numbers. MVB goes by frame number.
Below the numbers is the cam driven breather, correct for 1971.

Yes it's dirty and grungy but maybe that's why it's not badly rusted like so many others. It's the right thing that you're going to change all the fluids, eng, tranny, primary and fork tubes.

Great pictures, hope to meet you next weekend!

Thanks for all the info Rennie!

Ok, I suppose the next step is to order up a couple gasket kits for these carbs and keep cleaning. I'll look into how to test the diode. I found the shop manual online, so that should help.

I'll also look into the breathers.

Cheers

Nortiboy · Oct 22, 2012

danfr said:
[ Unfortunately it is a 30mm

Mate, trust me, 30 mm on a Std 750 is plenty. I run away from good 850s with 30mm carbs. Velocity is the key here. Std commando cam is pretty good for the road so if its in good condition, its fine. 10:1 compression gets them going.

Cheap breather solution, duplicate a standard 850 from the timing side. Keep the original as well. Its actually what I have on a MV 750 (1973)and its works well.

Cheers

DogT · Oct 22, 2012

I think you can check the zener just like a diode, with an ohm meter, or if you have a power supply, put 15-16 VDC on it (ground is +) and see if it regulates it down to 14V or so. It should actually be mounted on the z plate, there should be a hole and flat area for it down there. If it's defective, cheaper and better to buy an electronic voltage regulator. Get a larger capacity one, not the smallest.

Dave
69S

bwolfie · Oct 22, 2012

You have the early "pointy" style primary cover. I had one with a similar hole that I welded back up. They bring some good money compared to the later ones. I sold my repaired one for $150. I have purchased later ones for $40 to $50.

MFB · Oct 22, 2012

My local bike shop got my primary cover welded up when I was rebuilding my basket case back in 1983. He did a really good job. I never met the welder, who was nicknamed "Kiwi", but it was said that he could weld two milk bottle caps together. The old foil ones that is. It's nice to keep original parts, even if they are a bit battle scarred. You'd never know mine was welded unless you looked at the inside.
It was Kiwi who also welded my shattered crankcases back together. They're still good.

Cheers
Martin

RennieK · Oct 22, 2012

Just wondering, do you have a headlight, tail light, tach, speedo, handle bar switches , side cover and chain guard?

Careful with the rectifier, you can ruin it by turning the 4 wafer plates against each other. I'll see if I have a spare zener.

danfr · Oct 22, 2012

RennieK said:
Just wondering, do you have a headlight, tail light, tach, speedo, handle bar switches , side cover and chain guard?

Careful with the rectifier, you can ruin it by turning the 4 wafer plates against each other. I'll see if I have a spare zener.

I have a headlight and fork ears, oh and a side cover.

I do not have a tail light, tach, speedo, chain guard and handlebar switches.

Thanks for the offer on the spare zener. I have no idea yet how to test if it's buggered or not.

Cheers

Daniel

Matt Spencer · Oct 22, 2012

OIL in the PRIMARY , please , unless youve got the cover off & spray it with chain lube . Bone dry would stuff it .

Acetone is good for cleaning alloy ( Youve got the EARLY cover there , dont toss it ) Masking tape over ' outlet ' .
Might indicate it was a Fastback originally , that covers only on ? ? ?

Ceck valve clearances BEFORE you go adjusting them . Check ignition timing BEFORE you go rideing it .
Ignition Timing is neumero uno in the tune up quest for optimum performace , or anything . ACTUALLY .

Car Wash here has good HOT , High Pressure wand thingo .

Will get in behind oil seals even .

8)

danfr · Oct 23, 2012

oh yes, I'll hold on to that primary cover. maybe down the road I can get it properly welded. And I don't plan on starting the bike until I get a well sealed primary.

My typical bike rejuvenation spa includes: oil change, check valve clearances, check timing, a good battery and fresh gas through some cleaned, synced carbs. So I'll be sure to give it the right ingredients if it wants to light up. So far, I've had 100% success rate, although top end rebuilds are sometimes not too far behind...

So! Apparently if I am to install this Boyer ignition, I'll need some sort of coil set up that needs to be less than 5 ohms. Good grief. I have the stock coils which will be 7 ohms. Soooooo.....Dyna? The DC7-1 looks like it would work. I see Britcycle is offering one from Emgo, but I can't say I trust the quality with Emgo. hmmmm.....

Hobot · Oct 23, 2012

If you are leaving the Norton points behind I am collecting left overs, especially them flaky advance units.

danfr · Oct 23, 2012

hobot said:
If you are leaving the Norton points behind I am collecting left overs, especially them flaky advance units.

I'm happy to share spare parts, but I'll need to log some miles on the Boyer to have the confidence to give up the advance unit. But I'll keep it in mind!

Hobot · Oct 23, 2012

Ok I've been the Boyer route and its nursing of innate failing trigger wires and low voltage backfires and sluggish advance curve so I now prefer to stick with points curve but that needs a stock pile of AAU parts as I've been through two decent ones in 15,000 mile last couple years and current one is beginning to stick at fast idle or slight backfire advanced starts after ~8000 miles so may have to install the Pazion ignition if I can't restore left over AAU's in time. Greg Fualth has the trigger wire kit and its garantee'd you'd have trouble too soon on Boyer supplied trigger wires. Once re-wired cheap Boyer can last for decades w/o service as should all the other electo sparkers.

Mark · Oct 23, 2012

danfr:
You can start your bike with an open primary - no problem.
stock coils also work with a boyer.

hobot:
30,000 mile on a out of the box boyer and my trigger wires are still fine, never a problem.

dave M · Oct 23, 2012

Mark is absolutely correct, the oil in the primary case is simply to provide lubrication for the chain, so the bike can be started and run without this being sealed, although for long term use you would be advised to either repair the case and fill the correct amount of oil or else go to belt drive which can be run dry.

I don't wish to rain on your parade, but I doubt very much that this bike was raced successfully or safely in dirt track racing. I can think of almost nothing other than a Harley Bagger that would be more unsuitable than this particular bike on a dirt oval, particularly with that 16" rear wheel. My suggestion is that you have a look through various Commando photos on the net, see which style you find most attractive and model it after that. Norton had quite a few different models all based on the same frame and engine platform, so your bike could be made into a Roadster, Fastback, Interstate, High-rider, SS, production racer etc with the simple fitting of the appropriate tinware, exhausts and one or two other fitments. The 16' rear wheel will not give optimum handling on the road.

danfr · Oct 25, 2012

dave M said:
Mark is absolutely correct, the oil in the primary case is simply to provide lubrication for the chain, so the bike can be started and run without this being sealed, although for long term use you would be advised to either repair the case and fill the correct amount of oil or else go to belt drive which can be run dry.

I don't wish to rain on your parade, but I doubt very much that this bike was raced successfully or safely in dirt track racing. I can think of almost nothing other than a Harley Bagger that would be more unsuitable than this particular bike on a dirt oval, particularly with that 16" rear wheel. My suggestion is that you have a look through various Commando photos on the net, see which style you find most attractive and model it after that. Norton had quite a few different models all based on the same frame and engine platform, so your bike could be made into a Roadster, Fastback, Interstate, High-rider, SS, production racer etc with the simple fitting of the appropriate tinware, exhausts and one or two other fitments. The 16' rear wheel will not give optimum handling on the road.

Thanks for the heads up on the primary. I'll pull it off this weekend and have a better look at it and the primary chain.

No offense taken on the bike. I don't think the bike was used for any high level racing. It was probably armature weekend racing. My first goal is to get the bike in running order. After that I'll asses needs and then the luxuries.

I've ordered up a couple gasket kits and some fresh fuel lines. The saga continues...

danfr · Dec 4, 2012

Boyer Kit

Can anyone help me with this Boyer kit? I'm trying to understand what exact model it is. It looks to be a MKIII, but on the black box (pic 3), it states MICRO-MK III UNIT. SO is it a micro power or micro digital, and what exactly does that mean?

L.A.B. · Dec 4, 2012

It is the analog/ue 'MkIII' (Micro-MkIII) unit. Other types are Micro Digital (Red box) and Micro Power (Blue box)

http://www.boyerbransden.com/productinfo.html

BillT · Dec 4, 2012

Re: Boyer Kit

danfr said:
Can anyone help me with this Boyer kit? I'm trying to understand what exact model it is. It looks to be a MKIII, but on the black box (pic 3), it states MICRO-MK III UNIT. SO is it a micro power or micro digital, and what exactly does that mean?

I've got the same black box unit on my '73 and '69 - no issues aside from a broken wire at a bullet connector on the pick-up early on. Have since gone about 12000 miles on the '73 and 3000 on the '69

New member. First English bike!

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