First ride today! Jeers and tears

After some monkeying about with my wild running carb I found I had the slide on the Mukini upside down! Cue Fred Sanford, "You big dummy!". So this is sorted, then a new throttle cable had to be shortened an inch... So then off for a ride!

New brakes from Old Brits were installed a while ago with some minor issues, the result has been disappointing. The rotors still not scuffed off enough up front, the rear is useless. I used the old pads to remove the paint as per instruction from Fred. I'm sure it will take a little while to cut through the paint although the brake cleaner seemed to do a better job in places. I should have scuffed off the pads on my belt sander first and may do this tomorrow.

Brought her home from my pals place (gave me a hand with the carb) in Virginia back to Md, unloaded the old girl and went to start her up. No dice! No spark! Never an issue before... Old a Brits ignition was newly installed and worked perfectly.... So one step forward another back. I'm beginning to think this 75' MkIII is going to be my undoing.

I will the Avons did a nice job and the bike handles fairly well I think. I believe I need to investigate some clutch slippage and an oil leak beneath the primary case.
I'll pull the tank off and check all the grounds and connectors tomorrow, damnit, fall is here and I'm ready to ride!!!

Bummer on your troubles, You'll figure it out.

I guess some people have good luck with that OB / Power Arc ignition, but not me.
Startups were always a crap shoot and I got a lot of right leg exercise.
I finally replace it with a Tri-spark and both my Norton and I are much happier now.
One, or at most two kicks and off we go....

Well your discs were painted and your carb slide was upside down, I can't imagine what else could be wrong. You'll have to keep looking.
Don't give up on a Mk3, it will be worth it.

Jaydee

Did you get the chrome ground off the discs? 'Makes a world of difference.

Rusty bucket said:

After some monkeying about with my wild running carb I found I had the slide on the Mukini upside down! Cue Fred Sanford, "You big dummy!". So this is sorted, then a new throttle cable had to be shortened an inch... So then off for a ride!

New brakes from Old Brits were installed a while ago with some minor issues, the result has been disappointing. The rotors still not scuffed off enough up front, the rear is useless. I used the old pads to remove the paint as per instruction from Fred. I'm sure it will take a little while to cut through the paint although the brake cleaner seemed to do a better job in places. I should have scuffed off the pads on my belt sander first and may do this tomorrow.

Brought her home from my pals place (gave me a hand with the carb) in Virginia back to Md, unloaded the old girl and went to start her up. No dice! No spark! Never an issue before... Old a Brits ignition was newly installed and worked perfectly.... So one step forward another back. I'm beginning to think this 75' MkIII is going to be my undoing.

I will the Avons did a nice job and the bike handles fairly well I think. I believe I need to investigate some clutch slippage and an oil leak beneath the primary case.
I'll pull the tank off and check all the grounds and connectors tomorrow, damnit, fall is here and I'm ready to ride!!!

Click to expand...

Rusty B,
You mentioned old brits ignition. The start sequence should be to get the bike to the top of compression and then turn on the ignition...kick it over...if it starts then good...if not repeat the sequence. The counter disk counts every slot whether it is going in one direction or reverse but the brain of the EI thinks it is counting only in one direction. Not quite the same as a boyer or Pazon.
Always bring it up to compression then turn the ignition switch on. Kick it hard through.
Regards,
Thomas
CNN

I notice the clutch slip problem. This was a 'standard' 'normal' problem with heavyweight Norton twin clutches IF an owner put enough of the available engine torque through the clutch AND the oil contained within the oil bath CHAIN case had reached the friction interfaces within the DESIGNED to be run DRY clutch. On Commandos the oil level plug is tooooo high and the CORRECT oil level is below the level plug. The CORRECT amount of oil is 200cc as stated in the later genuine Norton workshop manuals after the then Service Manager (John Hudson) cut up a chaincase and inserting some perspex to see exactly what was occuring after which the later manuals were changed to state 200cc only. Filled to the level plug a friends Commando contained 290cc. Incidentally the oil originally intended to be used in Norton oil bath chain cases when designed in the early 1930s was a straight SAE10 or 20 oil and the correct level is that it should only just be touching the bottom of the chain....Of course in those days they also put a band around the basket which is shown in the spares books as an OIL EXCLUDING BAND.The oil bath chain case filling instructions for BSA Gold Stars which also employed a designed to be employed DRY clutch within their oil bath chain case states that oil should be seen to be just touching the lower run of the chain. Mind you Mr Hopwood once commented to me during a converation that the Gold Star was designed as a clubmans competion bike and as such the primary system would be subjected to very regular maintenance at which point any oil found to be entering the clutch would be removed.
When I described the Mk3 Commando clutch to the Engineering Director / Chief Clutch Designer of Laycock Engineering, the Company that designed and manufactured the FOUR different thickness diaphragm springs employed on Commando models over the years they were being produced I heard him using his calculator and then he said...'But surely oil works its way into the clutch via the slots in the diaphragm spring release ears and through the bearing eventally reaching the dry frioction interfaces resulting in slip and drag problems'...to which I replied 'GOT IT IN ONE'. A year or so later I learnt that for his calculation he had been using the clamp load of 800 lbf as given by one of his two Villiers Starmaker clutch diaphragm spring designs rather than the 380lbf and 550lbf given by the original 750 Commando and last 750 and all 820 model diaphragm springs.
It was because Norton had a serious clutch problem that they had Laycock Engineering manufacture each new batch of springs slightly thicker than the last batch so as to increase the clamp load and the torque capacity of the clutch .....and in so doing increased clutch lever action from easy two finger to very heavy requiring a serious grunt from the rider to operate t especially when in a trafffic jam..just that that joke they called the clutch fitted to production Triumph T140s!!!
UNFORTUNATELY very few Norton etc owners know anything about clutches and ASSUME that because the clutch is within the oil bath CHAIN case then it must of been designed to be run with oil on the friction interfaces...guess why the BSA 1949 B32 publicity sheet stated that the clutch was and I quote ' BSA multi dry-plate clutch with oil resisting fabric inserts''....From 1954 to 1956 Gold Stars employed Ferodo MZ41 friction material in the clutch and the Ferodo data sheet for it states it is unsuitable for use with oil.......To my knowledge Norton never stated that their clutches were DRY clutches but if you look in the book 'A racing legend- Norton'(ISBN 0-7858-0310-0) you will see that all Dommy and Commando clutches are CORRECTLY described as being DRY clutches within the oil bath chain case. Of course all my old Dommy manuals state on the problems page that one cause for clutch slip is overfillling the chain case and suggest that to cure the problem the clutch should be taken apart and the plates washed in petrol to remove the oil causing the slip problem..NOT that many owners apparently ever read those pages sme even thinking the clutch slip was down to their tuning abilities!!

Barnett Kevlar run-in-oil friction plates will fix it right up. CNW has them. You should also add a Dyno Dave pushrod seal if you don't already have one. Walridge has these. Also, follow the clutch stack info on Dyno Dave's website Atlantic Green, or do a search for "clutch stack height" here. It looks complicated but it really isn't.
The final item to make it really work well is a Venhill Featherlight clutch cable, a stock item available from Venhill cables. It will never require maintenance and I think it will take a long, long time to wear out.

Mine is the last model Commando, so according to the info posted by JM Leadbeater, it should have the stiffest of diaphrams. I don't think the diagphram has ever been changed and it is a one finger pull, no-slip no-drag clutch.
Can't really ask for more than that.

Glen

I'll look into the clutch and ignition when time permits. Hopefully I'm not looking at too many new tools lol.

Nater_Potater said:

Did you get the chrome ground off the discs? 'Makes a world of difference.

Click to expand...

There are Lightened and cross drilled then ground flat, the problem now is the paint needs worn off and new pads added. Until that point I can't say whether the brakes were worth the effort. In the long run I feel the more economical and surely easiest route would have been to add an aftermarket setup.

why is there paint on your rotors?

Mark said:

why is there paint on your rotors?

Click to expand...

The $65,000.00 question...

grandpaul said:

Mark said:

why is there paint on your rotors?

Click to expand...

The $65,000.00 question...

Click to expand...

"Andover Norton paints new rotors and we paint our used rotors. The reason for painting the friction surface of the rotor is to keep the rotor from rusting before that rotor is put into service and to paint the holes on the lightened rotors."

https://www.oldbritts.com/14_061885.html

I guess that it must be slightly better than cosmoline.

Gentlemen I thought the same thing regarding the paint. I'm sure the old pads are a bit soaked with old fluid too. I just hope the spark issue is easier to sort out. I'm going to use a brake rotor ball hone on the disks when I get the chance.

Does anyone know of a picture showing the guild passageways on the one piece Lockheed calipers? I'm going to pull them loose and try to get the holes positioned to push any residual air out. I bleed these brakes to the point my damn hand was waffled on the rear and probably went through two small containers of dot 4. I used a syringe, and a vacuum bleeder as well as good old pump and dump at the bleeder.

I used SS calipers from Commando Specialties I believe and Norton seals. The bores looked fine and being aluminum I did not home them. No leakage was found at any joints, seals, or fittings. I still think there is air trapped somewhere. Any ideas? New master cylinders fore and aft.

Compress the brake lever with a strap or a clamp and leave it overnight.
Seems to work to allow any residual air bubble to migrate up and out.

SS caliper pistons are the way to go. Do not clean up mechanically the bore.Gentle and CLEAN. Did you fit the new seals for them the correct way ? They are tapered square section. The inner higher edge fits towards the back of the bore. Clean brake fluid on them too. Bleeding requires opening and closings of the blled valve each lever pump. Do not leave the valve open or air will enter. :wink:

I cheated when bleeding mine, as the front end wasn't completely assembled at the time; with the caliper connected to the line, it was rolled around during the bleed operation in hopes of moving internal passages such that the air would find its way out. A soft-faced mallet was lightly applied to the caliper to assist with the dislodging of any bubbles that may have attached themselves to the internal surfaces. It took all of ten minutes with one person running the lever, and the second flopping the caliper around.

Nathan

Yes all new seals lines, the whole kit. Is used the rubber band trick which works well but only for a short time.

Tomorrow am I trouble shoot this power arc shit and pray I can get a ride in and try and cut these rotors in.

I have the Power Arc and it is faultless Mostly one or two kicks. I went straight from the battery to the ignition for ground. Most of the problems seem to come from bad ground.

I tickle till fuel flows turn on the ignition and kick through, about a quarter throttle. Occasionally it is stubborn, turn ignition off Open throttle and kick a couple of times turn ignition back on almost always starts seems flooded

Runs smooth 2000 miles in the last year and no problems.

Dennis