74 Mk2 - disc rotor removal - any tricks?

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joe czech

joe czech

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removal looks to be simple enough. anything besides the 5 nuts (and lock washers) holding the front disc rotor to the hub? my 74 MK2's seems to be frozen to the front wheel hub. I don't want to start beating on anything and the service manual is a bit vague. so, before I get a big friggin hammer :D - am I missing something? TIA....
 
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Corrosion between aluminium alloy and cast iron will be the likely culprit. The disc is cast iron so no direct hits, use some wood as a shock absorber.
 
True Disc - did two for me .
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1620 West Newburg Rd
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thanks guys - got the rotor off. a dead blow hammer and a 1 inch nylon rod. guess it was just a little corrosion. :)

my next dumb question - rebuilding the brake caliper. stay tuned.... :D
 
joe czech said:
thanks guys - got the rotor off. a dead blow hammer and a 1 inch nylon rod. guess it was just a little corrosion. :)

my next dumb question - rebuilding the brake caliper. stay tuned.... :D
Click to expand...

You must heat the caliper to EASILY UNSCREW the plug.
Much easier to do if it’s bolted to the fork & motorcycle. If you don’t have a face pin spanner, get one.
 
concours said:
You must heat the caliper to EASILY UNSCREW the plug.
Much easier to do if it’s bolted to the fork & motorcycle. If you don’t have a face pin spanner, get one.
Click to expand...
pin spanner is on order - this is the one I bought - should be here by Wednesday

74 Mk2 - disc rotor removal - any tricks?


thanks for the tip on the "bolt to and heat" thing. finally can see the light at the end of the tunnel. handlebars were shipped from AN yesterday, and I should be able to wrap up the front end. after that, all that's remaining - carbs and fuel tank. she's been lifeless for 6 years now - it will be good to get her back on the road. target date - feb 14, 2020

not to go off topic, but I seem to recall you posted a pic of some alpha-numeric code that was stamped on the underside of your fuel tank (74 roadster). I have a similar code. were you able to decipher it? i'm finding a lot of stampings and engravings of various parts. one thing in common on my pieces is the letter "D".
 
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joe czech said:
pin spanner is on order - this is the one I bought - should be here by Wednesday

74 Mk2 - disc rotor removal - any tricks?


thanks for the tip on the "bolt to and heat" thing. finally can see the light at the end of the tunnel. handlebars were shipped from AN yesterday, and I should be able to wrap up the front end. after that, all that's remaining - carbs and fuel tank. she's been lifeless for 6 years now - it will be good to get her back on the road. target date - feb 14, 2020

not to go off topic, but I seem to recall you posted a pic of some alpha-numeric code that was stamped on the underside of your fuel tank (74 roadster). I have a similar code. were you able to decipher it? i'm finding a lot of stampings and engravings of various parts. one thing in common on my pieces is the letter "D".
Click to expand...

Yes I did post it, and no, I never found a scrap of info that meant anything.
 
concours said:
Yes I did post it, and no, I never found a scrap of info that meant anything.
Click to expand...
mine was stamped as "R 269 D". i'm speculating here, but i'm almost convinced the letter "D" has something to do with 1974. "R," guessing roadster. the 269 number I thought it might be a julian date, but that doesn't fit my bike's build date. it could be the 269th candy red tank or the 269th tank overall. again, just guessing. I have the letter "D" stamped on my brake caliper, "D" engraved on the master cylinder, "D" stamped on my exhaust header pipes, and "D" on the fuel tank. i'd bet money it has to have something to do with manufacturing or production.
 
Stainless caliper pistons are the way to go. My originals were corroded and needed persuasion to remove. I had to reconnect the hose and master cylinder with fluid to break them free.

Bleeding it all took quite a lot of effort. The caliper has a fluid path that tends trap air. I feed fluid in from the bleed screw up to MC using a syringe. Still had mushy feel after many replenishment. Did several overnights with lever strapped in. Still no good. Ultimately in frustration I started flicking lever fifty or more times rapidly while watching inside reservoir and saw a few very tiny air bubbles emerge from the smaller hole. Everything firmed up. This was with the madass sleeve kit. Braking pretty good.
 
Scout63 said:
Sorry for hijacking this thread, but any suggestions for someone to grind a rotor?
Click to expand...

Ask around the machinist and hot rod crowd for someone who does precision grinding. There are several in my home town(Cincinnati).
Don't go to the Auto Parts store they aren't equipped to do the job on their lathe.
Ride On
Dave
 
Tornado said:
Stainless caliper pistons are the way to go. My originals were corroded and needed persuasion to remove. I had to reconnect the hose and master cylinder with fluid to break them free.

Bleeding it all took quite a lot of effort. The caliper has a fluid path that tends trap air. I feed fluid in from the bleed screw up to MC using a syringe. Still had mushy feel after many replenishment. Did several overnights with lever strapped in. Still no good. Ultimately in frustration I started flicking lever fifty or more times rapidly while watching inside reservoir and saw a few very tiny air bubbles emerge from the smaller hole. Everything firmed up. This was with the madass sleeve kit. Braking pretty good.
Click to expand...
Struggled with mine equally until realizing the passage through the caliper goes against gravity as it's mounted to the fork leg. I removed the caliper, inserted a wedge between the pads, then rolled the caliper into different positions while pumping the lever. A number of large bubbles rose to the top shortly after that, returning a firm lever.
 
update on removing my caliper plug. pin spanner removal tool, an impact wrench, and about 2 seconds. no bolted to the fork thing, no heat, no muss, no fuss.

internals, still not a pretty sight, but got an email from Ella - shipped out the rebuild kit/parts yesterday - :)

74 Mk2 - disc rotor removal - any tricks?


update on the handlebars - received the "correct" UK/euro bars from AN yesterday. they measure out at 27.25 inches width. there is no way that they will work with the master cylinder. the brake hose actually comes out toward the inside of the upper fork yoke. Old Britts list their UK bars (p/n 064123) at 31 inches (3.75 inch difference). I moved out the throttle grip assembly and MC, along with the clutch/switch bank 1.88 inches on each end, and low and behold, everything falls into place. unless I'm missing something with mounting the MC and clutch lever, I can't see how the AN bars are correct. ???????
 
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If what your bar issue is referring to, that the MC/brake switch cannot be rotated downwards sufficiently without hitting the rising part of the bars, yes, that is what happens on my "Euro-style" re-production bars. One thing that helped a bit. swapping the brake switch & brake hose positions into the MC gives a little bit more rotation room...but it's still not as downward as I'd like. So I ride with clutch lever where I want it and the brake lever higher than I want it.
 
Tornado said:
If what your bar issue is referring to, that the MC/brake switch cannot be rotated downwards sufficiently without hitting the rising part of the bars, yes, that is what happens on my "Euro-style" re-production bars. One thing that helped a bit. swapping the brake switch & brake hose positions into the MC gives a little bit more rotation room...but it's still not as downward as I'd like. So I ride with clutch lever where I want it and the brake lever higher than I want it.
Click to expand...
I thought about swapping the switch and hose positions, but every time I deviate from the norm, it injects a new set of problems. right now, I've got a 31 inch wide set on order from old britts. i'll give this one more try. here's a couple of trial pics with controls located at the 31 inch wide bar position.

74 Mk2 - disc rotor removal - any tricks?


74 Mk2 - disc rotor removal - any tricks?
 
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Went out to the garage and measured my bars. Roughly 30" end to end. Brake hose is not up against the yokes. I got these in the 80s. At the time I found the real Norton bars had longer ends than most, to solve this problem. I also seem to have a shorter set so probably went through the same exercise back then. I'm going the other way this winter - back to stock bars.
 
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