MK3 Front Brake,Master Cylinder and Caliper Rebuild with Photos

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hobot said:
Mr. Rick, I tease thee not, the slighter ease of 90 or 100 tire handling delight is totally shredded on crisis brake needs compared to 110 on WM2 rim. The only thing no restriction provides is ability to squeal loudly down from 100 mph w/o much worry of lock up till below 60 then need skill letting off some so not to lock up or fly over bars.

Parts manual describes this restrictor as a valve which preplexed me why till removing it. With restriction valve, at some point even white knuckle panic grip did not slow any more but w/o it i could always lock tire if scared enough but rather easier to control that than not stopping a bike length or more shorter.

Wider profiles only feel better planted in turns till at limits then they get unpredictable for sudden let downs. If not exploring luck pressing un-tammed isolastic rubber baby buggy into escalating 'hinging', or need to slow as good or better than moderns - (which I find stopple limited), then
go with the normal wisdoms of tire/rim matching. For up to Combat power I like 110 both ends but if nearing 70 hp, 120 on WM3 hooks up better on max leans than heated 160-170 size race only compound on on 6" wide rim on my modern SV650, WHICH let me down so many times I gave it away last summer to ex-racer along with 4 soft race tires. Its 120 front made just curising more effort than a front 110 Commando that spoiled me. 120 rear on factory power Commando feels like heavy boot vs tennis shoe, until enough power to spin at will on leans over 70's, or swinging out into traffic lane, then feels like cleat-ted sports shoe.

Getting brake innards corrected or modified is fairly straight forward but I've run into the lever side of m/c bore not holding the retaining winged jam washer to hold seal in so weeps fluid out, more on road use unseen than parked at home. Do not know a solution but maybe JBW fill and rebore or modified washer or give up and try another Lockheed m/c or non Norton replacement.
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At my age, I don't anticipate the need to come down from 100 in crisis mode. I weigh almost nothing, so by the time I hit 75, I'm holding on for life, the wind blast picking my ass off the seat.

I'll check the size of the stock restriction, and maybe go bigger but less than 3mm.

Good info on the tires/wheels. I admire and envy your adventurous explorations. I'm on a stock bike and my personal situation at home precludes such shenanigans, unfortunately.

I've not had the jam washer issue. If I did, I'd prob just stuff another one in there, and dare them both to come loose.
Thanks, Hobot, for the comments and clarification!

I shd also clarify: The idea of wider tires leading to reduced handling that I mentioned in my earlier post actually came from Tonti as told to Ivar deGier and quoted in Falloon's '07 book, Guzzi Sport & Le Mans Bible in the "Squareheads" chapter. And what he really said was "... the easiest way to improve any Tonti-frame Guzzi big twin was to fit the wheels and tyre size of the original V-7 Sport." Which were WM-2-18, Borrani Record Cross. If you find one it's worth big $.
 
Ha! Mr. Rickie Ya left hobot head smacking grinning by insight to put two cog washers in! Dang it thot I'd heard of or tried all the Norton work a rounds. Crisis brake events are not voluntary so did not start out shunning narrower front on factory Combat Trixie but Ozarks hazards did - to shatter my opinion of those so pleased with unknown less braking reserves. Hot nail alone was enough to reveal 100 size let down. Only heard one other trying hot nail to complain only seemed to reduce distance by maybe a third but still took more than two fingers.

I'll eventually use up more of the 100 on Trixie, mostly by vital reflex brake practice on touchy 100-80 19" tire before fitting more secure 110. Both because of THE Gravel and surprise hazards i can no longer over grip in panic because past results have made it feel like grabbing red hot metal rod. If ya die from hobot advise, like others, be sure to tell everyone.
 
hobot said:
Only heard one other trying hot nail to complain only seemed to reduce distance by maybe a third but still took more than two fingers.

If ya die from hobot advise, like others, be sure to tell everyone.
Click to expand...

Distance reduction by a third wd be huge, take it any day!
And if I die from yr advice, I'll definitely post the reason here afterward, and then have THE cremains scattered over the Ozarks to keep you on yr toes.:rolleyes:
 
Just to follow up, I measured the restriction hole in that valve 06-1944. Turns out to be 0.034 inch, or 0.86mm, not very big, and a relatively long way from the 6 penny nail diameter of 3mm. To be able to quantify the improvement in stopping distance (if any) of opening up the valve to say, .067", will require some planning and time. MIght be able to use the nearby DMV parking lot on the weekend? Most likely, real life will intervene and give me something more urgent to attend to.
 
Scientific creeping up or just rationalizing scaredy cat? I could not get a decent rubbery hole expansion via normal drills, just pushed hole open to spring back. Braking is most risky skill to do and conditions skew as brake, fluid and tires heat. Need at least 3 sessions, one as is, one semi removed and last all possible restriction opened. Also realize takes less pressure to squeal 90 & 100 tire vs 110 so if tiny hole allows locking a 90 then will not notice much improvement. hobot mod only pays off if enough patch area to take it and bravery to resist ~1/3 more tendency to lift rear to swap ends or flung over bars. Tri-linked Ms Peel did not wiggle like un-linked isolastice when tire restraint removed and her forks did not dive like regular roadholders, so be alert. My factory Trixie forks tend to jutter or rear wants to lead if too aggressive. Have fun setting up the experiment and video too?
 
hobot said:
Scientific creeping up or just rationalizing scaredy cat?
Click to expand...

Some of both, I reckon.

hobot said:
I could not get a decent rubbery hole expansion via normal drills, just pushed hole open to spring back.
Click to expand...

Understood. Prob use the lazy end of a hot drill bit.

hobot said:
Braking is most risky skill to do and conditions skew as brake, fluid and tires heat. Need at least 3 sessions, one as is, one semi removed and last all possible restriction opened.
Click to expand...

Right. Pull apart the MC each time, prob have to bleed each time, uggh. Ambient temp/humidity shd be the same, not easy...

hobot said:
Also realize takes less pressure to squeal 90 & 100 tire vs 110 so if tiny hole allows locking a 90 then will not notice much improvement.
Click to expand...

Understood. Haven't locked the 90 since new tire, but haven't seriously tried, either.. Will have to try again.

hobot said:
hobot mod only pays off if enough patch area to take it and bravery to resist ~1/3 more tendency to lift rear to swap ends or flung over bars. Tri-linked Ms Peel did not wiggle like un-linked isolastice when tire restraint removed and her forks did not dive like regular roadholders, so be alert.
Click to expand...

Alert? You don't ask much, eh?
Guzzi linked their brakes long ago, great and proven idea, even if not actually proportioned, as (I think) they did later.

hobot said:
My factory Trixie forks tend to jutter or rear wants to lead if too aggressive. Have fun setting up the experiment and video too?
Click to expand...

Scaredy cat thinks this really shd be done with some kind of reverse dyno, bike stationary, measuring what kinda torque it takes to make the tire break traction for a given amount of (measured) lever force. Any ideas?
Video, sure! I'm lucky if I can just find my phone...:rolleyes:
 
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Mr. Rick said:
Haven't locked the 90 since new tire, but haven't seriously tried, either.. Will have to try again.
Click to expand...
With the upgrades on my '74, it will most certainly make the front Avon RoadRider 90/90 squeal at freeway speeds! 'Not something I'd be inclined to repeat too often... Methinks it's time for some bigger rubber.

Nathan
 
<Guzzi linked their brakes long ago, great and proven idea, even if not actually proportioned, as (I think) they did later.>

LInked brakes are the cat's meow for most sane tame civilized situations and I particularly like it on my wife's and other big step through scooters, with or w/o ABS. Just not effective in crisis maxium braking as rear lifts and locks aiming to swap ends. The toughest interval of braking is just before stopped not hi speed pull downs. Takes more brake power to squeal above 60's mph. Moderns have enough power to lock front in surprise even 100 mph which in my case delays the quickesness of max slowing compared to factory Lockheed minus restrictor valve i can grab w/o much skill for best squealing slowing till having to let off below 60's to prevent lock up. Often down long steeps which also makes rear braking nil help but maybe some engine drag.

I'm tested many rides by surprise braking to have developed a reflex to stab rear brake to dive forks an instant before grabbing front hard, but only an instant, unless on THE Gravel or grass or mud/snow slopes then must use both brakes rather delicately which is about impossible on my modern 27 ratio dual rotor 120 tire cycle, but more so its touchy rear grabs/slides leading way down.
 
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