P11 Special... CRS front end and brake

If one doesn't mind cross species modifications, the late 60s BSA/Triumph 8" 2 LS is a great brake for a road bike and it isn't overly heavy.
I wouldn't hesitate to fit one to a Norton, but then my current Norton project has 2017 GSXR600 Showa Big Piston usd forks and a 2014 GSXR600 twin disc brake, so I might not be the last word in tasteful modifications

Glen

worntorn said:

If one doesn't mind cross species modifications, the late 60s BSA/Triumph 8" 2 LS is a great brake for a road bike and it isn't overly heavy.
I wouldn't hesitate to fit one to a Norton, but then my current Norton project has 2017 GSXR600 Showa Big Piston usd forks and a 2014 GSXR600 twin disc brake, so I might not be the last word in tasteful modifications

Glen

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You should stick a Triumph 2LS drum in those big Gixer forks Glen… THAT would be special…!

I do agree though, my ‘68 T120 has one of those stoppers and I am quite surprised just how good it is.

No rain today, so I got out for a ride.

It sure is nice having a real front brake. That stock 7" SLS brake was dangerous on my Norton.

All my sniveling internal to my head complaints about the CRS brake/wheel combo went out the window. I'm very satisfied with this setup.

I still have to dial in the forks, but I'm already close. Too frigging cold out for this old man to ride much anymore until spring. I'll be ready for it though.

worntorn said:

If one doesn't mind cross species modifications, the late 60s BSA/Triumph 8" 2 LS is a great brake for a road bike and it isn't overly heavy.
I wouldn't hesitate to fit one to a Norton, but then my current Norton project has 2017 GSXR600 Showa Big Piston usd forks and a 2014 GSXR600 twin disc brake, so I might not be the last word in tasteful modifications

Glen

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The CRS 230mm 4LS weighs 7.5kg according to CRS, but it's a 9" 4LS. It sure seems to work well on the road regardless of the weight. It took me all of 3 minutes to familiarize myself with using it. After reading commentary here, I thought it was going to be some kind of monster to deal with. Piece of cake to modulate on the street. Might be a different story at race pace trying to out brake somebody. Fortunately, the only person I have to out brake is myself.

I like the GSXR fork and brake setup on your Norton project bike. I am not the Norton tastemaster general though.

Schwany said:

No rain today, so I got out for a ride.

It sure is nice having a real front brake. That stock 7" SLS brake was dangerous on my Norton.

All my sniveling internal to my head complaints about the CRS brake/wheel combo went out the window. I'm very satisfied with this setup.

I still have to dial in the forks, but I'm already close. Too frigging cold out for this old man to ride much anymore until spring. I'll be ready for it though.

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A fair difference in the length of the forks between our bikes

Is one of you niggles the brake arms not being parallel ?

storm42 said:

A fair difference in the length of the forks between our bikes

Is one of you niggles the brake arms not being parallel ?
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The forks are 800mm with what looks like a different head set rake than your Seeley. My forks are currently dropped in the triple clamps more than they will be once I shorten my goofy kick stand. The pic where the forks look really long is because my kick stand is too long, and nearly all the weight is off the forks with the wheel turned slightly to the right. If I turned the forks a little more to the right, the bike would fall over. I like that goofy kick stand. It is small and stays up. Unfortunately, .5 inches to long for the angle it is mounted at. The stock stand can be a real PITA to install from what I have read. I'll cut what I have and weld the foot back on until I work up enough courage to install a stock kick stand. Although it would add more weight.

The brake stays run parallel with the fork sliders and each other. Both have a .25" spacer between the brake stay and brake stay mount on the brake plate. The stays are bolted squarely against the collars. If bolted up against the brake plate without a spacer, the brake stays will not run parallel. They would be way off. The brake stay spacer width used would depend on the triple clamp stanchion centers. If the collars had moved, they would not run parallel either.

The niggles are the wheel is a Spanish Morad, not Borrani mentioned on the CRS website, and it is not what I consider first quality. The rim has a little wiggle in it as well as a small hump at the rim joint and the rim or the drum hub are way out of balance with or without a tire mounted. Not unusual to be out of balance, but it is significant. I haven't ridden over 55mph yet to see when or if any of those factors will be noticeable at higher speed. Up to 55mph I can't feel anything unusual, so maybe I'm lucky or just comfortably numb. I only do something about wheel balance on the P11 if I notice it when riding. I don't think the hump or wiggle in the rim are going to be an issue at all. The tire seems to negate those two things. So far, much ado about nothing.

Other thing that bothered me is the plates have stains on them from one thing or another during handling at the factory. That might be normal, but I was not expecting it. The shocks and forks looked great right out of the box, so I figured the brakes would too. I had to clean them with lemon juice and baking soda.

Enough of my whining.

Fast Eddie said:

Magnesium brake plates are, as you rightly point out, only a minimal saving.

Full magnesium hubs are a different kettle of fish… very light.

You’re right tho, magnesium does degrade faster than aluminium. The guys racing 60+ year old Manx’s are getting concerned about that now.

If being able to still use the same drum in 60+ years is a concern, magnesium might be best avoided…

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Good point

To be honest I didn't go the higher end route because of money more than anything else. I paid less for the brake/wheel combo, forks, and shocks combined than I would have paid for an all magnesium 4LS brake close to the same size. I'm not racing, so I had to draw the line somewhere. It didn't make a lot of sense to me to put that much money into the brake on a P11. The P11 is not a heavy road bike in stock trim. My P11 is still a little lighter weight that a stock P11, but a Fontana replica magnesium brake would have been a great addition. I know it would have been a better brake. I talked myself out of it though.

Hmm, I have a Morad rim that has a bump at the join, anoying.

Nothing wrong with the look of the forks, I was thinking back to when I bought mine, I didn't have a bike to put them on at the time and I nearly went for the next length up, that would have been a mistake for the Seeley.

I didn't mean the brake stays, I was looking at the brake arms, the bit the cable pulls, the bottom one doesn't look parallel with the top one, it pokes my ocd.

Non of which matters of course, the bike looks great.

storm42 said:

Hmm, I have a Morad rim that has a bump at the join, anoying.

Nothing wrong with the look of the forks, I was thinking back to when I bought mine, I didn't have a bike to put them on at the time and I nearly went for the next length up, that would have been a mistake for the Seeley.

I didn't mean the brake stays, I was looking at the brake arms, the bit the cable pulls, the bottom one doesn't look parallel with the top one, it pokes my ocd.

Non of which matters of course, the bike looks great.

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I misunderstood that question and rattled on about the brake stays. Oops

Part of what you are seeing in the pic is due to the bright highlight off the bend in the lower arm. The lower arm is straighter than it appears. The brake arms are different lengths and have different bends in them but are parallel at the rod connection points. There is no bind at the rod clevis, which would be a concern if the arms were not running parallel. What is not running parallel to the brake arms on my bike are the cables. To clear my fender and make getting my wheel on and off easier I moved the cable stop/adjuster mount out .125". The fastening stud on the adjuster mount was interfering with the tire when pulling the wheel up into place. I might be able to use an offset cable clevis to correct it but haven't looked into it, because it seems to be working alright without any bind.

Finally getting some better riding weather. I went out on the damp roads a couple months ago, and that was just a bad idea with a big lump 4LS brake I didn't have any time with. (Insert boo hoo story here.)

The suspension is settling in and getting close. Way better than Koni shocks and Betor forks. I'm getting accustomed to the big lump 4LS. It is one heck of a brake though and one has to take it easy on the lever. It's on right now, and I'm not looking forward to any emergency stops anytime soon, and I'll never ride in the wet again.

I like it, but I think a disc or discs would be easier to modulate to a stop. A smaller 4LS would probably be easier to get used to as well. Enough babble.

Stay frosty

Schwany said:

Finally getting some better riding weather. I went out on the damp roads a couple months ago, and that was just a bad idea with a big lump 4LS brake I didn't have any time with. (Insert boo hoo story here.)

The suspension is settling in and getting close. Way better than Koni shocks and Betor forks. I'm getting accustomed to the big lump 4LS. It is one heck of a brake though and one has to take it easy on the lever. It's on right now, and I'm not looking forward to any emergency stops anytime soon, and I'll never ride in the wet again.

I like it, but I think a disc or discs would be easier to modulate to a stop. A smaller 4LS would probably be easier to get used to as well. Enough babble.

Stay frosty

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Hmmm, I seem to recall someone recommending the smaller one

But, being serious for a mo’ these big drums do settle in a lot. Drag the brake while riding to speed up the bedding in a little. When bedded in fully they’re both more powerful and less grabby.

Fast Eddie said:

Hmmm, I seem to recall someone recommending the smaller one

But, being serious for a mo’ these big drums do settle in a lot. Drag the brake while riding to speed up the bedding in a little. When bedded in fully they’re both more powerful and less grabby.

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Oh I remember.

The big brake was getting better by the time I got home.

I didn't write that up so much for my whining benefit, but for anyone thinking about a big 4LS coming from a smaller SLS or 2LS. It is a significant stopper. I've had several big dual disc brake bikes. They definitely stop well, but not like a new pair of 4 fat shoes up front. Discs start out not working as well as they can, but shoes start out with the ability to put one on the tarmac so quick it seems like a dream. That is about life 7 used up for me.

Csaba talked me out of the smaller brake that I originally asked them about. Said it was too small for a Norton 750. Your Fontana suggestion was right about the same time, but a good suggestion just the same. No regrets. I'll get use to them.

Thanks for all the help from backstage so to speak. Much appreciated. I had to remake the cables 3 times before I got all the stretch out of them and dialed into full on scary.

The 30lb fork springs I requested from CRS turned out to be too light of a spring rate. I emailed Csaba about getting some 40 or 50lb springs, but I think CRS is finally completely shut down. Csaba responded to email within a couple of days right after the announcement that they were closing, but no response anymore.

The CRS springs are 26.72mm x 355mm, which is not a common diameter as far as I can tell. I ended up ordering a set of longer 26mm x 425mm springs in 44.8lb spring rate from Racetech. Paid too much for them but is what it is. I'll have to make a shorter spacer, or in tis case I could shorten them since they are standard wound, not progressive wound. Probably won't be using a lot of preload with the higher spring rate, but don't know yet. I have 15mm of preload adjustment in the fork caps, and can add a little more if needed. The springs will be here in a couple of days. It looks like it will be raining for a week or more, so a final report on ride won't be anytime soon.

Not looking for any helpful advice on how suspension works or how to tune it. I am familiar. I unfortunately thought my bike was lighter weight than it apparently is, and ordered the wrong springs. Feel free to tell me I am an idiot and coudn't possibly know what I am doing with suspension for ordering the lighter springs. I won't care at all. lol

Point of this is if the 44.8lb springs work on my P11 they may work on a Commando stripped down for track use that uses CRS suspension, or a lighter than stock Commando street bike. Or an Atlas, G or N15 with CRS forks on it. Probably none out there but just in case.

The Racetech 26mm x 425mm 44.8lb/inch 80kg/mm spring rate springs are working much better in the forks on my P11 setup. My P11 weighs 374lbs wet. The bike was 6 lbs lighter with the stock front brake. I have no idea how much a stock P11 weighs wet.

I ran across a useful fork spring rate calculator that I used after getting/guessing on the Racetech springs and it seems to agree with me for typical road use. A slightly stiffer spring might be better for highly spirited riding or racing a 374lbs bike, but of course it depends a lot on the rider's preference. Here is the Fork Spring Rate Calculator

I also reduced the amount of fluid used in the forks. There were contradictory fluid specs in the documentation that came with the forks. CRS only provided fluid quantity information, not fluid level. I was using the greater quantity which made the fork travel stiffen up too early. That excessive fluid combined with too light a spring rate is a nightmare on rough surface streets. I will eventually measure the level, and use fluid level in the future, because using quantity of fluid is not very precise.my forks now have approximately 200cc of fluid in them. I was using 250cc, which I think may be closer to the correct number for a set of new completely cleaned out dry forks.

My only take away from all this is weigh the bike first before ordering springs. I knew that but didn't follow the rules, and really screwed up on the 30lbs springs. If I had weighed the bike first, I would have ordered the 50lbs springs, which would be a little stiff, but better than too soft.

Additional info: I do not know if CRS is still selling forks, but they typically ship with 40lbs/inch springs which are too light for Norton twins that are not made from titanium. The 40lbs springs are for bikes that weigh in around 304lbs.

I jumped the gun on CRS being totally closed down. Csaba Kalderal is still minding the store and responding to questions. He was sick for a few weeks when I emailed about springs the first time. He got back to me two weeks later. Unfortunately, I had already bought the Racetech springs. He said he had 40lbs springs. I don't know if he has 50lbs springs.

Schwany said:

More shiny parts on the way for my P11 Special. I'm waiting for CRS GP35R forks, and a 230mm Ceriani replica drum brake in a 1.85x18 Borrani WM2 wheel to show up.

The bike currently has a Betor front end with the stock P11 7-inch SLS brake and a 19" chrome wheel. Nothing really wrong with it other than it really does not stop all that well with the little brake.

The GP35R forks are externally fully adjustable, and the brake is an 9-inch 4LS brake.

This is the first time I've installed a 4LS brake on a motorcycle. To be honest it is sort of a PITA figuring it all out. Disc brakes are a lot easier find parts for, and are cheaper to put together. Possibly lighter, but then again maybe not. And last but not least, more than likely safer to modulate at pace. A really good drum brake will probably take some getting accustomed to. Disc brakes just kind of work. I went with the drum for nostalgic I'm not sure why reasons.

Once I get the parts on, I'll update this thread with what I thought about it all. For now the images below are what I'll be pulling the front end off of except for the triple clamps. Those will be used with the new forks.

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would you be interested in selling the old front p11 front hub?

luis said:

would you be interested in selling the old front p11 front hub?

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Along with the rest of the bike, sure nuff. Otherwise, I'm not parting it out.