[MikeD]

Once I used the ratchet strap to compress the legs against the main springs, I was able to get the top nuts off the damper rod to release the leg.

Then screwed the top bolts back in and hammered them to break the taper between the stanchion and the top crown. (Because why pinch bolt when you can taper, say the British...)

Pretty simple arrangement after that.

Studying the damper tube and rod to determine if I'll be plugging and/or redrilling any of the orifices (heh heh). The basic issue is that the hydraulic bump stop arrangement from the factory fails to work, most obviously under compression...the hole that provides the alleged hydraulic lock seems to be positioned too low on the tube to actually provide any cushion.

Simple to tap and plug the existing hole and re-drill another above it...maybe I'll try 5-7mm or so if I decide to do it, after consulting with the brit bike gurus on other forums.

JBP was reporting top-out, too, but I haven't gotten any in my mild use so far. Might see how they go with fresh fluid before doing anything on that end...but pressing some bronze bushings into the damper top cap for better tolerance might help with any top-out by preventing oil escaping through it, too.

 

[rideit]

Yeah, that really is an old Marzocchi.

 

[jstuhlman]

every time i see this thread title i keep thinking i'll see this inside

 

[rideit]

Needs a ‘stache photoshop

 

[MikeD]

Iiii've beeeen woooorrrkinnngg on sussspppeeennssion, all the livelong day...



Goal was to get into the fork, inspect internals, and install a kit meant to cure some of the top-out woes endemic to the Roadholder fork. The G15-CS, however, has a modified Roadholder and the purveyors of the various kits were unable to tell me exactly what I'd encounter and what I'd need to make it better. JBP had warned me that the top-out was really harsh and encouraged me to make the mods #1 on my list. Given that I'm waiting for a registration and some parts, figured now was as good a time as any to dig in.

Getting into the fork was a little nerve-wracking. I know it's a simple design, but the way things fit together is often problematic on anything British. Fork fits to the top crown with a taper...why bother with simple things like clamps?

Ultimately, one leg came off easily and the other needed some encouragement, which led to some mashed threads which let to some time with a file, a wire wheel, a carbide bit, a cold chisel, and the top cap in a vise and me turning the leg on and off it slowly using a screwdriver through the oil holes. This is why I am always apprehensive about digging into something new on this thing...ugh.



So once I had the top cap threads rehabilitated, it was time for the modification kit. The mod kit was simple: tap 4 existing small holes in the stanchion to 6-32, plug with provided set screws and some bearing-retainer loctite (or JB weld or other goop of great permanence), then slide on some aluminum sleeves to sit below the top bushing. The sleeves blank off the oil hole at the right time in the fork stroke to (somehow) result in a hydraulic cushion on topout. I also used some needle files and a dremel flap wheel to smooth out some snags on the rim of the existing oil hole, which tended to catch the aluminum sleeve.



I'm not honestly sure about the exact oil flow in the fork in use; the "plunging damper" arrangement is something new to me, and there's oil passing between the slider and the stanchion aside from what's going on in the damper tube. I almost wonder if the brass static "valve" and the damper cup on top could be replaced with a shim-stack arrangement of some sort...hmmmm... If it could, however, I bet the Norton racing community already would have thought of it; even Racetech told me they couldn't do a cartridge-emulator with this style of fork. (I have one of the emulators in my Enfield fork...tasty and easy...)







There's a bottom-out remedy that's similar and normally comes as part of this kit, but the damper tubes on the G15-CS won't fit these collars. Nor does it seem to need to; the oil hole on the damper tube seems to be in the right place (above the apex of the taper) that the kits relocate it anyhow. If I have clanking on compression, I'll re-visit it.



So it all sits here, awaiting a few more small parts...had to mutilate a drain plug to free it, etc. In the meantime, I may try some experiments with the damper to see if it's doing the right things. Or maybe I won't...we'll see.

 

[johnbryanpeters]

Iiii've beeeen woooorrrkinnngg on sussspppeeennssion, all the livelong day...



Goal was to get into the fork, inspect internals, and install a kit meant to cure some of the top-out woes endemic to the Roadholder fork. The G15-CS, however, has a modified Roadholder and the purveyors of the various kits were unable to tell me exactly what I'd encounter and what I'd need to make it better. JBP had warned me that the top-out was really harsh and encouraged me to make the mods #1 on my list. Given that I'm waiting for a registration and some parts, figured now was as good a time as any to dig in.

Getting into the fork was a little nerve-wracking. I know it's a simple design, but the way things fit together is often problematic on anything British. Fork fits to the top crown with a taper...why bother with simple things like clamps?

Ultimately, one leg came off easily and the other needed some encouragement, which led to some mashed threads which let to some time with a file, a wire wheel, a carbide bit, a cold chisel, and the top cap in a vise and me turning the leg on and off it slowly using a screwdriver through the oil holes. This is why I am always apprehensive about digging into something new on this thing...ugh.



So once I had the top cap threads rehabilitated, it was time for the modification kit. The mod kit was simple: tap 4 existing small holes in the stanchion to 6-32, plug with provided set screws and some bearing-retainer loctite (or JB weld or other goop of great permanence), then slide on some aluminum sleeves to sit below the top bushing. The sleeves blank off the oil hole at the right time in the fork stroke to (somehow) result in a hydraulic cushion on topout. I also used some needle files and a dremel flap wheel to smooth out some snags on the rim of the existing oil hole, which tended to catch the aluminum sleeve.



I'm not honestly sure about the exact oil flow in the fork in use; the "plunging damper" arrangement is something new to me, and there's oil passing between the slider and the stanchion aside from what's going on in the damper tube. I almost wonder if the brass static "valve" and the damper cup on top could be replaced with a shim-stack arrangement of some sort...hmmmm... If it could, however, I bet the Norton racing community already would have thought of it; even Racetech told me they couldn't do a cartridge-emulator with this style of fork. (I have one of the emulators in my Enfield fork...tasty and easy...)







There's a bottom-out remedy that's similar and normally comes as part of this kit, but the damper tubes on the G15-CS won't fit these collars. Nor does it seem to need to; the oil hole on the damper tube seems to be in the right place (above the apex of the taper) that the kits relocate it anyhow. If I have clanking on compression, I'll re-visit it.



So it all sits here, awaiting a few more small parts...had to mutilate a drain plug to free it, etc. In the meantime, I may try some experiments with the damper to see if it's doing the right things. Or maybe I won't...we'll see.

Never had problems with bottoming, YMMV. Those top cap threads are a bitch.

 

[MikeD]

Well, JBP, looks like Walridge has new G15 stanchions on sale for $125 a pair...Canadian! I think I will give the original items a well-deserved tag-out and let some fresh blood take the reins. The old ones read like a map of awesomeness, however.

This should give a nice fresh taper fit, good threads, and even more peace of mind.

 

[johnbryanpeters]

Well, JBP, looks like Walridge has new G15 stanchions on sale for $125 a pair...Canadian! I think I will give the original items a well-deserved tag-out and let some fresh blood take the reins. The old ones read like a map of awesomeness, however.

This should give a nice fresh taper fit, good threads, and even more peace of mind.

I think that's long overdue. The top cap threads on at least one side have been questionable.

 

[MikeD]

I just need Mike from Walridge to provide me the right top cap part number, too, since I definitely injured the threads on one of them in the Great Removal Debacle of 2019. The G15 top caps are a different PN than the Atlas or the Commando...but it doesn't show up on the Walridge site.

Worst comes to worst I'm sure I can re-use these, sans the initial threads on one of them.

 

[Westy]

Put a Monster T on it.

 

[MikeD]

Put a Monster T on it.

I dunno, the fork offset might be all wrong. And it's not a UST-rated bike.

 

[MikeD]

But maybe if I can find some Gazzalodi 3.0s with downhill tubes it'd work.

 

[MikeD]

New fork tubes and sundries ordered...

 

[johnbryanpeters]

Regarding top caps: Check this place out; I used to get G15-CS parts from the previous proprietor, and god knows what's in their attic.

Home - The Nickwackett Garage

Nickwackett Garage, bmw motorcycle, motorcycle repair, classic BMW and Triumph, Triumph, Bud Provin, Buffalo Bud

thenickwackettgarage.com

 

[jdcamb]

I broke my fork on the MB-3. I didn't tell JBP. I did go out and buy a new one. Same color and everything. I am hoping he doesn't find out and want it back.

 

[MikeD]

Regarding top caps: Check this place out; I used to get G15-CS parts from the previous proprietor, and god knows what's in their attic.

Home - The Nickwackett Garage

Nickwackett Garage, bmw motorcycle, motorcycle repair, classic BMW and Triumph, Triumph, Bud Provin, Buffalo Bud

thenickwackettgarage.com

Found them at Walridge but I'll tuck that URL away for sure!

 

[MikeD]

Did a little more clutchery today.

Had an issue with the pressure plate riding on the mainshaft, so I had to grind and reshape it. (awww yeah.)



Plus I wrapped up the stator wires which had a couple nicks and abrasions.

 

[MikeD]

I am pretty proud, actually. I trimmed 2mm off the transmission mainshaft freehand, in-situ, with a dremel cutting wheel, and shaped/rechamfered with carbide bits and a flap wheel. The point was to increase clearance for the upgraded clutch...it had been slipping on install, and I traced it to the pressure plate riding lightly on the mainshaft. I ground a little away from the pressure plate and it worked great, but I realized that would only last until the clutch pack wore ever so slightly.

So I did the job the clutch manufacturer recommended...I didn't want to do it at first, but realized there was no real downside to doing it right. And it didn't need to be removed from the bike to be lathed, since the idea was creating clearance...not a precision job.

Did it neatly enough, using my vernier's depth gauge to get it more or less even, and let the flap wheel smooth it all out.

What I'm REALLY happy with was the second half of the manufacturer's recommendation. It'd get too complicated to explain why, but I had to reshape the clutch pushrod along with the shortening of the mainshaft, and so I put it in my drill like a mini-lathe, and shaped it perfectly with the flap wheel. It was so cool, after all the guesswork of freehanding things, to watch the lathe effect just make the shape so symmetrical and perfect.

Then I got to heat it, quench it in oil, and temper it...first time doing anything like that, either.

 

[MikeD]

One step forward, six steps back...

Worst part: UPS gave my parcel to USPS, who delivered it to my welder buddy sans contents. So...no damper tubes now. Found some, I think...we'll have to see about getting them ordered over the holidays. Guessing there won't be a run on G15-CS fork dampers in the next week tho. Hopefully I can get a couple insurance bucks.

 

[johnbryanpeters]

One step forward, six steps back...

Worst part: UPS gave my parcel to USPS, who delivered it to my welder buddy sans contents. So...no damper tubes now. Found some, I think...we'll have to see about getting them ordered over the holidays. Guessing there won't be a run on G15-CS fork dampers in the next week tho. Hopefully I can get a couple insurance bucks.

Wow...

 

[MikeD]

I'm still on pins and needles hoping I can get some of them, and that they're actually the right part. The holidays aren't helping me get answers from any of the usual sources.

 

[MikeD]

Looking like nigh-unobtanium but still scavenging.

Other options are installing available roadholder-style internals from the 66-later models, rigging a dummy tube to accept a Racetech gold valve and internal main spring, or a custom cartridge arrangement. A guy does those cartridges pretty cheaply but we would need to work out the custom details for a G15 vice Commando.

 

[jdcamb]

I replaced the Sakae headset with a Cane Creek. Only because I couldn't find a lower race that fit. The Cane Creek will last forever so its all good. Don't tell JBP...

 

[Full Trucker]

Checking in again.

Yep, still the best thread on the Monkey

 

[MikeD]

Gonna be even bester if I can get these installed...

 

[johnbryanpeters]

Are those steel or Al?

 

[MikeD]

Yo no se, but top caps at least are AL I would guess.

 

[lovebunny]

Hey dude! I saw your post the other day about your favorite trails, so glad I got to be a part of a couple of those rides! Bike looks amazing and I'm sure you will find a solution to your never ending fork woes.

 

[MikeD]

Hey dude, those were the best of times for sure. Soon as I can get a measurement on the stock damper arrangement, I'll have the cartridges made.

JBP's old notes provided some info on the internals but the full length of them evades me...need someone with a unit in-hand to measure, and/or take a shot at measuring it on an assembled empty fork leg with no spring in it.


I need to post some choice pages from his notebook here, chronicling the history of the bike and his efforts to keep it going. I'm continuing it, too...in the same old book.

 

[MikeD]

Waiting on a dude in Italy to get off of vacation abroad so he can measure the damper on his disassembled AJS33 (same bike under a third marque aside from Matchless and Norton...). Once I have that measurement, the guy who makes the cartridge dampers will make one for me.

It's an extreme step, but given the scarcity of the parts I lost and the overall cost of replacing with new guts that then require additional mods to function half-decently, I think this is a great and fairly cost-effective solution at this time. Buying new internals just to buy cartridges later would be the least-eopnomical way to do it. Will keep an eye out and try to get the proper dampers at a cheap price just to have on-hand tho.

 

[MikeD]

New stanchion tubes and top caps arrived. Stanchion already had a mashed top nut thread on arrival, still to be cleaned up...and they use the Norton type circlip bushing retainers rather than the nuts on JBP's original forks, necessitating another $20 on eBay.

These hybrid bikes are kind of a parts-number nightmare. Never know what's going to be going on at any given time.

 

[MikeD]

Well, I have plates and a registration...!

The clutch is nearly sorted through addition of a pushrod seal to keep transmission oil out of the primary, though this caused more old-lady-who-swallowed-the-fly types of problems.

Should have the fork dampers soon, and then I think it is ready to ride for reals.

 

[MikeD]

Substitute parts found for the lost bits! Likely also go forward w cartridges.

 

[MikeD]

Yay, forks! Complete with anti-top-out mods, even, and fresh stanchions to boot.

Gonna need some time to get everything re-mounted. Then the clutch has to get back together, but that shouldn't be much of an issue. Just experimenting with two different ways of sealing the clutch pushrod against transmission oil migration into the primary.

 

[jdcamb]

Thanks for sharing. Awesome thread.

 

[MikeD]

Welp, made a new one-piece clutch pushrod in the appropriate length from some drill rod which I cut, shaped and hardened as above. Works well with the new pushrod seal and another steel plate in the clutch stack for some more clearance.

Also cleaned up the top cap threads in the new stanchions. Just had to run the old top cap through using a big wrench with the stanchion held in the vise with rubber jaws to chase the slightly distorted threads clean. Now the new cap screws in easily.

Bad news is the anti-top-out fix I installed left the forks unable to extend fully. While trying to figure out what I could do to make it work, I wanted to measure the fully compressed spring length. I rigged up a pogo stick looking way to do it out of a wooden closet hanging rod and a 2x4 , and was quite proud of myself till I decided to double check my measurement, let it bounce too much underneath me, got some coils caught underneath it, and ended up bending the spring slightly. (Which seems like it might have been clapped out anyhow...perhaps it was for the best?)

Don't seem to be replacements readily available for those...just shorter ones for older Nortons and the newer, longer internal arrangements. I'm pursuing the cartridge dampers again now, but at least now I have all the measurements I need to get them right.

 

[MikeD]

So those babies should be in the mail tomorrow...sweet sweet drop-in cartridge dampers with integral springs.

 

[MikeD]

So these came in. And they don't fit inside the new stanchions, argh! Looks like the new ones are thicker-walled than the originals.

They do fit in the old ones, though I've gotta check if they bushing retaining nuts on that style of stanchion will be wide enough. (Can turn or just hand-grind them to open them up if not...but another pain...)

Maybe weds-thurs I can get some time to mess with it.

 

[jdcamb]

Keep us posted. I am sure I am not the only one hoping you fix JBps' Old bike.

 

[Randomshot]

Pretty sure we all want on a spin on it...