There is myriad of shimming and distance pieces on these frameless machines - starting with the seat riding on 5 pivot points no less! - from the forks to RFM, steering head and wheels. Take the time to set it up correctly before riding it the very first time or at a minimum scare yourself silly subsequently or possible worse as I witnessed on several AMC Road Runs. Unlike any vintage machine ever made, these lull one into complacency with effortless performance and, like race cars, straight line stability is a function of wheelbase and unlike long wheelbase Indians and such, at only 57 inches, onset of instability is instantaneous.
- Fork Assembly (Girdraulic): Though much stronger than the Bramptons, they replaced, they are heavier and with significant more steering head forward offset and must not have lateral or axial play in the bushings. For extra insurance against unwanted tank slappers, it is important to disassemble a high mileage machine indicating lack of maintenance in components elsewhere or one stored for a very long time in poor conditions. Look for where (notches) in the spindles shafts, worn bushings and on the eccentrics, the bushings in the FF4 and the lobes of the eccentrics. Attention to the forks and the bearing setup on the RFM are you best insurance against weaves or worse.
- Shock Absorbers: Vincent shocks represent one of the first purpose applications of hydraulic shocks on a motorcycle (Indian introduced same in 1946 but only on the front). Like the ATD, intent was good and results more effective than friction type or none at all. The biggest shortcoming is that stroke length in relation to volume of oil displaced related to load was not fully understood. One thing you will note with these shocks is a significant dead zone range in compression/rebound transition as this critical point is managed only with a floating metal diaghram. Richardson and others attempted to mitigate this effect by better oil flow porting but more on that in a moment.
With relaxed fork rake little braking induced dive, weight transfer to plant the front is minimal, and even with that - unlike modern machines - there’s not a wide rear contact patch to harness the resulting over steer when the power is applied. Thus, for stability on original looking tires (Speedmaster front, SM rear), you are looking for what can be compared to as thrust in a car chassis, sacrificing outright efficiency for stability. In this case, a push or under steer condition on turn-in and down to the apex with a lightly overrunning throttle (completely closing the throttle will tighten your line for a safety net) and some simultaneous front and rear brake to help rotate followed by mild over steer working against that front under steer to help complete the turn and accelerate out of the corner. Stock shocks on original viscosity oil will jack themselves down on rebound when rapidly cycled because of diaphram bleed-back limitations. Perform P.E. Richardson’s mods to alleviate under the understanding that there are other variables also effecting the outcome: your body weight, chassis integrity, tire quality/size and actual cycling rates of your now 60 year old springs. With very high unsprung mass which almost makes the front end feel rigid on quick bumps and lack of dive on braking it’s hard to get a read on it. In the end I opened the front ports further and increased the viscosity which meant these shocks were very compliant over smaller bumps but almost went rigid over large elevation changes where my weight coupled with these relatively weak front springs would already have the suspension dangerously closed to full compression on level ground. The rears were drilled as specified by PER but running a much lighter oil.
Shock filling/bleeding. I use modern shock oils in the range of 10 - 20W. After cleaning/modification, mount the shock at a 45 degree angle in a vise with the bleed port standing vertical. Take a very small soft plastic funnel, thread into this port with the plug removed, compress the shock fully, fill the funnel resorvoir and then slowly pull the shock eye upward refilling the dropping level as you go only to the point where it does not draw air. Do not fill the funnel fully as you'll be slowly compressing and drawing the shock eye/shaft to eliminate bubbles which at their minimum level cause the fluid to look barely cloudy. It will not be perfectly clear but the object is to minimize as much of the aeration as possible. When that is achieved, compress the shock about 20% of its travel (otherwise it will be locked up when you close the vent port), remove the funnel and reinsert the plug. The objective is to enable full stroke length with minimal transition free range between compression and rebound. Unlike pre-loaded gas shocks, this design will still have some transition but with rather a significant level of unsprung mass of the girdraulic setup - especially with cast iron Shadow drums - your principally looking the control the inertia of this mass on rapid compression to keep the suspension from bottoming out. Stock Vincent suspension is very firm in the front.
- Spring Boxes: The rear easier to rectify than the front. Two reasons for wear: either/both through bolts (F28/2) partially seized or the SP4's binding on the faces of the RFM lugs now cocking the assembly under compression but more likely the SP1/1's faces not parallel to each other. If your wear is such that the inner box lip is actually starting to recede then the inner face of the outer box is likely no longer smooth, now notchy and going to bind if this side thrust no relieved. If not keen to grind on your SP1/1, face off a thin car fender washer at the appropriate angle and place between the SP1/1 and the underside face of the F84AS to restore linearity between the two covers. Grease all springs heavily with a heavy bodied wheel bearing grease.
Be sure to adjust your SP4's when finished so the eyelets line up with each other on both assemblies ensuring equal loading of both when in service. Though you'll see custom made tools for refitting front springs boxes to the forks, merely releasing the lower shock eyelets from the FF4 will provide more suspension travel enabling you, with the lower shocks anchored to reinstall the upper bolds at the eccentrics by hand.
- Balance Beam Brace: Better front brake feel can be imparted by supporting your front brake balance beam pivot with a support brace, these can be sourced from John Healey. This feel can also be enhanced with the addition of one of his thicker front brake cables leading from the level to the balance beam.
- Brakes: Another hotly debated subject. Fortunately, not being stressed by spoke tension drums are not prone to warp. Coefficient of friction is a function of abrasion, resist shoeing with metallic based compounds, rather work with what you’ve got by radiusing your shoes to the drums. They’ll never match the performance of the engine, but at least you’ll have a confidence inspiring firm lever.
02/09 Update: Most of the linings available in the aftermarket are quite hard for longevity and are affixed to the shoes with rivets. For the best stock appearing performance, you can have your shoes religned with softer modern bonded material from commercial truck clutch rebuilders. I get mine slightly oversize and longer, then radius carefully to fit. I have my shoes religned locally, bonded on, slightly longer and thicker then manually radius them to the drums with a rasp backed with 220 and 320 grit sand paper using a scribed line with a Sharpee bearing against the drum as a guide. Reasonably priced and turned around within a week, I highly recommend Laycook below. Though example to the left is from my 1941 Indian Four, this illustrates difference in appearance to riveted items.
To improve lever feel.
Laycook259 East Butler Ave.
As an aside, you can read about Laycook's lengthy history here, very interesting. More info on brakes and their restoration can be found here at thevincent.com
Memphis, TN 38126
(901) 523 1418
- Brake Arms: As levers acting on a fulcrum (part no) you want your brakes, which travel in an arc when the pedal/handle applied to move quickly to the point of pad engagement whereupon you will have maximum leverage and that is 90 degrees measured arm to pivot in relationship to the rod or cable, thus, the cable anchor points should lead in front of the pivot in relation to the cable drawing from behind..
- Side Stands: Though equipped with dual stands swinging to either side, neither are of adequate length to provide the secure support one is accustomed to like Triumph and HD Attaching an extending "foot" is only rendering a parked machine more vertical but no more stable as that contact pad is still to close to the centerline of the machine. The only stock appearing solution comes from Michael Breeding here, but some advise on setup that will ensure leverages for secured deployment are maintained. I'd forgo bending of the arms to achieve your objectives regarding deployment or retraction, rather, remove some metal from the appropriate faces of the mounting castings where they abut your FT118. By virtue of casting stop radius to pivot relationship vs foot pad to pivot very little removal is required here to achieve major repositioning of said foot pads.
Besides lighter foot pad loading - an additional objective is some resistance to rolling of the stand when deployed. The farther you can position the foot pad forward of the 90 degree line of perpendicularity to the machine (#1) where the stand pivots when viewed overheard, the more you'll have a chance of decreasing this tendency because the radius of the pad to pivot decreases relative to that 90 degree line measurement requiring the machine to jack itself slightly when rolling forward in order to fall over. I add a slight measure of insurance and achieve more side ground clearance when retracted by welding my feet pads with their top face tilted towards the rear.
With installation on a B series this won't be as noticeable as on a C, let alone a C with longer springs, but, you will notice by virtue of their increased length they hang down a bit lower than the shorter originals. If you grind the stand bosses slightly you can achieve full retracted tuck against engine plates like stock and the reduced ground clearance shouldn't be an issue.
- Rear Stand: Do not start your machine on the rear stand or heave it backward onto the stand when parking. With the stand legs canted at 15 degrees rearward, ground contact points well forward of both the pivot (fulcrum) provide by the fixing bolts and the pads to which the leg stops bear, you will spread you lower axle slot brackets downward leading to less secure axle retention and wheel alignment problems - at a minimum. If your axle slots are no longer parallel and this situation begun to unfold, you have two choices. The recommended but more difficult to execute is the heating and closing of the slots (with the axle adjusters in place to keep the threaded bores from distorting). More expedient but putting off the inevitable is to slightly build up the rear stand ears abutting the pads on the underside of the RFM to reduce deployed stand leg angularity. Adjusting the chain on a machine with damaged slots requires putting a slight upward load on the rear wheel to ensure the axle is firmly planted on the faces of the upper slots before tightening with the tommy bar.
- Bushings/Pivot Points: Vincents employ many bushings and distance pieces which can be prone to wear but especially seizure if not lubricated. Both the ET64 and F57 should be free to rotate in the UFM and have end play distance to the UFM that prevents either the forward seat brackets or spring box eyelets from dragging on the UFM bosses. A replacement seat pivot bushing will likely be a bit long and will need to be cut to about 10 thou end float to prevent your forward seat brackets shifting from side to side banging against the UFM mounting tube thrust faces. If any of these bushings are seized fast and your UFM still affixed to the power plant, do not attempt to hammer them out with a drift, especially the suspension pivots can be knocked out of alignment. Instead, carefully cut them through longitudinally with a scroll saw in two locations so the bushings are now in halves and then drift them out. You'll need to dress the bores lightly with sand rolls on a Dremel. If the rear spring box mounting bushes (M022 - FT117) are worn, replacements are thin, fragile and will have to be clearance with a hand reamer following fitment as insertion in the UFM bosses causes them to collapse slightly.
Few machines have survived with the pre-50 multi piece shift linkages but these are best shelved and the aluminum 50-later single piece lever substituted. Rear brake pedal locating accuracy was marginal even when new but confidence can be restored with a new G90 bush and by making up a very thin distance washer between it and the mounting bracket (F52/11), I made mine out of an appropriate thickness of feeler gauge. The more commonly used left hand pivot tube on the FT119 supporting both side stands can wear on high mileage machines making for an even more precarious lean angle with the side stand deployed. If a weld up and re-drill is not in your plans, the most expedient solution is a straight bolt on replacement from Michael Breeding. More common, is the tendency for the side stand bolt (FT122) to work itself loose and this should be blue Loctited and occassionally checked. Though small machines, Vincent foot pegs are a bit too widely placed apart for smaller riders, a bit of weld on the butting face of the F72's then ground to personal preference can provide better foot positioning.
Brake and clutch levers are prone to wear at their pivots, as over tightening the pivot screw/nut leads to collapsing the lever slot its best to make shims as outlined for the rear brake pedal.
- Wheels (general): Focus here is on refinishing in situ. Vincent rims were originally chromed with black painted centers lined with red. To ensure paint adherence, only the rim edges and about 1/2 inch of the faces back from edges were buffed, thus the chrome finish is matt over the area to be repainted. As seen here in before/after images, seemingly perished chrome can be brought back, but, do not use any aggressive polishes, instead work the area repeatedly with soft brass brushes.
To avoid dragging rust and other abrasives over the chrome, start with single strokes and only when the bulk of the rust removed should one use any back/forth motion. Clean the surface with Brake Clean and a rag. Like Kroil is to freeing rusted parts, so is Wenol metal polish for reviving chrome without any scratches. To paint, stripe of the center section and paint the center first, once dry, follow up with 3M Scotch Fine Line Paint Striping Tape removing pull outs equivalent to just wider than 1/8". Following hand painting/lining, as it is porous, keep the chrome waxed to prevent/reduce rust returning.
- Wheel bearing adjustment: If properly adjusted the tapered roller bearing variety can be nearly life of the machine. To tight and they will drag on the outer races which if rotated in the hub ruin the interference fit. If you have adjusted your bearings/serviced your brake shoes thus disturbing your shim stacks, ensure you re-stack the spares on the outside of the bearings supporting the brake plates with adequate clearance to prevent your brake shoes/linings dragging on the face of the brake plates. On the rear, never stack shims such that you have to pry your RFM axle slots open to refit the wheel, this will change the perpendicularity of the slot faces where they abutt the (M001 - E80) nuts, you want full face contact with the RFM around the perimeter of the nut.
- Swing Arm Pivot Bearings: Like the use of needle bearings in the hub carriers of Jaguar XKE's, use of a needle bearing in this application probably not the best as it concentrates stress on very little surface area and is compounded by relatively little movement thus, the bearing races can divot over time on machines in hard use (heavily laden touring/side cars). Recommend servicing and adjusting these, if nothing else to carefully rotate the bearing where rollers will contact previously unused areas of the race but also as insurance against tank-slappers as any slack here will increase propensity for the machine to weave at speed.
- Stripped Axle Adjusters: It is not uncommon to have the axle adjuster bore(s) completely stripped. As it is not advisable to over-drill for modified TimeSerts or helicoils and you may be reluctant to send off your matching number RFM for professional reclamation, a small fix can be effected for this situation in which your Vincent cannot be safely operated without these (on the driven side) operational. As the direction of loading is rear to front from chain draw, you will be preparing a nut for insertion in a small landed bore drilled from within the adjuster slot. Take a nut of suitable thread pitch, turn off the flats, drill a land within the stripped bore the depth of nut's width, notch the sides of the axle adjuster root such that the sides of the inserted nut
now visible and then weld up these voids with the nut inserted in the bore
and anchored by the bolt and grind off the excess.
- Wheel Alignment: This comes in two forms, front and rear wheels tracking within the same line and rear wheel orientation relative to the front. Though other machines far less accommodating of errors in either, the risk you face here is that a Vincent goes about its business in such a relaxed fashion that you are lulled into higher velocities where an inaccuracy in either can have more dire consequences. Issues with the former relate more to chassis buckling via bent fork links (MOx - FF3/FF4) as wheel shimming errors at the axles are so incrementally made it is near impossible for the wheels to be offset significantly. Unlike other machines having wheel hubs offset relative to rim centers, Vincents are symetrical but still worth checking. A machine having the rear wheel toed out in either direction relative to the front can cause a dangerous over steer situation when turned away from the direction the wheel is pointed, ie, left turn on a machine with the wheel toed out to the right. Turn in is accentuated by a feeling of the
rear wheel almost tucking under the machining dropping your body to the left very rapidly. Align your machine on the stand held perfectly upright with tie down straps. Measure difference in front and rear tire widths, divide in half and make a shim to mount to a straight edge that will bridge the front and rear contact points on the tire sidewall as high up as you can manage without your straight fouling anything hanging off the side of the machine on the run to the rear tire.
- Fenders (Birmabrite): At .035 thick these fenders are very fragile, prone to corrosion and easily dented. Corrosion takes the form of pitting and as there is little depth to work with it is imperative they be dent free before undertaking any polishing. Depicted is a buck to work dents out from the inside where any hammer head marks will not show. Take a contour gauge and profile the rim in cross section. Cut 4 sections of 3/4 - 1" plywood/pine board, scribe lines in each approximately 10% over the profile gauge radius, lay on the fender, clamp, drill and screw together. Lay tin foil on the fender, work flat then tape to fender, take fibred high build body filler, lay over tin foil about an inch thick press wood lamination in and let cure. Attach a plate to the bottom for securing to your bench with C clamps. Required is a dead blow hard rubber mallet with a head profile roughly matching the inside radius of the fender. As denting this malleable metal stretches it as well, the objective here is to shrink it back while working the dent out, thus start at the deepest point of the depression and work outward.
Polishing. Unlike many alloys, Birmabrite does not corrode uniformly, instead developing small pits which may get very pronounced depending on how long deterioration has been permitted to continue. You readily run the risk of ruining the structural integrity of them if attempting to cut the metal down to the point where it's entirely smooth, some compromise may be advisable. High end chrome plating shops like Dan's Polishing Shop can straighten and polish your fenders but if you elect to have a go yourself it is advisable to take a slower route to ensure a satisfactory outcome. As opposed to aggressively cutting back on a bench buffer in the first stages block wet sand instead. I start with 1200, 1500 and then 2000 using a flexible rubber pad. The challenge you face with the customary 8 - 10 inch hobby buffing wheel is you will likely cut a series of grooves while working the surface that will then show up as waves once its finally polished to a sheen. Block sanding better controls the cutting process, squeegee off to check for surface imperfections just as you would under the fuel tank refinishing notes. The final buff can be done with a firm woven cotten mop on the bench grinder using Wenol.
- Tires: Though the touring configuration of 3.50 x 19 front and 4.0 x 18 rear poses far more options for rubber suited to one's liking, the sport configuration does not as it applies to the 3.0 x 20 front. Fortunately, Avon is reproducing the originally fitted ribbed-tread Speedmaster and through improved hysteresis it provides a pleasant confident inspiring envelope of performance as its cross sectional profile embraces the beginnings of modern tire technology wherein, the tire carcass/tread radius in cross section is more rounded and thus contact patch remains more uniform across the operational arc. Not so the rear - Avon SM - which is rather rectangular with noticeable fall off to the sidewall at the edges of the tread which does not extend much up the sidewall and thus this precarious transition is experienced regularly as only moderate lean angles are required to cross it. Altering air pressure for more tread deformation to maintain contact patch through this transition is not advised so if you are not comfortable with over steer on a motorcycle and want to hustle your Vincent through bends at speed, the only solution is to be rider provided. Instead of pitching your machine over with a lean angle in line with your body, you may have to lean a bit off the side, keeping the machine more vertical "squared" to the road to retain as much contact patch as possible. I reduce the severity of this transition buffering slightly by reducing overall grip at the rear by moving my weight forward as well as down.
Inner tubes (3.00 x 20). Can be a challenge to locate in the U.S. and will likely be 21 inches and intended for dirt bike use. As our machines are much heavier than most dirt bikes, get the heavy duty puncture resistant version if available. I'm currently using a Michelin AIRSTOP tube (2.50-3.0 x 21 Butyl 21 MD CAI 276900) sourced from BMW intended for their enduro
- Rim Locks: On original Vincent rims, there will be 3 rather long bolts protruding through the rims at roughly 120 degrees from each other. All served to hold wheel weights but one serves as a locking device to retain your tire from yielding to braking forces by creeping on the rim and in turn cocking your inner tube xx possibly causing it to tear from the tube. As it is difficult to position this lock wherein it doesn't pinch the tube for which that condition is difficult to even verify, many forgo refitting one. I'll leave it to your judgement. Whereas pre-DOT labeled and NOS Avon tires had beads fitting the rim lands far more firmly, they also employed harder rubber compounds which did not provide much engagement between the inflated tire and the rim edge to hold it in place. Modern tires have far better hysteresis and less likely to creep on the rim when inflated, but they also have beads of slightly larger circumference not gripping these rims which do not have the troughs that prevent de-beading on rapid deflation. Thus, one runs the risk of having the tire come completely off the rim if sudden deflation is experience. Closing this topic, though modern rim inner configurations reduce de-beading tendencies, rim locks are not used modern street machines.
A quick replacement for the rim locks is a half inch nut taking carriage bolt providing you with a nicely contoured head reducing the risk of abrasion on your rim tape, or worse yet, tube and lies in the rim well with a very low profile. To ensure it really nests more flush, I take mine and contour the undersides of the bolt heads with a grinder.
- Steering Dampeners: Your Vincent is fitted with a basic one or two fiber disc mechanical steering dampener intended for use, like most machines of its vintage, when a side car is fitted. In solo form, a well fettled Vincent in stock (tires) configuration should not need any intervention from
a dampener for stability beyond a light cinch to provide a firmer feel at the bars to increase rider confidence. Between the two chassis instability conditions of weave and a "tank slapper" the dampener is intended to suppress onset of the latter. This condition not necessarily be chassis induced, if unfamiliar with
the experience, you can induce a mild version of one at low speed by merely releasing one hand from the bars, compensating for your weight re-distribution by leaning the machine slightly towards the side where the bars still gripped and crossing a pavement irregularity or bump. You will feel an initially sharp jolt at the handlebar gripped which dissipates in intensity as a combination of the weight of your fork/wheel assembly and wheel gyroscopic effect serve to absorb and
diminsish this one time force input. Besides centralizing your mass over the
machine's CG, the mass of your hands/upper torso act as a dampener so for a
machine of this weight with only the leverage of 25 inch bars rotating almost on
steering neck center it is advisable to right with both hands on the bars.
Aftermarket hydraulic dampeners. No different than the shocks on your car, good ones are designed for specific stroke lengths, cycling velocities and leverages provide by anchoring positions at both ends. Making one fit within the confines of a Vincent and its Girdraulic fork system with differing geometries from telescopic forks to which these are most commonly fitted can lead to a situation most encounter - over dampening of routine steering movement restricting your ability to make those incremental counter steering flicks of the bars as needed. This manifests itself in a tendency for your machine to weave at speed as the dampener renders your movements a step late and often not to the extent desired. Again, more advisable sidecar use where chassis dynamics changed and steering forces greater, as well as these units more appropriate to heavily laden touring and track oriented machinery on aggressive tire compounds in solo use.