TELEDRAULIC TECH­NI­CAL..........................

As­so­ci­ated Mo­tor Cy­cles fit­ted their own form of tele front forks to AJS and Match­less mo­tor­cy­cles for over two decades. Martin Pea­cock puts the bounce back into his G80’s front end…

Real Classic - - What Lies Within - Pho­tos by Martin Pea­cock

As­so­ci­ated Mo­tor Cy­cles fit­ted their own form of tele front forks to AJS and Match­less mo­tor­cy­cles for over two decades. Martin Pea­cock puts the bounce back into his G80’s front end

Match­less in­tro­duced their tele­scopic forks quite early with the model G3L in 1941. This was con­sid­ered the first front sus­pen­sion in­no­va­tion in 25 years and was much ap­pre­ci­ated by dis­patch rid­ers at the time. The ‘ Teledraulic’ fork was mod­i­fied over the years with changes to ex­ter­nal el­e­ments such as the brake an­chor points and drain plugs. Triple rate main springs and buf­fer springs were added in 1947 and the stan­chion di­am­e­ter in­creased from 11/8” to 1¼” in 1955.

Pro­duc­tion con­tin­ued with nu­mer­ous de­tail changes un­til the in­tro­duc­tion of Nor­ton Road­holder forks for Match­less and AJS road bikes in 1964. Teledraulic forks were re­tained for the com­pe­ti­tion bikes, in­clud­ing forks from the tri­als model used on the G85CS to re­duce weight. These and other changes over the years are de­scribed in Roy Ba­con’s ‘Match­less and AJS Restora­tion Guide’ for post-war sin­gles and twins. Also, con­sult the man­ual for your bike and avail­able lit­er­a­ture, es­pe­cially an il­lus­trated parts list. Most of the man­u­als, parts lists and guides in­clude a di­a­gram but they are of vari­able qual­ity.

The Teledraulic fork has a de­served rep­u­ta­tion for good per­for­mance and re­li­a­bil­ity, pro­vided oc­ca­sional oil changes were car­ried out. Even so, wear­ing parts such as oil seals and bushes will even­tu­ally need re­newal and the forks will ben­e­fit from an over­haul. This guide is based on the later type (1961) used on my Match­less G80. Strip­ping and re­fur­bish­ing the forks is rea­son­ably straight­for­ward. The main chal­lenges can be free­ing them from the yokes and sep­a­rat­ing the slid­ers if the years and cor­ro­sion have taken their toll. The only spe­cial tool gen­er­ally needed is a draw bolt to refit the fork legs, which can also be help­ful for re­mov­ing them.

THINGS TO CHECK FIRST

You may be able to stop mi­nor leak­age from the seals by tight­en­ing the slider ex­ten­sions. These sit on the oil seals and this may at least buy you some time. Sim­i­larly, a stiff fork ac­tion may be due to a mis­matched or badly fit­ted mud­guard bridge putting side strain on the fork legs. Check for this by loos­en­ing the bridge and check­ing the fork ac­tion.

Sup­port the bike on a lift or on its cen­tre­stand with blocks un­der the crank­case. At­tempt to move the fork legs back and forth to de­tect wear in the bushes. Make sure any move­ment is not due to play in the steer­ing head bear­ings. You can check the bushes sep­a­rately af­ter re­mov­ing the front wheel and mud­guard, but there is no point in over­haul­ing just one fork leg.

RE­MOV­ING THE FORKS

Clean off any ac­cu­mu­lated road dirt and oil from the forks, wheel and mud­guard. Drain the oil from each fork leg by re­mov­ing the drain screws at the bot­tom of the slid­ers. You can speed this up by mov­ing the slid­ers up and down. Al­ter­na­tively, wait un­til the forks are out and sim­ply pour the oil out. This is a good op­tion – I have found there is al­ways oil lurk­ing in the fork af­ter drain­ing and ready to come out to make a mess ex­actly where you least want it.

Make sure the bike is well sup­ported with the front wheel off the ground and then re­move the wheel and mud­guard. This is eas­ier if you first move the mud­guard up, clear of the studs and then ro­tate the slid­ers so the studs are point­ing out­ward. Then lower the mud­guard about half way and ro­tate the slid­ers back to pull it all the way out.

Loosen the top cap screw and then the pinch bolt on the lower yoke in turn for each fork leg. Give the top caps a sharp tap with a soft-faced ham­mer to free the stan­chions from their ta­pers. If this works, breathe a small sigh of re­lief and un­screw the top caps com­pletely. Un­screw the damper rods from the top caps and then pull the stan­chions down, through the lower yoke.

In the likely event that a sharp tap or two fails to free the stan­chions, don’t re­sort to more force as this will dam­age the threads. Un­screw each top cap fully, re­lease the damper rods and then use a drift fit­ted to the stan­chion’s out­side di­am­e­ter to al­low a se­ri­ous clout or two. Once the tops of the stan­chions are loos­ened, pull them down through the bot­tom yoke. Cor­ro­sion can oc­cur on the stan­chion un­der the top cov­ers which carry the head­lamp mount­ing brack­ets. This might make it nec­es­sary to twist and pull the stan­chion a lit­tle to ease it free. If nec­es­sary use the draw bolt tool, care­fully, to tap out each stan­chion in­cre­men­tally in turn.

If the cor­ro­sion build up is se­vere, you may need to undo the steer­ing head and re­move the stem com­plete with the forks to al­low re­moval of rust and scale from the stan­chions. Make sure you col­lect all 56 of the 3/16” steer­ing head ball bear­ings if you do this. Re­mov­ing the steer­ing stem and bot­tom yoke will also re­lease the top cov­ers and head­light which can other­wise be left in place for the fork over­haul. In ei­ther case, the rub­ber buf­fers should be checked and re­newed if they are per­ished.

Lift off the bot­tom tube cov­ers. Some early ver­sions are se­cured by small screws at the bot­tom of the cov­ers, ac­ces­si­ble only from the in­side. You will need a long, thin screw­driver, torch and pa­tience to re­move these.

FORK LEG STRIP DOWN

Care­fully clamp the bot­tom of the slider in a vice with soft jaws, prefer­ably by the bot­tom cap studs. Lift off the main spring, check the leather wash­ers fit­ted at each end of the spring. Re­place them if they are dam­aged. In fact, plan to re­place them and sim­i­lar in­ex­pen­sive parts such as the stan­chion rub­ber buf­fers as a mat­ter of course.

Re­move the three rub­ber buf­fers fit­ted over the stan­chion to stop spring chat­ter and then undo the chromium-plated slider ex­ten­sion. A strap wrench (or a pipe wrench well-padded to pre­vent scratch­ing) is needed for this job. If this doesn’t work, heat the area at the top of the slider where it meets the ex­ten­sion and try again. Once the slider ex­ten­sion is un­done, be­ing care­ful with hot parts, take the slider out of the vice and grip the stan­chion hor­i­zon­tally at its up­per end to pre­pare for re­mov­ing the slider. Move the al­loy slider smartly to the ex­tent of its travel on the stan­chion a few times. At­tach the end cap and wheel spin­dle for more pur­chase if needed. This should drive the oil seal out. If it doesn’t, heat the area at the up­per end of the slider with a hot air gun or by wrap­ping it with rags soaked in boil­ing wa­ter. Re­peat the process un­til the seal comes free. At this point, you can check the damp­ing by pour­ing some oil into the slider and mov­ing the damp­ing rod up and down. If there is lit­tle damp­ing ef­fect, this may be reme­died by clean­ing all the parts be­fore re­assem­bly. Re­move the damper assem­bly by un­do­ing the screw at the bot­tom of the slider as fol­lows: Hold the slider by the front mud­guard tighten the vice just enough to hold it. Do not hold the slider it­self be­tween the jaws or you could cause eri­ous dis­tor­tion. The damp­ing unit s re­tained by a screw through the ase of the slider. Undo this with a ¼ Whit­worth box span­ner filed to fit to the lim­ited space around the hex aded screw or pos­si­bly a slim socket. Lift the damp­ing rod and valve em­bly out and set the slider to one e. Next re­move the fork bushes m the stan­chion. Cir­clips above and ow re­tain the hard­ened steel bot­tom h. Once this is re­moved, slide out the er spring, up­per (plas­tic) bush and oil seal.

PRE­PARE FOR RE­ASSEM­BLY

Ex­am­ine the sur­face of the stan­chion in the re­gion where the plas­tic bush and oil seal slide dur­ing use. Se­vere scor­ing, pit­ting or ridges in this area will need to be ad­dressed ei­ther by hard chroming and grind­ing back to size or re­place­ment of the stan­chion. Mi­nor pit­ting can be filled with epoxy and rubbed down to a smooth sur­face. Check the stan­chion for straight­ness (rolling it on a flat plate sur­face will do this) and clean off any cor­ro­sion on the up­per part if the stan­chion is other­wise in use­able con­di­tion.

The slid­ers should not give trou­ble pro­vided the oil is changed and doesn’t leak out. You can check them af­ter re­fit­ting the stan­chions by test­ing for lat­eral move­ment. Also, check the springs for any ob­vi­ous prob­lems, es­pe­cially if the forks have been bot­tom­ing out or are too stiff on the road.

Re­move the two damper rod sleeve re­tain­ing clips then strip and clean the damper assem­bly parts. If the quick test de­scribed above showed there was lit­tle or no damp­ing, test again for im­proved damp­ing. These parts gen­er­ally to not wear but re­place any parts that are badly worn or dam­aged.

Re­view your notes and have an­other good look at the fork parts af­ter clean­ing. Con­sult the parts list and di­a­grams. Now you have got this far, it is worth re­plac­ing the up­per bushes, oil seal and sundry wash­ers in­clud­ing the leather ones. Make sure you have the cor­rect grade of fork oil on hand. Bronze bushes are avail­able in­stead of plas­tic and were my choice, as can be seen in the pic­tures.

You can also re­place the chrome slider ex­ten­sions if they are in poor con­di­tion but I chose to have mine re-chromed at lower cost even though it meant a few weeks’ turn­around time. The bot­tom bushes gen­er­ally do not wear un­less they have been work­ing with­out oil or, worse, with wa­ter in the fork.

FORK ASSEM­BLY

Thor­oughly clean all the parts in­clud­ing the threads. Re­place any dam­aged studs and give the slid­ers a good pol­ish if you like a bit of sparkle. Smear the parts with oil as they are fit­ted, be­gin­ning with slid­ing the oil seal up the stan­chion, lip down­ward, from the bot­tom. Fol­low that with the top bush with its shoul­der against the oil seal.

Now fit the buf­fer spring, cir­clip and col­lar, hard­ened steel bush and the bot­tom cir­clip. Check that the cir­clips are cor­rectly seated in

their grooves. Make sure the drain plugs and the damper rod screws have new fi­bre wash­ers, then refit the damper rod assem­bly and tighten the an­chor screws at the bot­tom of the slider. Screw in the drain plugs.

In­sert the stan­chion into the slider and tap the oil seal lightly and evenly into the slider so there are suf­fi­cient threads ex­posed to start the slider ex­ten­sion threads. Screw the slider ex­ten­sion down so it pushes the seal into po­si­tion. Ap­ply a light smear of joint­ing com­pound on the thread to stop any chance of oil weep­ing.

Slide the three-rub­ber spring buf­fers on to the stan­chion so they are evenly spaced. Coat the main spring with some grease and slide it down the stan­chion. Make sure the more tightly wound coils are at the top. Check the fork ac­tion by mov­ing the stan­chion in the slider.

Fit each stan­chion with their leather wash­ers and bot­tom tube cov­ers into the yokes, us­ing a draw bolt to en­sure they are fully home. Tighten the pinch bolts. Use a piece of wire or mag­net to re­trieve the damper rods and at­tach them to their re­tain­ing caps, fit­ted with new wash­ers.

Fill each fork leg with the cor­rect grade and quan­tity of oil and screw down the caps. Then re­place the front mud­guard and wheel. Make sure the head races are cor­rectly ad­justed and the fork legs are par­al­lel so they can move freely. Check the drain plugs for leak­age, then if all is well, put the ket­tle on and bask in the glow of a job well done.

One fork bush and its seal, clean and re­fit­ted Us­ing a strap wrench to tighten the s lider ex­ten­sion. Note the spring buf­fers in place Fit­ting the legs back into their yokes is made much eas­ier by us­ing a de­cent draw bolt. You can make your own (as on...

Fork as­sem­bled and ready to put back in the yokes. Note the leather washer and close spaced spring coils at the top

Be­low: Fork damper bolt. It’s tricky to get the lit­tle devil out of its bur­row Right: Fork bot­tom bush cir­clip. The cir­clips are tricky to re­move and re­place and re­quire care Be­low: Fork is now ready to as­sem­ble. Damper rod and damper parts shown here

Caps un­done, damper rods still at­tached The parts were re­vealed to be gen­er­ally in good con­di­tion Teledraulic fork parts laid bare. New wash­ers, rechromed slider ex­ten­sion, bronze up­per bush and oil seal More parts than strictly needed for a fork...

First things first: get the bike into a warm, dry place and make sure you have room to work. Also avoid con­tam­i­nat­ing your Match­less with Tri­umphi­tis…

Left: It is im­pos­si­ble to be too well pre­pared. Con­tem­plate the ex­ploded di­a­gram to gain fa­mil­iar­ity with the oper­at­ing prin­ci­ples in­volved. Then, to calm the ter­ror, read com­fort­ing Match­less ads re­veal­ing that their forks are the best ever

Fork fit­ting fun! Care­ful use of the draw tool takes time but gets the job done Forks fi­nally fit­ted! Look­ing good along with the re­fur­bished gear­box (and speedo). The top cov­ers with the head­lamp mount­ing brack­ets have had the rub­ber re­placed. The...

Job done.Rea­dynow for an­other decade or two…

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