Burman Vintage Motorcycle Manuals

BURMAN & SONS, ,_LTD Ryland Road, BIRMINGHAM. BURMAN GEARS ARRANGEMENT OF GEARS Burman & Sons Limited Telephone : Midland 3877/8. Telegrams : "Burmanth, Birmingham."

BURMAN & SONS LTD. RYLAND ROAD, BIRMINGHAM. Instructions Leaflet for GEAR BOXES Mcdels "W" "T" "R" "G" "A" "BA" "C" & I N s.. -;tting out this leaflet, we will endeavour to explain the general features of the Burman Gear Box to the advantage of all users. A feature of the 3-speed Gear Boxes "T," "W," "R" & "G." is that the lay-out is identical in each box. The same practice is also followed in the 4-speed units "BA," "C" and "A," there being only a slight varia- tio-i in the Model "A" in the clutch operation and selector mechanism. In view of the above remarks, the following instructions can be applied according to the type of Gear Box (3 or 4-speed) which is being overhauled. One of the main features is that all gears, in both 3 and 4-speed units, are constantly in mesh, and gear changes are effected by means of dog clutches of ample dimensions (with the exception of certain 1934 Gear Boxes which will be described in a later paragraph). The positions of the gears themselves are controlled inside the Gear Box, independ- ently of tank quadrants, by means of a patent rack and pawl mechanism, this providing an efficient gear change without fear of overshooting the required position. Models "R" "T" "W" and "G" Gear Boxes. To dismantle a Gear Box of the 3-speed type, it is necessary first to remove the clutch lever bracket and kickstarter, after which the nut on the kickstarter end of the mainshaft should be unscrewed. To unscrew this nut (R.H. Thread) it is advisable to engage 2nd gear and lock the wheel with the foot brake, when no difficulty should be experienced in removing the nut. When the nut is unscrewed, the rachets can be withdrawn with the fingers and after removing the nuts, holding the kickstarter case in position, by drawing off the case, the internals will be exposed. To remove the gears themselves, the clutch and mainshaft should be withdrawn en bloc and after unscrewing the pawl spring plug, situated directly under the box on Models "R," "T" and "VV," but on the L.H. side of Gear Box on Model "G," directly above the kick starter centre pin lug, the gears can be taken out.

When reassembling, the two Sliding Gears should be correctly meshed with each other by means of the flanges provided, and also the operating block fitted in the groove in the Mainshaft Sliding Gear and connected to the peg on the bell-crank lever. We would particularly stress that on no account should the screw situated on the L.H. side of the Gear Box (looking from kickstarter side of Gear Box) be removed or loosened, unless when dismantling. Models "BA" "G" and "A" Gear Boxes. The construction of the 4-speed Gear Boxes differ from the 3-speed type, insomuch as the Gear control is governed by a camshaft fitted with Alum-Bronze operating forks. By reason of the fact that this camshaft is mounted on roller bearings, friction is reduced to a minimum and a very smooth action is produced. As with 3-speed units, the gears are in constant mesh and in Gear Boxes prior to 1934. Gear changes are effected by means of dog clutches, but for the 1934 season a me;hod has been evolved of gear changing which results in instantaneous, smooth and silent gear changing. In place of the five dogs, the actw.,I gear teeth are extended and engage with internal teeth cut on the face. of the adjoining gears, thus giving a minimum of backlash with gear change of extreme efficiency. To dismantle a 4-speed Gear Box, the outer lever should be -e- moved together with nuts around the kickstarter case cover, but unlii;.e the 3-speed units, it is unnecessary to dismantle the kickstarter. When the kickstarter case cover has been removed, it only remains to unscrew the mainshaft nut and the small nuts holding the case in position when the gears can be exposed. As with the 3-speed, it is necessary to release the gears by removing the pawl spring and the gears can now be withdrawn from the shell, although it must be noted that the whole assembly should be withdrawn en bloc. To reassemble the unit, the operations should be reversed, but particular attention should be paid to tke fitting of the camshaft rollers and sector mechanism. The rollers should be held in position by means of a thick grease, when the kickstarter case can be replaced easily. Both the small gear on the end of the camshaft and the gear sector are stamped with the letter "0 - and these markings should coincide when assembled, thus enabling you to determine that all Gears can be obtained perfectly. Model "H" Gear Boxes. The Model " H" unit is of the 4-speed type but the construction is similar to that of the 3-speed unit and it is, therefore, unnecessary to give details, with but one or two exceptions. .As with the 3-speed, when dismantling, the mainshaft should be withdrawn with the clutch en bloc which will enable you to remove the gears; but when reassembling, it is necessary to fit the layshaft assembly first, with the two sliding mem- bers together. It is between the flanges of these two sliding gears that the operating block is fitted and the two gears are, of course, held together by the ma.inshaft sliding gear which should be fitted to clamp the flanges of the la.yshaft gears before the mainshaft is fitted.

Clutches. The gcneral principle of the Clutch assembly is of the same throughout, of entire range, with the exception of Model "G." They are of the multi-plate type, consisting of insert plates and plain steel plate to which latter is given close attention to ensure the smooth- ness Attd lightness for which we are noted. Another feature of the Furman Clutch is the shock absorber, which consists of shaped rubbers and plates and this also assists in providing a smooth, even drive. All Clutches are provided with a roller race, which is not affected when withdrawing the Clutch, with the result that it runs perfectly true and eliminates undue wear. The operation of the Clutch is effected by means of a rod passing through the mainshaft and adjustment is provided in the clutch spring plate. In regard to the use of the Clutch, the following points should be noted:—,-L" clearance should always be kept between the end of the push rod and the ball in the clutch lever. The correct adjustment for the spring adjusting nuts is flush with the spring plate. Due to the lightneFs of the Clutch, it is unnecessary to fully withdraw the Clutch but only to momentarily free the plates to make a clean, silent gear change. The assembly of the Model "G" Clutch is different insomuch as it is only a single plate type, the spring tension being given by an ample sized spring and fastened by the mainshaft nut. Lubrication. We do not recommend the use of oil in our Gear Boxes. After exhaustive tests we advise Wakefield's Castrolease Medium, Gargoyle Mobilgrea.se No. 2, or Shell Motor Grease Soft. These are light greases, which effectually lubricate the wearing parts while not being subject to changes in viscosity to the same extent as gear oil, and actually results in less loss through friction and churning than does oil. These greases can be obtained at all garages, but should a user not be able for any reason to obtain them locally, we shall be pleased to make arrangements at his request for his nearest supplier to carry adequate stocks at all times. It is essential to pay careful attention to the lubrication of the Gear Box, particularly should speedometer drive be incorporated or a foot change fitted. When Gear Boxes leave our works they are fully charged with grease and there will probably be a slight leakage until the correct level has been reached, and to maintain this level it is necessary to add 2-3 ounces of either of the specified greases every 1,000 to 1,200 miles. If speedometer drive is fitted to the Gear Box we advise the occasional removal of the small spindle, which in the 3-speed and Model " H " type Gear Boxes is housed in the clutch lever bracket and in the 4-speed type Models "C" and "BA," in the kickstarter case cover, thus it is quite a simple matter to remove the part. Before replacing the spindle it should be carefully greased and when refitting the clutch lever bracket to the Gear Box it should be packed with grease; also it is advisable to add grease to the foot change mechanism periodically.

Foot Gear Changes. The general principle of the whole range of foot charves is on the rachet and pawl system, gear changes being effected by means of a double edged pawl engaging with a ratchet. A special feature of the mechanism is the aluminium box loaded with springs which, by reason of its construction, controls the amount of movement and prevents the user from passing through any particular gear, also the operating lever brought back to the same position after each gear change. To dismantle a foot change of the 3-speed or Model " H " type, it is advisable to remove the kickstarter case which will enable the user to dismantle the control without any difficulty. The whole assembly is mounted on a splined sleeve that passes through a special bush, which latter is a press fit in the kickstarter case and connects with the actuating lever inside the Gear Box, being locked together by a bolt which passes through the entire assembly. To assemble the control, the sleeve should be fitted after which the spring box and quadrant and it only remains for you to add the ratchet and pawl, following which the control should be locked tightly the bolt and nut. A very special feature of the 4-speed foot changes, Models "C' and "BA," is that the mechanism is totally enclosed, which not only excludes the entrance of any foreign matter but gives the control an extremely neat appearance. The principle of this type of control is similar to that of the 3-speed, the only actual difference being in the method of assembly. VVhen the foot change has been dismantled, which is carried out by unscrewing the six nuts around the cover and removing the latter, thus exposing the whole mechanism, you will discover that the assembly is very simple. To reassemble, it is necessary to first refit the sector, this engaging with the Gear on the end of the camshaft and the correct location is determined by the coinciding of the letter "0" stamped on both sector and camshaft. The remaining portion of the control is already in position in the kickstarter case cover and by affixing the pawl to the quadrant directly facing the ratchet by means of a thick grease, the kickstarter case cover can then be refitted to the Gear Box. VVhen this work has been completed the foot change should be carefully tested by operating with the hand. You will realise that it is impossible to fully describe all points in this leaflet but any points upon which you are not quite clear, we shall be pleased to assist you with if you will get in touch with us.

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