Unit 12 Star Industrial Estate, Star Road Partridge Green, West Sussex, RH13 8RA, UK. Company Reg: 2438157 Cardiff VAT NO. 550-6594-34 Registered in England No 2438157 Tel: 01403 711312 Fax: 01403 713207 Email: [email protected]
Fitting Guide for Nova BSA Goldstar 5 Speed Gearbox
This guide gives a step-by-step guide to fitting the Nova BSA Goldstar 5 Speed Gearbox
MANUFACTURERS OF TRANSMISSION SYSTEMS FOR RACING AND DEVELOPMENT
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Contents Page Contents Page Number 1. Parts Included in the Nova BSA Goldstar Gearbox 3 2. RRT2 or Standard Version? 4 3. Fitting the cam plate 5 4. Fitting the gearset 6 5. Modifying the inner case 10 6. Fitting the selector ratchet into the inner case 11 7. Fitting the gear shifter assembly 12 8. Finished Nova BSA 5 Speed Gearbox 13
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1. Parts Included In the Nova BSA Goldstar Gearbox
QTY Part Description Part no 1 BSA Goldstar Mainshaft 05055 1 BSA Goldstar Sleeve Gear Z25 05056 1 BSA Goldstar Sleeve Gear Bush 05068 3 BRG Needle 21 x 25 x 17 90144 1 BSA Goldstar 1st Mainshaft Z17 05058 1 BSA Goldstar 1st Mainshaft Z16 Low 05076 1 BSA Goldstar 2nd Mainshaft Z20 05059 1 BSA Goldstar 3rd Mainshaft Z25 05060 1 BSA Goldstar 4th Mainshaft Z24 05061 6 INA Snap Ring 23.5 x 1.2 90037 1 BSA Goldstar Layshaft 06095 1 BSA Goldstar 1st Layshaft Z26 OR 05063 1 BSA Goldstar 1st Layshaft Z27 Low 05077 1 BSA Goldstar 2nd Layshaft Z23 05057 1 BSA Goldstar 3rd Layshaft Z23 05067 1 BSA Goldstar 4th Layshaft Z19 05064 1 BSA Goldstar Layshaft Drive Gear Z18 05078 1 BSA Goldstar 2/4 Dog Ring 05065 1 BSA Goldstar 1/3 Dog Ring 05066 2 Nova Z15 Splined Washer 00012 1 BSA Goldstar 1st Gear Spacer 05074 1 BSA Goldstar Drive Gear Spacer 0.170" 05073 1 BSA Goldstar Drive Gear Spacer 0.100" 05075 Camplate Assembly 1 BSA Goldstar Camplate OR 02553 1 BSA Goldstar Reverse Camplate 03794 1 BSA Goldstar Camplate Drive Gear Z26 05070 1 BSA Goldstar Selector Ratchet 03795 1 BSA Goldstar Selector Quadrant Gear 02551 1 BSA Goldstar 4th Mainshaft Fork 06096 1 BSA Goldstar 2/4 Dog Ring Fork 06097 1 BSA Goldstar 1/3 Dog Ring Fork 06098
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2. RRT2 or Standard Version? The Nova 5 speed gear set is designed to fit directly into the RRT2 BSA gear case with out modification. However the Nova 5 speed gear set will fit standard gearbox cases which have had the following modifications carried out. Note: all modifications refer to the layshaft location
a) Bronze bushes replaced with needle roller bearings in both main case, adjacent to the output bearing, and in the sandwich plate. In this case we will supply thrust washers to suit both ends of the layshaft.
b) The Bronze bush is retained in the main case. The bronze bush in the sandwich
plate being modified by removal of the thrust portion of the bush. Once again a replacement thrust washer is supplied with the gear set.
Should you be in doubt as to which version of the BSA gearbox you have, there are a number of differences to look for. A genuine Gold star shell has indexing plunger housings drilled and tapped at both the top and bottom positions, whereas, a standard box only has the bottom position for the plunger housing. Further investigation is still required inside the gearbox as in recent years many shells have been modified in this way. If, on opening the gearbox you find needle bearings, this may not be indicative of a “gold star” shell, as again, many have been converted. Genuine shells have RRT2 and a number stamped on the sandwich plate adjacent to the moulded on pattern numbers. Once again this could have been added at a later date to give the appearance of authenticity. The final identification is to examine the needle bearing housing in the main shell. A genuine RRT2 has a deep annular machining around the bearing for a steel thrust washer. Whilst it is entirely possible to carry out all these modifications most gear cases will exhibit some standard features. This is particularly true of the thrust face in the main case, we therefore, offer a choice of spacers for this application RRT2 @ .170” thick or standard with needle bearing @ .100” thick. All gear sets are supplied with a thrust washer suitable for the sandwich plate end of the layshaft. Modified as previously stated in (b). It is suggested that new bearings, oil seal for sleeve gear, and gaskets be used when re-assembling. If using a standard case the bronze bushes supporting the layshaft can be replaced with needle bearings as in the RRT2 case.
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3. Fitting the cam plate
A. The following guide will show fitting a standard cam plate. The same applies for the reverse camplate apart from when fitting the sandwich plate, refer to note at the bottom of section 6). To start strip out the original gearset, cam plate, selector forks and selector quadrant.
B. Locate the Nova cam plate onto the boss as shown above.
C. Line up the threaded hole in the case with an indent in the cam plate.
D. Screw the standard BSA indexing adjuster into the case. Rotate the cam plate so the indexer sits in the neutral position. In the picture above the cam plate is sitting in 1st gear, so it needs to be rotated anti-clockwise so it sits in the small groove highlighted.
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4. Fitting the gearset
A. The top of our case has been removed for illustrative purposes only!! Please don’t do this to your own case. Locate the sleeve gear into the case bearing. It is recommended that the bearing and oil seal are replaced before re-assembling.
B. Ensure the three needle bearings are located inside the sleeve gear.
C. The selector forks supplied are as follows: 1: 1st/3rd Fork (marked ‘1 3’) 2: 2nd/4th Fork (marked ‘2 4’) 3: Top Fork (marked ‘T’)
D. Remove 4th gear from the mainshaft and locate the ‘Top’ selector fork into the groove in the gear. Align the 4th gear up against and concentrically with the sleeve gear. In this position the pin on the fork should locate easily into the back groove of the cam plate.
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E. Locate the standard BSA fork spindle into the case and push through the ‘Top’ fork you just installed.
F. This is how the assembly should look so far.
G. The layshaft will arrive as shown above. Refer back to page 4 for details on identifying whether you engine is the RRT2 or standard version.
H. Take note that both the 0.170” & the 0.100” spacer will be located on the shaft. Only use one of these depending on your shell type. Due to variation in the gearbox shells, it may be necessary to reduce the thickness of the washer to give 0.010” – 0.015” end float. The washer is hardened so material should be removed by either surface grinding or by using a suitable turning tip on a lathe.
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I. Locate the layshaft into the case with the relevant spacer. NOTE: Do not load the 1st mainshaft gear yet.
J. Locate the 2nd/4th selector fork into the 2nd/4th dog ring on the shaft and allow the fork pin to sit into the inner groove in the cam plate.
K. Push the fork spindle through further until it passes through the 2nd/4th selector fork securing it in place.
L. This is how the assembly should look so far.
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M. Fit the final fork into the 1st/3rd dog ring, and locate the fork pin in the outer groove of the cam plate. Push the fork spindle right in so all three forks are located.
N. Tighten the standard BSA fork spindle retaining screw (highlighted above) to hold the fork spindle in place.
O. The remainder of the gears on the mainshaft are retained by retaining clips. Locate the mainshaft through the gears already assembled into the gearbox. The splines on the shaft will have to line up with the splines on each gear. NOTE: Do not push too far through as it will jam in the sleeve gear.
P. Locate the 1st layshaft gear in place so it meshes with the 1st mainshaft gear. Then fit the 1st gear spacer up against the 1st gear as shown.
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5. Modifying the inner case Hatched areas highlighted in the inner case below need to be opened out to allow clearance for the Nova selector ratchet. Gearbox inner cover NOTE: Do not remove all the material around the selector rod (area 1) or there would be no support for the fork spindle.
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6. Fitting the selector ratchet into the inner case Removing original BSA selector ratchet A. To remove selector quadrant it is necessary to remove the locating dowel directly beneath it. B. After removal this will reveal the spindle on which the quadrant pivots. C. The internally threaded spindle can be withdrawn using one of the outer cover bolts as an extractor. Fitting new Nova BSA 5 speed selector ratchet A. Locate the Nova ratchet plate in place using the threaded spindle. B. Insert the locating dowel back in place.
NOTE: For the standard camplate ensure the camplate is now in the 1st gear position. For the reverse camplate ensure the camplate is now in the 5th gear position. Replace the gasket and fit the inner cover in place.
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7. Fitting the gear shifter assembly
A. At this point the selector quadrant should be identified with one tooth of the ratchet plate being visible. As mentioned above the gearbox should be in 1st if fitting the standard plate and 5th if fitting the reverse plate.
B. The outer cover and selector indexing arm are retained from the standard BSA gearbox. The cutouts in the case above are for illustrative purposes only!
C. Fit the selector indexing arm into the cover as shown.
Install spacer and kickstart gear assembly on mainshaft and lock with nut and tab washer.
Install kickstart quadrant and RRT2 type speedo drive.
D. Secure the cover in place with the standard BSA nuts.
Fit the gear lever and test operation.
The indexing plunger requires adjusting to give smooth gear changes. Adjust as necessary and lock in position when satisfied.
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8. Finished Nova BSA Goldstar 5 Speed Gearbox If you have any problems when fitting your gearbox don’t hesitate to contact us on 01403 711312 or email us at [email protected] For information on any other Nova products please check out our website at www.novaracing.com
