The same flywheel was used for all 948cc models up to the arrival of the 1098cc engine, it changed again when the 1098cc engine went to 2" main bearings. The flywheels cannot be interchanged. The flywheel can be lightened easily by 3lbs or more, this work is best left to an experienced engineer. The four bolt flywheel can escape on high revving engines, so it is a good idea to have 2 dowels fitted, this will aid location too. With the original smooth case gearbox the 948cc engine coil spring clutch cover can easily be replaced with a diaphragm cover to give greater clamping pressure and improved reliability. For harder use the larger 1275cc clutch cover can be fitted to the flywheel if the lugs are ground back to clear the bell housing and the flywheel holes re-pitched for the cover. It will still be necessary to grind some material off the inside of the bell housing to clear the cover; this is best done with a trial fitting. The front cover and fork from the ribbed box must be fitted to the early box as the clutch operating fork has a different pivot point. It is not a direct swap but will fit with a little light engineering, the 1275cc release bearing can then be used. If the ribbed case gearbox has been used you can use either of the above clutches and their operating mechanisms. We do not have any alternative clutch applications for the 1098cc engine although your best bet would be to utilise and modify components from the 1275cc clutch. We have listed the three release bearings to help you select the correct one if fitting an unusual clutch combination. It would be worth checking the geometry of the installation to ensure smooth clutch action, it is not uncommon for the operating arm to need tweaking a little to achieve concentricity. You should note that the 1275cc slave cylinder has a 1 bore diameter, not the earlier 7/8, a different hydraulic connection and a 69mm push rod length. It is a good idea to remove the various rubber bungs from the bell housing, they may let the dust out but it will also allow cool air to circulate. We recommend the purchase of the clutch aligning tool as it is specifically crafted to the Spridget and ensures perfect alignment.
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