This is a full kit for making up the distinctive Parallel Checkspring arrangement as fitted to competition Norton International/Manx girder forks pre war (except for clevis pins, which are sold seperately).
Unlike normal roadgoing Norton girder forks (1932'ish onwards) - which used a barrel shaped checkspring, these 'parallel' springs were fitted to some Inters and most pre-War Manx competition models - and had one clevis adjuster with a Left Hand thread, and the other adjuster with a (normal) Right Hand thread. This allowed the tension of the springs to be adjusted with the whole assembly in-situ, just be loosening the top and bottom locknuts and revolving the spring.
I am not sure how succesful these springs were - but you can see period photographs of them here being used on Works Nortons (Freddie Frith 1937 bike shown) as well as competition Inters. They are one of the definitive items to be seen fitted to competition Inters and the versions we sell are modelled on the original design - except our Clevis adjusters and locknuts are CNC machined in stainless steel. Note - these sets are complete assemblies (just requiring the springs and sping holders to be painted) - but do not include clevis pins, which are sold seperately: We sell two types of Clevis pins - normal modern plated clevis pins/split pins - Item 0242b, and our CNC manufactured Norton type clevis pin sets, which have greasong holes (Item 0345). Either will work, but the 0345 type are the genuine Norton design (in stainless steel), with greasing holes - and are obviously far more expensive than the 'normal, pins, therefore we leave it to the customer to decide which they prefer!
Update June 2022: We have now got a new batch of these back in stock, and will be contacting those who were already waiting for them. The price has risen slightly - but given the recent increases in material and machining, we have tried to keep as low as we can. These sets do not come with the clevis pins - but for those wishing to purchase our Norton type stainless Clevis Pin Sets (Item 0345), we now offer a small discount for buying both together - see below:
As one of the attached photographs show, these springs were originally fitted to the Works Norton race bikes, but were later made available for customer competition bikes.
The kit comprises:
- Two parallel springs
- Four Spring Connectors (steel), which screw into the springs on either end, threaded to accept the clevis's (two LH and two RH)
- Two sets of Left Hand thread clevis's, and locknuts - in stainless steel
- Two sets of Right Hand thread clevis's, and locknuts - in stainless steel (One left hand and one right hand clevis is fitted per spring, (it does not matter if LH fitted above or below - but both springs should have the LH/RH in the same direction)
- Four stainless steel washers that fit either end of the spring, and the clevis locknut locks against
- Although Clevis Pins are not included in this set - if Item 0345 Clevis pin set is ordered at the same time, we offer a combined price discount of £5.00, which will be deducted from the order total when final invoice sent. The last two photos show the stainless steel 0345 Norton type clevis pins fitted to these parallel spring sets - and they look very pretty
The adjustable clevis's and locknuts are CNC machined to the original Norton design and look very pretty. The special coarse 'worms' screw into the springs and are threaded/sided to receive either the LH or RH clevis threads. The springs and worms are supplied unpainted - I normally paint them in a black 2-pack finish, which seems quite durable, but ensure you degrease them first, as we supply them lightly sprayed in rust preventing oil. After degreasing I etch prime and black topcoat the springs/worms together, before finally fitting the clevis assemblies etc. You may wish to use a glue or adhesive when screwing them into the springs, to prevent them trying to unscrew from the springs when adjusting the clevis's. The spring sets can be final adjusted to your preference once fitted the forks by loosening the locknuts, turning the springs to adjust tension, then retightening the locknuts top and bottom.