Ariel Owners Motorcycle Club

H All,

I am still unable to source a replacement 12 tooth distributor drive gear, however a mate has a 1954 Mk2 SQ4 which is on the never never restoration plan. I hit him up for a look and use of his distributor and drive gear. Who'd have thank it, the drive gear is different from mine. His dizzy drive gear has 16 teeth and correspondingly the dynamo worm gear is also different. Other variations were the timing chest drive is a single row chain with a sprung tensioner while mine is a duplex chain and a fixed steel chain tensioner. My mate graciously offered for me to take the dynamo as well to swap out the dizzy and dynamo. My question is; are there any compatibility issues swapping the 54 dynamo/dizzy with my 56 version? I've not yet pulled my dynamo off so I can't do a direct comparison, the only potential issue I can see is my wider double row sprocket on the dynamo drive may not fit the 54 dynamo in regard to the timing chain sprocket alignment.

Obviously once I do find or have made a replacement dizzy drive sprocket for my bike I'll return and install my mates dynamo/dizzy although the engine needs to be pulled down anyway. I think he may be leaning toward selling it as a project bike. The frame and tinware have been repainted(ecluding fuel n oil tanks) but that's all the work done thus far. The engine has a dropped rod on number 2 cylinder so no telling what internal damage exists until its stripped down.

Thx all for any input.
Rgds Andy

2015 BMW K1300, 1989 Ducati 900ss, 1956 Ariel SQ4, 56 ES2 Norton, 1950 Model 7 Norton, 1973 Triumph T150 Trident, 1976 Triumph T140 Bonneville, 1974 Bultaco Pursang

Andy,seems strange going back to the single row chain drive, usually its a single to duplex upgrade.Where do you live? if in the UK, I wouldnt hesitate in getting an Ironhorse Spares alternator conversion,or alternatively a pair of 12t gears from them, Tel: 07801 374487 Email: bennet@ironhorsespares.co.uk

The later MkII motors, with the duplex chain, drove the dynamo faster - meaning a different ratio between the distributor & dynamo.

Be careful not to mix parts !

Bob.

Thx for the replies, I will retain the duplex chain and just fit the double sprocket to the older dynamo/dizzy combo. You do raise a valid point Bob, I need to check the number of teeth on the single sprocket from the older machine to ensure the ratios remain the same, otherwise the dizzy will move out of sync with the motor.... The fact that the dizzy sprockets are different was probably to account for the changed dynamo gearing....

I will try the Ironhorse lead.

Dave, many thanks, I contacted Iron Horse Spares and they are able to supply the gear. Just gotta hope the british post problems have been sorted. Last item I ordered from the UK took 2 mths to get here, it must have come via row boat!