Question re different types of primary drive and engine rotation direction

[bill_qaz]

Or input and out put in same plain but split shaft, chain or belt primary drives, all down to gearbox design

Harley gearbox.jpg (29.1 KiB) Viewed 1938 times

[willywombat64]

So ..in your example of the crf230 without idler gear does that mean the engine rotates in an opposite direction to the one in the diagram kindly presented by Hugh which does have the idler ? If not how is the countershaft direction corrected to get the bike moving forward rather than reverse!

[bill_qaz]

Unread post by willywombat64 » Thu Oct 18, 2018 4:11 pm

So ..in your example of the crf230 without idler gear does that mean the engine rotates in an opposite direction to the one in the diagram kindly presented by Hugh which does have the idler ? If not how is the countershaft direction corrected to get the bike moving forward rather than reverse!

Viewed from the right hand side: The crank is rotating clockwise so the clutch is rotating anti clockwise which is the gearbox input main shaft, it would then rotate the gearbox counter shaft clockwise. the output of which has the sprocket on the left side of the bike which is rotating anti clockwise viewed from the left, same as the rear wheel sprocket when going forward.

So in the case of the Honda CRF the clutch is on the opposite side to the chain drive.

Hope that makes sense Bill if not two paracetamol and a lie down in a dark room may help

[willywombat64]

So I was right ..the crank on the crf is rotating the opposite way to the one pictured on hugh's image ( which rotates anticlockwise when viewed from the right ) so I guess in a simple single cylinder the crankshaft rotation direction varies according to whether you have an idler gear . One of the reasons i pursued this question was that many people say / think that the crank ( on a single or multi inline engine rotates in the same direction as the wheels move which is not necessarily the case as you have shown ..it can depend on the type of primary drive configuration . You might need a co codamol now! Thanks for your efforts in explaining btw...unimportant maybe but much appreciated.

[willywombat64]

oh ..I forgot .. the clutch can be on either side of the engine to add in another factor as can the countershaft sprocket so lots of options to get the wheels turning the right way!