Chain and sprockets change HELP!

**Oscar** · 5th April 2009, 17:46

Originally Posted by Tony W

Please explain your way into my trap...!

If yer bikes in first gear, and yer trying to undo the countershaft sprocket bolt, how many times do you have to turn the wrench for one engine revolution? How many in top?

**Tony W** · 5th April 2009, 17:59

Originally Posted by Oscar

If yer bikes in first gear, and yer trying to undo the countershaft sprocket bolt, how many times do you have to turn the wrench for one engine revolution? How many in top?

If you put your bike in fifth and crash start it, you will easily turn over the engine.

Put your bike in first and crash it. The wheel and engine will lock up.

The same principle applies to the socket on the countershaft nut.

Can you smell that pie a-cookin' ! . . . or are you gonna dig yourself in deeper ?

**Tony W** · 5th April 2009, 18:12

Originally Posted by Oscar

If yer bikes in first gear, and yer trying to undo the countershaft sprocket bolt, how many times do you have to turn the wrench for one engine revolution? How many in top?

. .to answer your specific question.

Lets say for simplicity's sake 5th gear ratio is 1:1
one turn of the engine turns the countershaft one time..

Say first gear is 5:1.
five turns of the engine turn the countershaft one time.

This means it will be easy to turn the engine over in 5th gear as the leverage is one shaft turn = 1 engine turn.

In 1st gear one shaft turn = 5 engine turns. ie it is 5 times harder to turn the engine over in 1st gear.

**NordieBoy** · 5th April 2009, 18:17

Originally Posted by Tony W

That IS a very good question. Those big nuts are a pain.

(cue clever comment from Nordie)

The Nordie uses a big bolt with a weird sprocket.
I lost the bolt once. The chain took out a chunk of casing that had been designed to be taken out in that situation. That's Itialian thinking for ya.

That clever enough?

**NordieBoy** · 5th April 2009, 18:17

Originally Posted by xwhatsit

Two 10mm bolts holding an interference plate in place in front of the sprocket seem to do just fine and are a piece of piss to get on and off. Is this design confined to previous generations now?

The DR uses 3 bolts! Ha! We win!

**Tony W** · 5th April 2009, 18:46

Originally Posted by NordieBoy

That clever enough?

Pretty tame for you. . . I was actually going to say "big nuts are a pain in the arse" but wasn't looking forward to your 'rebuttal' !

**Oscar** · 5th April 2009, 20:22

Originally Posted by Tony W

. .to answer your specific question.

Lets say for simplicity's sake 5th gear ratio is 1:1
one turn of the engine turns the countershaft one time..

Say first gear is 5:1.
five turns of the engine turn the countershaft one time.

This means it will be easy to turn the engine over in 5th gear as the leverage is one shaft turn = 1 engine turn.

In 1st gear one shaft turn = 5 engine turns. ie it is 5 times harder to turn the engine over in 1st gear.

Er.. we're going backwards, turning the sprocket against the engine.

**Woodman** · 5th April 2009, 20:32

Originally Posted by Oscar

Er.. we're going backwards, turning the sprocket against the engine.

Which is the same as crash starting it, also depends which side the sprockets on.
I need to think about this though

**cooneyr** · 5th April 2009, 20:42

Originally Posted by Tony W

If you put your bike in fifth and crash start it, you will easily turn over the engine.

Put your bike in first and crash it. The wheel and engine will lock up.

The same principle applies to the socket on the countershaft nut....

+1 on this. This is the easiest explanation, but I agree that it is all to do with leverage. Long leaver (high ratio) will compress the air in the cylinder easier than a short leaver (low ratio).

If you leave the chain on and use the rear brake the gear the bike is in is irrelevant anyway. The XTZ uses the same system - big nut but with the right sized socket and a old torque wrench used as a leaver its a piece of cake to get off.

Cheers R