cam chain tensioner advance

[Davew]

I've been reading that to get the cam chain tensioner to advance the last few clicks, you can try rolling the bike back in gear with the plugs out to get the chain to slacken off so the tensioner can click.


My question is, why do you need to remove the plugs to do this?  Also, I'm buggered if I can get the bike to roll backwards in gear with my puny strength!

[richfzs]

My question is, why do you need to remove the plugs to do this?  Also, I'm buggered if I can get the bike to roll backwards in gear with my puny strength!

That's because you've got the plugs in

[darrsi]

You roll the bike back in gear with the clutch lever held in........then let the lever go and it will give the bike a jolt.

[Fazerider]

What gear were you in when you tried? Obviously the higher the gear, the easier it is for the wheel to drive the engine.
I don't see why an increase in cam chain tension at the back should encourage the tensioner to tighten, but if people say it works then I guess it does.


>edit<
Ooops, too early in the morning for logical thought... rotation's the wrong way, but yes, the tension is going to be at the front run of the chain.

[Robbus]

My question is, why do you need to remove the plugs to do this?  Also, I'm buggered if I can get the bike to roll backwards in gear with my puny strength!

Just to answer this, it so the engine has no compression, so when the pistons move up the cylinder they just push the air out through the plug hole. It's really quite difficult to turn an engine over with plugs in as you'll be compressing air in one cylinder, it normally takes a bit of an explosion to give the crank shaft the required force to keep turning over and compressing air in a cylinder prior to ignition.


Cheers,
Rob

[Davew]

My question is, why do you need to remove the plugs to do this?  Also, I'm buggered if I can get the bike to roll backwards in gear with my puny strength!

Just to answer this, it so the engine has no compression, so when the pistons move up the cylinder they just push the air out through the plug hole. It's really quite difficult to turn an engine over with plugs in as you'll be compressing air in one cylinder, it normally takes a bit of an explosion to give the crank shaft the required force to keep turning over and compressing air in a cylinder prior to ignition.


Cheers,
Rob

Ah of course!  thanks Rob!  That was puzzling me!


In response to the other point, I think that the idea is that the cam chain rolls backwards, taking the strain off the tensioner ratchet, meaning it's free to advance.  Thats the idea at least!    will see if it works!

[Paul]

If you don't fancy taking the plugs out, then:


Ride it part way up a steep (ish) hill, turn the engine off, put it in a high gear and let gravity help you.