Correct chain adjustment

[Corona]

I have recently noticed that I am getting some drive chain snatch when getting on the throttle. This is can be heard as a slight clank as the chain comes tight and a bit of a jerk in the movement of the bike.

Now the chain has about 4k miles on it and I have checked the slack. It is at about 40mm of slack when on the side stand and the manual indicates it should be between 35 and 45 mm.

Do other owners experience this behavior at normal chain tightness or should I put the rear wheel adjusters about it?

[TheVelourFog]

The chain should be at 35-45mm while on the center stand, not the side stand. Measuring on the side stand will give a false reading and will result in the chain being looser than it should be.

[jussaral]

Originally Posted by TheVelourFog

The chain should be at 35-45mm while on the center stand, not the side stand. Measuring on the side stand will give a false reading and will result in the chain being looser than it should be.

from the manual:

35...45 mm (Motorcycle with
no weight applied, supported
on its side stand)...

[The Griz]

Originally Posted by Corona

I have recently noticed that I am getting some drive chain snatch when getting on the throttle. This is can be heard as a slight clank as the chain comes tight and a bit of a jerk in the movement of the bike.

Now the chain has about 4k miles on it and I have checked the slack. It is at about 40mm of slack when on the side stand and the manual indicates it should be between 35 and 45 mm.

Do other owners experience this behavior at normal chain tightness or should I put the rear wheel adjusters about it?

Your chain is fine. The jerkiness you're experiencing is the nature of the the throttle control / fuel injection on this bike. Get a G2 Ergonomics Throttle Tamer and the Booster Plug and it will help kind of.

The chain slap against the swing arm is also unfortunately the way things are due to the fact that this bike has a very long swing arm and chain length. S'normal. The jerkiness is not due the the chain, it is due to the throttle control / fuel injection touchiness on this bike.

[The Griz]

Originally Posted by TheVelourFog

The chain should be at 35-45mm while on the center stand, not the side stand. Measuring on the side stand will give a false reading and will result in the chain being looser than it should be.

Wrong.

The bike should be on its SIDE STAND when measuring chain tension.

[soyanarchisto]

Originally Posted by TheVelourFog

The chain should be at 35-45mm while on the center stand, not the side stand. Measuring on the side stand will give a false reading and will result in the chain being looser than it should be.

Yeah, this is fundamentally flawed since the bike doesn't come standard equipped with a center stand. Although it wouldnt surprise me if BMW did that.

[The Griz]

[Flashback]

Interesting. Didn't know that they didn't come with the center stand but I've always done chain adjustments using "tires on the ground" for measurements anyway.

[Flashback]

Originally Posted by Corona

I have recently noticed that I am getting some drive chain snatch when getting on the throttle. This is can be heard as a slight clank as the chain comes tight and a bit of a jerk in the movement of the bike.

Chains not adjusted properly. I'm kind of a stickler for having a chain adjusted to the sweet spot and nothing irks me more than a chain that's so slack that it jerks the bike when throttled up. I prefer a smooth transition and even though the throttle is a little jerky on the F8, when the chain is adjusted correctly throttling up from stop can be smooth as butter.

Plus I've found that getting the F8 front wheel off the ground is so much easier when torque is automatically and smoothly transferred to the rear when gas is applied instead of having that 'jerk'. Jerky application of torque can't be good for the transmission, chain, or sprockets.

Just be careful not to adjust the chain too tight. A too-tight chain puts excessive constant lateral pressure on wheel and transmission bearings. This in turn causes increased stress on those bearings and elevates the potential for premature failure.

When in doubt, make sure the chain is loose. BUT don't do what I did with one of my beater thumpers. I let the chain get so loose that it managed to actually slip the sprockets one time. What a mess that caused as things got all bound and locked up.

[ride2little]

I too adjust the chain per he manual. That-is on the side-stand, no weight, 35-45mm.

And I too am a stickler for 'just the right' amount of slack.

And I TOO prefer it too loose rather than too tight (m/c chain...keep it clean).

But this bike is giving me more trouble in getting it there. It seems to be either too loose, so I tighten it up ever so slightly (or so i think) then it's too tight. Right now I hear the chain hitting the bottom of the swingarm when the going gets rough. I hate that.
Anyway, I need to tweak it a little toward the tighter-side of life. Wish me luck.

Between this and making sure of the proper tire pressures, this bike is HIGH-MAINTENANCE.

[dsrydr]

I agree there is a sweet spot where the chain doesn't slap and is still not too tight. Mine used to be there and it was sweet. Since I have changed tires it is loose again, I need to tighten it.

[The Griz]

Originally Posted by Flashback

Chains not adjusted properly. I'm kind of a stickler for having a chain adjusted to the sweet spot and nothing irks me more than a chain that's so slack that it jerks the bike when throttled up. I prefer a smooth transition and even though the throttle is a little jerky on the F8, when the chain is adjusted correctly throttling up from stop can be smooth as butter.

Plus I've found that getting the F8 front wheel off the ground is so much easier when torque is automatically and smoothly transferred to the rear when gas is applied instead of having that 'jerk'. Jerky application of torque can't be good for the transmission, chain, or sprockets.

Just be careful not to adjust the chain too tight. A too-tight chain puts excessive constant lateral pressure on wheel and transmission bearings. This in turn causes increased stress on those bearings and elevates the potential for premature failure.

When in doubt, make sure the chain is loose. BUT don't do what I did with one of my beater thumpers. I let the chain get so loose that it managed to actually slip the sprockets one time. What a mess that caused as things got all bound and locked up.

Actually, his chain is adjusted properly. It's at 40mm. The spec is 35-45mm. He's right in the middle. Perfect.

Since his chain is adjusted perfectly I still believe that in his case the jerkiness he is experiencing is simply the nature of "the beast's" fuel injection / throttle control system.

He could try and tighten the chain up 5mm from 40mm to the minimum 35mm, but should not go any tighter than that or it will cause undue wear on the chain and sprockets.

[The Griz]

Originally Posted by Corona

I have recently noticed that I am getting some drive chain snatch when getting on the throttle. This is can be heard as a slight clank as the chain comes tight and a bit of a jerk in the movement of the bike.

Now the chain has about 4k miles on it and I have checked the slack. It is at about 40mm of slack when on the side stand and the manual indicates it should be between 35 and 45 mm.

Do other owners experience this behavior at normal chain tightness or should I put the rear wheel adjusters about it?

To actually answer your question, Corona, I too experience what you speak of. I always have since day 1. Snatchiness, jerkiness, whatever you want to call it, it's there. The best one can do is keep the chain adjusted on the tighter side to 35mm, install a G2 Throttle Tamer, and install a Booster Plug. If you do these three things the power delivery / drive train will react/feel much smoother. Cheers.

[Corona]

Originally Posted by The Griz

To actually answer your question, Corona, I too experience what you speak of. I always have since day 1. Snatchiness, jerkiness, whatever you want to call it, it's there. The best one can do is keep the chain adjusted on the tighter side to 35mm, install a G2 Throttle Tamer, and install a Booster Plug. If you do these three things the power delivery / drive train will react/feel much smoother. Cheers.

The Griz, the thing that prompted my question is that the bikes current behavior and the noise has changed from what it was 1k miles ago. Yeah it still had a rather snatchy throttle but chain slap noise wasn't present. In that time I have also changed the tyres so maybe I did not set the chain slack back to how it was when it came from the factory.

The jerk is also different from the throttle aggressiveness and would happen when going off and on the power at high gears (say 5 or 6) where the gear would normally have tamed the throttles harshness.

Maybe I just need to tighten it a touch?

[JRWooden]

One think I think BMW screwed up on here is the tread pitch on the adjuster bolts - from my experience one "flat" i.e. 1/6 of a turn, results in a change in the slack of 5mm or more .... making it dang hard to find the sweet spot....

Most of the bikes I owned before were smaller displacement and used the "snail" type adjusters which I really miss