Chain tension affecting gearchanges

[Deranged Granny]

Sorry, I've used the search function to no avail.

Never had any problems with the gearchanges on my bike. Then "realised" the chain was too slack, so I tightened it to about .5" slack with me sitting on it. I reckon I over tightened it and that resulted in it running a bit on the rubber guard rail on top of the swingarm on deceleration (creating a noise/vibration). Now it has become a problem where if I decelerate and change down 2/3 gears in quick successsion (blipping in between), it will occasionally not change down on the final gear change (feels as if the gear lever is immovable for that split second) and I will lose out on the additional change down and resultant engine braking, leaving me entering the corner quicker than I planned. However, it seems only temporary; I can change down a bit later.

My question: is the gearchange problem due to excessive slack in the chain? Is it possible that having excessive slack in the chain stops the bike changing down as quickly?

I read it's best to have too much slack than too little but reckon I've gone too far.

Sorry if this doesn't make sense

Thanks.

Edited by Deranged Granny on Tuesday 23 September 00:07

[Mr2Mike]

Too much slack will spoil the gearchange action, but I doubt it would stop you getting a gear at all. Are you certain the clutch is adjusted correctly? This needs to be done properly on the SV or it will drag which will really mess up gearchanges.

[theshrew]

I find it does slightly alter gear changes.

Just do it to the spec and how it tells you to do it ( mine is done on the side stand ) in your manual. I normally set mine in the middle of tolerance the if it's not great slightly adjust either way to how you like it. Once you know what's what the next time you have a better idea.

[John D.]

Chain on my K3 SV650 was adjusted with bike on side stand. So sitting on it you might be setting it outside the correct range (tight or loose).

Clutch sounds like a good place to start.

[v60marko]

Half an inch slack seems too tight to me. I set mine to 25mm (1 inch) slack at the center point of the chain. Both bikes I've had have recommended this amount. In my experience chain tension definitely effects gear change.

[moanthebairns]

How the hell did you manage to measure it whilst on the bike?

[Prof Prolapse]

I don't understand why you're asking questions about this rather than just checking your chain again.

[Deranged Granny]

Thanks all. When I'm not on it, there's roughly an inch of slack, but when I adjusted the chain on my old bike with it unloaded, it was too tight with me on it, and restricted the suspension movement. So I thought it was best to adjust it based on the tension with me actually on the bike, since that is what matters. But it looks like I've not tightened it enough.

Prof Prolapse said:

I don't understand why you're asking questions about this rather than just checking your chain again.

Mainly because I don't have the time, and I also wanted to check with people who actually know what they're doing before I mess it up again.

[thatdude]

Set the chain slack as per the manual - note that you might need to inspect the chain fully to find it's tightest spot (spin the rear wheel and fel where it is most taught, adjust from there). A too-tight chain will cause an increased rate of wear on the gearbox output shaft...which if it were to fail, can be messy. You measure the chain slack halfway along the bottom run (halfway between sprockets). Tyhe slack should be about 30-35 mm (so 0.5 inches is WAY too tight).

As the suspension compresses, the chain will become more taught.

Check the chain is clean and well lubricated.

Check the oil level; on my SV650 I find that filling towards the upper mark makes the gearbox a bit less clever, and usually a really slick lovely gearshift is a sign I need to add oil! Yours may be different, but oil level can have an effect, as can oil type (i had better shifts using fully synth over semi-synth, but it uses more oil with fully...but this is a 73,500 miler).

Finally, the clutch. If you take off the front sprocket cover, you can see the "worm drive" mechanism. This requires some periodic cleaning and adjustment. You will need a flat-headed screw driver and a 10 mm spanner (or was it 8 mm...im sure it was 10).

First, slack off the cable at both ends (requires 2 x 12 mm spanners at the sprocket end).

Second, ensure the "arm" of the worm drive bit (where the cable attaches) is fully "up" as far as it will go.

Third, using the 10 mm (or 8 mm?) spanner, and the slat headed screwdriver, loosen the locknut on the end of the worm-drive shaft.

Fourth, screw in the shaft with the screwdriver until it touches (rock back and forth till you get the right feel). From it touching, knock it back 1/8th to 1/4th of a turn. Hold it in this position with the screwdriver, tighten up the locknut with the spanner.

5th, adjust the cable slack (leaving youself some adjustment at the handlebar to both slacken and tighten)

Make sure everything is clean and lovely, stick the cover back on



Sorry if that's sucking eggs OP but not everything is familier with the adjustment of that part.

Edited by thatdude on Tuesday 23 September 12:24

[Deranged Granny]

Wow, thanks thatdude! Not at all; I'm a real newbie at all that stuff. Don't think I need to go to that extent just yet, but very helpful to know for future reference. Cheers!