Hitchcocks Forum

hi guys,on my 1991 500 bullet when bike on centre stand slack at about 25 mm when of stand and me seated chain is tight is this correct my friend who noticed this has a 2007 electra dont have a problem on his chain being tight. should i slacken it of abit more or could it be another problem,shocks or something im 14 stone, any help on this matter greatly received cheers

You should have that 25mm of play when you are sat on the bike Phil. You really would be best to adjust it before you next ride the bike.
A tight chain will knacker chain as well as rear wheel / gearbox bearings very quickly.

Also remember there is probably a "tight spot" as the chain rotates, so have the bike on the centrestand, put it on a plank if you need to so you can spin the rear wheel and find the tightest spot on the chain, that's the right position to then take the bike off the stand, sit on it and you need to adjust for 25mm play at that point.

I have always understood chain slack measurements on any bike to be done with the wheel off the ground. The specified slack takes into account the tightening that occurs through the arc movement of the swinging arm. Trying to measure slack when seated is near impossible and will vary from one rider to another if their weight is different. As long as the tightest point is carefull found, the given specified slack at this tightest position will ensure that an over tight chain never occurs when riding. After finding the tight spot, my tip is to select 1st gear and apply slight pressure to the chain by trying to turn the wheel backwards (any actual rotation is held in check by the engaged gear). This will put all the slack on the bottom of the run and the measurement must be taken midway between the gearbox and rear wheel sprockets. The given measurement is the total up-down FREE movement.

Howard is correct that the chain tension when 'loaded' is what actually matters. Les H is of course correct that manufacturers take suspension movement into account when giving a specified chain tension, however many modern bikes don't have centre-stands, so their chain tension may be stated when on the side-stand - I have a bike with a factory sticker on the swinging arm saying this.

So now Phil is confused again Martin...so who is right as regards a 1991 Bullet please?

I give mine 50mm when on the centre stand. I once tested the slack while two up (and bouncing up and down a bit) while a mate tried to check how much slack was left. The chain never got totally tight during the test as far as he could tell.

The rear chain will be tightest when the centres of gear box sprocket / swing arm pivot bearing /rear wheel are absolutley in a dead straight line. Other Positions of the swing arm below AND above this alignment will cause the chain to slacken. If one could be bothered, the rear shocks can be removed and the swing arm held in the straight line alignment by a temporary distance piece in place of the shocks. With the chain set at its tightest point, the chain is adjusted to give someting like 1/2" / 10-12mm slack at this point Then the swing arm is lowered to the correct no load position as if the shocks were/are back in place. The new, more slack, chain whip is now measured and this is the measurement that is specified on the bike's manual, This is how the factory arrived at the specified measurement, and this measurement should be adhered to if one would like to achieve the smoothest, lowest backlash, most quiet, longest lasting chain. This seems very simple to me, and I can't understand why there is any need to select ones own preference. You also have to note that the tightest point MUST be found for the measurement to be accurate and effective, noting that at all other postions of the chain in motion will cause the chain to have even MORE slack. So no worries as far as being overtight. Thats my lot.

hi all thanks for all your replys,i will adjustthe chain in morning so i dont shag something out,25mm when the bike is of the stand and at the tight spot with fatty on it should do it thanks again fella!s time 4 a beer cheers

Hi PHIL }----------Taken from Hitchcocks "WORKSHOP MAINTENANCE MANUAL"-- MAN 16, Page 53, "-----With the machine on its' centre stand etc,etc, freeplay is 25-30mm checked on the TOP run and at 3 or 4 places... Don't rely on the snail cams being in the same slot but check the wheel alignment by use of taught string or a straight edge---------". So, no mention of comparing it with an Electra----or sitting on the bike---or bouncing up and down---and so on...Simple and straightforward..... And while your'e down there why not give the chain a bit of a clean then lube with your favourite potion or whatever ???

Hi Phil,
If the shocks are longer than standard, that would cause the problem you describe. I fitted [slightly] longer rear shocks to my Bullet greenlaner, which I built a couple of years back. While the bike was chocked up on the table, I fitted one of the shocks and set the chain free play correctly, only to find when I removed the shock and raised the swingarm and rear wheel a small amount, the chain went bar tight. I sorted this by running the chain 'too slack' but with a spring tensioner on the bottom run. I would check the length of your shocks compared to standard. Paul.