Chain Troubles

[bankz]

i have a slack chain on my pit bike, and its got these stupid nuts in a stupid position. you slacken both the axle nuts and then you have to get a spanner and tighten these nuts which are in the actual swingarm and you just cant get the spanner in to turn them. My chain is too slack even to ride, somebody please help. Would a chain tensioner be useful?
thanks v much,

 

[Jaybird]

The swingarm is a Honda type setup. When you loosen the axel bolt, there are two threaded rods that will force the wheel assembly back in it's slots.
If you adjust these as far back as you can go, and still not have the correct tension on the chain, then it's time for a new chain and sprockets.

The back nuts are the ones that will take the wheel to the rear when you tighten them. Loosen the back nut, then use your fingers to move the inside nut out of the way while you adjust the tension with the rear nuts. Once you have the adjustment proper, simply tighten the indie nut back up as far as you can with your fingers, and then do the tightening of the whole thing with the rear nut (which you can get your spanner on).


You need to be aware of what correct tension is.
You want the shock compressed until you have the front sprocket center-swingarm-rear sprocket center all in a straight line (or as close to this as the suspension lets you obtain). This will have the chain in it's tightest possible position...and at this point is where you should still be able to move the chain up and down about 1-2cm. The chain should not be bound at all when it is in it's tightest position.

Many times this will leave the chain looking very loose when the bike is in it's normal postition, yet tightening it up any from there can spell a fast demise of your chain, sprockets, and bearings.

 

[Nathan Rubin]

I adjust 4cm of slack in the middle between rear and front sprockets.While adjusting, keep machine strait vertical under its own weight. It works just fine for Enduro.

 

[Jaybird]

It doesn't matter what sort of riding you do...and I don't know of many pit bike mini's are going to be involved with many enduros. lol...

Nathan, you should try the method I explained above just one time. You can confirm where you chain is on tension when you return the bike to normal position. You can always adjust to that from them on. But until you do this, you are only guessing that your chain isn't getting bound up when the suspension compresses.

Chain tension is of extra concern on a pit mini, I mean...we have a bike made for a little kid with grown folks bouncing around on it....

 

[bankz]

cheers very much for the help lads, i got my chain tightened today and was pulling wheelies in the field. now i am looking for a spare new chain.

 

[Nathan Rubin]

Hi Jaybird.
Actually you are saying that it should be 2cm of slack with fully compressed rear suspencion? If it is so, how exactly I suppose to bottom rear spring without sitting on the motto?
KR

 

[FruDaddy]

Some people use a strap under the swingarm and over the seat to compress the suspension while the do this. Also, it is NOT fully compresseed, it is compressed to the point that there is a straight line through the centers of the sprockets and the pivot point. This is where the chain will be at its tightest.

 

[Nathan Rubin]

Aha, I will try to perform this check.
Actually I can push back end as far as I can and tight the wheel to the rear fender with a rope. Than perform the measurement. :nod:

 

[Jaybird]

Nathan,
Simply unbolt the shock and take it out, until you get the chain properly tensioned. Put the shock back on and place the bike in the normal ground position...and then see where your chain is at that point. You can always guage it from then on by your final measurement on the ground.

I tie my wheel up just like you described. But with the shock off it is an easier job to accomplish.

Alwasys check and recheck your alignment and redo if it changes when you tighten everything up. Many make the mistake of only trying it once, and having it slightly off. Things change very easy when you tighten things back up, but keep re-checking until things are spot-on.

 

[Nathan Rubin]

Yep, I know that after tightening the slack changes a little.
Now I am positively sure that this is the best and the only wright way to deal with the slack.
It is a bit complicated task to disassemble rear absorber on DR-350. Anyway, I will use the "Rope Technique". If my force will not be enough I will call my kid or wife.