how much play in the shaft drive ?

hi guys i just got my first xj, a '81 650 and i was wondering how much movement should the rear wheel have when the bike is on the centre stand and in gear, at the moment it moves about 3 to 4 inchs at the wheel. I am waiting on my xj cd but i dont want to be riding it if the shaft is worn out.
cheers brenton

 

Im not sure what the backlash specs are, but between the hub drive and engine output shaft there are many parts that can introduce slack into the line. The transmission does introduce a certain amount, which could very well translate into a couple inches at the rear wheel due to the gearing. The only way to know for sure where the slack is, is to peel back the boot covering the CV joint, and using a white grease crayon put a reference mark on the CV joint flange and a non-moving part of the transmission, then turn the wheel VERY slowly in both directions and observe how much the wheel turns before the flange of the CV joint starts moving. This should be a very tight unit, with less than 1/2 inch of slack (about 3 degrees of wheel rotation). If there is more than that, then either your final drive gears are worn (unlikely, unless they've run without gear oil, or the oil was contaminated with water), or (most likely) the CV joint is worn. Either way, it's dangerous and you should replace the bad part.

If the final drive unit is tight, then the slack is in the transmission, and those 3-4" may be acceptable. Again, I'm not sure what the specs for gear slack in the transmission between the input and output drives are..

-Matt

 

thanks mate

 

yeah i looked at the cv joint and it has no play in it so it must be just in the gear box , upon closer inspection it is only moving about 1 to 2 in max at the rear wheel, so is that normal amount of freeplay in the gear box?
and do they normally kick abit when u put shaft drives in first ?
cheers brenton

 

brenton, I've got just about the same amount in my 81 650 H. I think it is normal. 80,000 miles later I've not had any problems. Hope all is well with your steed. Cheers, Rob.

 

cool thanks, im just puttin the bike all back together after i took it apart to give it a once over, and mild repairs. since i brought it of a guy i dont know, wouldnt want to take his word for the safety of the bike.
ill put pics up after the rebuild