I've just serviced my new toy ('95 748) and replaced the timing belts. I didn't fancy paying the £370 quoted from my Dealer for the tensioner meter so I used Nelly's 4mm Allan Key method.
I just have one concern and that is on the horizontal cylinder when tensioned correctly the belt between the adjuster pulley and the opposite pulley is approximately 2mm apart. I don’t remember it being that close when I started. Is this OK? Or have I done something wrong?
Hmm, the only way that i can see something like that happening is if the belt was too long. There is no way you could over tension it so much without snaping the thing!
Also worth turning the engine over a few time and trying the tension again (by hand not on the button)
Is there a possibility that you turned the tensioning pulley the wrong way? ie you tensioned the belt by moving the pulley clockwise instead of A C/W ??
The allen key method, slipping it between the idler pulley is for 2V motors. The 4V are a little more involved. You need to measure the belt deflection between the two cam pulleys. It should be 5mm. Tenion the belts "tight", turn the motor over a couple of times and then line the timing marks up. Scibe or pencil a line on the cover behind the belt, between the pulleys. Use this as the datum to measure the 5mm deflection. Tension the horizontal cylinder only. The rotate the motor 3/4 turn anti clockwise to put the vertical cylinder at TDC. Then tension that belt. Only add tension to the belts turning the tensioner anti clockwise.
I understand ( and I await elaboration from those who know better than me) that not all 748 engines are the same, and they can take different belt part numbers. My bike although nominally a 748E, does not, in fact, have a an "E" engine, but a Bip engine, which has different belts.
Not saying this is Roy's problem, of course. Just thought it was worth mentioning.
18-Feb-2005, 15:55 
simonducati
skidlids
Linear Mode
