Read the performance bikes article, they say you should just be able to twist the belt through 45 degrees on the longest piece... It's how I've done it on numerous ducatis
These are quite good. Except….the video for 749 says that after tensioning horizontal belt, one should turn the crank backwards by 90deg to put the vertical cylinder at TDC on compression stroke. I believe this is incorrect. One should rather turn the crank 270degrees forwards to get the vertical cylinder at the correct position. http://www.exactuk.com/ducatitech-instructional-video-s/
Or, turn it back a bit more than 90 deg and then turn forwards to the 90 deg position, you're only trying to eliminate any backlash.
No. The idea is to position the piston at TDC at the top of the compression stroke so that both valves a fully closed and there is no load on the belts from the closer springs. Turning the crank back 90º puts it at the top of the exhaust stroke where both valves are still partially open.
Fair enough, wasn't doing the maths. I was just dispelling the myth that you can't turn the engine backwards.
Amazon - but came directly from Kbike. £30 incl delivery and the Kbike paperwork shows €28 (no Italian VAT), so I think I got a good deal
You did,I had to dremel a little out of one of the pieces to get the holes to line up,all good now,doing the belts this weekend,should be pretty straightforward…..
Whenever I have done a cam belt change, as the horizontal cylinder is at TDC on the compression stroke, there’s no load on the cams. I have always found it easier not to use a cam lock tool on that cylinder as without such a device, one can “wiggle” the belt on easier as the pulleys are not locked. On the other hand, the vertical cylinder cams are loaded so one of the pulleys (can’t remember which) will want to turn when the belt is removed. I have used a tool on that cylinder, but these days I just hold the pulley in place with my hand while putting the belt on (having marked the tooth and belt to ensure correct location).
It is the vertical inlet that wants to move because the valve is fully open. If you are lucky, on some engines the rocker will sit on the cusp of the cam and stay there and if you are very careful you can fit the belt without it moving
Agree Derek, always done belts on all my bikes that way. Never used "holding tools" prefer to just concentrate on making sure that all the pre made timing marks line up after the belts are fitted, personally think that the majority of people over complicate what is really a very simple straight forward procedure. You have five marks to align, just slip the belts on and check that they are all as they were before you removed the old belts and the job is done. It takes literally a few minutes to do, what is more important is to get the tensioning right afterwards.
Those cam locking tools hold the pulley, which is incorrect. To do the belts correctly, you lock the timing shaft, via the cover on the generator side, you lock the cams themselves, not the pulleys! You should loosen the three screws that hold the pulley to the cam, that will allow the cams to move relative to the pulleys. You lock the camshafts themselves, leaving the pulleys loose, you tension the belt with the timing shaft & cams locked, then you torque the three bolts that will then re-connect the cam pulleys to the cams.
That is the correct way to do it on later engines which have releasable cam pulley screws. Loosening the screws allows the belts to be tensioned with no load applied to them by the closer springs (only the vertical cylinder is affected). However, in the absence of the proper cam lock tools the pulleys can be locked to fit the belts but to tension the vertical belt the engine needs to rotated 270º forward from the timing position so that the vertical cylinder is at TDC at the start of the firing stroke with all valves fully closed. This was the procedure that was used on the Desmoquattro engines which had fixed cam pulleys.
