Going to attempt my first belt change soon but wanted to ask a dumb question about the camshaft locking tools that are available. Can someone please explain why some tools have teeth both ends and look like they would lock both camshafts together in-place but some only have teeth one end and look like they would potentially let the other camshaft move when fitted ?. Sorry if it's a dumb question :angry:
When you take the belts off the right hand cam on the vertical cylinder head is under load and will turn the others are not so they don't move unless you move them. So the cam under load is a little tricky to hold in place while fitting your new belts, I did my belts yesterday for the third time and have never used a holding tool. Steve PS the timing marks are quite clear on the cams and casings so it's easy to check and double check after fitting.
Cool, thanks chaps, makes perfect sense. As they're only a few quid I'll probably get one to make it easier (especially being a Ducati Belt Virgin :flushed: :smile: ). I assume whipping the spark plugs out must make everything a bit easier or less likely to try and move ?. Anything else I might need for the job ?, what do people use to turn the engine over to get everything lined up ready to change the belts ?. Cheers
Taking the plugs out helps turning it over to line all the timing marks up, the easiest way to turn it over without a special tool is to put the bike on a rear paddock stand put it in a high gear and turn it over with the rear wheel. Steve
I bought one but it actually makes the job harder for me, as having had the cams dialled in they don't quite line up properly with the tool and belt in as much as when the belt's on and fairly tight the locking tool holds the pulley about 1/2 tooth out of line with the belt teeth so when removing the tool and the cam jumps into the tooth and it invariably jumps 1 tooth out. The only way it works is if I 'set' it 1 tooth the other way before it jumps. This maybe because I have larger idler pulleys to take up the 1mm head skim, combined with offset keys in the pulleys to get the timing right? but whatever it is I find it easier without...
Can't remember the numbers as it was done by Chris at CJS some years ago using offset woodruff keys, and they are standard (not SPS) cams but when the belt is on the 'engine' pulley and then I try to get it on both the cam pulleys it just sits slightly out between the pulleys and as the larger idler pulley means there's not much slack in the system it makes it tricky to work round (unless the holding tool is slightly off?).
Unless i am missing something it can only be the larger idler pulley making the difference, the adjusted cam timing shouldn't alter the position of the pulleys, the pulleys should stay in the same position and the offset woodruff keys alter the position of the cams. Presumably the required adjustment couldn't be achieved with woodruff keys alone hence the larger idler pulley. Or am i missing something? Steve
Larger idler pulley was to compensate for 1mm skim off the head, otherwise the belts are too short and so can't get enough tension on the belts without them touching where they pass between the pulleys. But, yes I think this is probably the cause of the discrepancy as it moves the whole belt position one way as the tensioner pulleys are still the original size. I suppose the ideal solution would have been to use both larger idler and tensioner pulleys and both by the same amount to keep the timing 'central', but the larger idlers are a readily available part as used on another model and so do the job fine, although obviously the cams need timing afterwards as the skim and subsequent belt shift would otherwise move the timing.
Yes, at least one of two or three that he did around the same time. I think mine was the last one, all standard parts with just the skim/gasflow/valve timing and mapping. Still going strong at 45k+ miles.
