Adjusting cam timing using offset keys - Ducati Desmoquattro 916
Adjusting the cam timing using offset keys, in this instance a Desmoquattro 916. But it's the same concept across any of the fixed pulley engines. Old stuff nowadays - all the 2V engines went to adjustable pullies for 2001 model year and all 4V (Desmoquattro and Testastretta) for 2003 model year.
With the expected rambling - specifically, the variation in timing with different timing belt tension, timing belt tension conventions and anything else relevant I could think of.
The offset keys I buy through Reed Herman in Minneapolis - aka Speedmade on various Ducati forums. Reed has a friend who makes them, but isn't inclined to retail them as such. We had nearly exhausted his stock, but since the last time I bought them he made another batch, so there's a plentiful supply. They tend to be very accurate in my experience. The old Ducati / Ducati Performance keys could be a bit +/- at times - you'd fit an 8 degree key and get anywhere between 6 and 10.
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Пікірлер: 11
Thanks so much for this. I'm gearing up to do this for my mono build. I'm going to watch this a few times to go through the maths calculator section😅
Thanks again for making these videos and sharing your many years of experience.
Thanks Brad for another great video. I learn something new from you every time and see you got a new degree wheel. Bet it was a bittersweet moment. Can’t thank you enough for sharing your expertise! Cheers!
@bradthebikeboy
3 ай бұрын
i just had to find one with the same numbering pattern as the crane one. i have a vee two one, but the numbering is just bizarre.
Spot on, but it assumes that viewers have some basic knowledge of whats going on
Hello! It's a shame that Ducati doesn't install a roller with automatic timing belt tensioning.
Are offset keys still available at Ducati? I thought no
@bradthebikeboy
3 ай бұрын
no. long gone.
Other than a rebuild, would this be required?
@bradthebikeboy
3 ай бұрын
in the desmoquattros, usually the inlet cams were 4 to 8 degrees retarded, and the exhausts not so much. so to get it to the factory spec you could do this. if you set the squish, which involves moving the head closer to the piston crown, you'll also retard the cams a couple of degrees as a general rule, so best to reset the timing after that too. but, overall there is just plain better timing to use though, which is to advance the inlet cams 10 to 12 degrees and retard the exhaust cams 5 or so degrees from the spec. which means you could be moving (advancing) the vertical inlet cam (always the least accurate) 20 degrees at times. so it depends if you're a "happy with the way it came", or you're a "factory knows best" or you're a "lets make it as good as we can" kind of person. i'm the latter.
@scottishguydownunder544
3 ай бұрын
I have only just come across your videos, I will be watching all if them... fantastic.