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Discussion Starter · #1 ·
I'm building up the bottom end of my 853 motor today and I'm hoping somebody can steer me in the right direction here. The motor that donated all of it's rotating bits for this build was an '01 748 with the Basso heads; on tear down, I found the outer pulley on the layshaft was fitted with an offset key as pictured.

The new motor will be going together with standard superbike heads with adjustable cam pullies. I've checked the fiche on both engine configurations, and neither one indicates that there should be anything but standard woodruff keys used on the layshaft. My inclination is to chuck the offset key and assemble per the fiche, but I wanted to check with brain trust first to see if anybody had a compelling reason for or against that notion.
 

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I'm building up the bottom end of my 853 motor today and I'm hoping somebody can steer me in the right direction here. The motor that donated all of it's rotating bits for this build was an '01 748 with the Basso heads; on tear down, I found the outer pulley on the layshaft was fitted with an offset key as pictured.

The new motor will be going together with standard superbike heads with adjustable cam pullies. I've checked the fiche on both engine configurations, and neither one indicates that there should be anything but standard woodruff keys used on the layshaft. My inclination is to chuck the offset key and assemble per the fiche, but I wanted to check with brain trust first to see if anybody had a compelling reason for or against that notion.
Only way to know for sure is to get a degree wheel on there and measure the cam timing. It might just be correcting the variance in timing you get from the factory but without knowing the history or measuring yourself, you'll never know.

They look like non-Ducati offset keys though as they have dots stamped into the top and the entire key is offset, not the 2/3rds as seen in your picture

Thanks
Luke
 

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The original keys would not likely be offset.

When I had my cams degreed after a 1mm head skim, we used a combination of offset keys on the layshafts and camshafts because you can only go so far with a key, plus if both cams need moving the same amount then you only need the one key.
 

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I am not sure that all Bassa engine's are the same but my S4 had offset keys in stock configuration. From memory one cylinder had a 6 degrees offset at the layshaft and the exhaust (from memory) on both cylinders had 16 degrees keys. I think i still have it written down some where if you want to know.

Sent from my SM-G935F using Tapatalk
 

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Discussion Starter · #5 ·
I appreciate the offer, vij, but not necessary. I think I'll put it back together with straight keys and dial in the timing at the cams. Whatever the reason that this offset key was fitted, with the new heads & such, I'm going to have to start over from scratch anyhow.
 

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2001 996 had offset keys on the timing shaft to advance all cams 4 degrees from memory. never had the pullies of a low head 748. don't recall any of the st i've done having offsets on the timing shaft, certainly do on the cams.

i'd probably just fit straight ones, altho if you have adjustment at the cams it's kind of irrelevant.
 
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