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450 cases were changed from engine serial 453509
Before this number they had a smaller right main bearing, after they had the same size main bearing as the left side (6306)

I'm building a late model 450 engine out of parts. (engine number 463106 DM450D)
I picked the best parts from about 3 sets, some from earlier engines.
All the bevels etc have been packed in bags as pairs with the grind marks matching. (but not in with the cases they come from originally)

I picked the best set of lower bevels, replaced the bearings and fitted the double bearing carrier and lower bevel to the cases. (the main bearing was fitted)
The lower bevel interferes with the main bearing with only about 0.5mm clearance to the ball cage in only one position up or down.
?????? WTF
Measure the bevel and count the teeth = 30 teeth. The other two spares are also 30 teeth "but one has the edges or the teeth ground off" to make the OA diameter 3.5mm smaller. This would solve the problem but I have to clean it up before fitting it.

Did Ducati change (alter ) the lower bevel to clear the larger main bearing ? It would seem so.
The ground smaller lower bevel only has one circlip groove where the others have two circlip grooves.

Can any of you experienced Gents comment on this ?

Am I right to assume the ground smaller bevel is indeed for the late cases ?

Been pulling my hair out trying to understand what I had done wrong trying to get this to fit.

Regards
Graeme

http://www.ducativintagestore.com/top_b ... case_450cc

I can't remember where the dimensioned drawing came from, but include it just in case it's useful.

Thank you Jordan
That is the dimensions of one I will try

Graeme

Thank you Jordan
That is the dimensions of one I will try
All the bottom bevels shown on scrambler club are the ground smaller ones as in your drawing.
I can ably assume the others I have are from very early cases ?
Graeme

In 2015 I did the same job - building a 450 D motor for a good friend. He had given me a big box with all the parts he had collected from different sources over many years. He might have mixed up parts from different models, as he had gathered many n/c and w/c bikes in his garage, together with a lot of bits and pieces. Hence, I cannot tell if the gear in the box came originallyy from a 450 motor, or even from a 175 n/c.
I just looked up my old project-notebook. Apparently I encountered the same problem wth a gear of 53mm diameter. I wrote down: "chose to grind the gear down to 50.5mm".

cheers Hans

I fitted the ground gear.
All good now, I can remove the lower bevel without removing the bearing carrier to change shims.
In the past I have only rebuilt complete engines and re used the parts from the engine.
Never had this problem before.
But it did keep me busy for a few days making a bearing carrier extractor tool (thank you Hans and Nigel) and many times removing this to see what I had done wrong.
Traps for the unwary,,,,,,

Thank you.

Regards
Graeme