Page 1 of 2

Top bevel assembly

Posted: Wed Sep 23, 2026 4:13 pm
by ranton_rambler
I was at a VMCC meeting today and met a guy with a 250 narrowcase race bike, which is currently out of action. I don't think he has worked on the motor much himself. The problem he has is that the top bevels appeared to be incorrectly meshed, which caused the camshaft gear to chip a lump off one tooth. The loose piece must have got "in the works" somewhere as the camshaft key sheared. The key has been replaced and it now runs but he wants to replace the chipped gear and sort the meshing out.

I will send him some scanned bits of the workshop manual so he can see where the shims go, and I will also point him to Doug for the shims etc. I also recommended finding a matched set of gears, but if not possible what's the collective opinion on putting an random pair together? I know the factory grind marks will be invalid and the dots may not line up, but neither is insurmountable.

Ian P

Re: Top bevel assembly

Posted: Wed Sep 23, 2026 4:29 pm
by blethermaskite
Ian,I have done this, I used 'engineers blue' to get as good a mesh as possible then set back to give me just perceptible backlash with dry gears, what I found was the mismatched gears had a 'tight area' so I set minimum backlash at this area and ran it. It was hard to tell over the normal 'Ducati clattery' but it seemed normal noise and no whine, ran that bike for a couple of thousand miles before I sold it...no issues... this is just my experience.... however I suspect some mismatched gears just may not go that well together. Cheers George

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 7:10 am
by Duccout
Eldert? Nigel? Those gentlemen will give you the definitive answer.

Cheers,

Colin

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 2:08 pm
by themoudie
At present Nigel is trying to reduce his stocks of second-hand engine parts. It's an Aladdin's cave of goodies when you want them, but a nightmare if you have to store them and they just sit on the shelves. Hence Nigel's desire to sell some stuff on.

Give Nigel a shout at https://www.facebook.com/LaceyEngineering/ where he has posted about the spares and see how you go.

Alternatively, here is his current email: info@bevelsingleparts.com

Telephoning him will just distract him from the engineering and there is nothing worse! ;)

Hope this helps both you and Nigel.

Good health, BillR

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 3:19 pm
by ranton_rambler
Yes, I saw that on a FB post of his recently. I will pass on to Phil, who owns the bike.

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 8:04 pm
by themoudie
Aye Ian,

Cheers. Some of the 175 bits might be of use for yourself?

Good health, Bill

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 10:15 pm
by LaceyDucati
Thanks Bill for sharing my post/info, much appreciated. However my direct email for used parts/engineering is info@laceyengineering.co.uk. I do see the info@bevelsingleparts.com emails, but that's mainly for Doug and the new parts sales.

Regarding N/C 250 bevels I do have some nice sets of those, if required. You can "sometimes" mix and match successfully, but it requires considerable extra care and patience. Be aware some gears appear to have different helix angles/profiles and will never match.

Regards Nigel

Re: Top bevel assembly

Posted: Thu Sep 24, 2026 10:53 pm
by themoudie
Aye Nigel,

My apologies for publishing duff info! :oops:

Hope all is well? I suspect the line up for winter rebuilds/mods is ever growing.

Good health, BillR

Re: Top bevel assembly

Posted: Fri Sep 25, 2026 9:24 am
by ranton_rambler
LaceyDucati wrote:Thanks Bill for sharing my post/info, much appreciated. However my direct email for used parts/engineering is info@laceyengineering.co.uk. I do see the info@bevelsingleparts.com emails, but that's mainly for Doug and the new parts sales.

Regarding N/C 250 bevels I do have some nice sets of those, if required. You can "sometimes" mix and match successfully, but it requires considerable extra care and patience. Be aware some gears appear to have different helix angles/profiles and will never match.

Regards Nigel

Thanks Nigel - information passed on.

Re: Top bevel assembly

Posted: Fri Sep 25, 2026 5:37 pm
by LaceyDucati
Hi Bill
No need to apologize, I am flying a bit incognito since we passed on the operation of the parts business on to Doug. All is well, but still struggling to actually get my of own Ducatis sorted and back on the road. I have a 450 scrambler now, but as usual it came to me in many pieces and the engine is in need of some TLC. Just got another 450 scrambler for Doug, so we now have a matching pair. Will 2027 be to year I actually get to ride a Ducati single of mine? Ever the optimist!

Regards Nigel