250 narrow case noise question

[bikester250]

My Mach 1S has a poor fit between the crankshaft gear and the clutch housing. There is noticeable slop between the pair. The parts book shows crank gears with teeth with oversize thicknesses but I've never seen any for sale.
Anyone out there know what sort of noise this might make (I'm trying to track down a tapping sound that I thought was due to excess valve lash but that isn't the case)?
Anyone have experience with have an oversize crank gear or have one they'd part with?
Regards,
Phil

[Jordan]

I don't have a spare crank gear, but a suggestion as what else to check for the tapping noise.
There are reports of the bearing seating in the head, for the top bevel shaft, developing play and noise.

[graeme]

And the start of big end bearing fail, or piston slap in a worn cylinder.
I've had both sound like the noise was coming from the top end.
Also loose rocker pins in the blind bore in the head

[bikester250]

Jordan, Graeme
Thanks for that.
I replaced every bearing in the engine except those in the head so I don't think the bevel bearings are at issue.
I also installed a new piston/rings/liner (thanks to Lacey Ducati for those)and a e-Bay crank that felt to be in excellent condition. The rocker pins feel like a very good fit.
I am going to check to make sure that the rotor isn't getting loose.
Thought I'd ask about the crank gear/clutch basket fit making noise since I know there is slop there and there is clutch basket for sale on e-Bay
Regards,
Phil

[motoital]

Are you saying there's too much backlash between the gears? The two are a match set and unfortunately they aren't always kept together so that's something to think about.

That eBay crank sticks out tho. Was it taken apart and checked? Especially for ballance? I've seen cranks that feel super tight but when disassembled the pins showed surface damage from sitting. It wouldn't have lasted long if run like that.

Good luck!

[bikester250]

Motoital,
That's correct-there is quite a bit of backlash between the gears.
Back in the bike's race history the clutch housing and drum were drilled full of holes to lighten them. I think this was done at H&H since the result looks like the drawings shown in their "Blueprint for Power" and they did other work on the engine. It's possible this was done on an exchange basis but I don't know that as it was about 50 years ago.
The crank was not taken apart; according to the seller, it came out of a running bike with about 9K miles on it.
Phil

[Jordan]

It's Ducati's suggested way to lighten the clutch, not just H&H.
A booklet was published by the factory with most of the Blueprint drawings and data.
Note that the suggested way to increase port size is questionable, has been criticized by Frank Scurria who suggests the Cycle World method instead.

I did my 350 steel clutch, a little differently.