Speed and Sport, Inc.  has the tachometer drive gear and shaft you need.

Oh I was under 10psi, but the inline gauge I used only has a tick @ 5 and 10. Was somewhere around 6-8psi, just a bit hard to read. Will use more accurate gauge next time. However I have not moved the bike since I pressure tested so the seal must’ve been pushed out prior to that, hence the damage from hitting clutch gear. Will update as I go along! Thanks 

Yes, spring is from seal...  make sure new seals you get are OEM type true dual lip seal with spring loaded lip on each side of seal. 

Mismatch is likely from replaced half...  probably came out of a different mold.  Worst problem I've seen with replacement half is the base gasket surface is higher on one half or the other.  The minor external mismatches are probably not a problem.. 

not sure if anyone's mentioned the circlip is missing that stops the seal escaping. Has one behind & one in front. The arrow cast in the case is where the circlip should be gapped, although that's more for the inner one as the groove runs through the oil hole "fuel mix to lube bearing--not pump feed". So have the gap there on the inner circlip. Don't worry if the seal is already in as i've seen the inner circlip crossing the oil hole but never mattered as still gets to the bearing. I've forgotten what we're talking but looks 250,360 early. Don't want to loose my typing going back lol.
Number 13 in the link. Drawing shows the gap at the bottom but in fact the case pointer is up high & around 2 o'clock if i recall right.

www.partzilla.com/catalog/yamaha/motorcy...970/rt1/crank-piston

Thanks RT325, diagram for the 68 dt1 shows just one circlip between bearing and seal.  Certainly seems like a good idea to have one holding seal in though. Good info on inner circlip gap alignment, was wondering what the arrow was for. Found a NOS seal on eBay part no.  93103-42045-00 1 .  

I’m curious if your case has a circlip groove outside of the crank seal as your case does not have the raised portions which holds the clip on my case.

 

i have two ‘68 Parts Guides and the early one shows only one circlip between the bearing and the seal.  The later Parts Guide shows two circlips. One on each side of the seal. 

Early Parts Guide:

 

Late Parts Guide: 

 

No groove....circlip installed correctly. Bearing feels tight no play in any direction.    

I need a cuppa & a lie down. Just when i thought i knew everything--i know Nathing. Thought they all had the outer clip from day one. Learning curve thanks. Must've had a problem to modify it later i guess. Hope your new one stays put. Cheers.

I found three part numbers for the right side case half in 1968...  so they definitely made upgrades/changes that first year. 

First RH case version VIN 0001 to 2758
Second version VIN 2759 to 3382
Third version 3383 to 15000

Fourth version 15001- on  (ISO type)

All of the above RH cases can be interchanged if other parts are also used/changed...  details can be found in bulletin found in back of 1971 DT1E service manual in tech library.

Great research MarkT, 'i wouldn't know where to start lol'. First one must be the most valuable collectable one even if it can pop seals.