Hi all, great to finally join you all, the technical threads have been invaluable to help complete my build.

Need a little more advice!

Recently re commissioned my ‘89 nc30 only to find a leak from the output shaft oil seal.

Is there ANY way possible to safely replace without splitting the cases.

Even if it gets me through the summer months before stripping down over winter time.

2 x new seals ordered to see what can be potentially done.

Or if anyone in central Scotland and done this before, can you help!!!?

No need to split the cases.
Can get the old one out by screwing self tappers into the rubber then pulling them with pliers.
New one should go in fine with a bit of red (rubber safe) grease on the faces. Make sure you use a drift a little smaller than the od of the new seal so when you tap it in it spreads the force evenly and goes on straight.
If you warm the engine up first it may be slightly easier.

Really appreciate your reply.

Just to confirm this is the seal behind front sprocket and not the clutch push rod seal I’m looking to change.

Should still drift straight in?

Cheers, Graeme

Thinking hard about it graeme I remember changing a few, but not 100% on which bike as i've a few hondas of that vintage. Maybe best to hold off until someone else can jump in and confirm. Though that's the normal procedure I use for seals in situ.

Cheers Tom.

Reason for asking is that the output seal is not parallel and has a ‘step’ halfway down. So by rights think the cases should be split to fit.

Conflicted opinions in other posts.

Was hoping someone had found an alternative solution or successfully fitted in situ.

I have a couple of seals arriving tomorrow so will see what can be achieved.

Ps- good post on your bike build. Great to chat with likeminded people.

Cheers.

I've not done it - but would be thinking it is a case splitter...

I don't remember encountering that so I can't have done one on an nc30, sorry for the misinformation. Bit of a rubbish design if you have to split the cases though.

Agree- not a great design.imop. The only bike I’ve worked on that doesn’t use a std parallel oil seal that simply “taps” in.

Some of the info on line suggests the rib on the seal serves no purpose other than for production line assembly and recommend to “buff” it down but as an engineer that doesn’t sit right with me.

But equally behind that, neither does splitting the casings to change a £5 seal.

Anyone done one of these?

Replaced.... and no leak after 20 mile run. Will double check garage floor in morning.

Thanks for all the advice.

Graeme

Did you have to split the cases?