81 R100RS into a 80/7 frame.

[SteveD]

While I'm waiting to hear re the state of the crankshaft, I thought I'd clean and inspect the casing.
This hole is the inner end of the drilling for the short stud that enters the casing at 8 o'clock (viewed from the front. When I first looked at it, the hole was partly covered with 3 leaflets of thin casing. There was a small hole, presumably where the fourth piece had been. I cleaned the three bits off. They were loose. Looking closely there appears to be a couple of possible loose bits outside the periphery of the hole, 6-8 o'clock. Potential problem averted, if this engine ever goes back together.


This is the oil pressure switch hole. I found some bits of cork way up there. The outlet at the other end is in the edge of the opening for the crank.


All cleaned and flushed, then cleaned and flushed again. Hot soapy water, rinse well, spray with degreaser, spray with brake cleaner. Tomorrow I'll have another good look.
In the meantime, I've done the outer casing with rub 'n buff. Took no more than 15 minutes.

[Rob Frankham]

If you have access to a compressor, a very useful accessory is a 'Paraffin gun' at least that's what we call it in the UK... not sure what paraffin is called in Oz... probably Kerosene. This is a form of spray gun adapted to spray a fine jet of paraffin (Kerosene... whatever) through a long nozzle. Spraying through the various oilways will remove any old oil, gunge, etc... along with any bits and pieces stuck in them...

Don't know if you are aware but the studs in the front of the block that secure the timing cover double as blanking plugs for the longitudinal oil galleries. Removing them will get you access to clean the oilways out. Refit with stud lock and seal...

I would think that the bits of cork must have been introduced into the oilway from the oil pressure switch port. It's most unlikely that they came from the sump. In order to get to that location, they would have had to go though the oil pump, then through the oil filter, then via the front bearing carrier and a long carrier to the oil pressure switch port adjacent, as you say, to the rear bearing feed. I don't think I'd be happy to run the engine unless I had made absolutely sure there was no other detritus in the galleries...

[SteveD]

Thanks Rob. It'd be no surprise that a cork was used to block the hole from spiders etc. This motor has been separated from it's frame for quite a while. I think the last owner bought it to do up, then he had a long distance relocation to a house needing renovating and it got left as a future project. They'd be flat bits of cork I think if they went thru the oil pump?

I'd been spraying stuff up holes for quite a while. If the crank comes back ok I'll investigate those other oilways.

Cheers

[SteveD]

I poked an endoscope into the oilways and they all look clean. Sprayed brake cleaner into them and it all comes out the upper stud holes very easily. So happy they're good.

Still waiting for the crank to come back.

In the meantime, looking at the heads. I've pulled the valves. No recession They all sealed well, no leak if fluid poured into the chamber. The left exh valve had some movement in the guide, the inlet a tad but less. The right head guides were good.
I still need to measure the valve head seating area.

No pointy edges on the exhaust valves, the seats were all smooth and clean. Might lap them.

The right exhaust threads are toast. They'll need a rebuild. The left ones I'll dress up a bit, but they'll be ok.


The intakes look like someone has scratched in some roughness just before the valve?


So, one exhaust thread repair needed, one, maybe two new guides? A bit of a clean up and should be good.

[Zombie Master]

Can't wait to see how this turns out. I wish you smooth sailing!

[SteveD]

Can't wait to see how this turns out. I wish you smooth sailing!

Be patient...it'll take a looong time.
It won't be a high end pristine flash resto, more a get the mechanics ok and stick it all back together and see what happens.

[SteveD]

Crank is back, all good, linished and ready to go. Just need to sort out a few of the parts to sort with it, eg bearings, seals, chains, sprockets etc....then order and pay! Then wait.

I have scored an old police tank and a seat for cost of postage from a very generous Taswegian, Michael from Burnie.



Apparently the lining is good. I haven't seen the seat yet but it's a single type with some rear set up. Feeling very thankful.

Ultimately, this would be a good combo.

That would set me towards a naked bike, wider bars, single seat, no white box...more g/s than /7?

[SteveD]

Question. Should the main bearing be routinely changed if it's removed?

[MikeL46]

Question. Should the main bearing be routinely changed if it's removed?

If the oil was properly maintained the main bearing should last nearly forever. I wouldn't change it unless it needs it. I did change one on my 90S. Not particularly difficult, but you have drill the oil feed hole through the bearing after installation.
Mike

[SteveD]

Question. Should the main bearing be routinely changed if it's removed?

If the oil was properly maintained the main bearing should last nearly forever. I wouldn't change it unless it needs it. I did change one on my 90S. Not particularly difficult, but you have drill the oil feed hole through the bearing after installation.
Mike

Thanks. The oil pump is badly worn but the crank was professionally declared very good. No evidence that I can see that oil delivery was ever a problem. I might keep it as is.

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