AY50 WRY Katana - Replacing main bearings

I bought my super cheap AY50 Katana (2000 LC) as a summer project to get me back into scootering and as a handy commuting tool. The horrid example I bought had allegedly had head gasket failure and was then left in a garden for 9 months.

Turning the engine over gently via the kick start produces a noisy bearing rumble so my first thoughts are that the main bearings are shot and will need replacing.

Having never worked on a scooter engine before, is this a fairly simple job and has anybody done it? I have rebuilt an NSR engine and do all my own car stuff.

Thanks

 

It's not a bad idea to replace the bearings and seals if you're not sure of them.
The thing that is a bitch is the water pump. The seals go due to corrosion in the side case and if the side wall where the seal seats is pitted it wont seal properly with the new seals. The two lower panels are like rockin horse shit to find if they need replacing, i got mine from CMS.com, took about 6 weeks to arrive.

 

Thats what I figured, I don't think that they'll last long if I don't swap them. I just wondered if anybody had some words of wisdom about the replacement process. From looking at it, to take the engine out you just undo the suspension and the engine mounting bolt, undo a few cables and your done? Do I need any special tools eg pullers.

The waterpump has new bolts on it so hopefully it's had some attention recently and both bottom panels are serviceable. I'm just waiting for a replacement petcock before starting it anx seeing what happens!

 

That rear tyre looks a bit skinny, profile wise. Should be a 120/70/12
And it's got the battery cover as well, thats normally something thats missing.
Stick a photo up of the other side, lets have a look at the speedo drive please. The early ones were different and tended to sieze due to road grime and snap the lugs off.
You're quite right about taking the lump out, rear shock bolt, front mount bolt, cables and hoses. Bear in mind you will have to support the bike very securely, because the stand is attached to the engine, not the frame.
Yay, i've just noticed it has the flashes in the rear wing as well, something else that is sometimes missing.
If you ever get the urge to take that apart, to paint it for instance, resist at all costs. The flashes are glued in place, and the 4 screws that hold the wing together are behind them.
I've already done one of these and i'm now on the later model, here's the link if you fancy a read.

http://www.scootershack.co.uk/threa...-ill-never-know-katana-ay50wrw-project.30879/

 

Probably looks skinny as it'a lacking any air your thread is a good read I just wish I had the ability to paint as well as you, looks professional!

Managed to get the bike started today after fitting the new petcock and realising that you must removed the tissue bung from the carb for it to run.............I couldn't run it for too long as the hole in the exhaust made it quite loud, seemed to warm up and the bearings seemed to get quieter as it ran more.

Disaster struck though as I was tightening the front exhaust stud, it was fairly corroded and just snapped off the barrel so I guess I'll be needing a new / seconhand barrel.....not an expense I needed.

Here is the other side of bike

 

great, thats the later model speedo drive, means the front wheel has been changed as well, they are a damn site easier to get hold off.
if you need to change the barrel may as well just go straight for the 70 kit, but run it in properly; thats 300 miles at 30-35mph.