Sq 4 engine: dismantling ANYWAY before using it?

[Alberto.Flisi]

Good morning friends.
What do you think about this stuff?
Do you thing a wise measure, when the bike was out of use for a lot of time, in case of purchasing it,to proceed anyway to dismantle the engine in order to check the inside conditions?
Thanks a lot for your answers and greetings from Italy

[brenton.roy]

Hi Alberto, it is pretty common that the crank oilways in square fours are blocked, particularly if they have been run without a filter or there has been a change to multigrade oil. I am taking the Mk 2 engine apart, mainly for this reason - as it hasn't been running for a number of years and I don't know what oil the previous owner used and whether he did clean the crankshaft oilways when he did a rebuild. BTW, cleaning the crank oilways needs to be done properly - more than blowing air through them...
I have heard that early (mazak?) oil pumps swell (I think these might be in early cammies?) and cause problems and that later oil pumps (MK2) aren't great either. The pushrod engine plunger pumps (4F, 4G Mk1) are OK if working properly.
It is also a good idea to know where your engine is at. The slipper main on the timing side can cause oil pressure problems and bearings overall are far cheaper than disasters.
When apart, you get a great opportunity to measure bores and crankshafts, check camshaft profiles etc, clean everything and look for bodgy threads, poor repairs, evidence of seizures and so on. Like bearings, engineering work is relatively cheaper and easier when the motor is apart.
Then when you ride the bike (the point!), you will have the best possible idea of it's strengths and weaknesses and more fun (also the point).
So, yes.
regards, Brenton

[Alberto.Flisi]

Thanks a lot, Brenton.
Now, more than before, I am convinced that, when I will purchase such a bike, the first thing to be done will be to strip down the engine due to the several reasons you have told me.
Unless, of course, it happens to me to buy from another enthusiast who regularly used the bike and who has already done this job!
regards and thanks again,Alberto

[brenton.roy]

Thanks a lot, Brenton.
Now, more than before, I am convinced that, when I will purchase such a bike...

Good luck Alberto. I hope you can find a really good one. They are a lovely bike to ride.