Another PU8

Glad to see it's being of some use already.

Interesting to see the differences between three supposedly identical engines.

Two have screened ignition, one has unscreened.

The cowling on the original genny engine fouls one of the cylinder heads, the other two do not.

Magnetos appear to be the same, with the exception of the plug leads.

Carbs and linkages seem to vary between the three.

And so on.

It took three hours or so to get the old exhaust off, take the one off your engine, try it on the genny, only to find that it had a bent/damaged retaining finger. Took the one off the other (Derby) engine, all was fine, so that went on.

The connections betwixt the cylinder port and the silencer are cast ali with fins, so delicate for such a lump! Out of six potential castings I have two fully OK and four with various amounts of damage. Might be worth trying to get a few cast as spares.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

Peter,

You will find the engines aquilles heel when you run it in this weather, the carb is so far from the cylinders you will have your own ice maker :-))

Martin P

Quite possibly, but they all have the two outer cowls missing, so that air doesn't get blown across the inlet pipes.

I know not if that is deliberate policy or just that they got left off, but the cowls do direct a flow of air towards the middle of the engine at the front.

I have borrowed one to copy, but they are handed so may be a little bit of trial and error for the other side.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

My PU8 had the cowls and the bugger still froze up :-))

Martin P

I found icing to be a problem in my fairly well shrouded back garden on a warm day in spring! What they must have been like on the Thames Estuary on a frosty December night with Gerry dropping bombs on yer mates across the way can only be now imagined.

On cold days, I poured hot water over them on my PU4 to achieve an easy start, a tip given to me by an old boy at a rally who recognised the beast.

Regards,

Kim & Martin:

We pulled the heads this morning, two stuck open valves and a stuck cam follower, plus one tappet with zero clearance.

Bores were fine, oiled them up and feed off the valve train bits.

Now have some compression on both sides, but no go yet. Squirted some petrol down't carb and gave a prolonged whirl with the handle but not a bit of life, so we are putting the genny back on now, and will try some easy start tomorrow.

Looked for some plugs, RML-60 by KLG, found 6 new ones in Illinois of all places, $4.49 each plus postage to our mates in Arizona.

Cut off the copper inlet pipe which hangs on two small 1/4" screws in the carb inlet flange, that should prevent the thing coming loose and damaging the carb body. I've got some convoluted rubber hose to replace it with, lighter and obviously more flexible.

Just having a break for a sandwich then back to the genny!

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk

Peter,

Just thought of something else, if I remember correctly looking from the rear on the right there is a tell tale button to tell you if you have oil pressure, if it is free it will pop up to indicate pressure. If it is stuck down don't try to free it off especially if the engine is running because it will leak oil like there is no tomorrow if you get it free. They are also a sealed button and dont come apart willingly. I found out this from my own and ended up putting a small gauge in place. When you crank it which end to you fit the starting handle as the rear is half speed, again taken from a old memory store :-))

Check that the mag is firing on the correct cylinder at TDC, the Douglas flat twin gave me a nice runaround until I figured that the mag was 180deg out so firing the wrong cylinder.

That's a good point, it has been apart before.....

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk

Good tip about the oil tell tale - I'd forgotten that rather slimy experience. Mine was indeed stuck & whilst it comes out readily enough, I could find no way into it without destroying it. The act of removal freed it off & it now rose from its casing upon a column of oil, most of which thrust its way out around the button!

Very useful.

In the end I'm afraid I gave up & fitted a blanking plug, but obviously it would make a good place to tap off an oil pressure gauge. Not that I'm to be found teaching aged relatives about emptying the shells of avian embryos ...........

Kim

This is your Granny speaking... :-))

One of the PU8's has got a proper oil pressure gauge on a long extension tube, looks original enough.

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk

Sorry Peter, If the gauge is on the PU8 that you had off me (the Derby one) its not original, the long tube is original but yet again the tell tale was stuck, so i replaced with the gauge.

Paul Swindell.

Oh well, another theory shot down :-))

Thanks for letting us know, Paul, at least it does look the biz.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk