TW wrecks a perfectly good Commando etc.

Back when we could still go to jumbles and meets I often saw piles of Whit spanners on offer. Most were old school makers and if you pawed through them you could find ones that were not yet beat to death.

After all that it looks like the spanner will clear the carburetors nicely but hit the plastic air box engine in the frame, I grabbed the exact same spanner off eBay for $20 posted (US$1.95) and will modify it to suit unless I come up with some other hare brained remedy before mileage retorquing..
Being a boilermaker/welder I could have fired up the Lincoln V200T after a trip for sacrificial sockets but that seems to easy. (Maybe not so much now mind you)

I was getting a bit ahead of things installing the cylinder head wanting to put the new might be Lucas rotor in the dividing head once I have established true TDC and machine the degree's in (Something like the Moto Guzzi but totally different )

The finger of truth.









First the rotor has to fit.
Oddly it fits the old (cracked) crank cheek sliding up and down nicely with a precise fit but the replacement crank won't have a bar of that hitting the nut (inner spacer removed) at any key out rotation and stopping dead (The nut shank fits nicely in the rotor bore, the nut screws on nicely) which means it will not start parts together and risks damaging the end thread.
Now to find out why, might be a 'thou eccentric, might be way more and hope it is not the crank end.



#
Done, the replacement crankshaft end thread was slightly eccentric to the shaft section the rotor runs on.
That might explain why there was some (nice) linishing on the end prior, perhaps not the first time someone was scratching their head for a bit.
I modified the new nut then went to fit a new degree plate but its needs some rework to line up with the hammer pin holes. (All 3 new ones)
Perhaps enough reason to modify it to be adjustable.
The new Lucas stator only needed the resin removed in a couple of the holes (8 mm drill in a tap wrench) to fit over the studs.

Time Warp said:

View attachment 20943

Click to expand...

TW, did you take this pic with the pushrods in place?

ludwig said:

TW, did you take this pic with the pushrods in place?

Click to expand...

No Ludwig, I did try them yesterday (Kibblewhite) with the head in place but that is the engine on the workbench.
Did I forget something obvious to you ?

Will these longer studs mean a problem removing the head in the frame, I do not know. (On the bench I will fit each rocker after the head is in place at each cam base circle)
Of course I have the stock AN gasket set inlet valve stem seals in there now, the Teflon Kibblewhite seemed very high in stiction so they are sitting on the bench but now wonder now to hone them a little and fit those. (A 5 minute job on the bench))

I still have some things to do before fitting the cylinder head and today will make the decision to modify the front primary sprocket to take advantage of the IWIS duplex.
If I do that I can move the stator and perhaps even the rotor inboard a little (6 mm) or at the least line the two up, there is quite a mismatch vertically as normal.

TW: like I said before, because of the angle of the pushrods, you cannot lower the head on the barrel vertically. Too long studs can make it difficult, or even impossible. Try first.

ludwig said:

TW: like I said before, because of the angle of the pushrods, you cannot lower the head on the barrel vertically. Too long studs can make it difficult, or even impossible. Try first.

Click to expand...

I tried it the other day and it fit no problem with the KW push rods, rolled forward a bit then roll back and down but will have another look.
#
The new studs are 43.5 mm from the head surface (+14.5 mm in the head) up for the two front sleeve nuts.

The single rear stud for the tall nut is now 43.5 above the surface but all three studs allow 2 mm for the factory heavy washers.
All are originally 20M3S head bolts.

I don't think I will be able to undo this one.

90 passes at 4°.

Sprocket outer face to rotor gap back to 0.250".



Move stator 0.500" inward.
46 year old inner primary machined on 'worn out tooling ?
All three pedestals in the same 0.001" to the back mounting surface.



12 mm Cobalt cutter @ $76, over two weeks wages long ago.



5/16 BSW.



8 mm counterbore @ 1 mm deep for no exposed thread.

Done, IWIS solid pin Duplex primary with inboard rotor and stator.

Nice !

Really interesting thread, almost a form of technical porn but it does seem an awful lot of work just to go to a duplex chain. Is the clutch basket getting the same treatment as well?
Just wondering what the advantages are of doing this, other than being able to fix any errors in the stator mounting bolts.

The problem with threads like this though is that it does make one feel totally inadequate, nothing more than a slapper-together of parts, a bodger of bike bits

Here in Denmark, there does not seem to any from of training available for adults in the use of lathes, mills etc., other than the "professional" trade schools. No evening classes, unless you are a graduate of the Technical University (which I'm not), where they do have these. This does rather set a limit on how much interest there is in acquiring these things. I d ohave several contacts who can help out, but it's always an awkward feeling, having to go to someone else to get something done. Especially if it's a job requiring a lot of setting up.

Sigh!!

"Night School" is becoming a thing of the past. Trade schools in general seem to be on the slide too which is hard to understand when training can get you a decent gig.

SteveBorland said:

.. Is the clutch basket getting the same treatment as well?
Just wondering what the advantages are of doing this, other than being able to fix any errors in the stator mounting bolts.

Click to expand...

I suppose TW will remove the outer row of teeth.
Because of my obsession with weight, I did the same many moons ago, before belt drives were readily available.
Surprising someone with his capacities still opts for a chain..

I was surprised there was only around 120 grams difference in the weight of the stock sprocket and triplex chain compared to this duplex.
The IWIS chain is not that much lighter.

I tried the cylinder head again, no pushrod problem (bind or touching) that I could see/feel so might have got lucky.



Of course now the charge rotor is some distance from where the scale will be but can now get back to verifying TDC etc.
Perhaps it will need converting to threaded attachment with spacers to get it closer.
Open one door, find three more.





This duplex could go to the 750 as an option but have not found any long term feedback on the Iwis as a primary chain as far as longevity. (One person posted of it stretching quite quickly > RTW Commando and replacing it with a good used OEM triplex in the US section )
I had considered a belt drive primary once but the $600 to $1000+ did not add up.
If this chain holds it length it should be fine (On 46 year on drive teeth might be another thing)

For the 850 I want to keep it close to stock looking or as close to the Commando experience as possible but perhaps (attempt) fine tune some area's.
Of course without a few machine tools in the garage that would be hard to do, the other thing is sources for outwork seem to be diminishing by the year.

#

I wonder how thick that green stator potting/resin/something else is, it sure would be easy to leave the stock degree scale plate out and mill the graduations direct into the stator.
Much easier to see for old people.

Tw love your detail. Not able to machine the timing on my rotor, ( no machine skills) I download a degree disc from the web of the correct size & glue it on. Much kinder to old eyes to strobe to.

That would work for me Chris.
I am about to machine the stator body so am hoping to not see copper (windings) while doing so.


Depending on the accuracy of the stock scale to rotor mark that might be the difference between a bike that kicks back or not. (For the supporters of a dial gauge over a positive stop)
I will do it same as the Moto Guzzi, remark each side of TDC with the positive stop then split the difference in the rotary table then do the ignition settings.
A nut might do the camshaft lobe centres at the same time.

I do rather like your machined piston stop, but I presume that you put a spacer under it so that the piston actually stops a bit further down the bore?

I'm certain that TW knows this, but for the new people, there's a fairly large dead spot around TDC (and BDC of course), where there is very little piston movment for several degrees, which makes finding the actual TDC rather difficult.

Indeed, the dial gauge mark is quite a bit off in the picture above.
This bar stop has a projection underneath (along with a piece of printer paper)
If machined flat underneath a suitable disc can be slipped under (on an 850) to avoid having to wind the crank a full turn.



As per the TDC post in the main forum I have this also, the ceramic was removed and tapped M10 to suit a brass insert threaded ID and OD , the alloy end screws in allowing others to be made to suit other engines. (Taking note of possible valve clash/closeness)



The stator surface was a bit wavy but has some timing marks now, it will still need checking for clearance to the rotor but no surprise, trying a few other outer primary covers showed the stock degree plate was pretty much on the money (1 degree either way at most)

Time Warp said:

Indeed, the dial gauge mark is quite a bit off in the picture above.
This bar stop has a projection underneath (along with a piece of printer paper)
If machined flat underneath a suitable disc can be slipped under (on an 850) to avoid having to wind the crank a full turn.

The stator surface was a bit wavy but has some timing marks now, it will still need checking for clearance to the rotor but no surprise, trying a few other outer primary covers showed the stock degree plate was pretty much on the money (1 degree either way at most)

Click to expand...

Ah, that's clear now. When I checked my setup, there was an error of a couple of degrees, which would have made my ignition thing slightly retarded from spec. I was very interested in checking this after my rather expensive JS pistons overheated at Spa in 2019, so I spent quite a bit of time checking the accuracy of the marks. Now I have a correction factor to work on when I eventually get the bugger back together again.

I used a similar ( but much cruder) setup with a lump of alloy between the stop ( a bit of steel bar I had lying about) and the piston, so that the piston stopped about 10 or 15 degrees BTDC. I think this reduces the error in the measurement to get the true TDC, but I suspect you work to much higher standards that I do

Envy is a terrible thing, but I have to admit to being somewhat green when I read your stuff!!

Don't forget I am a Boilermaker/Welder not a machinist so anytime I get anything close to usable is a bonus.
The 4 axis DRO makes things much easier than the days of calculations for many things.

These timing marks will do and are easy to see through the cover port.
I had machined that plastic to mount the stator on in the rotary table, it got a push fit 3/4" hole milled into it to fit over the crankshaft end.
That should make setting the stator easy (Enlarged mounting holes if necessary) and will use cupped/wave lock washers.

The luxury of these machines being at home is even though it takes time it makes things much easier ( enjoyable)



It was very close to fitting but drilled the mount holes to 8.2 mm for some wiggle room (+ 0.2 mm / 0.008")



Fit the plastic disc which centres the stator which has that clearance on the holes now, tighten the nuts and fit the rotor.
The gap, rotor to stator poles is very even in the 0.009/0.010" - 0.25mm range.

Out with the old.