New project

Good spot. The "pins" (cylindrical pieces at the corners which retain the side seals) should have "springs" behind them, which push them out into firm contact with the end (or centre, intermediate) plates.

On stripping, a few of these pins did not have these springs to apply force "outwards". Omitted during a previous rebuild we would have to assume.

This is likely the cause of the blow by. Presumably also not helped by the scuffs on the end plates, and as it progresses more and more carbon builds up making sealing even less efficient.

Hopefully I will be able to replace these springs (not from Andover, tho, as they are NLA ... ) and allow the rebuilt motor to be better than it was in a previous incarnation.

Fiddly indeed!!

Andy

Ok some some progress.

A nice man took my cases to get cleaned up (he also did my rotors and the eccentric shaft, not being at all impressed with my efforts).

He then skimmed them to clean up the scuffs, measured, checked, did clever things, and I came up to (watch him) build the motor.



He had already chemically etched the fresh end plates and put the stationary gear and studs back in.

The mating surfaces of the rotor chambers are coated with Wellseal.



Much cleaner. Embarrassment. These beautiful big roller bearings are very expensive. The eccentric shaft has been hot, but is usable. NLA, so I would likely have been looking for another motor if it were gubbed...



1st rotor (right) and shaft. Note the side seals and springs (underneath) are fitted to the rotor here, but not the apex springs and seals. (Also eye-wateringly expensive)





Apex seal, with spring hidden behind it.



Left hand chamber and rotor. The side seals total free play is 5 thou to 7 thou, against the 2 corner seal pins.


And put the top on.



11? (very expensive, of course, non standard, and strangely one of the few imperial fasteners) nuts behind the alternator rotor/ flywheel. I can probably take 4 or 5 or the 7 kilos off of this, but I want lights for now (and setting up idle etc), so it will stay as it is. And its a relatively easy thing to. Hmmmm. Thinks: may look for a flywheel to play with tho....

The engine itself is really beautiful internally. It appears, to my very untrained eye, to be really nicely engineered and developed.

(ok, not perfect, a bit hot maybe, but...)

So I also got the gearbox at the same time. The kindly uncle also drilled out a seized centrestand pivot bolt, meaning, I can rebuild the gearbox. I got it stripped, and am glad I did...

The gearbox bolts onto the face of the primary, driven by a duplex chain. 3rd and 4th gears apparently get noisy on these. So we want to replace as a pair, right? Ideally. I think its a T140V derived box, and the 4th and 5th gears are captive on the layshaft. Of course. So I have spoken to Graham at Startright, and got the gearbox stripped. It was suspiciously clean inside, with quite a lot of case hardening on the magnetic plug. The case hardening has started wearing through on the 3rd & 4th gearsets. Graham to advise. So I cleaned about 30,000 miles worth of road dirt off the box, and waved a spray can at it.

Lets see how this bit pans out...

Andy

Well, I discussed with Graham Wilshaw at Startright, and sent him some pics of the offending gearsets, and in conversation he said "Do you want to just send me the box, and I'll rebuild it?". So I took him up on that offer, given the fact that he has a great inventory of good used parts, and this is not his first rodeo with these bikes.

And I am grateful, because while the box wasnt by any means worn out, it was definately "used"...

And given that basically all of the bike bolts to the gearbox, I dont want to be taking it out again if I dont have to!



The swingarm pivots in the back of the gearbox casing; centre and side stands also attach to the box. The swingarm is shimmed to size in the taper roller bearings- a bit of a pain.






So with the box and swingarm in, I could get the stands on, but I didnt have a lot of the required bits to make this fit and function, so Graham's help was invaluable here.

From there, I could then bolt the engine/ primary to the gearbox face.



The engine is also suspended by the "air transfer ports", which double as engine mounts, which carry hot air out of the engine and into the plenum chamber.



And of course, once you have half the bolts in, you can put the tank and seat on, and throw on a couple of the filthy engine covers from the boxes of bits to make yourself feel a biut better about your skint knuckles and empty wallet.

I am of course skirting over the minor annoyances. And the major ones, and the little bits you spend an evening making (twice), before realising that you either already have it, or don't actually need it.

Or indeed the little, specific, no-longer-available hen's teeth parts (that you dont realise are hen's teeth) and then take a file/ dremel/ hacksaw/ axe to and wreck them, before looking online to find you shouldnt have done that.

I am too used to an almost entire inventory of my vehicles' parts being available quickly onine!

ANyway, the road is still a while away. And it may have a different face, but I am not sure yet how this will pan out. Best guess is currently the ex-XT600 headlamp cowl.





Next I will get the carbs on, then clutch and primary, and flesh out under the alternator cover too.

Progress is slow but I like this but of a rebuild where a big pile of parts gets a little smaller every visit to the shed, and a bike slowly grows!

See you!

AndyDMC said:

Well, I discussed with Graham Wilshaw at Startright, and sent him some pics of the offending gearsets, and in conversation he said "Do you want to just send me the box, and I'll rebuild it?". So I took him up on that offer, given the fact that he has a great inventory of good used parts, and this is not his first rodeo with these bikes.

And I am grateful, because while the box wasnt by any means worn out, it was definately "used"...

And given that basically all of the bike bolts to the gearbox, I dont want to be taking it out again if I dont have to!

View attachment 125184

The swingarm pivots in the back of the gearbox casing; centre and side stands also attach to the box. The swingarm is shimmed to size in the taper roller bearings- a bit of a pain.

View attachment 125185


View attachment 125186

So with the box and swingarm in, I could get the stands on, but I didnt have a lot of the required bits to make this fit and function, so Graham's help was invaluable here.

From there, I could then bolt the engine/ primary to the gearbox face.

View attachment 125187

The engine is also suspended by the "air transfer ports", which double as engine mounts, which carry hot air out of the engine and into the plenum chamber.

View attachment 125188

And of course, once you have half the bolts in, you can put the tank and seat on, and throw on a couple of the filthy engine covers from the boxes of bits to make yourself feel a biut better about your skint knuckles and empty wallet.

I am of course skirting over the minor annoyances. And the major ones, and the little bits you spend an evening making (twice), before realising that you either already have it, or don't actually need it.

Or indeed the little, specific, no-longer-available hen's teeth parts (that you dont realise are hen's teeth) and then take a file/ dremel/ hacksaw/ axe to and wreck them, before looking online to find you shouldnt have done that.

I am too used to an almost entire inventory of my vehicles' parts being available quickly onine!

ANyway, the road is still a while away. And it may have a different face, but I am not sure yet how this will pan out. Best guess is currently the ex-XT600 headlamp cowl.

View attachment 125189

View attachment 125190

Next I will get the carbs on, then clutch and primary, and flesh out under the alternator cover too.

Progress is slow but I like this but of a rebuild where a big pile of parts gets a little smaller every visit to the shed, and a bike slowly grows!

See you!

Click to expand...

Great progress Andy. Looking forward to seeing it at High Beech some time!