Tales from the Sherpa Shed

[Heavyspanners]

Burlen has now got back to me, and yes, their carb refurb service will be happy to sort out my carb.

Turnaround time is 14  weeks (FOURTEEN WEEKS!) and the price is £500 (FIVE HUNDRED POUNDS!)

For £500 I'd want 24 hour service and a gold-plated dashpot.

Incidentally, Burlen will chrome-plate my dashpot - at extra cost. All the carb refurbishers seem to offer a make-it-shiny option, which is presumably aimed at all those MGB owners who you see at shows, with their blinged-up cars with all the Traditional Classic Car Owner accessories added (headlamp peaks, wood veneer dashboards, those little Union Jack badges rivetted to the wings, a picnic basket which nobody has ever opened on the seat...)

I've got a Sherpa. I don't do bling. And I certainly don't do £500 for a carb job.

So, lets have a look at the DIY option...

There's lots of bumph online about HS2 and HS4 carbs, as used on Minis and MGBs, but relatively little about other variants. My Sherpa has an HIF6, which seems to be quite rare as a single carb. The HIF6 was used in twin-carb form on the Rover V8, and you'd think that was the only engine that ever used it. Rebuild kits for the HIF6 are available - but only, it seems, for twin carbs, so you get two of everything.

A twin carb HIF6 kit can be bought for around £100 (but this doesn't include needles). I suppose having two of everything would be useful when I inevitably drop the fiddly bits on the floor and lose them.

I could soak my carb in a bucket of cleaning fluid, like this stuff, and scrub off the gunge on the outside (presumably the gunge on the inside would just be lifted off by the cleaning fluid). I suspect the rusted-up idle adjustment screw might be a problem, but I'll assume I'll be able to free it off using standard methods. I couldn't really attempt tricky stuff like reaming out new bushes - assuming that's necessary, which it may not be, but how do I tell? Why do the bushes need to be reamed anyway? Shouldn't they be the right size, straight out of the box?

I could do a fairly basic clean-up job without too much trouble, and maybe that's all it needs. 



Then again, I could buy two ready-refurbished HIF6 carbs for not that much more than Burlen would charge for doing one. It seems nobody sells just one HIF6 - they're only available in pairs, because everyone's got a V8, right?

OK, I've made a decision. I'll buy some cleaning fluid. And a bucket.

[Heavyspanners]

47 minutes ago, Westbay said:

https://www.ebay.co.uk/itm/175150742747?_skw=sherpa+carburator&itmmeta=01KKK3ZP78ZMSPQV1WYZYA9T0J&hash=item28c7cc3cdb:g:ZB0AAOSw98ViA8-C&itmprp=enc%3AAQALAAAA8GfYFPkwiKCW4ZNSs2u11xBZ4qW62w6DPX%2BC2SDBXjyr%2B4UC7E0g2NdcF2EI6HiSGLIQ43hWzc4ha0VddW6mh3H7k4uYkHakRDGYrpi6PpN%2FZ2JHnuNkMITadb9zO9oZvYc54roHSagb9s5rfTe%2FTDH6%2BbXWdJRH%2FgOXVJ9BRIImnS%2Bxy82sAsxZ6nJHfINTiHxghz67hYWZ5msBtJddBKSROiQUg1Ot1bmPgUiiIq%2Bm6MeMMS%2BhdFpe2X1lk0WOakWwkMDCfOo9J8%2Fmf3CDALhNe5Z9jkBOlo1BCakUgvbrvFOWXLvpXwJiWObBTGYySw%3D%3D|tkp%3ABk9SR9Tk_uOcZw

It says Stromberg but is all "Brand New" £270+ postage ....

That's a weird one. A conversion kit - I've never heard of anyone converting their Sherpa engine to a different carb. And it apparently suits (and fits) both the B Series and O Series engines. I have to say I'm a bit sceptical about that. What's the advantage? It's not like the SU carbs are inadequate in any way.

It would be interesting to try it out, but I'm not sure if it's £270 worth of interesting!

[High Jetter]

9 minutes ago, Heavyspanners said:

OK, I've made a decision. I'll buy some cleaning fluid. And a bucket.

Well worth trying that first, little to lose.

[Mr Pastry]

19 minutes ago, Heavyspanners said:

Burlen has now got back to me, and yes, their carb refurb service will be happy to sort out my carb.

Turnaround time is 14  weeks (FOURTEEN WEEKS!) and the price is £500 (FIVE HUNDRED POUNDS!)

For £500 I'd want 24 hour service and a gold-plated dashpot.

Incidentally, Burlen will chrome-plate my dashpot - at extra cost. All the carb refurbishers seem to offer a make-it-shiny option, which is presumably aimed at all those MGB owners who you see at shows, with their blinged-up cars with all the Traditional Classic Car Owner accessories added (headlamp peaks, wood veneer dashboards, those little Union Jack badges rivetted to the wings, a picnic basket which nobody has ever opened on the seat...)

I've got a Sherpa. I don't do bling. And I certainly don't do £500 for a carb job.

So, lets have a look at the DIY option...

There's lots of bumph online about HS2 and HS4 carbs, as used on Minis and MGBs, but relatively little about other variants. My Sherpa has an HIF6, which seems to be quite rare as a single carb. The HIF6 was used in twin-carb form on the Rover V8, and you'd think that was the only engine that ever used it. Rebuild kits for the HIF6 are available - but only, it seems, for twin carbs, so you get two of everything.

A twin carb HIF6 kit can be bought for around £100 (but this doesn't include needles). I suppose having two of everything would be useful when I inevitably drop the fiddly bits on the floor and lose them.

I could soak my carb in a bucket of cleaning fluid, like this stuff, and scrub off the gunge on the outside (presumably the gunge on the inside would just be lifted off by the cleaning fluid). I suspect the rusted-up idle adjustment screw might be a problem, but I'll assume I'll be able to free it off using standard methods. I couldn't really attempt tricky stuff like reaming out new bushes - assuming that's necessary, which it may not be, but how do I tell? Why do the bushes need to be reamed anyway? Shouldn't they be the right size, straight out of the box?

I could do a fairly basic clean-up job without too much trouble, and maybe that's all it needs. 



Then again, I could buy two ready-refurbished HIF6 carbs for not that much more than Burlen would charge for doing one. It seems nobody sells just one HIF6 - they're only available in pairs, because everyone's got a V8, right?

OK, I've made a decision. I'll buy some cleaning fluid. And a bucket.

Just soak it in petrol?   Free everything off and it will probably work.  They have to be very badly worn before they won't.

[tooSavvy]

The reaming is to ensure the two bushes (located opposite each other) are exactly in line [.. the spindle holes]

IIRC PTFE plastic bushings are available [squidgy but won't crimp butterfly spindle] and are airtight/no idle leaks 🔧✔️

Centring the needle into the jet orifice is important for smooth operation and it will reduce any tendency of the piston to stick in the bell... Some thin valve lapping paste blobbed onto the rim of the piston and spun/zigzaged up and down will ensure no crusty gritty blemishes inside the bell [RINSE thoroughly 🤣]

Much debate on S.U. dashpot oil.... My MM1000 flew with 3-in-1 (... just sayin, lyke 😁)

Bon chance M9

🚙💨

[Matty]

You can also do the drop test to check for wear between the piston and the bell. Seal the (transfer?) holes in the piston, take the needle out, put the piston in the bell and hold upside down over a soft landing. If it takes 7 seconds or over to drop then the wear between the piston and its housing is within acceptable levels.

[Matty]

HS6s are readily available for cheap. Inch and 3/4 like a HIF6 but seperate float bowl. @Mr Pastry will know if its possible to fit one on an O series but id imagine its a ballache. 

[Westbay]

Yes you can use HS6 instead of HIF6, but basically,  the HIF6 is regarded as an improved HS6 , doubtful you would you see any degradation in performance in this appliocation 🤔

[Sigmund Fraud]

It's an SU, not a nuclear reactor !

Take the top and bottom off, give everything a good clean with carb spray and a rag, try not to bend the needle. Then put it back together and test the car. Chances are, it will be fine and you won't need to bother with a service kit etc.

[Mr Pastry]

6 minutes ago, Sigmund Fraud said:

It's an SU, not a nuclear reactor !

Take the top and bottom off, give everything a good clean with carb spray and a rag, try not to bend the needle. Then put it back together and test the car. Chances are, it will be fine and you won't need to bother with a service kit etc.

And if it works, leave the bloody thing alone!   The worst thing BMC ever did was to publish SU tuning instructions in the drivers' handbooks, so everyone down the pub instantly became an expert and applied the magic screwdriver when it wasn't even necessary.   And that is how SUs got a reputation for "going out of tune."  No they don't.

[goosey]

2 hours ago, Heavyspanners said:

Burlen has now got back to me, and yes, their carb refurb service will be happy to sort out my carb.

Turnaround time is 14  weeks (FOURTEEN WEEKS!) and the price is £500 (FIVE HUNDRED POUNDS!)

For £500 I'd want 24 hour service and a gold-plated dashpot.

Incidentally, Burlen will chrome-plate my dashpot - at extra cost. All the carb refurbishers seem to offer a make-it-shiny option, which is presumably aimed at all those MGB owners who you see at shows, with their blinged-up cars with all the Traditional Classic Car Owner accessories added (headlamp peaks, wood veneer dashboards, those little Union Jack badges rivetted to the wings, a picnic basket which nobody has ever opened on the seat...)

I've got a Sherpa. I don't do bling. And I certainly don't do £500 for a carb job.

So, lets have a look at the DIY option...

There's lots of bumph online about HS2 and HS4 carbs, as used on Minis and MGBs, but relatively little about other variants. My Sherpa has an HIF6, which seems to be quite rare as a single carb. The HIF6 was used in twin-carb form on the Rover V8, and you'd think that was the only engine that ever used it. Rebuild kits for the HIF6 are available - but only, it seems, for twin carbs, so you get two of everything.

A twin carb HIF6 kit can be bought for around £100 (but this doesn't include needles). I suppose having two of everything would be useful when I inevitably drop the fiddly bits on the floor and lose them.

I could soak my carb in a bucket of cleaning fluid, like this stuff, and scrub off the gunge on the outside (presumably the gunge on the inside would just be lifted off by the cleaning fluid). I suspect the rusted-up idle adjustment screw might be a problem, but I'll assume I'll be able to free it off using standard methods. I couldn't really attempt tricky stuff like reaming out new bushes - assuming that's necessary, which it may not be, but how do I tell? Why do the bushes need to be reamed anyway? Shouldn't they be the right size, straight out of the box?

I could do a fairly basic clean-up job without too much trouble, and maybe that's all it needs. 



Then again, I could buy two ready-refurbished HIF6 carbs for not that much more than Burlen would charge for doing one. It seems nobody sells just one HIF6 - they're only available in pairs, because everyone's got a V8, right?

OK, I've made a decision. I'll buy some cleaning fluid. And a bucket.

I sorted the carb from my escort using a £40 gasket kit of eBay and a good clean, take loads of pictures for reference, take your time and you’ll be fine- I figured no matter what I did I couldn’t make it run any worse than it was 

[Somerset Suffolk]

Nuclear reactor service items

 

Moss should be able to sell you individual HIF6 spares (for the mighty MGB V8 !)  should work out cheaper  than a complete rebuild kit - the HIF4 on MGB GT are pretty good - as @Sigmund Fraud all I did was replace the float bowl seal - worth having a look to check for crap etc  - I did bung mine in my cheap sonic cleaner, but a bucket with petrol should be good enough (No Smoking ....)

[tooSavvy]

@Somerset Suffolk.. "but a bucket with petrol should be good enough (No Smoking ....)"

Smoking + petrol in bucket = enough Nuclear for Iran! 🤣

All top tips here.... 🔧✔️

🚙💨

[grogee]

@Heavyspanners a man of your calibre will find an SU carb refurb a walk in the park. 

I did my motorbike one, not an SU but smaller and fiddlier, it's pretty easy. 

The harder part is getting it set up afterwards, maybe Gunson Colour Tune could help to get it in right ball park? Or get friendly with your MoT tester so you can use his gas sniffer. 

[tooSavvy]

@grogee.. "The harder part is getting it set up afterwards, maybe Gunson Colour Tune could help to get it in right ball park? Or get friendly with your MoT tester so you can use his gas sniffer".

Very old-skool tuner/mech offered advice when I rebuilt my MM1000 SU.... he showed me how to lift the piston a *little, when running, with a skinny long screwdriver and to tell the change in revs = good/bad.

I had read up (in our AA Book of the Car) about SU setting up... and reference to the 'lift pin' >> for lifting the piston ✔️

I confidently advised he should use said pin... 😵...

"Screwdriver does fine FOR ME! 🧐"

...... lesson learned..... 🤣🤣

🚙💨

[Mr Pastry]

IIRC when new, the HIF had the mixture adjustment set and sealed with a pressed-in plug, and "normally" no adjustment would be required.   It is a small adjusting screw, not a large brass nut as on the earlier carbs.  This was at the beginning of emissions regulations and was designed so you could not set it too rich.  If the plug  is still in place, leave it, the mixture is probably OK.    

[grogee]

2 hours ago, Mr Pastry said:

IIRC when new, the HIF had the mixture adjustment set and sealed with a pressed-in plug, and "normally" no adjustment would be required.   It is a small adjusting screw, not a large brass nut as on the earlier carbs.  This was at the beginning of emissions regulations and was designed so you could not set it too rich.  If the plug  is still in place, leave it, the mixture is probably OK.    

Except @Heavyspanners can only get it to run with the choke pulled right out... 

Admittedly this could be due to a manifold air leak but I'd imagine the carb is out of whack somewhere. 

[kevins]

it could also be dodgy fuel, if its old and gone off you need more to make it run and hence thr choke out.

[goosey]

“Will only run with the choke fully out” 

I had the same issue, then found my fuel tank looked like this inside 

[Homersimpson]

The SU's are very simple and generally a strip down and clean up is all that is required, if you do need to rebuild it the gaskets etc should be available from Burlen, if you can't see what you want on their website give them a ring, I'm sure they can sell you what you need.

Rebushing the spindle is the only slightly awkward bit if you have to do it but it can be done with just a pillar drill if it becomes necessary.

[Mr Pastry]

6 hours ago, grogee said:

Except @Heavyspanners can only get it to run with the choke pulled right out... 

Admittedly this could be due to a manifold air leak but I'd imagine the carb is out of whack somewhere. 

Stuck piston, possibly.

[Heavyspanners]

I had almost definitely decided to try refurbishing my Sherpa carburettor myself when I stumbled on a company in Bradford called Yorkshire Restorations, who offered a decent price and a two-week turnaround on carb work. So I thought I'd save myself a job. After all, I've got a lot of other stuff to be going on with.

The carb is now in their workshop. I've had a work-in-progress update, and - well, it's not too good.

This is a picture they sent me of the carb body after blasting. The metal is quite severely pitted. It looks more like crumbly cheese. I'm no expert on alloy castings, but - it's not supposed to look like that, is it?



I'm not sure if that's repairable, or whether the carb is toast. I'm awaiting the official verdict. The refurb guy did ask me if the engine actually ran with this carb on it...

Here's a thought: Could the metal be porous? Could air have been leaking in through the carb body itself? That would explain why the Sherpa would only run with full choke.

In the meantime, I've knocked off one job on the Sherpa Revival list. When I bought it, the wipers were obviously in a bad state - the blades had almost completely worn away, or possibly the rubber had perished. At any rate, new wiper blades were needed. Apparently, Germany is where all the best wischerblätter come from these days.



Wiper operation was painfully sluggish. I thought this was most likely due to dried-up grease in the mechanism, which could be fixed by a clean-up and re-lube. So I found the wiper motor, hidden under the dash, behind some interestingly random disconnected wires...



...and took it out, complete with the flexi-gear which works the wipers. At some point the Sherpa changed to a rod-operated wiper system, but in 1985 it was still done with a long worm drive.



The grease inside the gearbox wasn't totally dry, but it had gone like earwax, still greasy but rather stiff. I shouldn't think anyone has looked in here for 41 years. I suspect we might be just over the service interval.

Let's clean it out. I don't have a workbench, so I'm improvising here with a cardboard box on a building site.



New grease in. Works up to 135 degrees, so my wipers will remain fully-functional in the Sahara desert.

Reassembly is the reverse of removal (and for once, it really is). Now let's provide some artificial rain, and test mein wischerblätter...

That's the slow setting. Sherpas (of this age, anyway) have two-speed wipers, plus a flick-wipe option, where one nudge on the wiper stalk gives you one wipe. All work correctly, so that's one thing off the list.

I've also had an eBay coup. I managed to buy this (not that there was much competition - I was the only bidder). It's a Sherpa spare wheel cradle. The original one on my Sherpa was missing, removed by the farmer when he fitted his DIY tow hitch. The spare wheel has just been randomly rattling around in the back ever since.

Of course, I didn't think about spare wheel cradles when I fitted my DIY number plate plinth right across the rear of the chassis, where the spare wheel would normally be hung. I assumed at the time that I would never find a spare wheel cradle, and I'd work out some sort of alternative arrangement for carrying the spare wheel (mount it on the tailboard, maybe, Land Rover style). But now I do have a spare wheel cradle, I might have to modify my plinth, because I think it'll get in the way. Still, the plinth is only a piece of plywood. I'm sure I can tweak it in a suitable fashion.

The cradle is a bit battered and rusty, and it'll need more than a quick wire brushing to restore it. I think I'll fire up my back garden blasting zone...

I also managed to buy another rare item - a complete set of those elusive dashboard switches, which as far as I can tell are unique to the1984-85 model year Sherpa and not used on any other BL vehicle, although some had switches that were similar but not quite the same. So these grubby old switches are treasure, I tell you. Treasure!

One of the switches is a dummy. Not a blanking plate - it's a switch with nothing behind it. I suppose on upmarket Sherpas this switch actually did something, but not on British Telecom below-base spec vehicles.

Theoretically it should be easy to fit the switches - just plug 'n' play.  But I'm sure it won't be as simple as that, because someone made all sorts of 'adjustments' to the under-dash wiring, and it's definitely not factory spec in there any more.

So, not for the first time,  it's all a bit one step forward, two steps back at the moment...

[grogee]

I did something similar to my Maestro wiper motor which was also full of dry old grease. It didn't seem to make much difference, but then I scored a NOS motor and fitted that. It's still not great, but I expect it's back to 1988 levels of wiperage. 

I need some new blades for it though as they are juddering across the screen. Consensus here seems to be they're all as shit as each other and may as well just buy cheap ones. 

Edit: well done with your work, and good scores on the obscure parts. Sounds like the carb may be scrap, will they charge you full whack if they halt work now? 

Did you say it was an obscure SU? Shirley something else could be persuaded to fit? 

[Heavyspanners]

On 04/04/2026 at 08:25, grogee said:

 

Edit: well done with your work, and good scores on the obscure parts. Sounds like the carb may be scrap, will they charge you full whack if they halt work now? 

Did you say it was an obscure SU? Shirley something else could be persuaded to fit? 

The HIF 6 carb seems to be a bit rare in single form (well, it wasn't rare in its day - it was fitted to every Morris Ital and Austin Ambassador, but where are they now?). These days they're much more common in twin carb form.

However, there's a solution to my Wensleydale cheese carburettor. The refurbisher has a good carb body in his box of bits, and he'll build up my carb on that. One slight difference will be that the fuel inlet will be on the opposite side. Apparently HIF 6 carbs came in left/right fuel pipe versions, probably for twin-carb set-ups, with the fuel pipes coming in from opposite sides.

That's no problem for me, with my humble single carb, because there's plenty of room to route the fuel pipe to the other side. In fact it may be a better option, because at present the fuel pipe does a loop around the carb to come in from the front. Connecting the pipe on the bulkhead side would be neater...



I wonder if that's a replacement carb, and the factory original had the fuel pipe inlet on the other side. It would be much more logical to do it that way. In which case, the re-replacement carb will actually go back to the original fuel pipe arrangement.

Here's a twin-carb O Series engine (from here - interesting stuff about BL's experiments with the O Series in the TR7). Fuel inlet definitely on the left in the front carb. Not visible on the rear carb, but it must be on the right, surely. There'd be no room to get it up the middle...



Theoretically I could put twin carbs on the Sherpa, but it would probably be a bit silly to do that on a low compression commercial engine. It would probably just increase fuel consumption without giving any extra power. It might be worth doing on a car-spec 2 litre version of the O Series. I'll keep that thought in mind in case I ever buy a Morris Ital (you may not be entirely surprised to learn that a Morris Ital is indeed on my list of Cars I Would Like To Own - apparently the late models, with parabolic rear springs and telescopic dampers, handle quite well...)

 

[M'coli]

Just as an aside, an HIF6 is but 0.45mm bigger than an HIF44, and they're far younger.

[Heavyspanners]

My carburettor is back after its rebuild.

I didn't go for any of the make-it-shiny options, but it's impressively shiny even so. It's almost too shiny to be bolted on to a grubby old Sherpa engine.



It's not quite the same carb, of course, because it's been rebuilt on a different body with only a few parts carried over. 

Now here's an interesting thing. I also got the original carb body back, which wasn't fit to go again because of all the pitting in the metal (the rebuilder said he could use the poor body again, but he couldn't guarantee it would perform well).

The new carb body has the SU logo cast into it, while the original carb body just has a blank circle. Does that mean it's not a genuine SU product? Is it some sort of aftermarket lookalike? If so, it may have been made with poor quality alloy, which might explain why it turned into Wensleydale cheese.



There are minor differences in the castings, too - for example the blank boss at 7 o'clock to the logo is different. So was the old carb SU or not SU? Maybe not.

The next thing to do is to bolt the shiny new carb onto a grubby old Sherpa engine...



 

[Matty]

This is what mine looked like after. 

Yer man wins 🤣

[Heavyspanners]

The shiny carb is now back on the engine. Does this mean the mighty roar of a 1.7 litre O series Commercial engine has been heard up and down the land?

Well, no, not quite. The engine hasn't actually started yet, for a very silly reason. But the carb is on, so that's progress. A bit.

Here's how I did it. First, find your Sherpa. Ah, there it is. I knew it was in here somewhere.

Now assemble all parts. The carb is just loosely placed on its studs here - actual fitting has not occurred yet.

The carb came with new gaskets, but just in case I managed to damage them in the fitting process I bought an O Series engine top end gasket set, so I'd have some spares. This, of course, ensured that I wouldn't damage the gaskets in the fitting process, because you only damage gaskets if you don't have spares. This is authentic engine builder lore.

The air filter attachment was full of oily gunge - rather worrying in itself. How did it get so dirty? The only thing that's supposed to pass through this pipe is filtered air. Well, I cleaned it all out and shininess was restored.

The carb doesn't sit directly on the manifold. There are several layers of other things which locate on the studs before the carb finally goes on.

First layer is this - a heat shield, which is in fairly grotty condition. I didn't think of this at the time, but now I'm wondering - it's not asbestos, is it?



It's not clear how many gaskets there should be, between all the components which sit between carb and manifold. The Haynes manual doesn't help much. It just says 'refitting is the reverse of removal - use new gaskets'. But how many gaskets? Between which bits? 

There was no gasket between the heat shield and the manifold, but then I think the heat shield actually is a gasket. It's certainly got a sealing ring, like a cylinder head gasket. So should I fit a new heat shield? If so, where do I get one?



In the end I just cleaned up the mating surface, applied a bit of sealant, and stuck the heat shield on again.



The next thing to go on is a mounting plate, which exists to give the throttle cable and return spring something to attach to. Nothing else is directly fitted to this plate. (Photos a little out of sequence here - the heat shield has not yet been re-fitted):



There was no gasket between the heat shield and the mounting plate, so again I just cleaned it up and put a bit of sealant between the heat shield and plate. 

There was a gasket between the mounting plate and the next component - a spacer, which isolates the carb from the hot parts of the manifold. I don't know how it does this, since it's only plastic, but perhaps that is all that's necessary to stop metal-to-metal heat transfer. My Land Rover has a very similar thing.

Of course, all this heat shielding is only necessary because the fuel/air mixture goes in to the engine on the same side as the hot exhaust gases come out. If the carb and inlet manifold were on the other side of the engine, they would be safely out of the way of the hot stuff, and you'd have much more efficient gas flow, too. You could call this kind of engine - let's see now - how about 'crossflow'?

Seriously - given the obvious advantages of a crossflow engine, why have so few manufacturers used that design? Ford did it (a bit), and when Reliant designed their own engine they were canny enough to make it a crossflow, which is why the Reliant Robin could always punch above its weight, performance-wise. But it was never the norm. Why wasn't the O Series engine a crossflow?

Anyway. Here's the spacer, putting that vital bit of distance between the hot and cold parts of the manifold:




And finally, the carb goes on - with gasket. The throttle cable looks slightly distressed, but I think that's just the plastic covering. The cable inside is fine. Famous last words there, of course - it'll probably snap next week.



Weirdly, new throttle cables are available at a not-bad price of six quid, from "The biggest dealer of ex-MOD Harley Davidson MT350 motorcycles in Europe". So British armed forces use Harley Davidsons? Who knew? I bet they're a bit miffed by that over at Triumph.

Now the air filter pipe is on, and I'm giving the carb a dose of specialist dashpot oil. This is probably a bit over the top. Engine oil will do the job, and that's what it says in the manual anyway. I think Penrite are selling this stuff to a market which they created themselves, really. But I admit they reeled me in.

I fully expect my Sherpa to have the performance of an AC Ace as a result of putting this oil in.

And finally,  the whole thing was fully assembled. Fuel pipe going in on the bulkhead side, because the replacement carb body is opposite-handed to the original. The other, bigger, pipe is coming in from the crankcase breather.

On older engines, pressure within the crankcase - and any oil which came along with it - was simply vented into the engine bay, via a crude filter which usually looks like a canister full of wire wool (my Maxi has this kind of set-up - or, at least, it used to, because the filter is missing).

By the time the O Series engine came along, the done thing was to duct all this effluent into the carb, so it would go into the combustion chambers and be burnt along with the petrol/air mixture. This was supposedly better in terms of emission control, because you no longer had an oily miasma wafting out into the engine bay. But on the other hand, the engine was now burning this oily miasma, which surely can't have done anything to improve the tailpipe emissions.

I've never really understood why ducting crankcase emissions into the carb to be burned was considered a good thing, but as so many engines had this arrangement it must have worked. The O Series engine was quite a clean engine for its day, so burning a small amount of its own oil clearly wasn't a problem. But I still don't get it.

Nevertheless, the breather pipe was connected. I'm not going to pick a fight with the designers of the O Series engine at this late stage!



Unfortunately, combustion didn't happen, because....the Sherpa has run out of petrol.

When the Sherpa was delivered it barely had enough fuel in the tank to drive the 20 yards between the transporter and the shed where it now resides. Since then I've put a few litres in from time to time, just to give me enough juice to run the engine occasionally and shunt the Sherpa about. But the tank has never had more than a slightly moist bottom. It's such a big tank, a few litres barely covers the bottom of it. I don't think the pickup pipe has ever been more than about 1mm under the surface of the fuel.

I think the last time I ran the engine it went down to nothing - and of course the shiny new carb has nothing in the float chamber, which usually acts as the reserve tank of last resort. So I need petrol, quite a lot this time. That means the big start-up will have to be postponed until I can pop down to the local pharmacy for a jug of Pratt's Motor Spirit.



According to the internet (the Haynes manual maintains a stony silence on the matter, as it does with much other stuff) the Sherpa truck cab fuel tank capacity is 68 litres. That'll be about £120 to fill, at current prices. At this rate it'll soon be cheaper to run the Sherpa on Glen's Vodka.

[grogee]

8 hours ago, Heavyspanners said:

So should I fit a new heat shield?

Yes

8 hours ago, Heavyspanners said:

If so, where do I get one? 

No

[grogee]

8 hours ago, Heavyspanners said:

Seriously - given the obvious advantages of a crossflow engine, why have so few manufacturers used that design?

I have wondered the same. Although packaging can be a bit neater when you do it BL style with all the innie and outie on the same side. Customer is presented with nice, neat spark plugs and nothing fancy or complicated (in a FWD application)