Yanmar clone reliability issues....?

[GeoffK]

First of all, thanks to Dan J for his detailed explanation of the adjustments and mods he has made to his HP Enfield/Yanmar bike. (See 'Insurance UK' thread). That was really useful.

My purpose in getting the bike is that I want to take it out into the depths of the Sahara desert! I have been out on three expeditions to the distant reaches of the Western Desert in Egypt now, where the nearest sealed road is 600 miles away.

I was looking around for a vehicle in which I could go out into the desert as a self sufficient unit, having the reach to go out into the depths of the Sahara - and get back again. The usual vehicle of choice is a Land Cruiser, but at over two tons all loaded up, you really need at least one other person to help push when it gets stuck in the sand.

The motorbike seemed like the answer. When the back wheel looses traction - just put your feet down and start running. Petrol bikes are too thirsty. Too much fuel to carry for a 2000 mile round trip. But a diesel bike - ah now, that starts to look feasable!

Adventure bikers generally load up their bikes with panniers, top boxes, tank bags and bungy chords to strap on what is left over. But that makes the bike top heavy, unstable and strains the frame over rough country. With this in mind, my final rig will be an Enfield/Yanmar combination from Henry Price, pulling a small trailer which I will build myself in which I will put the water, food, tools, tyres, spares and the thimble full of diesel I will need for the trip.

So, with this as the background, I am looking for information from those who have experience in running the Yanmar as the power plant in a bike. What are the weak points of this engine. What should I watch? What is likely to wear out or go wrong? What maintenance is needed to keep these engines running sweet? And - most important - what spares should I take with me?

Thanks a lot.

Geoff (from the Border country of Scotland)

[andrewaust]

Hi Geoff



Boy that is adventurous !!!!! If your running on hard ground I'd consider it, if your going to hit sand I wouldn't recommend it, especially carrying a load and pulling a trailer, the engine would be overworked and would more then likely die, or for that matter kill you from exhaustion pushing the bike.

The Enfield will handle some country road stuff including dirt, but the Sahara Desert needs specialized vehicles, either a good 4wd or a powerful dirt orientated bike, even then things do go wrong.

The 10K that I have done with the Enfield has seen very little go wrong, a broken chain guard bracket along with a battery bracket is all that has failed. Chains and sprockets would be handy to take along on a long trip, as well as spare cables, tubes, fuel line and filters etc etc.

The clutch could also be a weak spot, and I'd guess the gearbox wouldn't handle a lot of abuse if your going to use the 4 speed clunker .

Remember these engines are good for a continuous 8hp and a max of around 10hp in ideal conditions, desert heat etc may see hp drop to a max of 6hp, it would be like riding a Honda 110cc motorcycle, actually the Honda would probably go better .





Cheers


Andrew

[GeoffK]

Thanks for yours Andrew.

Most of the going will be on firm or hard sand. There are large areas (called 'serirs') which are very flat and have a gravelly crust over which you can run pretty fast for huge distances.

Even in the Great Sand Sea, South of Siwa, the dunes form corridors with quite firm sand in between. Though there are soft patches into which one runs at times and where the ill equiped can spend an inordinate amount of time extricating themselves.

Temperatures in the Egyptian desert are hot, for sure - but not even this Englishman would attempt a trip in the summer. In late autumn, early spring, the temperatures during the day are in the high 80s or low 90s (old currency) and it does not get too cold at night.

So, while I hear what you say about the low power of the Yanmar, I think if I keep my dune leaping to a minimum I do not see that the Yanmar will pulled far away from its optimum envelope of long running at an even load.

Sounds like you find the Yanmar to be pretty reliable though as spare pistons and the like do not appear on your must-take list.

Thanks for your comments -

Geoff

[Sphere]

What is your expected cruising speed? It might be optimistic to expect the same from a diesel enfield as from a landrover.

[taildraggin]

As an engine, yes, the yanmar (can't speak for a clone) is bet-your-life good. It's just a piston, crank and a stone simple fuel pump, all made of good material. Keep the sand out and it'll last as a long as the pyramids.

But, as Andre says, it only eeks out a few horsepower and the Enfield has many weaknesses, particularly as a cross-country machine.

I like the concept, though. I'd want to calculate the load to keep rider going and the load required for the vehicle. Cross country or two-track road? There's a big difference there in consumption/load.

If you're going 2000mi in the hot desert, loaded, figure your mpg will drop to 70-80mpg (maybe worse?), which means you'll need 25+gals (200+lbs) of fuel at the start. The trailer should be a little tank car or a wagon with 6 jerry cans. (To that you'll need to add spare parts, oil, a welding unit, and lathe. )

That said, they got a Vimy around the world. If you persist, I'd have Henry build one, rigged with the scrambler gear, build a tank trailer, load it up and test it out. If it fails, you'll still have a great little town bike and a nifty trailer.

The right bike would be the MoD HDT, but...

[GeoffK]

Sphere - I would hope for a cruising speed over the flat sand of about 40 mph.

Taildraggin - Thanks for yours. Glad to hear the engine seems reliable. As you say, it is pretty simple and no electrics to go wrong. In fact, no electrics needed at all.

On the matter of cooling, Henry tells me that the Yanmar actually runs cold in our climate. In fact, he has removed the little cowling which directs the forced air around the head of the engine to try and retain some heat. The engine is, of course, designed as a standing engine and the extra cooling due to air passing over it at the forward speed is possibly too much of a good thing. So, with the cowling back in place, I am hopeful that the engine will feel nice and comfy in the desert and not get anywhere near overheating.

As for power, it is worth remembering that back in the 1930s, the desert car of choice was the Model A Ford. It had a 40 hp engine and a curb weight of around one ton. Early explorers like Bagnald and Almasy would load the car up with another half ton of gear and head out into the desert. You can still come across their tyre tracks out in the desert - the narrow tyres they used are unmistakable.

My 10 hp Enfield/Yanmar has a quarter the power of the Model A Ford, but the unladen weight is only a fifth that of the Model A. With me on top and pulling a laden trailer, total power to weight ratio will be pretty much equivalent to what those early explorers had. It didn't stop them going anywhere anybody goes today.

As for range, sorry, I meant 2000 km, not 2000 miles. Based on the Model A Ford again, where fuel consumption, loaded up in the desert, was around half that for the unladen car on a tar road - I will need around 70 lb of fuel (plus what is in the tank) to get me there and back. Two 25 litre gerry cans should be more than enough.

I figure it will be do-able so long as I do not push things too hard and nothing catastrophic happens.

Geoff

[Sphere]

Please make some photographs, have a safe journey

[sbrumby]

I have a lot of experience of desert driving although 30 years ago. The vehicle most people used was toyota land cruiser 4.6L petrol. Bags of power but most importantly sand tyres. These are not at all like road tyres. On the black top 40psi on soft sand 5psi. Easy going hard to soft but returning to black top you could only drive 30mph until you reinflated to 40psi or tyres would blow.

[taildraggin]

20*4L/km (@72Imp/60US mpg) = 80l (25 Imp/21US gal) x .85kg/L = 68kg(148lbs)

20L (4/5 gal) are in the bike leaving at least 3 cans @ 60L (13/16 gal) to carry at 51kg (112lbs).

How much water? 8-10 gallons, no? That's another 36l and 80kg (175lbs).

If you're just heading down a hard two-track, you might make it. If the frame doesn't crack from the bumps or the clutch doesn't cook away smoking in the sand.

But, an overloaded bike, with a nice view to the top of a sand dune and 105 degrees in the shade might be a little more than should be asked of those 8 little horses.

No matter the equipment you choose, test it all out beforehand very thoroughly. I work in marine assistance (towing and salvage) and we deal with distressed vessels daily. We are always amazed at the risks people take and the situations they put themselves into in an unforgiving environment.

[oldbmw]

I wonder if you might be better off using a diesel quad bike ?

[andrewaust]

Good points guy's, I like the quad idea oldbmw, one of them Polaris bikes fitted with a L100 would make a great desert mount. I heard the original Polaris diesels had a lot of problems, the reason for mentioning the L100 installation.

[GeoffK]

Well, sounds like I am going to have a lot of problems in the desert, but the Yanmar engine cracking up ain't going to be one them

Thanks to everybody for their comments. I will let you know how it goes.

Geoff

[taildraggin]

Andre: I've got some Ozzie "Old Man Emu" suspension and ARB bars on my jeep. Great stuff. (I'd like to tour africa with it...)

But, how's that for a brand name, though? Here in the States, we don't have too many emu and people are confused by the name, so they mostly go by "OME".

The diesel quad is a great idea. I'd imagine a cranky Polaris diesel would be far better than a DEnfield. I'm not fond of the handling of handling of quads and their short wheelbase is for the woods and farm.

I could get very interested in a diesel dune buggy or sand rail, though:



This one looks VW bug power and suspension. These are pretty common out west for Baja trips. They're very light and easier to handle than a quad. They're pretty cheap, as it goes, and simple to modify and repair.

Here's an idea of cost:http://www.miltonsandtoys.com/ and http://www.dunebuggy.com/

[Fiddler]

Geoff,

Im hoping someone else can help out here as my rusty memory fails me.
There was a guy who attended both the British and German Rally this year. He has completed some pretty big Overland trips, Russia and Mongolia if I recall correctly, on a converted Mz in Trail Bike mode with a 10hp Lombardini.
Whilst I appreciate neither the machine or terrain are identical. He may be the ideal person to give you an idea of laden performance, laden fuel economy, overheating, unforseen difficulties etc.
If anyone can remember the chaps name and whether or not he hangs out on the German forum, or even better has contact details, it would be an ideal place to start.

Cheers, Mark

[TimppaX]

I wouldn´t suggest having trailer connected bike to Sahara. It tends to dig it´s own hole quite easy. I´d prefer 4x4 ATV instead with extrawide wheels.

I once towed cannon with my soon to be dieselDnepr, yet with original powerplant, and surface was about 5cm/2" deep soft sand. Underneath it there is ex tenniscourts. As long I drowe straight all was OK but turning caused bike to stall.



As picture shows rearwheel had problems with friction.

Cannon weights about 50-75kg.

[andrewaust]

Hey Traildraggin


Yeah them OME products are good stuff. I have a set of OME shocks on the 4WD too along with ARB products. I worked at a 4WD specialist center as a Mechanic many years ago and got a chance to test some of the products they produced. I was also told OME nitrocharger shocks are made by Monroe but SSSHHHHHHH!!!!!! mums the word ................. lol.

For those wondering what we're on about !!!



TimppaX, great piccie - how id love to haul something like that through the main street. I was also looking at the Dnepr clone "Chang Jiang" for a project, but to much red tape to jump through at the moment.

[taildraggin]

Didn't know it was Monroe; probably made in Michigan . I put 70,000 miles on them (113,000km) and they were still good as new. They, and the springs, are very well tuned to the rig. ARB makes a good difflock that is very popular here.

Wouldn't mind taking the heep around Oz, either - but she is a fuel hog.

Timppax - Looks like a Win '92 or '94 up against the rig. Varmint problem?

[arnaud]

responding to your title, my chinese 418 yanmar clone did almost 30 k. and still running fine.
Keep away from the cheapest ones and change oil according to specs(often).
the quality looks reasonable and far better than some of the chang jinag motorcycles i've seen.
But, also with these bikes they say there are better versions around.

[Diesel Dave]

I'm going to throw a bit of a spanner in the works here.

The old BSA M20 was used extensivly and it desert heat and would only make about 5hp at these temperatures.

I'm a bit biased but I would choose an old Lombardini 6LD series motor with a 4 speeder.

Stop laughing, and I'll tell you why.

1) You can remove the head without even moving the tank.
2) It can be kick started relatively easily (18:1 compression)
3) It's unfussy about fuel - even used sump oil works.
4) The regulator controls are accessable on the front of the motor and don't have exposed springs.
5) You can change the big ends by removing the sump with the motor in situ.
6) You can remove the crank with the motor in situ.
7) The injector line is safely tucked away behind the motor.
You have space to fit a huge air cleaner - I'd choose a massive Land Rover one.

On a more serious note, tyre choice will be key, I have managed to fit a 3.50 front and 4.00 rear on the std rims if you add an extra link to the chain.

You will want to reduce the gearing, this is a lucky coincidence as this means you will need the machined brake drum that takes seperate sprockets - carry a spare then!

21 litre tanks are available though.

Dave

[TimppaX]

Timppax - Looks like a Win '92 or '94 up against the rig. Varmint problem?

Jup -94. Cheyenne karbin .44-40- drag to use - Borrowed it for that shot

My -75 musket in .45LC is far more better tool Left it @ home.

There is also Winchester -97 pump action shotgun + two Remingtons (-58&-75)

Just for sake of peacekeeping

[taildraggin]

I like just about anything Browning designed.

[arnaud]

I'm going to throw a bit of a spanner in the works here.

The old BSA M20 was used extensivly and it desert heat and would only make about 5hp at these temperatures.

I'm a bit biased but I would choose an old Lombardini 6LD series motor with a 4 speeder.

Stop laughing, and I'll tell you why.

1) You can remove the head without even moving the tank.
2) It can be kick started relatively easily (18:1 compression)
3) It's unfussy about fuel - even used sump oil works.
4) The regulator controls are accessable on the front of the motor and don't have exposed springs.
5) You can change the big ends by removing the sump with the motor in situ.
6) You can remove the crank with the motor in situ.
7) The injector line is safely tucked away behind the motor.
You have space to fit a huge air cleaner - I'd choose a massive Land Rover one.

On a more serious note, tyre choice will be key, I have managed to fit a 3.50 front and 4.00 rear on the std rims if you add an extra link to the chain.

You will want to reduce the gearing, this is a lucky coincidence as this means you will need the machined brake drum that takes seperate sprockets - carry a spare then!

21 litre tanks are available though.

Dave

Most of these points are also in favour of the china 1 cylinder.
Exept the feul line which goes partly at the drive side. But i would not know how that's going to be in danger of damage..