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-   -   How to desert-prep a scooter? (http://www.horizonsunlimited.com/hubb/other-bikes-tech/how-to-desert-prep-scooter-54534)

henryuk 30 Dec 2010 14:03

How to desert-prep a scooter?
 
Dear HUBBers,

I have been accepted on the 2012 Budapest to Bamako rally on an ex pizza delivery moped:scooter:, racing alongside the usual assortment of GSAs, XTs and KTMs.

I am guessing that I will have to make up the prep as I go but on the off-chance that someone here has raced a scooter in deep sand are there any pointers?

A frontal lobotomy has already been suggested!

farqhuar 30 Dec 2010 23:58

Henry, I offroad a Suzuki Burgman (650) and have taken it through most major Australian deserts (and a few non-Australian ones in Kazakhstan/Russia/Mongolia).

I do NO major preparations whatsoever - I don't even let air out of my tyres.

The biggest challenge is having the small front wheel dig in in deeper sand, so you will often prefer to ride slower - this where you have an advantage, however, as you can ride slowly without needing to worry about a lot of fancy clutch work,

Many of the dirt bike riders would often prefer to go slow in these conditions too, but find they can't because the engine will die at low revs (without a lot of clutching/declutching) so they have to go faster to maintain momentum.

When I rode the Sahara I found that the dunes had a hard and soft side, provide you get enough speed up on the hard side you will maintain sufficient momentum to cross the soft side of the undulation before sinking too deep (most of the time anyway :smartass:).

henryuk 31 Dec 2010 09:06

Great info, thanks a lot!

'Riding Slower' wont be a problem, the stock bikes we are getting wouldn't go past 30 mph/45 kph on flat tarmac anyway. we are going to derestrict, swap the barrels out and get them up to decent speed for the european stage (day one is over 1000kms) then gear them back down for the desert stages.

Hopefully I will have the bikes back on the road in time for Ripley!

KTMmartin 31 Dec 2010 11:44

I would strongly suggest new clutch plates and plenty of adjustment allowance in the mechanism. I took a 125cc on the mongol rally and damn near ate the clutch because it didn't have enough power to free itself from sand without slipping. If your scoot is an auto then check whatever mech it has.

henryuk 31 Dec 2010 11:58

Cheers Martin

the exact bikes haven't been sourced yet, it's kind of out of our hands. They might be CVT in which case springs, bearings and belts are going to be needed by the bucket full, or they might be semi-autos in which case plates and springs aplenty I reckon!

Did you go through the Turkmen desert on the Mongol, I love that place!

Nath 1 Jan 2011 11:27

Obviously the correct tecnique for riding in deep and soft sand is to accelerate through it. Riding below 30kph is a recipe for wobbly disaster. This should pose a bit a problem for a low powered slow bike.

If you are genuinely expecting to encounter soft and deep sand you should definately fit a rimlock on your rear wheel. A front rimlock probably wouldn't serve any purpose though. You can buy them for about a fiver, and fitting requires only drilling a hole in your rim. You will then comfortably be able to ride with tyre pressures as low as 5psi without the chance of your valve stem being ripped out the tube. An added bonus is if you get a puncture somewhere a bit hairy, you can continue riding on the flat and the tyre will stay on the rim, and if you're lucky the tube could survive as well.

Are you taking something like a c90 clone with big wheels? Here in London most food delivery bikes are Honda 'Innova 125's.

Quote:

Originally Posted by farqhuar (Post 317455)
this where you have an advantage, however, as you can ride slowly without needing to worry about a lot of fancy clutch work,

Many of the dirt bike riders would often prefer to go slow in these conditions too, but find they can't because the engine will die at low revs (without a lot of clutching/declutching) so they have to go faster to maintain momentum

What a strange thing to say.

henryuk 1 Jan 2011 12:11

Nath,

The honda would be my preferred choice but we'lll take whatever we can.....

I was going to do the budget rim lock option, i.e. some cheap self-tappers, they work pretty well!

From what I remember from riding on sand I reckon I want ro try and keep it above about 50 kph which might be a problem if we end up on 50s!

KTMmartin 1 Jan 2011 17:35

Actually what may be a solution is one of those pedal/engine Peugeot bikes as seen in morocco. No top speed but amazing on the sand due to lightness. Couldn't lose a beduin kid on a piste, very embarrassing!

henryuk 20 Jan 2011 15:35

We have now decided on the mods we are going to make to the bikes (assuming we get the Honda Innovas)....

1) Knobbly tires
2) Budget Rim locks (short self-tapping screws)

That's about it. Hopefully I will have one ready for Ripley!

IainHarper 20 Jan 2011 15:59

Presentation in the making?
 
Hi Henry,

Does that mean you might be able to do a presentation at Ripley about your plans?

Iain.

Joe C90 20 Jan 2011 23:54

honda cub 90 is the way to do it!
they are pretty indestructable, and will go forever if you keep the oil topped up.

henryuk 21 Jan 2011 09:21

Iain - I certainly could do a presentation if required/desired.....

Joe - unfortunately there aren't any ex-delivery C90s coming onto the market - hence the hunt for an Innova (essentially they are the replacement for the C90 and have the same design ethos - big spoked wheels, light but solid backbone and small but indestructible engine.

Nath 22 Jan 2011 11:37

Quote:

Originally Posted by henryuk (Post 320462)
2) Budget Rim locks (short self-tapping screws)

Well I guess the only way to know is to try it out, but I'm pretty skeptical of this idea. I know Chris Scott always goes on about it, but can't remember how much he reckons he's used it. What happens when you get a puncture? If you try to ride on it the tyre will obviously come off its seating on the rim and pull away from the screws, but then there is the risk the inner tube will get caught on the screws as the tube and tyre flap around, and be irrepairably ripped.

Honda innova seems like the best bet to me. C90s are way overpriced whenever I've looked. Think about cheapo chinese trials pattern tyres. Used them successfully on cg125s. CG rims are meant to take 300 on the rear but I think I used 410 on mine without trouble. Those cheap trials tyres are way narrower than you'd expect. // Tyres & Tubes - Got mine here, rear 410 cost around £15 a couple of years ago but you do need a trade account (you can buy their stuff from smaller bike shops, but obviously they mark-up the price)

henryuk 22 Jan 2011 12:25

Cheers Nath,

Just saw your blog (someone tweeted it) - gutted I never made it to the Pamirs - visa prob in UZ meant my TJK visa had expired....

Time will tell with the rim locks, we'll be testing them with low pressure tyres on redcar beach. We're going to have to take quite a few spare wheels anyway, I can easily imagine them collapsing from rock abuse.

Joe C90 23 Jan 2011 00:21

TBH I think you are going up a blind alley with lowering the tyre pressures. The main effect is to lengthen the tyre foot print, this isn't going to make a huge difference on a relatively long foot print anyway. The rubber will dig in anyway. best thing is to use a trials type tyre, not a knobbly, they will just dig holes. 3.00 17 catspaw tyres work really well in just about any concieveable conditions. vee rubber make them.
The big disadvantage is that any stoney surface will immediately rip the innertube to shreds when it pinches on the rim. We race offroad with 40psi in them to prevent this.


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