Holy grail of gearing a DR-Z 400E (Australian Spec)

Found lots of comments on re-gearing but just not exactly ….so here goes….

Here in South Africa we are blessed with long hard pack gravel roads, that in an instant turn into sand tracks and dunes; and before you know it into rocky tight paths with steep inclines. SO here is yet another gearing dilemma.

My DR-Z 400E has standard 14/47 gearing, and running a 120/90 x 18” tyre – as we regularly do long stretches at 112-115km/h (70miles/hour) the bike sits out at about 7800rpm – to much screaming for my liking. I do like the power and “cool” running of the motor in thick sand and steep inclines, even though it might be in high ambient temps (30-38deg C) - making the standard gearing good in that way. I have no cooling fan (stock), as space is nonexistent behind the radiators to fit one due to Acerbis long range fuel tank.

I changed gearing to 14/44 and fitted Maxxis 120/100 x 18” rear tyre. This improves hard pack cruising at 112-115 km/h at a more respectable +/-7200rpm. A short run on a sand track (cool ambient temp) proved rather pleasing. The motor still delivers acceptable performance without excessive labour when you drop speed in the gears, but the power edge is somewhat off compared to the previous gearing.

What about overheating in the think technical stuff? Any experience out there to help on this one.

Apart from the airbox mod al is stock. Most riding is done at moderate altitudes and in stock I have not had any obvious glitches….

because the terrain is constantly changing you need to make it simple to have different gearing options . try the 15 front or 14 front leaving the rear in place .

use a quality coolant like silkolene , my advice is to modify your motor to produce a greater level of torque to cover the changing conditions .

for example my motor has a high level of torque ,,, i rev no higher than 8500 rpm with 15 ~41 gearing ,,, all dirt use .

You should be ok, up until the point when things get sticky or steep for longer periods. I have come to prefer a 15/47 ratio over the very similar 14/44 for extended work at speeds up to 120km/hr.

Thanx for good advice gents – I just had to test the gearing (14/44) in to work this morning (with a slight detour), which included 8clicks on tar (115km/h), 5 clicks on hard pack gravel (good for 90km/h), and 8km on a servitude with a thick sandy track with whoops and some really loose bits – no steep inclines – this will have to wait for my dune ride. I sustained a comfortable 40km/h in the sand (faster makes my self preservation part of the brain kick in in this bushy terrain). As the tyres were a bit hard I needed to work a bit harder, but the bike kept it’s cool. It was however only about 22DegC outside, so rather comfortable.

I cannot find Silkolene in SA, but used CASTROL SF (Nitrate and Silicate free), 50:50mix as coolant. As our hot weather sets in I will see how things go.

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