I have been looking on ebay and there seems to be some good cheap gortex overpants mainly x army. Has anyone used this I think someone mention Dutch army gortex is good. I want to use them in the tropics. Cairns Australia so not to heavy. Some of the army desert gortex looked good.
Any help with ideas would be great.

They are pretty heavy for the tropics.
I have a set of the Bundeswehr ones and they are hot on a dirtbike offroad.
Surely a set of vented enduro pants would be the best thing up there?
You'll get as wet from sweat as you will stay dry from rain and river crossings.

I can speak from experience on the US goretex, both desert style and woodland, I would not want to wear those in the tropics. They will manage to keep you dry but after 4-5 hours they start to soak through. They will not breathe so prepare to turn into a miniature sauna.

I would look for something with some vents.

If you still want to give it a shot, I have a couple spare goretex suits laying around I could part with.

I brought a pair of Dutch Army Gortex trousers. I agree with the other posts that they will sweat up in the tropic. They are tailored for people walking not sitting, so they tend to ride up towards the knee on a bike. This means that rain will get in over the top of your boots. In short, they're good at what they're designed for but not a lot of use on a bike. Perhaps a pair of salopettes would work, I brought a pair from Aldi just before Christmas for £17 and they really work well and fold down quite small.

I just rode into work wearing a pair of ex British Army gore tex overtrousers. They are great, cheap keep you dry and keep all the cack of your good riding pants.

They offer weather protection but no impact/abrasion. They last a good while, I make sure they fit over other pants so that they dont ride up and I wear highish boots.

I have used similar including some ex Dutch Army salopetes and have always been happy with how versitile they are.

I am not sure I would use them in the tropics but then to have strapped to the bike as a wind/water proof layer they work just fine.

I have also used them to snowboard in etc and they work fine for that over other ski pants or thermals.

I also have some very long gore tex over mitts, these cost £5 and work great in heavy rain/cold weather to cover my gloves. again they are cheap and roll up small and stop you getting wet and cold. They replaced a pair of gore tex climbing mitts that cost more than 10 times as much and there is absolutelty no difference in quality.

As long as you don't mind the camo look ex army gear can be cheep and cheerful and lasts a good while. (be careful where you buy it some places rip you off)

A vented protective jacket and trouser combo with a gore tex jacket and trouser cover would not cost much and would provide all the protection any one would need for many different climates. just layer up underneath and you can stay warm and dry and not sweaty. Think of this a cheap alternative to a KLIM suit and you can be on route for about £200 max

My set up cost me less than £100 but I was lucky to get an airflow jacket and pants for £50 from a bike show and the gore tex jacket/trousers and mitts for less than £50 as I have a great surplus dealer just across the way.

Try RTI Military Surplus - Wholesale Army / Military Surplus these guys are cheap have a massive stock and public showroom just off the M1 at Junction 20