Well, considering its a honda I think you suspension is fine and I wouldn't be buying a $25 carburetor for it, it will currently have either a mikuni or keihen carby which are both great brands, so clean you carby out (free). Tune your carby (also free), there are tutorials on here if you need help. Theres not a lot that can be done to jap bikes without spending big bucks, my bro has the xr100 and is installing a 120cc bore in it but thats arounf $300. If you can find a bore kit for your bike that will help. Another thing is to install a exhaust system, however the only major difference is the sound it makes. Can you post some pics of it to help us get a better idea of its condition, does it blow smoke? If you don't mind loosing a bit of top end speed then you could go for a bigger rear sprocket, this will increase acceleration. Another mod worth considering is a racing cdi unit. Look into these mods and see what you think and also if anybody else here has some suggestions.
I find it hard to make jap bikes faster without the big $$$, bbr kits are very good at aftermarket parts but it will cost ya.