OK last year I replaced all the carb stuff and that's as far as I got. It's a new year and decided to have another go starting with the rusty tank. So far took tank off and tried to get the rust coloured petrol out - easier said than done! Cleaned out the diaphgram and seems to work OK but only a trickle came out so took the whole tap off (now looking for a new o-ring). Bit I'm stuck with is the gauze flter that did not come out with the tap - does it come out as it looks pretty gunked up - anyone else done this? Finally, what's the best way to clean out the tank or should I bother and just fill it up and hope for the best - it would be a shame to have to clean carbs all over again!

This may be of some use to you;
viewtopic.php?f=24&t=25775&p=185199&hil ... 300c#p1851

Thanks for the link - also managed to get the gauze filter out by pushing it back in to the tank and fishing it out of the filler hole - so far so good. Like the idea of using a bike chain to knock the rust off from inside but still not sure how far to go with the suggested rust eating chemicals and resealing the inside afterwards - is it worth it - anyone done this?

Tried the Gold Standard Tank Sealing Kit off eBay and it worked a treat - if you've got the patience to sit and rotate the tank over and over in all directions then I would recommend this. The actual tank sealing stuff is pretty good but don't forget to take everything off and plug all the holes! A wine bottle cork fits great in the fuel tap hole but the fuel cap hole is more of a problem to seal!

and the good news is the bike started this weekend for the first time in 5 years and sounds pretty good :)

Vinegar works surprisingly well, but you need to coat it with something after or it will probably start to rust again.

I used a product called Tank Kreem on my GPZ900. The de-rust solution didn't do as good a job as vinegar but the coating part seems ok. So far.

Useless trivia:
Probably safe on the NC, but the GPZ has internal breather pipes, so when I tried the "length of chain" method for loosening the heavy rust the chain got tangled around the pipes. It was the mother of all bitches to get out.

:)

Nice one.

Al.