gk73a air box question

[DirtMcGirt]

I am a newbie mechanic, also to riding. I was able to purchase a gk73a model bike which I am trying to fix up a bit. When I purchased the bike two of the carb diaphragm caps were cracked and I believed leaking fuel into the air box. I realize the carbs are in pretty bad shape and boggy around 2nd to 3rd gear. I completely removed the airbox and I would like to put pod filters on each carb. Question - where does the hose go that was running to the top of the airbox? it seems to spew quite a bit of fuel? Do I put a cap on it or what?

[cdegk73a]

Maybe this will help a little.. Pretty sure these are right. The carb overflow and airbox overflow pipe just vent to atmosphere.. they just tuck down the back of the air box.. and exit at the bottom of the bike.

[DirtMcGirt]

thanks so much that helps out a lot. I seem to be missing a lot!
My airbox has no hoses or anything in it, just the plastic box

Here is a picture of my setup. Is it possible for you to tell me where I should direct the hose I have circled? and also what I should do with the female nipple I have circled also?

Thank you so much for your help!

[cdegk73a]

Ok, the pipe from the top of the cam cover is an engine breather (Labeled breather in my pic) and used to connect to the top of the airbox so the vented gases were re-burnt by the engine. The other one from the top row of the carbs is the overflow (labeled overflow/breather) and that used to come over the top of the air box and vent to atmosphere out the bottom of the bike...

[DirtMcGirt]

!! thanks!
I really do appreciated your help, i wish i could buy you a beer or something! So since i will not be running the airbox, those can just be left as is?

[cdegk73a]

Yeh, the fuel overflow is fine to leave as is.. and vent out the bottom. The engine breather might chuff some smoke out while running.. especially at high revs.. you may have to add a little catch tank/can to trap the oil/smoke vapour.. that comes out over time. Some people add a very small air filter etc..

[cdegk73a]

I just sent you a pm, but it's stuck in my outbox.. Don't know if that's normal, so ill post it here too..

If your just changing the oil it's 2.3 litres, oil and filter is 2.8 litres, and if the engines been apart and is completely dry it's 3.2 litres. Luckily there is an inspection eye glass on the lower right side of the engine so you can visually see how much oil is in. Just make sure the bike is upright and not been run when you check the level. The filters are available on ebay for only a few pounds.. think i paid 4 or 5 pounds for the last one. As for running problems, unfortunately the gsxr 400 has quite a reputation for poor running, and is mainly down to the carbs. Inspect the diaphragms for splits and make sure they seal properly on the carb tops. Check to see if the main needles ( the long ones attached to the black slides) are not notched or worn in any way... Mine were and it made it run really bad.. I managed to replace mine. And then unless they have been changed, you will need a new set of o rings as well.. Variablevalves on this forum sells kits for the 73a. These are the crucial steps to getting the carburation anywhere near right on these bikes.. Another thing to think about is that without the air box it will run differently too. And finally strip and clean the carbs to remove any crap and varnish... Good luck.

UPDATE. Here is a link to the oil filter you need. http://www.ebay.co.uk/itm/290705995078

[jamesgoodfella]

Very glad I've stumbled on this thread, I didn't know what lines went where! Cheers!

[pobrika]

I'm currently going through the dagger process, thought I'd attach the images of what I know for the next person.

[pobrika]

I'm currently going through the same process, thought I'd attach the images of what I know for the next person.