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Discussion Starter #1
Ok, so I want for a ride today with my 98 gpz500s. Ran good for about 20Km when I stopped for gas. On the way home I pushed it a litte, 140-150 Km/h and then it wont rev up. I give it full gas and it wont rev and chokes, like when I run out of gas. If I hold the gas, it barely makes it to around 8k rev and then it pulls like it should. I had this problem before but about 1k Km ago but I don't know how I fixed. I took the air box of and cleaned it from oil residue, looked at the carbs but I didn't stripped them because I don't know how to work on them and left them alone. Put everything back together and it fixed itself.

Now while medidating over what could be the problem, I blew in the hose that connects to the "T" that links the carburatos and ends somewhere near the battery . It was plugged at first and I kept bowing ari till it unclogged and fuel leaked under the bike trough the hose at the bottom of the air box. I figured out that emptyed the carbs of fuel and I tryed to start the bike after. Took a few seconds of cranking then it fierd up. I didn't had time to test it on the road to see if it fixed the problem but could that be the problem? if not, what else? It's the second time that happend and I don't know what coud cause this.
 

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So you had something that clogged your vent hose and you blew it back into carbs? It could've been some sort of trash, bugs, mould or fungus. I recommend complete tear-down and disassembly of carbs down to last nut and bolt for thorough scrubbing and cleaning. Otherwise this problem with occur over and over again until true problem is resolved. For example, whatever crud you blew back into carbs will clog things up again and again until it is actually removed. Not blown back into carbs, which is just covering up symptoms.

Your carb passages are most likely clogged with dried petrol varnish as well. It's similar to plastic and nothing can dissolve it, especially not modern day spray "cleaners" that no longer have chlorinated compounds. Pressurising vent-hose temporarily increased float-bowl pressure and forced some petrol past clogged passages, but that's only temporary and bike will die after 5-10 sec. Need to fix actual problem.

Airbox drain doesn't connect to carbs in any way. There is crankcase vent that connects to airbox. If you've got petrol coming out of airbox drain, then there's petrol in your crankcase. Not good for lubrication...
 

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Discussion Starter #3 (Edited)
Yea, I think I fked up when I blew and un clogged the vent hose in carburstors. But why gas came out at the same time I did this trough aibox hose? It never dropped a single drop of fuel or oil trough there before. And bike never sat unused more than 3-4 days for gas to dry in the carburstors. I used it all year constantly. Plus I did an oil change about 200km ago

Plus the bike idles fine at about 1400rpm for as long at I let it
 

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throw that damend hose away, as you can see it does nothing unless your bike is upside down the cars must be open to atmospheric pressure or the float levels won't be correct.

FOG
 

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What FOG said.... While I haven't had the carb vent hose on my EX plug up yet, mud dauber wasps decided to move into the water tank vent on my camper. Raised hell with the system before I finally figured out what was going on.
 

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Discussion Starter #6
I run the bike today, pulled like a beast! I guess that vent hose was plugged. I didn't take the reservor down to take the hose out but I will do next time and maybe take the carbs to a full clean-up. One more qustion: how do you prepare the chain for winter? I cleaned it well and leave it like that. I need to lubricate it or treat it with something? I keep the bike in a garage so no moisture to corode it
 

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Discussion Starter #7
throw that damend hose away, as you can see it does nothing unless your bike is upside down the cars must be open to atmospheric pressure or the float levels won't be correct.

FOG
I did some work on the bike today and removed the hose between the carbs. Should I cover the hole with somethig like a sieve to keep dirt from going in? I'm guessing I can't just plug it, right?
 
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