GS425 E - Need Help

[JonathanHassler]

Hey chaps,

Recently bought a 79 gs425. Since buying I have stripped it down to the frame and been cleaning/replacing everything that needs it. Today i took off the carbs and cleaned them. Internally they looked pretty good, no leaks and it looks as though the previous owner replaced all the gaskets. Once I cleaned the carbs I put them back on the bike. Here is where the trouble ensues. I recently put pod filters on the bike, and it already had cut off exhaust. I know this means it needs to be jetted accordingly but I wanted to see if I could improve the bikes idle. Origionally it was sitting around 800 rpm, however, after cleaning the carbs and assembling them onto the bike again I started the bike (with the choke on) and it screemed all the way up to 5000 rpm. I switched the choke off and the bike just dies. Any help would be really appreciated. Im pretty sure I need to adjust my throttle cables as they are clearly leaving the butterflies on the carbs open even in closed throttle. But If anyone has some tips or suggestions I could try I would appreciate it. Thanks!

[pete]

Hi mate, welcome!

Two stand out things in my mind will make it idle high... one is intake or vacuum leaks between the carbs and the cylinder head due to old/hard intake boots and the O rings that sit underneath to seal them.

The other is a lean condition, which is quite possible given you're running pods.

Of course you could have both which means fixing one may not resolve the issue completely...

How well did you clean your carbs as well? Typically they'll need a good dip overnight in some good carb cleaner to make sure all passages are clear. You should be able to get all new O rings from www.cycleorings.com as well if you haven't done that already.

If the O rings are shot in the mixture screws, that can let air in there and again lead to a lean mixture at idle.

Also, post a g'day thread over in the GS Owners section so BassCliff can give you your mega welcome, plenty of helpful stuff on his site

[ender22]

Dying when the choke is off sounds like it's lean.

My K&N pods had a range comparison for CFM of Pods vs a stock airbox. Pods were 843 CFM and the stock airbox was around 520 CFM. This is means that there is 1.6 times more air flow than stock. This airflow means there's up to 40% less vacuum in the carbs. So your carbs may be up to 40% lean.

Order those o-rings, and the hex screws for the bowls and the tops of the carbs. Start with the pilot system if you want to fix the idle. Pilot fuel screws out 1/2 turn and pilot jets up 1 size. Note this is just a starting point.

[JonathanHassler]

Thanks chaps,

I'll start with the O'rings, and the pilot screws. I adjusted the throttle and got the bike to sit around 1200 rpm at idle but with the choke on. With the choke disengaged the motor just falls off and dies. I checked the plugs and it is running lean. So I'll order some new jets right away. Again, thanks a lot. I knew this place was the best community to address and ask questions.