I'm rich, really really rich...

Message

peterman · #1 Unread post by **peterman** » Fri Oct 21, 2005 8:05 am

I am thinking that it could be the float level in the carb but don't really know for sure.

After putting in new spark plugs it fired right up and even idled great for a while but eventually started to bog down and eventually die. After pulling the plugs they were filthy black.

So I figure its the floats or some other portion of the carburetor I didn't clean well enough.

Any idea where I should start?

#2 Unread post by **9000white** » Fri Oct 21, 2005 3:20 pm

what kind of bike is it???????????????????????????????????????????????

beerbaron · #3 Unread post by **beerbaron** » Fri Oct 21, 2005 5:41 pm

Running rich is probably related to the carbs. Unless of course your bike is a fuel injection.

Are all spark plug carbonised?

BeerBaron

peterman · #4 Unread post by **peterman** » Fri Oct 21, 2005 7:13 pm

oh my mistake, its a 1982 yamaha maxim 400. I'm not sure what it means when you say "carbonized" but the plugs get black quick.

I took the carbs apart tonight and here are two things I noticed. The first is a small hole in one of the rubber diaphrams. The other is a screw (I don't know which one, yet) was very loose and I suspect it has to do with the mixture. The screw is right next to the throttle body.

Off to search the internet as to what my discoveries mean when it comes to my rich mixture.

nitrus · #5 Unread post by **nitrus** » Fri Oct 21, 2005 8:25 pm

If the screw you are talking about is on the engine side of the carburetor its a fuel screw.. if its on the airbox side, its an air screw.. sounds to me like it's a fuel screw though since you said it was really loose.. that would make since with your rich condition.. You'll need to find the setting of that screw.. or, just turn it in untill it lightly seats, then back it out 1- 1 3/4 turns or so.. and just listen to the bike.. it should idle, rev to 5k rpm, and then fall back to idle with no hesitations.

also, CV carbs right? if so, a hole in the rubber diaphragm will affect the slide lift.. I know there is a thread somewhere on this board on how to fix those with glue? ..

*fix the rubber diaphragm before setting your screw.

I hope this helps.
-Ryan

peterman · #6 Unread post by **peterman** » Fri Oct 21, 2005 8:54 pm

Thanks Ryan,

I was just out there looking at it again. It turns out the screw I thought was the pilot air jet was actually just to keep the throttle plates from going past parallel. I was thinking the exact same thing you did that it was causing me to be rich but I am no so sure now. I didn't see any other screw on the outside of the carb that would adjust fuel or air. Or I just don't know where to look.

I also noticed that the slide lift (piston looking thing) on the side with a hole in the diaphram was stuck in the down position. I got that all cleaned up and it slides well now. I was thinking silicone to fill the tiny hole but will gas disolve that?

What's a CV carb? (central vacuum?)

nitrus · #7 Unread post by **nitrus** » Fri Oct 21, 2005 10:49 pm

Peterman,

CV = Constant Velocity carburetor.

a pressure difference causes the slide to lift as you increase throttle.

There should be some sort of air/fuel mixture screw somewhere on
your carb, i'm not sure where though since i'm not familiar with that particular model.

Here is a link for the diaphragm repair..
viewtopic.php?t=5858
-Ryan

peterman · #8 Unread post by **peterman** » Mon Oct 24, 2005 7:07 am

Thanks Ryan, I got the glue and put it all back together. Although I don't think I found air/fuel mixture screw it seems to be running A LOT better. I will run it a little more and then check the plugs again. Thanks for the help and the link.

Peter