89 Exciter carbs

[ljnicolai]

Hey everyone, I am working on an 89 exciter I just kind of inherited (It has had some jerry rigging done on it.). I cleaned the carbs and new metal tip needles and seats. But I can not get it to run good. It is getting way to much fuel. The float level is set right. The only way it runs good is if I turn the gas off. Once I turn it off in about 15 seconds it will run awesome for about a minute till it runs out of gas. I am a Polaris guy so this thing is pretty foreign to me. Not knowing its history I am looking for information on the old power jet update to see if any or all of it is done. It does have the BBs in the hose. I am wondering if there is a vent hose or something hooked up wrong? I know this is kind of vague so please ask questions if you have them.

 

[Maim]

sounding like it might have a split diaphram in the fuel pump. had one fill an engine full of gas when it did this.

 

[74Nitro]

Describe the poor running situation.
Does it idle good?
Is it just the midrange rich?
Does it rev out properly?

 

[ljnicolai]

It’s seems to start and idle ok. If I run it on a stand it seems ok sometimes. If I take it out for a ride I make it about 50’ and it just loads up horribly at that point there’s nothing but bogging and a cloud of smoke. Once in a while I can play with the throttle and maybe get it out of it for a couple minutes. It’s just like the choke is on. If I turn the gas off if I can keep it running a minute she clears up and goes great till it runs out of gas(or just flip the gas on for a second). I have the choke plungers adjusted all the way down or in however you see it. I have not checked the plunger itself to self to see if they are hanging up. I keep going back to wondering if there is a vent line hooked up wrong. I have a service manual for it but it doesn’t say much about the vent lines. But that’s where I’m wondering what that power jet update/bypass consisted of. Like I said I do not know the history and this is not the normal brand I play with.

 

[74Nitro]

It’s seems to start and idle ok. If I run it on a stand it seems ok sometimes. If I take it out for a ride I make it about 50’ and it just loads up horribly at that point there’s nothing but bogging and a cloud of smoke. Once in a while I can play with the throttle and maybe get it out of it for a couple minutes. It’s just like the choke is on. If I turn the gas off if I can keep it running a minute she clears up and goes great till it runs out of gas(or just flip the gas on for a second). I have the choke plungers adjusted all the way down or in however you see it. I have not checked the plunger itself to self to see if they are hanging up. I keep going back to wondering if there is a vent line hooked up wrong. I have a service manual for it but it doesn’t say much about the vent lines. But that’s where I’m wondering what that power jet update/bypass consisted of. Like I said I do not know the history and this is not the normal brand I play with.

If it sits and idles OK, then the chokes must not be the problem.
If the power jet circuits are still functioning, be sure the jets are placed in their proper positions.
The most likely culprit is that the needle jets are badly worn at the top.
This is almost always overlooked when carbs are serviced.
#20 in the picture of attached file.
Looks like not available from Yamaha anymore, but Kimpex or other suppliers, or ebay should have brand new ones. There are identification numbers on them.

1989 Yamaha EXCITER DELUXE (ELEC START) (EX570EN) Carburetor | CyclePartsNation

Shop online for OEM Carburetor parts that fit your 1989 Yamaha EXCITER DELUXE (ELEC START) (EX570EN), search all our OEM Parts or call at 269-385-1540

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[74Nitro]

If you're not sure if the vent lines are hooked up properly, just take them off completely. All they do is direct any potential fuel spill to the bottom of the sled.
One other important thing to check is the 0-ring on the needle jet setter. #45 in the picture. It must be in good condition, or it will let fuel come by causing a rich condition. To check it, remove it from the carb and slide it into where it goes in the bowl. You should feel some resistance.

 

[ljnicolai]

If you're not sure if the vent lines are hooked up properly, just take them off completely. All they do is direct any potential fuel spill to the bottom of the sled.
One other important thing to check is the 0-ring on the needle jet setter. #45 in the picture. It must be in good condition, or it will let fuel come by causing a rich condition. To check it, remove it from the carb and slide it into where it goes in the bowl. You should feel some resistance.

Sounds good, I have new o rings coming and I have found the needle jets online but I’ll probably re-disassemble to check first. For luck they were reasonably priced. Thanks for the info. I’ll update hopefully when it’s fixed.