signal generators... rectifiers... needle valves

[AnOleGS4me]

ok... first question... could a needle valve be leaking and still show up as normal via the float hight check test?  My left cylinder keeps getting fouled cause of rich mixture and i'm out of ideas... i replaced the coils, rebuilt the carbs... sync'ed the carbs... replaced all o-rings, etc...

Part 2:  Could a partially... or dying signal generator cause this (p.s. if so... i need a used one)
Part 3:  What does a rectifier do?  (the think on the clutch side with fins on it)

[3imo]

The rectifier takes an AC input and "rectifies" it to a steady DC output. 

[3imo]

I had this problem but it was my coils. 

I know how frustrating it can be.   does the bike run ok... sometimes?  or are you not able to ride at all?

some people have mentioned a ground being loose.  but I don't know too much about it.

[scratch]

I can only answer the first part - No.  Conjecturing that there might be a hole in the vacuum diaphragm of the frame mounted petcock, allowing fuel past, down the vacuum tube, might be possible, and is easily checked by pulling the vacuum hose off the carb and setting the switch to PRIme.

The only other thing I can think of is the float height is set too high, and the fuel is overflowing into the cylinder, which would give you a false 'level' reading, but the reading would be higher than the floatbowl gasket.

You already checked a leaking choke plunger, the mixture screw is not broken or missing, one of the other jets is not missing, the floats don't have a hole in them.

[MarkusN]

Could it be oil from bad valve shaft seals that's fouling your plug?

And, yes, I think a foulty ignition might also cause this

[Wrecent_Wryder]

3e

[KYGS500E]

hey guys... i'm pretty sure its not oil fouling the plugs... they're brand new valves in the bike... i do not have a petcock... the previous owner removed it and connected the two places on teh tank with a "Y" connection... the drain has nothing attatched to it and the main fuel line dumps into the bottom of the carbs

[Egaeus]

I'm going to pose this as a question, because I haven't tried it (and don't need to), but it seems like it should work...

Wouldn't it be possible to set the petcock on "on", drain the carb bowl into, say, a drinking glass, leave the drain tube in place, the valve open and tube in the glass, mark the level, and come back in a few minutes to see if the level has changed? How could this NOT detect a leaking needle valve?

Because when the carb bowl is empty, the floats would go down and open the float valve (not needle valve) and eventually empty your fuel tank into the glass.

[sledge]

I'm going to pose this as a question, because I haven't tried it (and don't need to), but it seems like it should work...

Wouldn't it be possible to set the petcock on "on", drain the carb bowl into, say, a drinking glass, leave the drain tube in place, the valve open and tube in the glass, mark the level, and come back in a few minutes to see if the level has changed? How could this NOT detect a leaking needle valve?

Because when the carb bowl is empty, the floats would go down and open the float valve (not needle valve) and eventually empty your fuel tank into the glass.


It would depend if the fuel drained out of the bowl faster than it went into the bowl, which in this case I think it would.

[Egaeus]

It would depend if the fuel drained out of the bowl faster than it went into the bowl, which in this case I think it would.

It would still drain.  It might drain, slow, drain, slow... but it eventually would all go into the glass.  Well, that is, if you have a really big glass.

[Wrecent_Wryder]

4d

[sledge]

I know a simple way to check float hight and valve operation if its any help. Fix a piece of clear tube to the drain point and bring it verticaly up to the level of the carb in a U shape. The level of fuel in the tube will indicate the level of fuel in the bowl, in effect its a simple Manometer. If the valve is not sealing for whatever reason the level will rise above the bowl.

[Egaeus]

You're right. Don't know what I was thinking yesterday.

I've done worse, believe me.

[KYGS500E]

thanx sledge... already done that... matter of fact its a faq here...

I'm going to post this on a new thread.... but just in case...

I replaced the coils and cdi box... this helped some...

here's the test I did next... i put two new spark plugs in

Pulled out the left plug and wire (letting fuel/air out of cylinder into atmosphere.... this was the plug that was fouling) and the bike ran steady on just the right plug/cylinder

When I switched and took out the right plug and wire (the good cylinder) it ran terribly and would die if I didn't give it gas

If I have new coils and cdi... would this point to a signal generator?  a ground?  the rectifier?

[Egaeus]

thanx sledge... already done that... matter of fact its a faq here...

I'm going to post this on a new thread.... but just in case...

I replaced the coils and cdi box... this helped some...

here's the test I did next... i put two new spark plugs in

Pulled out the left plug and wire (letting fuel/air out of cylinder into atmosphere.... this was the plug that was fouling) and the bike ran steady on just the right plug/cylinder

When I switched and took out the right plug and wire (the good cylinder) it ran terribly and would die if I didn't give it gas

If I have new coils and cdi... would this point to a signal generator?  a ground?  the rectifier?

Can you get it to run decent on the left cylinder if you adjust the idle screw?  If so, it could just be a carb balance issue. 

[KYGS500E]

hmmmm..... its possible... i'll try it today

[LimaXray]

the rectifier converts the AC from the generator into a DC that can be used by the bike... if this was bad, you would either have electrical problems across the board or it would run fine off the battery until it died

I don't know what a signal generator is other than the thing that sits on my workbench that I use for testing various circuits 

It's probably not a ground either because it sounds like you have one cylinder running strong

I would check all the electrical connections.  It's often over looked, and even the slightest damage or corrosion can cause an ignition system to opperate irregularly. 

It could also be one of the hall sensors is bad.  Try switching them and see if that does anything.

[KYGS500E]

what is a hall sensor?

[LimaXray]

well im guessing the're hall sensors... the 2 little sensors that trigger the ignition

[LimaXray]

they're inside the cover on the right side... hmmm... now I'm curious if they are hall sensors, I can't tell from the ignition advancer pics... I'm tempted to go pull mine apart and look