Need Help! excessive fuel/oil leak!!

First time poster, long time fan of the Maxims.

I'm rebuilding an 81 XJ650 Maxim and can't seem to figure out the leaking issue. I've heard many possible causes yet it's still leaking...bad.

I've taken apart the lower portion of carb bowls 3 times now, and replaced needles, floats, etc. When I try to turn over the bike, it runs for a few seconds, stops, then fluid starts spewing through the breather tube and into the airbox. Could it be blow by? Petcock doesn't leak. I can't have the bike running long enough for the rings to warm up. Would Seafoam be another solution? Am I missing worn needles? Something in the upper portion of the carbs I need to take a look at?

I'm so itchin to get on the road that it kills me each time I can't get it to turn over.

 

Order of things to check

1. Is the oil full of gas? remove the fill cap and smell. Smell gas? if so chagne oil and filter.
2. float levels - clear tube method. You may have perfectly good needles and misadjusted floats that cause it to allow fuel by.
3. compression - if it's pumping something out the breather tube the crank case if way overfull and/or you're getting far too much pressure in there.

Also add your location to your profile and bike to your signature. Someone may be just up the street to help you out.

 

You have a float issue of some sort; most likely the crankcase is overfilled with a gas/oil mixture at this point and that's why it keeps pumping out the breather.

It would be best to drain the oil, replace with the proper amount and monitor the situation closely. You may have already fixed the problem that the motor is full of the results of.

If it keeps happening, then you still have a float valve that isn't doing its job. Did you check the float levels using the clear tube method as recommended above?

 

Thanks guys, I'm suiting up as we speak to yank out the carbs again. I hope it's just the float levels and not anything serious. I'll update my progress.

 

I agree, it sounds like float issues, easy fix. Have you re-built the carbs? That might not be a bad idea also.

 

Polish the Inside Diameters of those New Float Seats.

Eyeball how the Float Needle "Hangs" over the seat. If the Pin looks a bit off-kilter, ... flip the Wire over to the other side or make a correction so that the Pin is lined-up true.

Test the Floats and Set the Float Heights by using the Clear Hose Method and checking the Height of each Float for being within Specs

Specs:
GREEN ~ YELLOW = OK
RED -- ReSet
<><><><><><><><>

 

Okay, took the carbs out, inspected height, floats, and seat, all seem okay. I then noticed the smaller secondary jet (pilot?) had crud all over it. Appeared clogged again! Man, my previous tank must have been dirty. Could that be why I had fuel/oil spitting everywhere?

 

Okay, I think that was the issue, no more leaks (for now).

Question, when I drained the oil via drain plug, and filter, I let it sit. Afterwards, I placed a stick into the crank and it still had a considerable amount of oil (half an inch), is this normal? I don't want to have tainted oil locking up my engine.

 

The clogged jet was probably not why it was leaking.

As for the oil left, I've never measured but I'm sure some would stay. I would fill it with oil (to the proper level), run it to warm it up then drop that oil and filter as well. Also, did you drain it on the center stand?

And if you ever need a hand with it let me know. I'm up in Baltimore.

 

"seem okay." Did you CHECK the float heights using gas and a clear tube, as shown in Rick's colorful diagram?

You CANNOT TELL if the float heights are OK by simply looking at them.

If you didn't check them as recommended it could still be your problem.

You are "shortcutting" (or at least trying to) and it won't get fixed that way. Honest.

 

Okay, allow me to reiterate, I did not "shortcut" I took the carb apart, measured using a ruler and while at a 90 degree angle measured the distance from the top of the float to where the bowl meets the carb (around 14mm) I measured the level (took me a while to find a tube) and it was leveled to the screw bolt. I merely wanted to indicate that there must have been a lot of residue from the previous tank in which I dropped a little bit of seafoam in it and re-clogged the jets. In doing so I removed the floats, needles and cleaned the seat. I did notice that although everything was clean that the pin that holds the float on #4 was bent (replaced). Other than that, I just cleaned the jets again. Thanks guys for the assist.

This site rocks!

 

Install ... an ... Inline ... FILTER!

If you have any suspicion that there is a possible contaminant in the Gas Tank; put-on an Inline Filter to PREVENT the debris from getting down to the Carbs.

The few dollars you spend to buy and install a Filter will save you hours of having to pull the Carbs and reclean those Pilot Jets.

FRAM makes a Miniature "Generic" Inline Filter that just a couple of bucks.
It's clear and uses a paper element.
Stops the smallest particulate and is easily checked with just a glance.