Fuel puking out overflow line

[SpudRider]

Thank you. It will be interesting to hear what Joe has to say regarding this topic.

[Inroads]

Meanwhile I am going to run a test...I am going to eliminate the separator,clear standpipe and air box from the system and run the crankcase tube right where it comes out of the crankcase into a breathable catch bottle then go out for a high speed run of 10-20 miles and see what if anything is in the catch bottle.

[SpudRider]

If you have time, please examine the oil separator, and take a few photographs of it. Also, please examine the hose leading to the air box. I suggest you cover the area where the hose entered the air box. This area is behind the air filter, so any dust particles which might enter it will be ingested by the cylinder.

[Inroads]

I am having a hard time believing me and detours are the only 2 guys catching fuel in the clear tube.
I wonder how many riders are watching for it because it will empty itself on its own.

[SpudRider]

I hope anyone else who is collecting fuel in the down tube will report it in this thread.

[detours]

Originally Posted by Adjuster

Sorry for the trouble your having but thats a cool picture.
/

If you like the pic, check out the video

https://drive.google.com/file/d/1ZXR...ew?usp=sharing

[SpudRider]

Originally Posted by detours

If you like the pic, check out the video

https://drive.google.com/file/d/1ZXR...ew?usp=sharing

Egads! Is that the fuel you collected from your crankcase vent collector?

[detours]

Yes, when we got back from our 4-hour ride yesterday, the catch tube was full. I dumped it all into this can and it burned like you see.

[SpudRider]

My goodness! It's not safe to be collecting that fuel near the engine. Have you had a chance to examine the oil separator?

[detours]

No, I can see how to disconnect it, but I'm not sure what to look for when I get it off.

[SpudRider]

Originally Posted by detours

No, I can see how to disconnect it, but I'm not sure what to look for when I get it off.

I haven't had mine apart, so I don't know what to look for either. I'm reluctant to take mine apart, since it is working so well.

I would look for goop which creates obstructions, holes, obvious manufacturing defects, et cetera. The hose leading to the air box should not have any holes or kinks, et cetera.

I will probably pull mine apart in the next few days.

[Lee R]

Gatling (Joe from CSC) just posted on page 47 of the advrider forum on this topic, looks like it's normal for the bike.

http://advrider.com/index.php?thread...007040/page-47

[3banger]

Mine collects fuel at the same roughly the same rate as detours. I've since drilled a small whole in the bottom of the plug as a temporary solution. I think a lot of people don't notice because the plug can be a poor seal in the tube due to molding lines on the plug and the fuel slowly drains away. I cleaned mine up with some sand paper and that's when I would notice fuel accumulation. Also after and extended high speed run near red line and I stop there will be fuel driving from the line

I still believe it's fuel vapor from the engine crank case condensing out at the separator. But I want to separate the air box fro the crank vent and test to know for sure. I need to prove to my self that under some strange flow condition it's not coming from the fuel injector back down the crank vent tube. Unlikely but I've seen stranger things in my years of engine related stuff.

I'm also considering removing all of the separator stuff and just pluming strait to the air box like every other engine I've dealt with does.

[Weldangrind]

Originally Posted by 3banger

Mine collects fuel at the same roughly the same rate as detours. I've since drilled a small whole in the bottom of the plug as a temporary solution. I think a lot of people don't notice because the plug can be a poor seal in the tube due to molding lines on the plug and the fuel slowly drains away. I cleaned mine up with some sand paper and that's when I would notice fuel accumulation. Also after and extended high speed run near red line and I stop there will be fuel driving from the line

I still believe it's fuel vapor from the engine crank case condensing out at the separator. But I want to separate the air box fro the crank vent and test to know for sure. I need to prove to my self that under some strange flow condition it's not coming from the fuel injector back down the crank vent tube. Unlikely but I've seen stranger things in my years of engine related stuff.

I'm also considering removing all of the separator stuff and just pluming strait to the air box like every other engine I've dealt with does.

3banger, you've made some very interesting comments. I'm aware that gasses from the combustion process leak past the rings and end up in the bottom end. I'm also aware that such pressure needs to be vented from the bottom end, or it will find a way out.

What hadn't occurred to me is that fuel in suspension could be condensed and collected. I now wonder how much fuel would be produced by any of the bikes I have. I always presumed there would just be pressure and a bit of oil; I never considered that fuel could be returned to a liquid state like that. This is fascinating to me.

[SpudRider]

Originally Posted by Lee R

Gatling (Joe from CSC) just posted on page 47 of the advrider forum on this topic, looks like it's normal for the bike.

http://advrider.com/index.php?thread...007040/page-47

That is not exactly what he said. He said it's normal to collect oil, water, and contaminants in the down tube. He also said the liquid collected is not fuel. However, we know the fluid collected by Detours is very combustible. Here is an exact quote.

"Although it smells a bit like gasoline, the Zongshen engineers tell us it is not fuel. It is a mix of oil and water (condensate) from the crankcase."

In effect, he said the Zongshen engineers told him the down tube is not designed to collect fuel.