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-   -   Hawk 250 Blow By valve question (http://www.chinariders.net/showthread.php?t=18307)

txgringo 02-22-2017 10:14 PM

Hawk 250 Blow By valve question
 
So I got a used Hawk 250 with only 250 miles on it last October. I've put about 200 on it since then. Lots of mods and updates, new chain, sprockets, Mikune carburetor, tires....
The big question I have is regarding the crankcase blow by valve. The guy I got it from had a PCV on it. (tube from the crank case to the PCV which was mounted, poorly, in the space in front of the rear tire and engine) It came loose and the chain actually rubbed a hole in it over the course of a few rides. I removed it and ran the hose from the crankcase blow by valve to what I believe is the now unused air box under the seat. I can wipe out oil that collects in that reservoir. There is a nozzle there that the original owner plugged up with silicone. I think blow by valves in older cars just spat the excess gas/oil via a tube under the vehicle. (the Mikune carburetor's air intake/filter is outside this box, behind the right side panel. It doesn't untilize that box, if that is what it is for)
The big question I have is, what was the original configuration of the blow by valve/venting? Did the original blow by valve have have a tube running out of it? Was there a filter on the end of the tube? I can order parts from a place in Dallas, TX, but I'm not even sure how to refer to it.
Thanks for any help. I've enjoyed reading the forum.

Ariel Red Hunter 02-23-2017 10:29 AM

Quote:

Originally Posted by txgringo (Post 243987)
So I got a used Hawk 250 with only 250 miles on it last October. I've put about 200 on it since then. Lots of mods and updates, new chain, sprockets, Mikune carburetor, tires....
The big question I have is regarding the crankcase blow by valve. The guy I got it from had a PCV on it. (tube from the crank case to the PCV which was mounted, poorly, in the space in front of the rear tire and engine) It came loose and the chain actually rubbed a hole in it over the course of a few rides. I removed it and ran the hose from the crankcase blow by valve to what I believe is the now unused air box under the seat. I can wipe out oil that collects in that reservoir. There is a nozzle there that the original owner plugged up with silicone. I think blow by valves in older cars just spat the excess gas/oil via a tube under the vehicle. (the Mikune carburetor's air intake/filter is outside this box, behind the right side panel. It doesn't untilize that box, if that is what it is for)
The big question I have is, what was the original configuration of the blow by valve/venting? Did the original blow by valve have have a tube running out of it? Was there a filter on the end of the tube? I can order parts from a place in Dallas, TX, but I'm not even sure how to refer to it.
Thanks for any help. I've enjoyed reading the forum.

Originally, these came from the factory with a hose running from the crank case to the air box with no filter of it's own. A lot of people had trouble with it spewing oil fog all over the paper element air filter that came with the bike. A paper air filter does not work once it gets oil on it. So, one of the reccomended fixes was to put a PCV valve in the line, and lead the end of it so that it would exhale the oil mist onto the rear chain. The PCV valve also reduced air pumping losses by keeping the crank case under a partial vacuum while running. This also makes life a little easier on the crank case seals. I think it is a good idea, but not everyone agrees with me....ARH

BlackBike 02-23-2017 12:10 PM

Quote:

Originally Posted by txgringo (Post 243987)
So I got a used Hawk 250 with only 250 miles on it last October. I've put about 200 on it since then. Lots of mods and updates, new chain, sprockets, Mikune carburetor, tires....
The big question I have is regarding the crankcase blow by valve. The guy I got it from had a PCV on it. (tube from the crank case to the PCV which was mounted, poorly, in the space in front of the rear tire and engine) It came loose and the chain actually rubbed a hole in it over the course of a few rides. I removed it and ran the hose from the crankcase blow by valve to what I believe is the now unused air box under the seat. I can wipe out oil that collects in that reservoir. There is a nozzle there that the original owner plugged up with silicone. I think blow by valves in older cars just spat the excess gas/oil via a tube under the vehicle. (the Mikune carburetor's air intake/filter is outside this box, behind the right side panel. It doesn't untilize that box, if that is what it is for)
The big question I have is, what was the original configuration of the blow by valve/venting? Did the original blow by valve have have a tube running out of it? Was there a filter on the end of the tube? I can order parts from a place in Dallas, TX, but I'm not even sure how to refer to it.
Thanks for any help. I've enjoyed reading the forum.

Doesn't rps (ricky power sports) web site have the exploded diagram parts listing for the hawk? Not sure, check it out

timcosby 02-23-2017 04:17 PM

Quote:

Originally Posted by txgringo (Post 243987)
So I got a used Hawk 250 with only 250 miles on it last October. I've put about 200 on it since then. Lots of mods and updates, new chain, sprockets, Mikune carburetor, tires....
The big question I have is regarding the crankcase blow by valve. The guy I got it from had a PCV on it. (tube from the crank case to the PCV which was mounted, poorly, in the space in front of the rear tire and engine) It came loose and the chain actually rubbed a hole in it over the course of a few rides. I removed it and ran the hose from the crankcase blow by valve to what I believe is the now unused air box under the seat. I can wipe out oil that collects in that reservoir. There is a nozzle there that the original owner plugged up with silicone. I think blow by valves in older cars just spat the excess gas/oil via a tube under the vehicle. (the Mikune carburetor's air intake/filter is outside this box, behind the right side panel. It doesn't untilize that box, if that is what it is for)
The big question I have is, what was the original configuration of the blow by valve/venting? Did the original blow by valve have have a tube running out of it? Was there a filter on the end of the tube? I can order parts from a place in Dallas, TX, but I'm not even sure how to refer to it.
Thanks for any help. I've enjoyed reading the forum.

someone posted in a "hawk mods" post a fix for this that wasnt a pvc but i cant remember who. it involved put a ss pot scubber in the triangular space where the tube entered the airbox and putting a sealled tube on the other side that collected any oil. kinda slick and thats what im going to do when i get time.

txgringo 02-23-2017 04:18 PM

1 Attachment(s)
So it looks like I could leave it as is for a while. (hose to the airbox) No need for a filter then?

I'll look at putting another PCV canister. Maybe a smaller one I can mount better than the previous one. Maybe stop by the Honda place on the way home from work.

I tried looking at the on-line manuals at the Motocheez site. I'll try the one you mentioned.

Here's a photo of the one that was on previously. Got to find a better place for it than the first guy. This was after just a couple of rides. Inspect your bike before riding!

Ariel Red Hunter 02-23-2017 04:50 PM

Quote:

Originally Posted by txgringo (Post 244079)
So it looks like I could leave it as is for a while. (hose to the airbox) No need for a filter then?

I'll look at putting another PCV canister. Maybe a smaller one I can mount better than the previous one. Maybe stop by the Honda place on the way home from work.

I tried looking at the on-line manuals at the Motocheez site. I'll try the one you mentioned.

Here's a photo of the one that was on previously. Got to find a better place for it than the first guy. This was after just a couple of rides. Inspect your bike before riding!

Most folks use an American car or truck type PCV control. Doesn't look like the one in your picture. But you do want one that plugs into the hose from the crank case, and that another hose can go on the other end.

joeboyk 02-23-2017 07:18 PM

tim i believe it was green hawk that did that i started that project but never completed it

ben2go 02-23-2017 08:40 PM

You'll need to filter the crankcase hose. It does pull vacuum and can suck up dirt and water.

timcosby 02-23-2017 09:59 PM

this was the link http://www.chinariders.net/showthread.php?t=18122

Ariel Red Hunter 02-24-2017 09:45 AM

Quote:

Originally Posted by txgringo (Post 244079)
So it looks like I could leave it as is for a while. (hose to the airbox) No need for a filter then?

I'll look at putting another PCV canister. Maybe a smaller one I can mount better than the previous one. Maybe stop by the Honda place on the way home from work.

I tried looking at the on-line manuals at the Motocheez site. I'll try the one you mentioned.

Here's a photo of the one that was on previously. Got to find a better place for it than the first guy. This was after just a couple of rides. Inspect your bike before riding!

The PCV valve works so that air leaves the crank case, but can't get back in. If you choose not to run a PCV, you will need some kind of filter to prevent dirt, water and whatever else being sucked back into the crank case....ARH


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