SuperHawkins

I am wondering if anyone has tinkered around with modifying the stock PCV system. I spend a lot of time in the higher revs during the spirited rides, old habits die hard I guess....forgetting that I don't HAVE to keep the bike up there

Well I get some oily residue in the airbox and although I know it would take a lot to have any effect whatsoever, I still have never liked the idea of it and have always rigged up inline filters and whatnot with all my hopped up cars.

I am wondering what you guys that have modified it have done with the system. I am thinking about buying lengths of the same size hose and running both tubes out of two holes in the airbox down through the frame. I had also thought about teeing the two into an inline filter and out of the box, but I think that would put too much restriction on the system, I know PCV systems need to flow very very freely, especially in the high revs.

What do yall think?

gboezio

The way I see it, the engine will suck air from these tubes along with dust.

Hawkrider

It already flows freely. There is no PCV valve, and thus isn't really considered a PCV system. It's just a breather, and the only restriction is what's in the airbox.

SuperHawkins

Didnt realize those little tee's aren't check valves...well that makes this even simpler. I'll just run a pair of in-line filters. I'm just really **** about having oil in my airbox, that's the only reason I'm doing this.

igeorgei

My bike backfires a little probably because of my 40 hp shot of nitrous or jet kit or airbox modification or my open exhaust. Whatever the reason, the back preasure from my carbs shot back through breather valves to the valve cover and blew out my valve cover gaskets.

OIL EVERYWHERE NOT PRETTY.

So I replaced and put everything back together except for the 2 breather hoses from the airbox to the valve covers. On the Air box, I sealed the holes with rubber stoppers and silicone. On the valve covers, I installed open breather filters that are made for cars(cheap like $40).

I did this modification 2 years ago and I have had no problems at all.

Hope this helps

SuperHawkins

This is exactly what I was thinking of doing last night after I made my last post... Are the valve covers baffled, to keep excessive oil out of the breathers? If not, I was going to run about 6 inches or so of hose and mount the breathers vertically to reduce the amount of liquid oil they'll see. But I imagine if you get away with running straight breathers right on the covers, I won't see any problems.

drew_c14

I agree. A filtered breather right on the cover would be my best bet. Even if the valve cover doesn't have a baffle it would take forever to get so much oil in there that it stopped working right. After all, it's just a vent. The only reason PCV's ever went to the airbox was to save a couple trees a thousand years from now.

igeorgei

Yes the valve covers are baffled, which means only oil vapour will come through unless your bike is upside down but then you've got bigger problems by then.

I also found that the filters that I installed are staying pretty clean after 2 years. It looks like I will be able to go another 2-3 years before I will have to change them.

Good luck guys! It's a cool little mod that I recommend because I found out the hard way that a little back firing causes a BIG mess.

Cheers

SuperHawkins

Well blowby will produce pressure in the valvecovers and if the motor is a little bit loose, and the covers are unbaffled, you'd be surprised how much oil will make it out...especially on a high-revving motor where it's being pumped up there and flung all around. That's my experience with car motors, I doubt a bike can be different enough to matter.

I had a mustang that saw almost 7000 rpms at the track and went through breathers every month or so....the covers were unbaffled and it just FLUNG the oil right into the damn thing.

Thanks guys, soon as I get some free time I'll rig something up. Right now she's torn apart and I'm part-less and tired. Beer me.

captainchaos

Forget the breather tell us more about the nitrous!

igeorgei

Nitrous very fun

Up to 6000 RPM, the VTR pulls strong but lacks the punch between 7-9000 RPM that a 4cylinder inline 4 has.

I hit it around 7000 RPM to redline and the VTR really wakes up STRONG.

I would say that it's more bling than bite now, It gets expensive fast. I've had it for 3 years and the bottle just runs out quickly. If I had to do it again, I would put a turbo on a VTR.


As for the baffles on the valve cover, I am pretty sure when I had the covers off, there was a shiny aluminum plate that covered the valve cover vent hole. It sat about an inch away from the hole which allowed vapour to go around and out the hole but would prevent oil from spraying straight out.

It's been 2 yrs so I may be getting my VTR valve cover confused with my other bikes......hmmm. You better double check before taking my word....lol

gboezio

I prefer a slight vacuum for better oil control, but it's not a problem on Hondas, as for nitrous, this is what I was looking for, someone that was beating up his VTR rods, so 3 trouble-free years of nitrous, interesting, no trouble at all ??
Check this thread for turbo discussion.
https://www.superhawkforum.com/forum...ead.php?t=5226

igeorgei

I used the nitrous a lot in the first year with a 20hp shot.
The second year I up'ed it to 30hp shot which was very fun and safe. I fired it that year about 20 times.

Last year I up'ed it again to 40hp shot and fired it around 15 times.

I have a feeling 40hp is too much for stock pistons so I may be taking it back down to 30hp which by the way is just enough punch and remain reliable.

One down side to my "Wet" nitrous system is that when the bottle pressure goes down your shot of nitrous decreases but your extra fuel jet is still shooting out enough fuel to support a full nitrous shot. In other words, as your nitrous bottle empties out with every shot, you run richer and richer until your bottle is dead. Not a big deal I suppose but it is something to mention.