TOPIC:

I was aimlessly browsing around on Webike last night, and ended up stalking fellow forum member Zaddict’s product reviews of parts installed on his ‘90 ZR550 Zephyr. One product in particular caught my attention, and that was the  Teramoto T-REV Air Box Type II . Based on the description, and Zaddict’s review I sort of understand what it does, but I guess I still just don’t quite “get it.” Can anyone help me out with a lamen’s terms description? And I also don’t understand where it goes on the bike or how it’s installed. Maybe Zaddict, if you’re reading this, can you take a picture for me? By the sound of it, I think I might really like what it does, but I am still confused on exactly what that is. 

Edit: Pardon the typo in the topic title, I can’t seem to change it. Would a mod mind fixing that? Thanks. 

I have corrected your typo, it appears to be a one way valve in the breather (some cars have a “poppet valve” in the airbox) not sure how much effect it will have

Is this some sort of "poor" mans vacuum valve?

I have seen on board vacuum units for drag bike crank cases and they can be worth some HP but the are only used for racing. The idea is to make negative case pressure to help ring seal and reduce any pressure buildup under the pistons. Having better or bigger crank case venting helps but sucking on it helps more!

On a street engine I doubt you would see 1-1-1/2 HP on that little valve, for $190 without tax/ship is it worth it? You would never feel that increase.

The drag race vacuum setups are for really high HP Pro Stock and Pro Mod engines up over 500HP, still they are only worth about 10-15 HP but that could be the difference in winning a race or not.

 

I think I mostly understand what you're saying, but I'm not really interested in it for any kind of HP bump. Here's a link to Zaddict's review:  japan.webike.net/prv/detail/1005703/p21717465/ . It's not so much a power boost, it's seems like it's just a sort of behavior of the motor kind of thing, I guess. 

I would be more concerned with oil vapor from your crankcase lowering your octane rating of your fuel as the oil vapor is going back through the carburetor.
You'll also be dealing with extra oil deposits on valves and carburetors.

It's not really environmentally friendly but I would run your crankcase vent hose outside the airbox and plug the hole in the airbox.
That may help your engine smoothness more than a $170 one way valve.

motorcycleproject.com/text/crankcase_recirc.html
 

Stereordinary wrote:

I think I mostly understand what you're saying, but I'm not really interested in it for any kind of HP bump. Here's a link to Zaddict's review:  japan.webike.net/prv/detail/1005703/p21717465/ . It's not so much a power boost, it's seems like it's just a sort of behavior of the motor kind of thing, I guess. 
 

I could not read the tiny print in the first link. What your describing is a sort of surge reducer, if Kawasaki thought that was needed they would have already put it on there bikes. Hell it may be on some of there newer stuff buried under all that plastic

It's simply a one way intake powered suction valve to lower or create negative crankcase pressure and reduce pumping losses which as a result will increase horsepower.
The more common method often used on race bikes etc is to run a crankcase breather pipe into the exhaust link pipe or silencer with the opening pointing downstream towards the exit of the exhaust and the passing gasses create a pressure drop in the breather pipe and consequentially the engine crankcase.


 

Yep, I was wondering if they did that on motorcycles as I knew about slash cut evacuation for cars.

Back in the day cars in the US made use of a road pipe to allow the crank case to release pressure, it sort of sounds like that is what this does.  Also just want to say good call out on Mike Nixon. 

I'm happy with the T-rev on my bike - the effect was much more noticeable than I expected. I didn't notice any power bump but it really smoothed out engine braking. It plugs into the airbox plenum where it connects to the crankcase breather elbow connector. I'll take a pic next time I have the air filter housing out. 

That said, if you're going to spring for expensive, high quality Japanese mods that you don't really need but might enjoy, I'd highly recommend the AS Uotani ignition system - very noticeable power increase complete with ignition timing control and an RPM limiter - 
japan.webike.net/products/21552786.html#recent-review-block

Here's my review of the ignition system.  They should probably pay me commission  but it really it really did make a big difference.  

japan.webike.net/prv/detail/1006482/p21586552/

There's another thread on here I started about installation. Loudvx helped so much with that, I miss him. RIP. 
 

I’ve had that ignition system on my wishlist since reading your review of it. It’s a little too pricey for me at this point, but maybe down the line I can make it happen. 

The T-Rev though, sounds like something I might like, and I think I understand what you mean about how it’s installed.