First off if you think you know everything and are here to flame then leave now. I was jus looking at a few honda cbr's and i started wondering if it were possible to have a variable-timing type of setup on a bike engine. I'm not a stunna that wants everything i own to have vtec but i figured on a such a high reving engine it could be helpful when tryin to stay in the powerband. Just wondering and would appreciate your opinion. If this is a repost then mods delete.

 

The Honda Interceptor has Vtec it's a 750 never ridden one but its a sportbike/cruiser pretty pimp. Not sure if there is anymore.

 

I was just wondering it's effect on a sportsbike.

 

I heard that you can't even feel it or hear it. Never ridden one either. Would like to though to see if it feels like a car.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">I heard that you can't even feel it or hear it. </TD></TR></TABLE>

It's worthless on the motorcycle. Honda bagged it.

 

Only 2 valves are being used below vtec, when it engages, all 4 valves work.

It uses special retainers, causing the valves to remain up if you are below vtec.( if im not mistaken)

 

No you're not mistaken, honda calls it 'hyper vtec' when the valves are completely deactivated. No really, thats what they call it. I get motorcycle mags from Japan mailed to me every month. I forget why. I think its a trade thing where he gets US mags in exchange. Grass is always greener eh.

I don't think the intercepter is 750cc anymore...hasn't been for a while, kinda like the cbr900. I've heard its a great bike. The VFR I mean. Not the CBR. But that one probably is too. Not saying its not. The CBR. Cause it probably is too.

Oh, and as for the orginal post, the power to weight ratio of a motorcycle is so much astronomically higher than most cars, that the vtec low rpm torque boost isn't needed. Motorcycle vtec would be a kind of solution for a problem that doesn't exist. That and vtec adds some complexity and extra weight. Not a big deal on a 2500 pound steel cage, but an added hassel for designers working on making a bike as compact and light as possible.

 

i looked it up the interceptor is like 780cc so its kind of an odd number.

 

thanks mos. it was just a random "what if" kinda question.

 

Got it. VFR800 MY2002+

Still breaking it in... but the rumors are it doesn't "kick" the way people think of VTEC autos doing. Truth be told... I really don't want a major change in felt torque at 7000rpm on my motorcycle.

However, I reckon the same things one does to aid breathing in a VTEC auto would make the power bump at VTEC more noticeable... I'll try a K&N on the VFR at some point... Opening up the exhaust would likely help, too.

If you follow B-Series tuners, there are two camps. One camp (Jack Harris, as an example) makes the VTEC transition on B18Cs (and derivatives) as smooth as possible. You can't even see it on the dyno graphs. There is a change in the pitch of intake/exhaust noise but the transition is smooth. I would contend these are the guys that track their cars. The last thing you want is a shift in balance mid-corner. The other camp (typified by Jeff Shaeffer at http://www.importbuilders.com) actually tune the bump INTO the curve. I would agree with Jeff it make it fun to drive... but again... back to motocycles... I'd rather have smooth than peaky any day.

And anyone who thinks a VFR is "soft" see "Spencer, Freddie". It's wicked fast and moves very well despite its weight. Plus, I can ride all day and no sore wrists or stiff neck. Try that with a CBR or RC51. Grantred, full-on track prowess, the VFR bows to the CBRs, but... the street is not the track.