faulty H-VIX system

as some of you may be aware there was a fault with my bike on the AR, looked it up and its a faulty H-VIX system (honda varible intake and exhuast system)



going to phone a freind of a freind that works in a main dealer, but does a bit of servicing in his spare time

i have no idea whats wrong with it though?

[yorkie_chris]

Does you year of bike have the moving intake trumpets? Might be like a secondary throttle valve on the suzukis, or an EXUP type exhaust backpressure valve

Originally Posted by yorkie_chris

Does you year of bike have the moving intake trumpets? Might be like a secondary throttle valve on the suzukis, or an EXUP type exhaust backpressure valve

no idea?

[yorkie_chris]

OK here's a disclaimer... the closest I've been to working on a blade is stood 6 foot away from yours...

Anyway, the EXUP valve is a valve in the mid-pipe of the exhaust system, it closes at low revs and opens at high to give better midrange torque with a tuned engine.

You'll find hidden in the fairing somewhere a servo-motor with control cables which lead down to the exhaust valve, it wouldn't suprise me if a cable has got stuck or the exhaust valve is siezed. Is it lacking in power/midrange?

Originally Posted by yorkie_chris

OK here's a disclaimer... the closest I've been to working on a blade is stood 6 foot away from yours...

Anyway, the EXUP valve is a valve in the mid-pipe of the exhaust system, it closes at low revs and opens at high to give better midrange torque with a tuned engine.

You'll find hidden in the fairing somewhere a servo-motor with control cables which lead down to the exhaust valve, it wouldn't suprise me if a cable has got stuck or the exhaust valve is siezed. Is it lacking in power/midrange?

Is that the same as the SET valve on later Suzukis?

[yorkie_chris]

If it's a butterfly valve in the exhaust then yes!

Yamaha did the YPVS valve on their 2 strokes... to vary the exhaust port height... kwak had the KIPS valve... cagiva now has CTS valve ... loads of acronyms ... same thing.

Yeah it's a butterfly valve in the exhaust, only thing is I thought it was for emissions not power...some people remove them cos they claim it gives more hp (one of those things, not proved conclusively).

Originally Posted by yorkie_chris

Is it lacking in power/midrange?

well i was undertaken by that kid on a 125

at 70mph

[yorkie_chris]

Nah what it is, with hot timing on the engine, i.e lots of valve overlap ... you end up with a powerful but peaky engine as the early opening exhaust valve loses torque at the bottom and in the mids ... so you want some backpressure, but this backpressure at high rpm totally kills the power.... so you put a valve in there.

If you find removing the valve adds power then chances are it's adjusted wrong and wasn't opening fully. (actual, dyno proven power)

It'll always feel more powerful as the lack of midrange grunt will make it feel peaky... sudden power feels more intense than smooth power.

[yorkie_chris]

Originally Posted by hovis

well i was undertaken by that kid on a 125

at 70mph

Does it still do 160odd though?

That'll tell you if it's stuck closed!

Is it clicking? Does the valve normally cycle when you switch the ignition on?