inTech vacuum control system?

[benny hedges]

anybody here use this device????

no point me explaining - watch ----> http://link.brightcove.com/services/pla ... 1315742466

as used by leon haslam and others

interested??? read on ------> http://www.urbaneracing.co.uk/single.htm?ipg=6227

better than a slipper clutch? defo the next item on my shopping list!
the only slipper i could find for the storm was from hsk (?) and it's discontinued... toyed with modding one off a tl, but this sounds the ticket

this is the one for the storm ----> http://www.urbaneracing.co.uk/product/acat/?pid=5088
£199

[benny hedges]

tbh after researching a bit i think i'll try some of these first... VOT-40110 1/8" BSP RELIEF VALVE More Details 22.50
from flowtech - seems they do the same thing, adjustable vacuum relief.
would do exactly the same thing imo, as in if i set it to say -250 mbar, when i throttle off and the engine makes a massive vacuum, the valve will open and allow air into the intake stub, just the same as the £200 shiny thing????

any opinions?

[tony.mon]

Sounds interesting!

Like those cans, too, as they would be quieter at low revs but let it breathe when you open it up.


Splash your cash and do the dyno thing, and post the results, will you?

[benny hedges]

yeh right lol! you first rockafella
bike's getting dyno'd soon enough, then any mods after that i'll have something to compare it with.
some interesting posts on powerbikes, cbr, aprillia and duke forums about them - seems everyone's a bit sceptical but i haven't seen anyone post up dyno results yet, just saying they make the bike smoother to ride.
i'd rather try the flowtech valves first for a fraction of the cost - might see if i can hide a pair in a job quote lol!
i think you would need one per pot seeing as they produce vacuum at different times - seems others agree, but the harris site just shows one unit teed together

interestingly, on the new blade they use a vacuum control valve.... so there must be sumat in it eh?

[tony.mon]

A lot of bike engines are now being fitted with an air bleed for emissions reasons, not sure if it's intake or exhaust side, though.

I'm sure you could rig a tee'd vac pipe so that you could allow air into the intakes, a soft bit of tube you could clamp to the LH handlebar with your hand and keep it closed while riding but then release it to allow air in when you close the throttle.

Then you could see what difference (if any) it'd make, without spending out on the unit.

Not a useful long-term solution, but at least you could see if the results would suit your riding style, and whether it'd stop the rear end locking up on big downshifts.

Personally, I like the engine braking, (especially as the back brake is so crap) and can live with the occasional lockup.
If I were racing or tracking it, maybe it'd be a big advantage, though.....

[benny hedges]

If I were racing or tracking it, maybe it'd be a big advantage, though.....

i race my own headlamp beam 1/2 the time.
nearly beat it a few times lol

[marlbororman]

i race my own headlamp beam 1/2 the time.
nearly beat it a few times lol

[Zakalwe]

anybody here use this device????

no point me explaining - watch ----> http://link.brightcove.com/services/pla ... 1315742466

as used by leon haslam and others

interested??? read on ------> http://www.urbaneracing.co.uk/single.htm?ipg=6227

better than a slipper clutch? defo the next item on my shopping list!
the only slipper i could find for the storm was from hsk (?) and it's discontinued... toyed with modding one off a tl, but this sounds the ticket

this is the one for the storm ----> http://www.urbaneracing.co.uk/product/acat/?pid=5088
£199

WTF was that twit form Harris wittering on about? "its controlling the reflections back to the head so it's making your valves open better"????? "you get a fuller burn", "you get that little more power"?? What? By bleeding air into the inlet on a closed throttle you get more power on an open throttle???. Really?

As for the comments on removing the cat....bullshit. The cat burn unwanted hydrocarbons in the exhaust, converts carbon monoxide to carbon dioxide and breaks nitrogen dioxide into oxygen and nitrogen. How would bleeding air into the inlet on a closed throttle change the basic chemistry of air/fuel combustion? There might be less emissions on a closed throttle on a carbed bike, as the air bleeding into the engine would allow the fuel to burn in the exhaust. On an FI bike, I would expect the ECU to cut the fuel on a closed throttle, so I would think that the effect would be negligible.

The reason why the dyno reads more power is that dynos estimate the power losses through the gearbox by measuring the rate the engine slows when the throttle is closed (ie, when the engine is running down). This is done to extrapolate an "at the crank" power reading, by taking a power run and adding in the estimated gearbox and power train losses. With the air bleed valve fitted, there is less engine braking, which "fools" the dyno calculations (a similar effect would happen if the dyno operator kept the throttle cracked open after the power run). I would like to see a dyno reading showing rear wheel power, without any correction factors, before and after the valve is fitted. My guess is that there would be no difference, as the valve only bleeds air in on a closed throttle.....which wouldnt affect a wide open throttle power run.

Yes the valve will improve corner entry by helping to prevent rear wheel hop (some of the early MotoGP bikes had a similar effect by employing a "kicker" on the throttle butterfly valves that partially opened the butterfly valves to bleed air into the engine on a closed throttle). I would like to see if bleeding air into the engine on a closed throttle leans off the mixture to the extent where the mixture becomes dangerously lean

This is a fantastic piece of journalism, easily up the the high quality of scientific rigour that we all expect from MCN (caution: this last sentence contains sarcasm ). Basically they show that removing the cat and fitting noisy exhausts makes a bike produce more BHP. No sh1t, Sherlock.

[mik_str]

The idea is sound (as it pertains to the reduced engine braking, the rest is just fluff IMO). Many engines (bikes, also a growing number of four-stroke snowmobiles that use just such a system to reduce engine braking) make use of somethign similar. The only difference is that they are fuel injected and ECU is calibrated to take this into account. I would certainly love to try something like this if it works and does not cause a problematic lean condition...

[benny hedges]

well i've ordered some cheap adjustable vac relief valves from norgren and will fit them to my carb balancing pipes & see what happens.
total cost was £18 - some saving over the harris item if it works lol!

plan is to set them at 20mm/hg so the carbs still have the vacuum they need to operate, and so long as i adjust them proper they should not let the vacuum go above or below that level.

my tank doesn't need a vac feed btw so it won't affect that

[Pete.L]

I've been running the Intech valve on mine for the last two years.
Does what it says on the tin Oh! and it wont work on a carbed bike, needs fuel injection Controlable back pressure and a few extra ponies to boot, Shame Harris are no longer supplying. I bought one of the last ones


Pete.l

[benny hedges]

i picked these up today....

the £7 norgren ones were shite tbh lol, plasticy and i was bothered that if i fitted them inside the airbox that bits might end up getting sucked in...

these look very well made - £22 each but i get a massive discount off them so worked out nice & cheap.
what i intend to do is attach the hosetail to my valved off balancing pipes, one for each pot, start the bike and give it some welly to check that the relief valve doesn't interfere with the normal operation of the carb slides, ie, it doesn't suck air in when the engine is powered, only on the over-run when the slides are shut and the vacuum goes up over say 30mm/hg.

the level of vacuum relief is adjustable by turning the long nut out and locking it up with the locknut behing the ptfe seal.
it's just a precision needle valve on a spring with like a suction cup on the end - when the vacuum exceeds the preset, it lifts the needle off it's seat and lets air in through the little poppet valve on the end, into the inlet port...

once i'm happy it's not drawing air into the fuel mix, i'll drill the airbox and mount them under the filter so when it relieves the vacuum it will use filtered air from under the bmc

the reason for doing this - i'm not arsed about fuel economy, and i'm not expecting a power boost, but it's to reduce the engine braking when gearing down in corners.
atm on tight turns, if i drop a cog, it very often hops the back wheel so i'm losing traction, and i reckon once the light flywheel is on, this will be even more pronounced as it won't have as much revolving momentum to counteract the vacuum...
i went for the 1/4" ported relief valves but thinking about it, i'm not 100% sure that will be big enough, seeing as the engine breather is 1/2" diameter???
as usual, a report will follow, and pics of my wrecked engine lol
the result i'm after is that the bike will keep the torquey power delivery of the v twin, but going into bends and throttling back, it should feel more like a 2 stroke or IL4

[benny hedges]

just fyi - part numbers for these items -

hosetail - FHT6/10 - £1.58
valve - VOT-40110-2 - £22.50
i got these from Flowtech at 50% discount, but might try fitting a larger diameter valve and see if i can get more control with it...
soon as i've got part numbers & tested it i'll update here. so far so good with the ones i'm using atm.

i'm sure flowtech are trade accounts only so if i can find an alternative supplier i'll post a link here, otherwise i'll order a dozen or so (as i get a good % off) and see if anyone wants to give them a try.
you need one per cyl, 2 hosetails, copper washers & vacuum lines same as for balancing the carbs - mine are attached to my balancing pipes so if i need to set the carbs up i can just unplug the vac valves.

effect so far... doesn't seem to be drawing air when under power (i don't want it to obviously) and on over-run & throttling back there is a satisfying hiss as the valve opens, plus a marked decrease in engine braking, giving a bit more predictable control in corners

[mik_str]

Hey Ben,

Did you ever go ahead and pick up a bunch of the vacuum relief valves (am interested in giving this a try BTW). Quick question: have you considered replacing the two small valves with one larger one (hooked up to tee with both line feeds)? The reasoning is to ensure that both cylinders are always in synch (one valve cannot be out of synch with the other, as there is no other valve). Quicker and easier to adjust the amount of relief you want.

Thanks in advance

[benny hedges]

yeh mik ive been running these since last summer, not the stupidly expensive intech ones, but the ones linked to earlier and they do make a difference especially in the twisties
the reason i went for 2 valves is cos obviously with the vee, one cyl is making a vacuum while the other is making pressure.... i didnt want the valves to interfere with intake pulses and stuff so thought it best to use one per pot.
tbh at the price they sell for it's no problem - not so sure about the intech ones at £200 each though!

also apparently they dont make them any more???