Equalizing Vacuum

[dannymax]

one thing to keep in mind, if you're using clear tubing it gets pretty 'gassy' coloured after a few rides. if its being covered no worries otherwise just something to keep in mind.

Might kinda match that beautiful golden hue of the S/S Mark's pipes....ya think? :ummm:

 

[tugla]

Might kinda match that beautiful golden hue of the S/S Mark's pipes....ya think? :ummm:

is this how we justify the new exhaust now dan-o hahhahaha i like it

 

[dannymax]

is this how we justify the new exhaust now dan-o hahhahaha i like it

Whatever it takes Rov....whatever it takes! unk:

 

[ninjaneer]

So I've cured my Mark's "jetting" issue and ended up removing the vacuum mod. I didn't like the way the advance meanders the idle up and down from 990-ish to 1.2K, causing it to thump on the low revs and roar on the higher end. without the mod, I am able to achieve that bellowing drone that reverberates off of the neighbors' houses. I'll hang on to the pieces, though and experiment with it later down the road.

{edit}
after dialing in the carbs with new jets and needles and afr tweaks, i put the mod back in. and quickly took them off after a spin around the neighborhood. the mod is way to intrusive in my low range.
{/edit}

 

[tugla]

Whatever it takes Rov....whatever it takes! unk:

im just trying to find a stronger excuse to chg the pipes on v1 unk:unk:

 

[KJShover]

im just trying to find a stronger excuse to chg the pipes on v1 unk:unk:

There are no excuses. :biglaugh:

• It needs to breathe better
• It craves the rumbley sound
• It's jealous of the other Vmax's sound
• It would like to give you better performance and mileage

Besides, The monkey is always watching.

 

[tugla]

There are no excuses. :biglaugh:

• It needs to breathe better
• It craves the rumbley sound
• It's jealous of the other Vmax's sound
• It would like to give you better performance and mileage

Besides, The monkey is always watching.

soo true man so true unk:unk:
happy new year

 

[RaWarrior]

I took mine for a short ride today(got up to a balmy 50*...w00t) to try out both the vacuum mod, and my Morley seat that came in.

Well the seat is phenomenal, but everyone here already knows that so I won't bore you with details.

As for the motor....idle speed was unchanged. Was rock steady at 1000rpm even once the motor got up to temp from riding. No "meandering" or up-n-down idle speed. It idles maybe a tad smoother than before, but tough to make a call. I haven't sync'ed my carbs since mid-summer either(the tool is at my seasonal workplace).
What I did notice a difference in was that the low-end was noticeably stronger. Lugging it around at like 2-3000rpm definitely had more grunt to it, with less of that "shudder" from too-much-load-too-few-rpm. Overall low-range operation seemed smoother and more powerful.
Once up to speed(I was only on the highway for a few min), it seemed pretty much the same. I didn't notice my bike's annoying misfire/lag, but it could have just been on a "good" day, need more ride time to make a call on that.
Once v-boost hits and beyond I noticed no difference from normal.

So I'd vote it in as a worthwhile mod. It's cheap, quick, easy, and 100% reversible. I noticed a stronger and smoother low-to-mid range, for less than $2.

You need:
About 2' of 3/16" tubing( was like $0.19/ft at tractor supply). You'll have some left over.
One 3/16" "T" fitting(was like $1.50, go figure)
A philips screwdriver(to remove H covers)
Pliers(to remove clamps from stock port covers)

 

[ninjaneer]

i took the bike out again this evening and quickly realized that my low end tuning is running lean. it's really unfair of me to dismiss the mod until every thing is in order. i'm gonna give the mod another chance, especially after reading ra's results. i'd love to have the same performance--sounds amazing.

 

[dannymax]

i took the bike out again this evening and quickly realized that my low end tuning is running lean. it's really unfair of me to dismiss the mod until every thing is in order. i'm gonna give the mod another chance, especially after reading ra's results. i'd love to have the same performance--sounds amazing.

I was really puzzled by the 'hunting idle' that you got with this mod....can't ever remember anyone else having that issue. I'm wondering if there was a small vacuum leak or something other than the mod causing that??? :confused2:

Maybe hook it back up and shoot some propane around the tubes? :ummm:

 

[ninjaneer]

so lesson learned: SYNC YOUR CARBS before you try this mod--especially if your in process of rejetting. yes i know you should sync before after and during rejetting, but i was just itchin to get going and figured i'd sync later--i mean how far off could they be, right? well, lemme tell you what. this mod seemed to amplify my unsynchedness, which i'm gonna attribute to the my bike's idle hunt. after a session with the carbtune, i figured what the hey and slapped the tubes back on and that meandering pretty much was gone. the idle is definitely smoother, more a rhythmic hum like a hive of bees.

 

[dannymax]

Cool! I HATE it when my unsynchedness gets amplified!! :hihi:

 

[dmax1]

Read evrything in this post and found it very interesting. Going to have to try it. My other question is your bike stock or modified? Has anyone put this mod to the test on a dyno? I would be interested in the numbers.

:rocket bike:

 

[bazwell]

well, lemme tell you what. this mod seemed to amplify my unsynchedness.

That is interesting!

 

[KJShover]

Cool! I HATE it when my unsynchedness gets amplified!! :hihi:

Then again, a little amplification can be a good thing unk:

 

[dannymax]

With a bass.....no less!! :git:

 

[dannymax]

Read evrything in this post and found it very interesting. Going to have to try it. My other question is your bike stock or modified? Has anyone put this mod to the test on a dyno? I would be interested in the numbers.

:rocket bike:

Well....sort of! Not a before & after but I dyno'd '99 with this and the COP mods and she pulled 117.1 hp & 79.6 ft. lbs.....no idea how much (if any) would be attributable to the mods tho.

 

[johnpclynch]

Thinking about trying this mod but I'm not sure...

Imagine 4 girls siting around a milkshake (vanilla) with a 4 into 1 straw, each girl gets a chance to suck from her end of the straw (not all at the same time) I can't see that milkshake going anywhere :confused2:

 

[tugla]

Thinking about trying this mod but I'm not sure...

Imagine 4 girls siting around a milkshake (vanilla) with a 4 into 1 straw, each girl gets a chance to suck from her end of the straw (not all at the same time) I can't see that milkshake going anywhere :confused2:

interesting idea.....unk: are they sucking or spitting otherwise wouldnt it go away eventually :ummm:

:rofl_200:

 

[ninjaneer]

Thinking about trying this mod but I'm not sure...

Imagine 4 girls siting around a milkshake (vanilla) with a 4 into 1 straw, each girl gets a chance to suck from her end of the straw (not all at the same time) I can't see that milkshake going anywhere :confused2:

so correct me if i am wrong, maybe i'm not thinking this correctly, but isn't that what you want ? if all four girls each sucks independently, one girl has to extert a certain amount of work in order to produce the desired equilibrium. however if each suck simultaneously, they all will produce the desired equilibrium with less effort from each of the girls over the same time interval.

The "vanilla milkshake" example isn't a good example. it is a finite volume which doesn't account for an equilibrium by replacing the milkshake that was displaced. you'd have to substitute the glass with a bottomless container holding an infinite amount of strawberry milkshake.