Jets, airbox, and pipes

[Bassett]

Hey guys!

 

I think I'm ready to move on to the next phase of my bike mod and start to do the carbs, box and pipes.

 

 

-I want to eliminate the air box and go into cones

-rejet the carburetors

-grab the left side pipe before the horseshoe and bring it over to the right. Hopefully going into one pipe. Hi at work suggested after they connect, using 2" pipe for back flow purposes.

-nice loud slip on to wake up the neighbors.

 

After thumbing through a bunch of threads I haven't found a good one to walk through airbox delete. I heard people use RoadKing pipes, and found a good write up in rebuild carbs but not rejetting.

 

Suggestions, thoughts, helpful threads, advise would be really appreciated!!

 

 

Cheers!

-Alex

[Patmac6075]

Alex, let me be the first to say, 'It's your bike....'

 

Unfortunately, I don't have any knowledge about how to do what you've laid to be done, but.....

 

The engineers who designed these bikes spent a lot of time and effort to get the intake and exhaust tuned just right in these bikes. Many have tried to "open up" or get theses bikes to "breath" better...at best it'll gain something at the very top end (not particularly useful on a street/touring bike), but usually it will come at the cost of reliability, driveability, gas mileage, and Or the ability to idle.

Sorry to be the wet towel...my advice, if you still plan on moving forward would be to make one change at a time and proceed in a scientific manner. Please post your results good or bad so others can learn from your efforts.

[CaseyJ955]

I would love to figure out now to do a 4-2-1 Kerker style exhaust, or even an 4-1 and eliminate the twin pipes. The single can is musical. I want mine to be just loud enough to hear the music but not loud enough to be fatiguing on long rides. I have failed to find any exhuast for the Venture other than a Marks Collector. In looking at this exhaust system, and IMHO, the restriction is not in the cans but in the downpipes and collector system. Someone please correct me if I'm wrong on this.

 

For going to cones instead of a factory air box you will need to use a carb restrictors to trick the carbs. To illustrate remove the air box and fire it up, you will notice it's very soft and stumbly when you blip the throttle. The restrictors are available from Sean at Morleys Muscle and maybe other places I dont know. They press into one of the small holes on top of the carbs so it's quick and simple. Another option is to customize the air box lid by cutting it out and grafting in a K&N style flat filter. My vmax has a setup like that and it sure breathes better, also you will hear a great deal more of the carbs and intake sounds. I'm not sure how much more intake CFMs you can really take advantage of without a free flowing exhaust. Maybe you can get a Marks collector, not sure where to get those but maybe someone else can chime in.

 

I'm collecting bits of Vmax exhaust to try and piece something together. I will be installing Vmax heads and cams on mine next winter and without free flowing exhaust a lot of that wont be usable.

 

A word on jetting a CV carb, as you free up intake and exhaust restrictions you may find that you are jetting down a step or two, CVs like to throw in more fuel with more flow. Correctly setting the float levels is going to be paramount, it's critical for CV carbs to do their thing correctly. Once you get the air box/cones and the exhaust you are looking for you will want to start the tuning by choosing the leanest main jets that will pull hard at the higher RPM range, then worry about needles and the lower jets, tune from the top down so to speak. It's a bit of trial and error to swap jets, ride, swap jets, ride on and on. Ideally you will find a dyno with a sniffer to check for CO at different RPMs and that would take some guesswork out of where in the RPM range you need to enrich or lean out. I didnt have that so on my Vmax (as you may know, same engine with different state of tune). I did not have acces to a Dyno so I set float levels, took my best guess at main jets, synched up the carbs and rode, I ended up swapping out jets 5-6 times until I was happy with the blistering top end performance.

 

All my tweaking experience is on the Vmax and I'm moving to the Venture now to do the same with jetting and dialing things in. I will say that the Venture has smaller cams, smaller valves and head porting so I'm still not sure how much free flowing exhuast and intake you can really use with the Venture heads. I suspect not to much, also suspect that to free of an exhaust would probably do more harm to low end torque and ridability than good to top end performance. These are super heavy bikes and will need to keep some of that low end torque. Doing this on the Venture is an exercise for me as well but I'll be using the Vmax experience I have gained with regard to how these V4s respond to changes in flow and jetting.

 

If your not going to break into the engine but your looking for a little more top end performance and maybe a few more RPM you could look into adding Vboost off a Vmax, it's only an intake system with butterflies and a couple guys here have already done the Vboost mod on the stock Venture engine.

 

I'm interested in what your performance goals are, more top end, angrier midrange or just generally more pep?

[Bassett]

I would love to figure out now to do a 4-2-1 Kerker style exhaust, or even an 4-1 and eliminate the twin pipes. The single can is musical. I want mine to be just loud enough to hear the music but not loud enough to be fatiguing on long rides. I have failed to find any exhuast for the Venture other than a Marks Collector. In looking at this exhaust system, and IMHO, the restriction is not in the cans but in the downpipes and collector system. Someone please correct me if I'm wrong on this.

 

For going to cones instead of a factory air box you will need to use a carb restrictors to trick the carbs. To illustrate remove the air box and fire it up, you will notice it's very soft and stumbly when you blip the throttle. The restrictors are available from Sean at Morleys Muscle and maybe other places I dont know. They press into one of the small holes on top of the carbs so it's quick and simple. Another option is to customize the air box lid by cutting it out and grafting in a K&N style flat filter. My vmax has a setup like that and it sure breathes better, also you will hear a great deal more of the carbs and intake sounds. I'm not sure how much more intake CFMs you can really take advantage of without a free flowing exhaust. Maybe you can get a Marks collector, not sure where to get those but maybe someone else can chime in.

 

I'm collecting bits of Vmax exhaust to try and piece something together. I will be installing Vmax heads and cams on mine next winter and without free flowing exhaust a lot of that wont be usable.

 

A word on jetting a CV carb, as you free up intake and exhaust restrictions you may find that you are jetting down a step or two, CVs like to throw in more fuel with more flow. Correctly setting the float levels is going to be paramount, it's critical for CV carbs to do their thing correctly. Once you get the air box/cones and the exhaust you are looking for you will want to start the tuning by choosing the leanest main jets that will pull hard at the higher RPM range, then worry about needles and the lower jets, tune from the top down so to speak. It's a bit of trial and error to swap jets, ride, swap jets, ride on and on. Ideally you will find a dyno with a sniffer to check for CO at different RPMs and that would take some guesswork out of where in the RPM range you need to enrich or lean out. I didnt have that so on my Vmax (as you may know, same engine with different state of tune). I did not have acces to a Dyno so I set float levels, took my best guess at main jets, synched up the carbs and rode, I ended up swapping out jets 5-6 times until I was happy with the blistering top end performance.

 

All my tweaking experience is on the Vmax and I'm moving to the Venture now to do the same with jetting and dialing things in. I will say that the Venture has smaller cams, smaller valves and head porting so I'm still not sure how much free flowing exhuast and intake you can really use with the Venture heads. I suspect not to much, also suspect that to free of an exhaust would probably do more harm to low end torque and ridability than good to top end performance. These are super heavy bikes and will need to keep some of that low end torque. Doing this on the Venture is an exercise for me as well but I'll be using the Vmax experience I have gained with regard to how these V4s respond to changes in flow and jetting.

 

If your not going to break into the engine but your looking for a little more top end performance and maybe a few more RPM you could look into adding Vboost off a Vmax, it's only an intake system with butterflies and a couple guys here have already done the Vboost mod on the stock Venture engine.

 

I'm interested in what your performance goals are, more top end, angrier midrange or just generally more pep?

 

 

 

Good information!

 

 

What im hoping to accomplish is more space so I don't have the big pinky air box, as this is not a traditional venture. I chopped this bike and bobbed it so I am bare bone. The airbox really causes me an issue up top because it takes up so much space. I would like some pipes on my bike to rev at red lights and let people know I'm there. If I could get some more fuel by adding a bigger jet, I would like to increase the performance of the motorcycle. Gas mileage is so down on my list because I have this for fun, and my car is electric. 😂 In Pa, we don't get a huge riding season, but we do get a nice one!! So in short- increased noise, performance, and more space utilization.

[snyper316]

Good information!

 

 

my car is electric.

 

Not trying to knock it or nothing but how long do you have to recharge every 60-90 miles?

[Bassett]

Not trying to knock it or nothing but how long do you have to recharge every 60-90 miles?

 

Plug in Hybrid.

 

37miles electric + regen braking; the rest hybrid.

 

 

If you're wondering, the mpg is 103 average from our driving.

[snyper316]

Lost me thought it was an electric car. So does it use gas too? I was next to a car the other day but every light he was by me you could hear the starter or something crank as he moved forward and then engine kicked on..

 

"Never ride faster then your guardian angel can fly."

[zagger]

Good information!

 

 

What im hoping to accomplish is more space so I don't have the big pinky air box, as this is not a traditional venture. I chopped this bike and bobbed it so I am bare bone. The airbox really causes me an issue up top because it takes up so much space. I would like some pipes on my bike to rev at red lights and let people know I'm there. If I could get some more fuel by adding a bigger jet, I would like to increase the performance of the motorcycle. Gas mileage is so down on my list because I have this for fun, and my car is electric. 😂 In Pa, we don't get a huge riding season, but we do get a nice one!! So in short- increased noise, performance, and more space utilization.

 

Hey Bassett,

I certainly agree on ditching the airbox. If you go to individual filters for each intake, they will make your carb unhappy since it is expecting a larger pressure drop on the intakes. Perhaps things have changed over the years, but I wasn't aware of carb jets, etc. which might have been used to help with the loss of intake pressure drop caused by removing the stock filter. I made airflow restrictors out of steel washers. The ID of the washers has to be machined to the correct dimension. This has the effect of putting the carbs back into their normal operating range.

zag

[Bassett]

Hey Bassett,

I certainly agree on ditching the airbox. If you go to individual filters for each intake, they will make your carb unhappy since it is expecting a larger pressure drop on the intakes. Perhaps things have changed over the years, but I wasn't aware of carb jets, etc. which might have been used to help with the loss of intake pressure drop caused by removing the stock filter. I made airflow restrictors out of steel washers. The ID of the washers has to be machined to the correct dimension. This has the effect of putting the carbs back into their normal operating range.

zag

 

Always good advise!

 

Is there a way to do four carbs connected with one cone filter using PVC?

 

(i saw it in this)------ http://www.kloppenberg.us/chopper.html

[zagger]

Always good advise!

 

Is there a way to do four carbs connected with one cone filter using PVC?

 

(i saw it in this)------ http://www.kloppenberg.us/chopper.html

 

I guess that kloppenberg's method would be as good as any. Of course, the single filter will load up with crud four times faster than having four individual filters (which I used). Depending on the complexity of the manifold, I would assume that each carb would need a separate and unique flow restrictor. If each carb is connected to a filter in the same way, a single flow restrictor design would work for all of them.

zag

[Bassett]

I guess that kloppenberg's method would be as good as any. Of course, the single filter will load up with crud four times faster than having four individual filters (which I used). Depending on the complexity of the manifold, I would assume that each carb would need a separate and unique flow restrictor. If each carb is connected to a filter in the same way, a single flow restrictor design would work for all of them.

zag

 

 

What is the CFM going into the carbs?

[CaseyJ955]

Get a hold of Sean Morley, one2dmax@aol.com what your doing is exactly why the little brass restrictor plugs were created. One for each carb, easy install and you can run the cones with little or no other fuss. I would be compelled to remove the carbs, dry set the floats and make sure all else is good, the float levels being to high will account for some crappy MPG and loss of power. My guess is it wont have to go into jetting until you have a free flowing exhaust going on.