88 venture royale Carb Jets

[VerntureVet]

It could be that its late and I am 1/2 asleep But I been digging for info on the 88 Venture Royale carb main jets and can't find what I am looking for. The local bike shop is more of an off the shelf trinket shop and the closest Yamaha dealer tells me the don't work on bikes as old as mine. so I turn to you all.

 

To my understanding opening up the exhaust will draw more air threw the engine and cause it to run lean (less fuel).

I thought more air flow would allow more pilot air making a richer (more fuel) running engine.

 

I am also playing with the air box to get more room and as a result there is not only less restriction of air flow I am getting ram air.

 

 

SO here are my questions

 

Should I be looking to getting bigger main jets to get more fuel?

 

Will restricting the air intake with say a plate make it run richer?

 

What is the stock main Jet size?

 

Please for the love of whatever entity you follow tell me what I can tell these people @ the bike shop to get me the jets I need. I read someplace that jets off V-Max and some Hondas are the same as in the 88VR1300 carbs.

 

I would love to just walk in and say "Bill I need this XXX jet off this XXX bike.

It's likely they have what I need sitting in there little carb jet box but its just labled for anouther bike, and Bill just don't know any better because he is just a guy tending a shop and not a real bike mechanic.

 

Links to need info is fine.

 

Thank in advance.

[Great White]

Problem with getting the jetting right on bike carbs is you have to run it to determine the right settings.

 

It's not as simple as install a jet and you're good.

 

You have to determine where it runs best on the pilot jet. Then it's a matter of the needle needed and jet. Then the main jet is mostly wot.

 

What you do is determine the best idle.

 

Then you run the bike at part throttle settings and pull the plugs. They will tell you rich or lean and you shim or change needles and try again. The main jet is another testing regime again.

 

Add to the complexity that you've changed both intake and exhaust. Putting "ram air" in there is going to add another layer of complexity.

 

The CV carbs also may not respond well to no air box. Every time I've put pods on CV carbs they have always been very fussy for me.

 

Hopefully, the guy who chopped a Venture similarly to what you're doing will chime in and give his experience with any carb issues.

 

You're not out on a limb by yourself, but it is pretty unfamiliar territory (ie: chopped intake/exhaust and CV carbs)...

[VerntureVet]

Problem with getting the jetting right on bike carbs is you have to run it to determine the right settings.

 

It's not as simple as install a jet and you're good.

 

You have to determine where it runs best on the pilot jet. Then it's a matter of the needle needed and jet. Then the main jet is mostly wot.

 

What you do is determine the best idle.

 

Then you run the bike at part throttle settings and pull the plugs. They will tell you rich or lean and you shim or change needles and try again. The main jet is another testing regime again.

 

Add to the complexity that you've changed both intake and exhaust. Putting "ram air" in there is going to add another layer of complexity.

 

The CV carbs also may not respond well to no air box. Every time I've put pods on CV carbs they have always been very fussy for me.

 

Hopefully, the guy who chopped a Venture similarly to what you're doing will chime in and give his experience with any carb issues.

 

You're not out on a limb by yourself, but it is pretty unfamiliar territory (ie: chopped intake/exhaust and CV carbs)...

 

Here are my plugs sitting idle. they looked the same if I kill the bike @ 1500-2000rpm.

 

I have never been good @ telling with the plugs but this looks somewhat normal if not borderline leanish.

 

What do you think?

 

I'm not dead set on removing the air box with the battery moved there is enough room for everything that need to move from the front end except the Venture Cruise stuff. I was trying to thin out the airbox to make room for cruise vacuum stuff. if push comes to shove I will just extand the cable and hide it under the seat when the tank comes off.

 

[Great White]

Hard to tell from a picture, but I'd say you're pretty close. A little lean maybe. Might not be a bad idea to fatten it up a bit for a little bit more "brown" on the tips....

[VerntureVet]

Hard to tell from a picture, but I'd say you're pretty close. A little lean maybe. Might not be a bad idea to fatten it up a bit for a little bit more "brown" on the tips....

 

I agree it is a tad border line. I did a high RPM in 2nd geat @ about 60MPH and @ the same time I pulled the clutch and hit the kill switch. The plugs still looked about the same.

 

So Great White if I read correct the main jet is a 125 would I be off in thinking a 130 or 135 jet would be the next step and then check plugs again?

 

I think I found the part number for the stock jet but I can't find a nice table or excel sheet showing the jet sizes with part #s or even if all 1300's have the same jets

 

P.S. I didn't add ram air so to speak it was the side effect or piping an intake out of PVC to the side of the motor to get into cooler air. it has to be ramming some air in @ speed the way I had it. For now I put the stock box back on.

[Great White]

Based on what I think your plug looks like in the pic, I'd probably try the 135 and then do a plug chop and read again. If it looks too fat on the 135 you can always drop to the 130. I'd rather run a little fat than lean.

 

All this is assuming you're starting with a 125.

 

You probably won't have to move many sizes. Even the Vmax only runs about a 150 main jet. I think i read that Dingy's hybrid vmax/venture only runs about a 140.

 

The main jet isn't as important in day to day riding as people think. Far more influential is the needle shape and settings:

 

http://www.jba.bc.ca/JBCycle/Resources/jet-chart.jpg

Do your pilot circuit first at the stock settings. You can tweak it if you want and get it so the bike doesn't dip or hang on throttle blip, Then on to the mains and the plug chop. Get that dialed in and then move back to the pilot circuit to make sure it still behaves properly. Finish with fine tuning the needle height for any surge or hesitation in the mid range. Sum it all up when you're done by the idle check and plug chops again to make sure you're sitting where you want to be. At least that's the way I do my bikes. If I'm changing needles, that's usually what I do before any of the preceding since the needle effects such a large throttle range.

 

Alway scheck your plugs for lean or rich. Rich isn't so bad other than emissions, carbon and MPG. Lean can take out a valve....

Edited September 20, 2015 by Great White

[syscrusher]

If you want to be sure about where you're running in the whole fuel/air universe you should probably go and have it dynoed about the time you think you're right about things. Make sure the dyno operators have the oxygen sensors that they jamb up the exhaust and have them chart your mixture throughout the range. You don't want any really lean areas, especially in your typical cruising band since that will make everything too hot and could perforate your pistons over a long ride.