Hey Guys,

I brought my bike from Queen Creek, AZ (about 1400 ft. above sea level) to Olympia, WA (about 100 ft. above sea level). I have a CV carb with a CV Performance carb kit on it. Per the instructions, I went with the #46 idle, #185 main jets, and EZTune screw it in to where it starts stumbling, then back it out, etc. In Queen Creek, I was able to tune it just fine, and was getting 125+ miles per tank. Here in Olympia, I tried to retune it, turned the EZTune screw all the way in without a single stumble. Had it out and about the past couple weeks, and am barely managing to get about 85 miles per tank, (if that). At idle, I have black puffs of smoke coming out of the exhaust, and it makes my eyes water every time. I also pulled the plugs and they are not oil soaked, but they have a lot of carbon on them as if I am running extremely rich.

I'm thinking the jets need to be changed out for smaller ones, but I figured that since I am at a lower elevation, there's more air, and would have to go to bigger jets. With the symptoms of it running really rich though, which sizes should I be looking to go to? Any input is greatly appreciated.

 

What size engine do you have and what mods? 46 pilot and 185 main seem a bit too much, usually 45/170 is common. Maybe you have some crud in your air mix screw, because it should do something. One thousand feet elevation is not going to change things that much, if any. As rich as your jetting, it should run better if anything at a lower altitude.

As you go up in altitude, you need to lean out your mixture, not make it richer. But, we're talking way more than a 1300' difference.

John

 

Its a 1200, and has Bassani Sweepers, and an upgraded air cleaner. Per the CVP install instructions, the #46 and #185 were recommended. I think #45 and #180 were in it when I did the install, but I can't remember, it was a while ago. My thoughts were the same about running better too. It acts almost as if it is choking on so much fuel here, but in AZ I never had a single issue with the current jets.

 

Black smoke at idle is exceedingly rich. You definitely need to back off your idle jet. The main jet only applies at over 3/4 throttle, so don't worry about that unless you plan to tune it on a dyno or drag strip.

 

I can understand that, but what would cause me to have terrible gas mileage? I didn't change anything from AZ to here...Would just idling too rich cause that much of a loss of mileage?

 

You're almost always in the pilot circuit. If its rich enough to spit black smoke (10-11 AFR), it would kill your mileage.

And AZ is nothing like Washington. Warm and dry vs cool and humid. This means a lot out bikes and can definitely alter mileage.

More likely is that it's always been overjetted and this just pushed it over the edge.

 

What size jet would you recommend? I have a #46/#185 in right now. I have a #45/#180 sitting in bags, but according to CVP, the #45/#180 is for a stock setup.

 

I too have the CV kit in my bike. I had to run the stock pilot jet and the stage one main jet for my bike to be happy (I tuned it on the dyno to confirm). The "stage one" recommended pilot jet left my bike belching black smoke. And for reference, from the factory the 883 and 1200 both came with the same pilot jet. They don't need a drastically different amount of fuel at cruise.

I would start with a 45/180 and 2 turns on the screw. I highly doubt you need any more than that. You can adjust the screw in 1/4 turns either way to fine tune it. I see way too many people overjet their pilot circuit and as a result end up with crap gas mileage and sluggish throttle.

 

Alright, I will try that. Just confusing, because my bike was running great in AZ with the 46/185, and good gas mileage and all. Donno why a drop in altitude would cause it to do what it's doing right now. Thanks for the info!

 

My guess would be the type of atmosphere. AZ is dry and warm, while Wash St. is cooler and more humid (much like Ohio). An elevation change of about 1000 ft has no where near as much of an effect as the change in climates.