Pilot screws

[jowens]

2009 Yamaha Venture with 9900 miles. Recently removed the tamper proof caps and adjusted pilot screws. Had a miss at idle and a stumble at low speed and popping back through the exhaust on decal at low rpms. Had to adjust cylinder #3 out a total of 4 turns after seating the screw. Other 3 pilot screws are about 2 1/2 turns out. Plugged the AIS system, Changed air filters, did the carb sync, changed plugs, checked both carb diaphragms on right side, changed a vacuum line and both vacuum port caps. Cant find any vacuum leaks. Even switched coils in the rear. The engine is a lot smoother at idle now and I don't get much of a stumble or miss but still have the popping back at low rpms on decal. I thought that this bike may have sat for a while before I bought it so i ran 3 or 4 tank fulls of seafoam through it. It seemed to get worse after I ran the seafoam. I removed the fuel filter and it was like a reddish brown color inside. Is this an indication of maybe varnish buildup from the bike sitting or will ethanol discolor it? Is having to turn the pilot screw out 4 turns an indication that I have a stopped up low speed jet on the carb on #3 cyl? Will it hurt to leave the pilot screw out 4 turns? A lot of questions I know but hopefully someone can enlighten me. Thanks!

Edited August 25, 2014 by jowens

[Neil86]

You don't mention the pipes on the bike if they are stock or not.

 

Might want to check for an exhaust leak typically at the front muffler joint.

At 9900 miles probably had a rear tire change already and removal of right

muffler is common with tire removal.

[Ace]

I would check for exhaust leak like Neil has suggested.

My RSV's have seemed to be a little leaner on #3 cylinder as well. If you are not the 1st owner, have a look at the air filters and the housings for them. On my last RSV I messed around with the openings on the filter housings making the opening bigger plus K&n's. This made the bike idle like crap plus stumble as it was very lean and needed more fuel. The opening should be a round hole in the front of the housing, it was popular quite a few years back to open up the hole to the shape of the "D" in the front of it, proved to be not good without rejetting.

[dacheedah]

if you havent already replace all the gas, put in a can of techtron and let it soak for 24 hours, drain and add fresh gas with a can of techtron and ride, after a tank change plugs.

[jowens]

The rear tire has been removed so both sides of the ehaust have been removed. Gaskets dont look bad but will be replaced. The mufflers are stock.

[Condor]

Just for the heck of it, check to see if you don't have a rusted tank. There's a lot of variables that could cause your symptoms, but the color of the fuel makes me think it's the tank. Could be when you ran the Sea Foam it liquefied the crud that had collected in the bottom of the tank and it's on the move... Rust will get thru the filter and make it into the carbs. Pull the fuel line off the petcock and put it on reserve and see what comes out....

[tz89]

Just for the heck of it, check to see if you don't have a rusted tank. There's a lot of variables that could cause your symptoms, but the color of the fuel makes me think it's the tank. Could be when you ran the Sea Foam it liquefied the crud that had collected in the bottom of the tank and it's on the move... Rust will get thru the filter and make it into the carbs. Pull the fuel line off the petcock and put it on reserve and see what comes out....

 

 

Yeah that