Running Rich

[BlueSky]

Well my newly acquired 89VR is running rich judging by the way it starts without choke and the smell of gasoline. It seems to run just fine. I checked the choke and it doesn't appear to be sticking. Then I pulled the side panels off and checked the two rear carbs pilot screw adjustment. Both are 1 full turn from bottom which should be too lean. Ideas?

[Razorback]

Pull the spark plugs and verify the rich condition.

[frankd]

When I purchased my 89 about 5 years ago, it appeared to be a touch rich, but only slightly. Then I checked and replaced the diaphrams and my gas mileage went down, and it got richer because the needles were being pulled farther out of the main jet. We went out west, and above 5000 ft. you could tell by the way it sounded that it was way too rich....everywhere. I pulled the carbs. and adjusted the float levels. This helped, but the cruise circuit still seemed rich and the gas mileage was about 38 MPG. I added a couple of washers to move the main jet needles in slightly, and now it seems great. It has just a light bog when it's cold out, the mileage is about 42MPG and it was great at high altitude last year.

 

Frank D.

[jfman]

Hello Frank,

 

what did you use as a spacer?!? How thick was it?!? Also, were you able to pull the diaphragm covers of all 4 carbs withouts pulling them from the bike?

 

thanks!

[MasterGuns]

When I purchased my 89 about 5 years ago, it appeared to be a touch rich, but only slightly. Then I checked and replaced the diaphrams and my gas mileage went down, and it got richer because the needles were being pulled farther out of the main jet. We went out west, and above 5000 ft. you could tell by the way it sounded that it was way too rich....everywhere. I pulled the carbs. and adjusted the float levels. This helped, but the cruise circuit still seemed rich and the gas mileage was about 38 MPG. I added a couple of washers to move the main jet needles in slightly, and now it seems great. It has just a light bog when it's cold out, the mileage is about 42MPG and it was great at high altitude last year.

 

Frank D.

 

Frank, doesn't adding the washers to the needles lift the needle further out of the jet allowing more fuel and making it run even richer? Or did you also remove the OEM plastic shim and replace it with two washers which then would allow the needle further in the jet reducing fuel and making for a leaner mixture?

[BlueSky]

Hello Frank,

 

what did you use as a spacer?!? How thick was it?!? Also, were you able to pull the diaphragm covers of all 4 carbs withouts pulling them from the bike?

 

thanks!

 

there are several posts about how to do this. And i think a member, skydoc? sells the washers needed to lean it out.

[skydoc_17]

Hey All,

To clarify some of the questions asked in this thread, lets walk thru the idle circuit of the Carbs. as well as the main jets, and see if we can solve this "running rich" condition for the members that are having this issue. First off, the Carb. Diaphragms can in fact be removed without removing the Carb. bodies. If your Carb. Diaphragms are 20 to 30 years old, I suggest you do this replacement. I also suggest that you start with all 4 of the Idle Mixture Screws set at 2 1/2 turns from bottom out as a "base line". Fine tuning can take place after the Diaphragms have been replaced, and the main jets have been shimmed, and the Carbs. have been Synced. By shimming the main jet needles, you are actually adding more AIR to the mixture coming down the throttle body, you are NOT adding more fuel. This is why shimming the main jets leans out the mixture, and improves gas mileage. The Needle Shim Mod listed below is NOT a performance Mod, it is a mod to increase gas mileage. You will loose a bit of "top end" but the gas savings will be well worth it, and frankly, I have never felt that this motorcycle lacked horsepower personally. Here's the link:

 

http://www.venturerider.org/forum/photopost/showproduct.php?product=202&title=first-gen-1983-to-1993-vr-needle-shim-mod-kit&cat=17

 

For a newly acquired VR, or a VR that has not been a "daily driver", these replacement parts and adjustments will get you well on your way to having a dependable motorcycle that runs well, and gets good gas mileage in my opinion. If you have any questions about the install or adjustment of any of the parts described above, please feel free to PM me.

Earl