newbie gas mileage question

[mcdds86]

Just recently bought a 87 Venture Royale with a voyager trike kit. It has about 30k miles.

Depending on how I ride, I get between 20 and 25 miles per gallon. If i keep it 65 mph or below it gets close to 25. It runs & idles smooth; accelerates nicely; it just needs help on the gas mileage.

 

I just bought some Sea Foam and am running that through it in hopes that will improve the mileage.

 

My question - is there something else that can be done inexpensively that could improve mileage? I'm not ready to tear down the carbs or anything that extensive yet.

 

Thanks for any/all advice

[sarges46]

Seafoam works great. I would ensure that the carbs are synced and you dont have bad diaphrams.

 

The bike will run real good with only three cylinders or even with bad diaphrams but your gas mileage will suffer.

 

The extra weight with the kit on will also make the mileage go down but I'm not sure it would be that low.

[CrazyHorse]

Some guys say they get 46-50 mpg I dont believe it unless they are running 25mph everwhere. I think realistically 37-42 is more in line. Now with a trike I wouldnt know. Your carb diaphrams may be leaking, spark plugs wires caps may be bad, your TCI computer or individual coils may be bad. Check spark to each cylinder, If you have one of those infrared temp readers check each exhaust pipe at exit to see if temps are close to each other. open up air box and look at the black sliders in the carbs when motor running and rev motor each slider should move about the same distance if not theres one problem. Each spark plug cap needs to be checked for corrosion for the parts inside it.

[Gearhead]

"open up air box and look at the black sliders in the carbs when motor running and rev motor each slider should move about the same distance if not theres one problem"

 

 

 

Not a reliable check. My slides appeared to all be doing the same dance, yet when removed I found that 3 of them had significant deterioration and cracking in the diaphragms.

 

I average about 37 on my 87 VR, and I've checked all that stuff! Can you take the trike kit off for a couple tankfulls?

 

Jeremy

[GeorgeS]

I would take the covers off of each Carb, pull out the Diaphrams and check the rubber for Holes. This is common.

If they have never been changed on your bike, you can assume that you need new ones, simply due to Ageing !! They are about $85 apiece.

Sorry:

 

Also, drain your Carb Bowls, and drain the gas tank, there is about 3/4 gallon of gas in the bottom of the tank that never gets used, Sombody may have drained it in the last 5 years, but make sure!!!

[Cutty]

After you complete your carb check, try a mileage check in 4th gear instead of 5th. Not knowing your gear ratio to weight, sometimes it doesn't hurt to try different things.

[mm482]

The pressure sensor may be bad. If it is bad the bike may run good, but gas mileage will be down. The sensor’s vacuum line connects to # 2 carb boot. Disconnect the line from the boot and see if it will hold a vacuum. If the sensor will not hold a vacuum it is bad. A new one is about 275.00. I would guess the 50% of all first gen. sensors are not working properly.

Earl

00 RSV

86 VR

[Gearhead]

On mine, the pressure sensor itself was good but the electrical connection was corroded preventing it from operating. Repairing that was good for about 2 mpg. There is a procedure online here for repairing the most common failure mode of these sensors, too.

 

Jeremy