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Fuel economy question.


Air Ready Auto

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I've been wondering about my fuel use on my 83 XVZ12 so I tested it out today. I filled up and went on an 84 mile trip that ended up at the same station I started at. Most of the time traveling at 45 or 55 mph. I used 1.6 gallons of gas. That comes out to 52.5 miles per gallon. Not that I'm complaining but that seams high. Just wondering what other people are getting.

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I've been wondering about my fuel use on my 83 XVZ12 so I tested it out today. I filled up and went on an 84 mile trip that ended up at the same station I started at. Most of the time traveling at 45 or 55 mph. I used 1.6 gallons of gas. That comes out to 52.5 miles per gallon. Not that I'm complaining but that seams high. Just wondering what other people are getting.

 

Umm sounds more like bragging I get high 30s and very low 40s....

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At 45-55 MPH that's what I used to get on my 83 with the YICS system. I know that most everybody feels that the YICS system didn't do anything and to take it off, but in 83' Yamaha bragged how it raised the gas mileage at lower speeds. However, at 70MPH, my 83 gets about 42-44 MPG. At 80 MPH, it gets about 28-30 MPG.

 

My 89 is a touch different. I've adjusted the floats and raised the needles in the carbs and at 72MPH, it gets about 42MPG. It doesn't seem to be nearly as frugal with the gas at lower speeds, and doesn't fall off as quickly at higher speeds

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32.8 seems thirsty for not flying along at 90. Mine was almost that good and nothing I did helped until I added the needle drop shims, now I'm around 40mpg. The fact that this worked makes me think that the emulsion tubes might be worn (known issue) plenty of these bikes are getting around 40mpg without shims. I set the floats at 1.125", installed new diaphragms and made sure the block plugs were snug and that got me from ~24 to ~ 29. Adjusting float levels made quite a difference on my VMX12

 

The worst part about getting poor mpg is where your fuel gauge is after only 100 miles. Now when I hit 100 mi I still have half a tank left, or very close to it. Are the diaphragms all good, all synched up and AF screws set? I use the backyard "by ear" method and I'm not quite 2 turns out on all. On float levels, I did both my Venture and Vmax and found the factory settings to be too high. These CV carbs really react to small changes in float levels.

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With my '83 I'd get 37-38 mpg on the slab, and 50 mpg in the mountains and staying out of 5th gear. 5th gear and wind resistance are your enemy when it comes to mpg. High R's in 2nd-3rd-and 4th are your friend. Works on my second gens too.... only about 10mpg less... My 2¢

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  • 3 weeks later...

I'm only getting 29-30 MPG from my '83 TK

 

I never did a true carb rebuild, just a thorough cleaning. I'd bet a true rebuild would help.

 

Yes, she's hitting on all four cylinders and has plenty of power with great throttle response and engine breaking.

 

It may be my riding style, I don't push the revs as I learned to ride on an 84ci Harley and have never gotten comfortable running over 5k rpm.

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I checked my fuel milage last week for the first time. I rode my bike to work which is almost all highway travel, filled before I left and filled at the same station near My home on the way home, travelled between 110-120kph ( 70-75mph), and a total distance of 197km (122miles) and my 83' ran at 42mpg. I thought that was petty decent and on par for what it should be

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The average Venture rider gets around 40 MPG. The 4 cylinder's power band does not kick in until around 3500 to 4000 RPM's and keeps going up to 6000 or more!! You will get lower mileage by NOT using the higher rpm power band than by driving it like a Harley... Red line is waaaay up there!!

 

There are other reasons for poor MPG however, and yes, carbs that are not properly sync'ed will do it as well as spark plugs, wires, valve clearance, float bowl adjustment, etc. etc.

 

Top end in 3rd gear is around 95 MPH...

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I get between 30 and 43 MPG depending on how much I roll the spurs into her sides.. Tweeksis likes to have her reigns and stretch er legs - our average MPG is closer to 30 then 43 :178:

 

PS - @Carbon_One - Larry if your reading this - WOW is having 2nd Gear and a good clutch FUN!!!:banana::cool10:

 

Ready - IMHO = +50 mpg sounds excellent!! Sounds like she's hitting on four and loving every minute of it!!:cool10:

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It may be my riding style, I don't push the revs as I learned to ride on an 84ci Harley and have never gotten comfortable running over 5k rpm.
Max torque is at 5000 RPM and there is still some get up and go between there and 7000 RPM. The engine is not at it's best below 3000 RPM but you can actually run in 5th gear down to about 2500 RPM if it is well synced but throttle needs to be applied gently and mileage will suck.
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And there in, more than likely lies my problem. I tend to piut her in 5th regardless of my cruising speed. Be it 35mph or 80mph!

 

I took a short ride yesterday and kept her down to third gear for a 40 mile cruise at 35-55mph and just judging by the fuel gauge, she did better than 30mpg.

 

 

Now I just have to order factory valve cover gaskets and get rid of the oil pour(not leak)!

 

BTW, in case any missed it last year. Don't buy cheap chicom valve cover gaskets!

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Here's my story and I'm sticking to it.... On the '83VR I got 37mpg around town and on the slab, but when I'd hit the twisties and never get into 5th gear... 2-3-4 only.. I'd get 50mpg. And that was a constant. The '99RSV.. pulling a trailer, and on the slab was terrible. 26-28mpg. No trailer and in the mountain twisties...40mpg. The '07RSV much the same as the '83. 34-37mpg and 47mpg in the mountains. So.... stay out of 5th gear in the hills. On the slab it doesn't make much difference 4th or 5th. I tried 4th with the '99 going over the Sierras to Reno hauling the trailer and the milage still sucked. Around 25mpg. So.... the enemy here is two fold. High speed/low rpms... in the 70's+.... and wind resistance... Slower speeds and higher rpm's are your friend... My 2¢

Edited by Condor
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And yet... I always wondered why more bangs per minute pulling fuel from a smaller jet would get better gas mileage than less bangs per minute pulling fuel from a larger jet. Heck, at some point in the throttle roll on and rpm range there should be a point where the smaller jet is maxed out and pulling fuel from the larger jet as well, at many bangs per minute. On the 2nd Gen, could it have something to do with the throttle position sensor taking the ignition timing down a notch above throttle being barely open, thinking the engine is under higher load, and thereby avoid pinging? Less ignition timing makes the engine less fuel efficient at lower RPM's with more throttle applied. More fuel efficient under light loads, low throttle angle, and higher rpms with max timing.

Igtiming.jpg

 

 

 

 

Does a 1st Gen have a throttle position sensor? Any thoughts on the above?

For what its worth, my bike , a 2nd Gen, is parked in the garage right now, ignition off. I swear it's still sipping on a little fuel...

Edited by Du-Rron
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And yet... I always wondered why more bangs per minute pulling fuel from a smaller jet would get better gas mileage than less bangs per minute pulling fuel from a larger jet. Heck, at some point in the throttle roll on and rpm range there should be a point where the smaller jet is maxed out and pulling fuel from the larger jet as well, at many bangs per minute. On the 2nd Gen, could it have something to do with the throttle position sensor taking the ignition timing down a notch above throttle being barely open, thinking the engine is under higher load, and thereby avoid pinging? Less ignition timing makes the engine less fuel efficient at lower RPM's with more throttle applied. More fuel efficient under light loads, low throttle angle, and higher rpms with max timing.

http://www.venturerider.org/forum/attachment.php?attachmentid=109565

 

 

 

 

Does a 1st Gen have a throttle position sensor? Any thoughts on the above?

For what its worth, my bike , a 2nd Gen, is parked in the garage right now, ignition off. I swear it's still sipping on a little fuel...

 

Nope,, no TPS on the 1st Gens,,,, at least on the MK1's = not sure on the MK2's cause I never worked on one... Many years I played around a LOT with vacuum gauges mounted in my cars.. Those great big steering colum mounted gauges were not only cool looking but VERY functional for keeping up a good fuel sip.. Keeping up a steady high vac was a way to really stretch those scarce fuel pennies back when I was a kid...

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Nope,, no TPS on the 1st Gens,,,, at least on the MK1's = not sure on the MK2's cause I never worked on one... .

 

Now that ain't true Puc... I distinctly remember you wrenching on 7of9's highway peg when we stopped for lunch at that WET FRIES :thumbsup2: restaurant in Oregon... That makes you a qualified card carrying 2ndGen wrencher... :hurts:

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Well I followed everybody's advice. New KN filters, synthetic lube. Sync carbs, Drive it different (keep revs hid and speed down) higher tire pressure. new platinum plugs. Changed the angle of the lower deflects cut down the windshield waxed the bike real good. took off all the extra chrome. Wear a skin tight leather suit, aero dynamic helmet.

 

Now I have another issue, every week I have to take gas back out of the bike!!!:banana::banana::banana:

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