very poor MPG viper

M

mjpowersports

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Joined
Jan 13, 2009
Messages
33
Age
44
Location
two harbors, mn
This is getting very annoying, I am getting like 3-4 mpg.. here is the set up, It has a 06 Nytro skid, 1'' energy track with 192 studs, the clutching is hauck and has a orange primary spring, not sure on weights havnt pulled them, helix is stamped V but is somthing 45, cant read first number, and it had a super soft spring that would just open right away so I tried a red and it didnt backshift so I went to a pink at 70 and now it BS ok but over revs to 8900-9000.. The engine has a stock pipe and can, looks like it has a thin head gasket, Jerry Hauck did work to it from what im told.. I have to check the gearing cuz it WAS drag raced at one time.. I am not sure if it ever had pipes.. It burbles really bad in the mid witch I now is normal.. And last night on my way home the temp light came on. It does have a cooler in the rear and I was riding in lots of snow. Thanks.. I do ride hard but I dont think it should be that bad or am I wrong?
 

Sounds like you need to go through the sled and find out what you're working with. Carbs, reeds, gearing etc. You have an overrev at 8900-9000. Should be right around 8500 without pipes. Plenty of guys on here that are clutching gurus. That, I am not. Have you bled your coolers? may have some air in there causing the overheat light. Could be thermostat. Someone will chime in on this.
 
Mine has been getting lousy mileage lately too. 1st things to check. What conditions are your reeds? Mine were shot at 6000 miles. Also check you vent line to air box connection and also clean your air jets. They get plugged with belt dust, etc. over time. Check fuel lines for cracks. From there it could be more serious like the stator.
 
so you go about 35 miles and your needing gas from a full tank start,right?

if your using that much gas you have got to have either smokin hot slipping clutchs or the needles and seat are leaking in the carbs and making it run pig rich, or possibly the choke plungers are not seating. I would remove the carb rack and clean them, then inspect all the jetting and report back, check the needle settings also.

what do the plugs look like?

can you put your hand on the clutch after riding it for a mile?
 
mrviper700 said:
so you go about 35 miles and your needing gas from a full tank start,right?

if your using that much gas you have got to have either smokin hot slipping clutchs or the needles and seat are leaking in the carbs and making it run pig rich, or possibly the choke plungers are not seating. I would remove the carb rack and clean them, then inspect all the jetting and report back, check the needle settings also.

what do the plugs look like?

can you put your hand on the clutch after riding it for a mile?
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Yeh 3-4 mpg is real bad. Doesn't sound right. Mine is around 7 mpg though. It runs good, but the last few years it's been getting lousy mileage. I noticed one of my ride buddies that came along on our recent UP trip had almost as bad as mine. I have around 8800 miles on it though. His is under 4000 miles. He was getting about 7.5-8 mpg. I was getting 70-80 miles on a tank. When it was new I was getting 120 miles to a tank of gas the way I ride and I think I've slowed down slightly with age....LOL! For instance one leg of my trip I got about 78 miles and the fuel light was on for a long time. I put in 11.1 gallons and I had left with a full tank. 78/11.1=7.02 mpg. Not too good, especially when you are riding with 4 stroke Yamahas. They fuel up every other time.
 
Something is definatly amis. We can consistantly always, unless powder running, get at least 120 miles usually 150 miles per tank. This is on both the SXR's and Viper. Heck the ol Phazer will run 100 miles on a tank and that is a 7 gallon. I don't see how anyone can get only 3 to 4 and have it even run. Shoot the gas station's are further away than that. lol.. Anyway, check you carbs for flooding. How, do you even ride, knowing you have to get fuel within 50 miles? That would be like filling up 4 times for us in a single day. Al
 
The funny thing is on mine I have had the carbs completely apart and back together cleaned. I changed the reeds as mentioned. I checked the fuel lines....good. The one thing that I am wondering about. One year I think I had the issue of the wire harness rub through grounding out on the chassis. I was riding in the UP at night and my lights went dead a few times and my tach went all wacky. Anyone that knows the western UP may know this trail. We were on trail #13 back from the Porcupines going back down to Bergland. The trail is kind of down hill, rocky, bumpy and alot of switchbacks. After about 10 miles of this bumpy twisty trail it came out of it and has never done it again. But it makes me wonder if I have a slight wear through in the harness that is touching slighty and causing an issue. I have also heard of bad stators and poor mileage but usually you have other issues like hard starting to go with it. I had my stator checked too and the output is good.
 
mjpowersports said:
14-17 MPG would be a miracle
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Yamaha tech told me that this is what I should be getting on a properly tuned, maintained motor with everything stock. Anything less and the motor needed to be rebuilt.
 
journeyman said:
Piped Vipers usually are poor on fuel mileage. Just a known on this sled.
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Im not talking about my reeds being bad lol. They are fine. I was hoping the reeds are the problem why mjpowersports is getting poor mpg.
 
to chime in on the gas mileage potential, imperial gallons which we use in Canada are larger than US gallons, so gas mileage would be better (appear better) with imperial. 14 to 17 is possible. My Dad's viper Venture regularly got 14. My SRX with new carbs got 15 and 16 a few times last year. Ran perfect just before I put it away for good!
 
I have owned 4 Vipers and all of them got or get different gas mileage.
In 03 my wife bought a brand new ViperER, she got 14 -16. Next year we bought my daughter an 02 ViperER, that one got 12-14. We put around 6K on these sleds and the mileage was consistant. I rode an SRX and an RX1 during that time and my wifes Viper usually matched my RX1 gas mileage !!!

Gave up the sport for awhile for different reasons, bought 2 well used Vipers for this season, this time my wifes new/old ViperER gets 10 MPG everytime, took it apart and all looks stock but it does have an over rev issue 8900-9000, I will fix that next year with a set of Heavy Hitters that I took off of my old RX-1 (prior to selling,) and maybe get better mileage on that one. The other Viper that I purchased this season is a Viper with reverse only, I put a set of Bender pipes, Bender clutch kit, V Force, cold air kit,23/38 gearing, etc. etc. and that one gets 11.5 -13 MPG... Don't figure!

Please note that most of our miles were and will be on fast groomed trails..
 
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