Guest nevermind Posted June 29, 2012 Share Posted June 29, 2012 Hey everyone. Just picked up a 1991 750. 19000 miles. just had everything done... oil,plugs,carb clean,air filter,coolant.. etc Well, im gettin 80 0r 90 miles till i have to fill up again!!!!! no fuel smells, no leaks. Anyone heard of this B4? Link to comment Share on other sites More sharing options...
Member Contributer kaldek Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 Sounds like it's running super-duper rich. Have you owned a VFR before so you can compare this bike to previous experience (with regards to its power delivery)? When you did a "carb clean", what did that include? Link to comment Share on other sites More sharing options...
Member Contributer vfrurknee Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 How many gallons on the fillups, average? Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 well it has a kerker left hand exhaust and i thought mabe no one jetted it. so i took it to my local shop and they said that it needed a carb cleaning. not sure what they did. it runs good but pops a little because the aftermarket exhaust. but no. this is my first vfr so cant compair. but dosent smell real rich either. what should i be getting? Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 3.5-4 gal average Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 where did u guys go! Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 helllllllllllllp!!!! Link to comment Share on other sites More sharing options...
Member Contributer vfrurknee Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 I can't figure what could cause the consumption to be so high. It must be running very poorly if there are no leaks. What is the running temp of the engine? A bad thermostat can cause poor economy butI would not think it would be this bad. Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 i know! its real bad most people think im mistaken. runs just under half most of the time. IDK im real lost111 Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 it really only gets like 87 average. its like a full size truck! lol... not that funny Link to comment Share on other sites More sharing options...
Member Contributer gll429 Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 lets see.. 1st.. pull the tank. 2nd . remove the 2 rear plugs .. the should be a tan to brown color.. black or sooty means too rich. white is too lean. after you do that PM me . Link to comment Share on other sites More sharing options...
cbkenison Posted June 29, 2012 Share Posted June 29, 2012 Is this a California bike? Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 My 91 gets about 40 mpg (+/- 5 but it depends on running it hard or goin real easy). I think mine is running a bit rich lately as it backfires alot when I allow the engine to slow the bike down. I'm told this is a symptom of being set too rich. So your getting 25-30 mpg it sounds like. I think I'd start by checking your plugs for signs of fouling. If everything looks good, I'd check electrical to include the R/R. Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 no. not a caliofornia bike. New york.... your thinkin because of emmissions controls? Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2012 Share Posted June 29, 2012 lahn... what is R&R... do i sound dumb? u guys know all the lingo.... lol Link to comment Share on other sites More sharing options...
Member Contributer dirtbag Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 what does a '91 have for vacuum hoses? i would try and pull a diagram and got through all your vacuum lines... and check your tees! i just had a 5way tee crack on my '02, and it was giving me miserable mileage... but not as bad as yours. Link to comment Share on other sites More sharing options...
V4 Rosso Posted June 29, 2012 Share Posted June 29, 2012 no fuel smells, no leaks. Anyone heard of this B4? On mine the fuel hose was leaking (deteriorated from age) but there was no gas smell as the fuel dripped on the hot rear header and most had evaporated before it was parked in the shed. Also check if it is running on all 4 cilinders. You can check by touching the downpipes immediately after the engine runs, they should all get hot pretty quick. Next also feel if the radiator or water hoses warm up quickly, that could indicate a stuck (open) thermostat. The VFR engine like to run hot. The choke cable is in perfect working condition? Link to comment Share on other sites More sharing options...
Member Contributer Dutchy Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 Unless you are doing nothing but max speed runs on a deserted highway, you should be able to ride at least some 275km. A dutch bike magazine did top speed runs on a few bikes, including the VFR1200 on a german autobahn (no speed limits). The fuel light came on after 80kms..... I think they logged 280kmh top... Link to comment Share on other sites More sharing options...
smoothsailin Posted June 29, 2012 Share Posted June 29, 2012 If you just paid a shop to have the motorcycle serviced and the carburetors cleaned and adjusted you should take it back to them and register a complaint. I'm wondering if the cold start/fuel enrichener circuits for one or more carburetors might be leaking or incorrectly adjusted and causing one or more cylinders to be running way too rich. Only 80-85 miles per tank is less than half what you should be seeing unless you're riding w/the throttle pinned most of the time. I generally get 45-50 mpg, or 225+ miles out of ~5 gallons from my 5th-generation. Note that I'm assuming you are being careful to turn off the choke/fuel enrichener control completely on the handlebar within 30 seconds, or less after each cold start. If the shop finds the caburetors are not set up right make sure they also replace the spark plugs (at their expense) for it's more-than-likely they're already carbon-fouled. I'd also recommend checking the motor oil for evidence of fuel dilution and have the motor oil and oil filter changed again (also at their expense) if necessary. If the motor is running way too rich it's likely some of the excess gas has been making its way into the motor oil. Also, if you bike has a manual fuel shutoff I recommend you be careful to shut off the gas each time you turn off the engine until these issues have been resolved, for it's possible fuel could be leaking from the carburetors and running into the cylinders when the engine isn't running. This represents a serious threat, for if fuel leaks and pools in one or more cylinders your engine could suffer catastropic damage when you try to start it. Liquids don't compress! Link to comment Share on other sites More sharing options...
Member Contributer mk2davis Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 When are you refuelling the bike? My gas gauge shows E after about 120-130 miles, even though I have a good two gallons left. It seems to be common to have a premature gauge. When you are filling up, how many gallons are you putting in? Link to comment Share on other sites More sharing options...
smoothsailin Posted June 29, 2012 Share Posted June 29, 2012 When are you refuelling the bike? My gas gauge shows E after about 120-130 miles, even though I have a good two gallons left. It seems to be common to have a premature gauge. When you are filling up, how many gallons are you putting in? In an earlier post he indicated 3.5-4 gallons, which only correlates to 25 mpg or less. 87 miles / 3.5 gallons = 24.86 mpg 87 miles / 4 gallons = 21.76 mpg Link to comment Share on other sites More sharing options...
Member Contributer mk2davis Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 So he did. Not sure how I missed that. The no smell thing is really throwing me. I'd think if it was an open carb circuit, horribly wrong jets, sticky choke, etc., I'd think it would smell really rich. Pulling the carbs is a good way to check, as someone already suggested. As V4 stated, I'd check hoses between the pump and the carb. Maybe something is leaking only under pressure (even if it's only the 2-3psi). When the bike isn't running, less pressure, leak goes away? Link to comment Share on other sites More sharing options...
Member Contributer CornerCarver Posted June 29, 2012 Member Contributer Share Posted June 29, 2012 Does it feel like a 750 or does it feel like a 600 when you accelerate? Or maybe a 450....it has to be passing a bunch of unburned fuel through one or two cyclinders and the result is you flogging the throttle to keep it up to speed...have you pulled the plugs yet? Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2012 Share Posted June 30, 2012 hey guys. thanks for the replies!!! im still pretty screwed at this point. i havent checked hoses yet will do that soon. NO GAS SMELL!! very odd. oil smells very good. has that fresh new oil smell. (one of the best smells on earth other than tire smoke) absolutly no gas smell in oil.. does not need choke to start even when cold. well that is not saying much because its been in the 90s all week. i will check choke cable but the bike dosent smell rich. BTW how many gallons does the tank hold because the light goes on and i put in 3.2 to 3.4 gallons. Thanks again guys. we will get to the bottom of this!!! Link to comment Share on other sites More sharing options...
Guest Posted June 30, 2012 Share Posted June 30, 2012 i believe thermostat is working. the temp is around the middle and fans come on when too hot Link to comment Share on other sites More sharing options...
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